Lancia Beta Forum

Hi,

Apologies in advance as it seems there is much discussion about this but there seems to be several conflicting procedures for brake bleeding on this forum which are also in conflict with the Haynes manual.
I was hoping that there is a "never fails" procedure that someone can tell me about.

I have just bought a 1982 coupe and I replaced the Master Cylinder to remedy a spongy brake pedal issue. I fully understand that spongy pedal is almost certainly air in the system but had read that spongy pedal is also a possible symptom of a bad MC, so I thought I would replace it anyway. Good job I did as the MC internal bore was rusty and the seals looked scored. Must surely have been the problem for my spongy pedal !!

However, now everything is back together and brakes bled using a pressure bleed apperatus attached to the reservoir (30 psi) and 2 litres of Dot 3. The brake pedal feels exactly the same as it was before.

The bleeding procedure I followed was as per Haynes.......With just the front of the car off the ground, I bled the system in the following order :

1. Front drivers side outermost bleed screw (closest to the disc)
2. Front passanger side outermost
3. Rear driver side (therefore furthest from the Master Cylinder
4. Rear passanger side
5. Front driver side innermost (furthest bleed screw from the disc)
6. Front passanger side innermost

Before fitting the MC, I did attempt to prime it on the bench before fitting.

I would appreciate any suggestions / techniques on how to get stubborn air out of the system

Cheers,

Steve

Is it possible to bleed the MC in situ in case the air is stuck there ?

Hi Steve

I replaced all the brake parts on my Spider when restoring, used a pressure bleeder and simply worked furthest to nearest to MC. Nothing special, it just worked. So I suspect you may have a problem with a seal of flexi pipe. What else have you replaced and if you repeat do you still get any air coming through? I assume you have flushed the old fluid?

Peter

Hi Peter,

Thanks for your response and to answer your questions....

Do I still get air coming through if I re-bleed ? Not sure so I will try this today and report back.

What else has been replaced ? I purchased the car in Jan where the sellers description included "drives like a new car" which was the most appauling mis-description ever....but anyway. As concerns the braking system, the flexi pipes on the front appear to have been renewed and also has new discs and pads on the front. When I bleed any of the front circuits then the fluid flows freely as you would expect. What has always struck me as strange is that the front discs still have all the machining marks from manufacture which suggests to me that the front brakes are just not gripping with any kind of force making the braking performance quite poor. So, my theory is that the air in the front circuits is making the pedal spongy and the front brakes ineffective.

There is also evidence that the previous owner has done something with the calipers as they have been cleaned but it doesnt look lihe the seals have been renewed as the piston seals looks quite old.

There are no fluid leaks from any of the joints throughout the entire system.

Your last question about flushing all the fluid ? Yes twice.

Everything I have done on the car to-date has revealed so many jaw dropping bodges so I think my only cause of action is now to remove the front caliper to see if they are working correctly. The pistons definitely move as they grip the disc enough to stop the wheel from rotating when the pedal is applied.

My best guess at the moment is that there is air trapped in the front calipers somehow.

What do you reckon ?


Cheers,

Steve

You could still have air trapped in the rear circuit which would give a spongy brake pedal? What's the grip from the rear callipers like? And what condition is the rear brake balance compensator in? If it's seized (especially in rear wheels off the deck) it'll make bleeding harder. You may need to peel back the rubber boot to see if the actuator piston on the compensate is moving and also disconnect it from the rear ARB?

Have you ever been able to lock the front wheels under heavy braking? If not that strongly suggests that there is air in the system somewhere or seals in the master cylinder allowing fluid past the pistons.

Guy

Hi Guy,

The grip of the rear calipers is hard to determine as all I can do is see is the brakes stop the wheel rotation when the wheels are off the ground...which they do....so the pistons actually do move.

The brake balance compensator is pretty crusty inside the dust cover and I doubt it works as I get a good flow of brake fluid when bleeding the rears with the wheels unsupported and off the ground. I have also tried bleeding the rears with the actuaror arm disconnected from th ARB and fixed up as if the wheels were on the ground.

Today, I tried to reverse bleed the fronts and when attempting the drivers side I easily managed to pump fluid back up into the reservoir using a simple syringe. I am thinking that this could have cleared any air in the Master cylinder for both circuits ?
However, on the passanger side it was having none of it (both circuits) and I just couldn't force fluid back up to the reservoir. I did think afterwards that I could have inadvertantly closed the bleed screw when attaching the bleed syringe pipe to the bleeder nipple. surely not and not on each circuit !! I am going to have to re-try the passanger side before I do anything else just to check and save me dismantling anything unnecessarily. strange though as yesterday, I was easily able to bleed the passanger side with my pressure bleeded attached to the reservoir.

I seem to be using up all the supplies of DOT3 in Western Australia....Doh

The saga continues.......

Hi Peter,

No, I didnt get more air coming through when I tried to re-bleed today.

Cheers

Steve

Hi Steve

All very frustrating. If it was me with your scenario I would try to isolate each section u til you find the problem. A bit of a pain as you need to blank off segments of the brake circuit and make sure no air is left in it.

I would start with the MC a check the new one is actually ok. You say the pistons on the front calipers are moving, but that could just be the second circuit and the primary circuit could be at fault, are the rear pistons moving ok when you apply pressure?

Also if you pump the pedal does it go hard and stay solid or does the pedal go down eventually?

Sorry, just thinking as I write…

Peter

Hi Peter,

first things first....Today, I am going to re-do that reverse bleeding on the front passanger side as I must surely...surely have inadvertantly closed the bleed nipple (on both circuits !)when fiddling with the syringe......or could be that the brake pedal didnt reset fully after I tested the pedal when I did the drivers side reverse bleed. I understand that if the pedal doesnt fully retract then the passage back to the reservoir is closed off. I have noticed the brake lights staying on sometimes as the pedal doesnt retract by a small fraction...could be just enough to close the passage to the reservoir maybe. I will make sure the brake lights are off before attempting the reverse bleed again.

Note : The brake fluid flowed freely when I did the initial pressure bleed from the reservior.

If I pump the pedal it does not make any difference to the sponginess and pedal travel. If i push the pedal hard it reaches a point and stays there. It does not gradually go to the floor.

This problem situation is exactly the same when I got the car and so with the old MC in place. This brand new MC seems to have made no difference to the sponginess despite thinking that I had found the smoking gun.

Is there a simple way to isolate sections of the braking circuits ?


Cheers,

Steve

Hi,

Today I tried again to reverse bleed the brakes and managed to pump fluid via all 6 bleed screws back into the reservoir using my trusty syringe. I only pushed about 100ml in each but figured this would be enough to purge the MC of any air. I tried the brakes and they were still as spongy.

Next I pressure bled to whole system from the reservoir ......still no different

I then had a look at the rear brake compensator and disconnedted it from the ARB. I pulled back the rubber boot and could see that the arm that was connected to the ARB was not acting on the compensator plunger at all. I am thinking maybe the plunger is pushed out by the hydraulic action of braking whuch then interacts with the lever connected to the ARB ?

Is this compensator device known to trap air especially if inoperative ? The device itself is pretty crusty but I was able to lever out the plunger with a screwdriver 3-4 mm (took a bit of doing though.

Just as a shot to nothing, tomorrows job is to remove this device and dismantle to see if this may be causing my problem.

Does anyone have any experience with thse compensation devices ?


Cheers

Steve

Hi Steve

Mine was also very crusty and as they are pretty inexpensive, just replaced it. No idea why it would cause your issue unless leaking?

As to previous question re isolating, not trivial as you would need to make up blanking pieces which also need to be able to bleed as well.

One point on the reverse bleeding. I tried to use a vacuum bleed originally and found it sucked in air via the bleed nipple thread when they were loosened, so made it impossible  to see if you have removed all the air. So I would be much more confident with positive pressure from the MC.

Peter

Hi Peter,

I managed to remove the rear brake compensator. Bit worried about the 40 year old connections being siezed and possibly having to make new brake lines but needent have worried as the whole thing came off easily.

I couldn't dismantle the unit itself by removing the big screw plug at the back so decided to just bench test it instead.  I found that wiggling the plunger made the action smoother and it gave about 4mm of movement. I then forced compressed air into the inlet port and got the full force of the air blowing out of the exit port. I then used plyers to pull the plunger out whilst blowing in air and the exiting air was significantly reduced. So the unit seems to be working as it should.

I can only assume the hydraulic pressure under braking pushes the plunger / piston and the "torsion bar" connection to the ARB then inhibits the plunger movement accouring to the ride hight at the back.

I am pretty sure that this device would not trap air and therefore be the cause of my spongy brake pedal but I can see that it could have an affect on the abaility to bleed the rear calipers if the wheels are off the ground (as stated in Haynes).

so....no closer to solving my problem of spongy brakes.

Today, I am going to try reverse bleeding the MC directly....still desperate for any help or suggestions.


Cheers

Steve


PS. I discovered a handy hack on the inerweb which was to use something to press down the brake pedal just a little such that the MC piston shuts off the passage back to the reservoir. This then prevents brake fluid from leaking out under gravity from any disconnected unions. I literally only lost a drip. I am sure everyone already knows this....so just me then  !

Hi Steve,
Just coming at this from a different direction to consider.
Maybe there isn’t any air in the system and you have successfully bled the system.
Maybe there is a mechanical issue introducing ‘play’ into the system. If a calliper isn’t sliding correctly in the cage then after you release the pedal pressure the calliper will settle back too far from the disc and the next time you press the pedal you will have to take up the play again.
On many cars with different calliper sliding designs they can experience seized sliders which would give uneven pad wear ‘and’ a spongy pedal.
Maybe, just maybe some mechanical part of the system is flexing, assembled incorrectly or simply not seated properly.
Presuming you have a right hand drive car? Then you also have a fair amount of linkage from the brake pedal to the master cylinder on the opposite side of the car. Many times I have found excessive play in these linkages which spoil brake pedal feel. RHD cars are more like factory converted LHD than true RHD cars in some ways.

If you can safely drive the car to a test station and put it on the brake testing rollers it will show you what is and isn’t doing it’s part of the work.


Good luck
Ian

Interesting....When I bought the car 5 months ago I have never since driven it on the road except to a roadworthyness testing station ( Western Australian equivalent of the M.O.T). When the car was delivered to me in the first place the front discs and pads were almost new so the previous owner had done some work on the fronts. This is such a simple job to change the disc and pads so cant imagine what he might have done to mechanically compromise the brakes. Having said this he did neglect to fit any spring retainers for the pads which is so typical of the sort of carelessness of all the other problems I have had to fix.

However...thanks for the advice, I will test out the mechanical operation of the fronts to ensure the carrier slides and centres. I will also remove a pad to ensure the piston is moving in and out smoothly, The previous owner had definitey some other work as the caliper has been cleaned or even replaced and also put on new flexi hoses.

Also, not sure how the linkage from the pedal is supposed to be set up. The previous owner may have tampered with this although I suspect not as there would ne no reason to.

This is all driving me nuts although I now understand the primative operation of the brake compensator device and have cleaned it all up and changed the bushes......just because that is we all do.

Cheers,

Steve

The saga continues........

I have now plumbed the 2 bleed scews on the passanger side front caliper back into the reservoir and then  contunually pumped fluid using the pedal. To ensure I was not drawing in air fron the bleed screw threads, I had an assistant pump the pedal whilst I opened and closed the bleed screws on each pump. There were no air bubbles visible and so I locked off the screws after about 40 pumps. I then pressure bled the entire system using 2 litres of fresh fluid.

and...would you believe it........made no difference to my spongy pedal whatsoever.

I then did the 2 man bleed just for sh**s and giggles. Made no difference at all.

However, I did notice that there was quite a bit of movement of the front flexi pipes when the brakes were being pumped...virtually nothing at the backs. Got me thinking that maybe the The hydraulic action was being lost as a consequnce of the flexi pipes moving. This can only because the pipes are stretching and/or expanding. Amplifying this over both fronts and to a far lesser extent the rears, then could this not give rise to a spongy pedal with too much travel ? The flexi pipes do give a little under normal circumstances but maybe not supposedly this much.

The front flexi pipes are new (by previous owner) but could be so cheap and nasty that they are creating this spongy pedal effect. The pipes also do not have the clips to carry the wear sensor wire suggesting that they may be non standard or an incorrect specification of flexi pipe for the Beta. (note the front caliper pistons move freely using just finger pressure)

I am tempted to order a set of braided flexi pipes all round to conclusively eliminate this issue and the more I think about it....this is a plausable expalation for my problem....is it not ?

I have money to waste ...NOT !! so would apprecate any advice before I take the plunge in desperation

Cheers,

Steve

I have another italian classic from the 80's and the braking system layout is virtually the same in that the pedal action is transmitted to the other side of the car to the the master cylinder. The pedal on this car is rock solid. The reason for mentioning this is to eliminate the possibility that this is a natural symptom of 80 braking systems on italian cars.

Oh and......just did same test on my other italian (only has a single front circuit) and the front flexi brake pipes do not move at all when the pedal is pushed hard.

I would change them. I used braided and never had an issue and should not be an expensive purchase.

Peter

Yep, agree. Have ordered a set of F & R braided hoses from Mark at Betaboyz. This will conclusively eliminate the flexi pipes as the culpret. I have a video clip of the front pipes "flexing"when the pedal is pumped....will add this to the thread if poss.

Cheers Peter.

Steve

Just an update...

I have now received my braided hoses and fitted them and what do you know.......made almost no difference to the spongy pedal and so back to the old drawing board ...Damn it.

To dateI,  have replaced the Master Cylinder and the flexible hoses which hasn't solved my problem, This is in addition to my many many attempts to bleed the brakes using the 2 man method, pressure bleeding from the MC reservoir and reverse bleeding at each caliper.

I am now turning my attention back to the rear brake compensator again which I didnt see as a problem as I was getting good pressure at the rear calipers when bleeding. I pulled back the boot on the compensator and took a video of the movement as I operated the brake pedal. The compensator plunger only moved 2 mm max when the pedal was pushed hard. Therefore I would say it is siezed but even so it is siezed in the fully open position such that it would therefore not be limiting pressure to the rear brakes ..me thinks.

I have sourced a bypass flexi pipe for the compensator to see if this makes any difference to the spongy pedal. There is a possibility that there could be air trapped in the compensator....hmmm possibly. I have also ordered a replacement compensator from the UK (3 - 4 weeks shipping from the UK to Australia).

Regardless, the issue almost certainly is air in the system...but where ? Once I have fitted the bypass for the brake compensator there is nowhere left for the air to hide unless it is still in the master cylinder.

Anyone had any issue with purging the master cylinder in situ ?


Cheers

Steve

The latest,

So... I removed the new Master cylinder and re-bled it on the bench. I had also made myself 3 port caps using M10 x 1.25 bolts cut down to a shank of approx 8mm. When fitted, the MC piston only moved approx 5mm before becoming immediately rock solid. I am happy that the MC is working correctly and is bled correctly.

I have also capped off the brake line to the rear brakes at the point where the hard line would enter the rear brake compensator....just to identify if the problem was with the front or rear brakes.

With everthing re-fitted, I re-bled the front brakes and find that it has all made no difference to the spongy brake pedal and excessive pedal travel.....

The only thing left to investigate now is the front calipers which seemingly had been refurbished by the PO as the calipers were very clean had new flexi pipes (since replaced with braided by me). Might try a quick re-bleed with the caliper removed from the Yolk so that I can move it about to ensure there is no trapped air in the caliper itself.

The saga continues....

Check the bleed screws conical seats and the matching callper hole for perfect condition. defects in this area will suck in air on shut screws. I would share your doubt on the re-build calipers and look for bore score of seal nicks.

Good luck

Eric   

Hi

Given the orientation of the bleed screws and the pathway to them, it would be very unusual to have air trapped in them.

If you have already tested the m/c on its own, you must have some blanks to block the ports. Try using them to isolate each circuit in turn to see if you can isolate the problem circuit.

You may find it is just one circuit that is causing the problem.

Peter

Thanks for all the good info Guys......appreciated

Regrettably still not solved the problem and still have a longish pedal travel and spongy brakes.

Since my last update, I have added brand new discs / Pads front and rear at a staggering cost !!!! (These items are enormously expensive in Australia and sourced internationally the cost of shipping is almost prohibitive).  The reason for the expense is that the discs, especially rears had a substantial lip and have been machined by the previous owner to well below minimum thickness. I had previously put new pads in the rear and had noticed that the wear on the pads suggested that the contact area was compromised by the lip....hence the new discs.
The discs will definately improve the efficiency of the brakes and may possibly improve the pedal travel...yet to be tested.

One thing I am getting obsessed with is the rear brake compensator valve....which is also new. I had someone operate the pedal whilst I was watching the compensator action and can see that the plunger / piston moves out about 2 - 3 mm with the action of the pedal......surely this will impact the pedal travel ??
Could be I need to adjust it better so that the resistance offered by the "torsion bar" is far greater such that it doesnt allow the plunger to move when the car is level and unloaded. Not sure how much force the plunger exerts upon braking.

My plan is to bypass the compensator valve altogether using a nifty little bypass connector I got and this will tell me for sure if the compensator action is the issue.

I am hoping that the above fixes will get the brakes into an acceptable operational state such that it will pass an inspection. A lot of me thinks that the young lads in the tester station expect that the brakes should be every bit as as good as a modern car....should they be  ?

The saga continues .....

Have a look at the state of all the bushes in the linkage. The ones on my car were falling apart when I dismantled it and are being replaced with new on the rebuild. If they have failed on your car then that might allow the piston to move as the actuator bar can move within the bushes and cause the symptoms you're seeing? You could eliminate the compensator and it's linkage by removing it and joining the in and out pipe feeds together. If that created a solid pedal you're closer to sorting it?

Guy

Beta Brakes are respected, were very good in their time and normally good for spirited road use. They should comfortably pass MOT testing standards but are not what you get with current generation German Autobahn designed machinery.   

Eric

Thanks Guy....yep, I found that too that the bushes disintergrated when I tried to remove them so all have been replaced. even then, the piston / plunger in the compensator still moves a couple of mm when the pedal is pushed. I even tried adjusting the compensator to its max tension and the movement of the plunger under braking is still enough to move it a couple of mm.

I wonder if the PO has moved the connection arm from the sway bar to the compensator torsion bar....and so not allowing enough tension to be applied when the car is level. I am 100% convinced that this plunger movement Must surely affect the pedal travel so I need to engineer this movement out by applying more tension on the torsion bar at the compensator or by elimination altogether.

Regardless, my next move is to introduce the simple compensator bypass pipe to conclusively tell me if the 3mm of plunger movement is enough to cause the longer pedal travel and create the spongy feeling.

One thought if your car is RHD is to look closely at the cross links and pivots from pedal to servo for excess play. The center of the link is LH and RH threaded to allow play to be adjusted out and the pedal ball joint has a cap that can be adjusted in to remove play.

Enjoy!

Eric
PS the Haynes Beta manual has a description on how to adjust the Bias valve for load.

Thanks Eric,

The problem is also that I have nothing to compare this to which has this brake compensator valve. It could be that this is how Lancia beta brakes are supposed to be as I am used to the my German daily driver. (as you said)

I need to put the wheels back on and get this thing on the gound for a road test. I am certain that the new discs/pads will make a massive difference and also the loading of the rear suspension could help the tension on the rear compensator.

watch this space....

Just to address your questions....I am confident the linkage has no play as I have taken a video of the fluid in the reservoir when I very very lightly touch the brake pedal and the fluid is disturbed suggesting to me that the pistons in the MC are sensitive to movement of the brake pedal.

As for the Haynes manual.....have followed that to the letter.

Maybe I need to get the car on its wheels and allow the suspension to settle to see if it lays lower that how I have the brake compensator set up for......might make a difference. My expectation is that the piston in the compensator should not move at all when he brakes are applied when stopped hence you should get a 50/50 brake distribution. When the nose of the car dips under braking then this is when the piston in the compensator should move to lessen the distribution to the rear.

Will test and report back....

Are the banjo bolts 10mx1.25

I spotted a link to this in another thread

https://www.ebay.co.uk/itm/131817736572 (https://www.ebay.co.uk/itm/131817736572)

If so I might replace these bolts rather than risk snapping the bleed nipples.

Hi John

There is no down side to trying to loosen off the bleed nipples, if they break, they remain sealed. These banjo bolts are a good solution if you do not want to have the calipers refurbished and one does break.

Normally when I have bought replacement break hoses I have received new banjo bolts and crush washers.

Mark also has these banjo bleed bolts on his site, but current showing as sold out.

In answer yes, M10x1.25, go for stainless ones if you can.

Peter

When I first approached the brakes on my car, the bleed nipples felt very tight.

I used a plumbers torch to warm the caliper, just around the nipple.
All the nipples came free after that. I then replaced them, adding some copper-slip on
the threads.

I'm not sure the banjo bolt bleed option would get all the air out.

Nigel

Hi Nigel

Yes the banjo bleed option is not ideal as the bleed nipples are direct from the cylinder, however the orientation of the banjo bolts being at th top of the calipers should allow the oil to fill the cylinder and allow the air to escape.

Peter

Hi Guys,

I regret to report that I am still no further on with my issue of spongy pedal with too much travel....lost my mojo a bit with this thing and need to get stuck back in.

My wife is telling be to take it to a brakes specialist and this is killing me as I have replaced the MC, new discs, new braided brake lines, new discs/rotors & pads (originals were contaminated), new rear brake adjuster, tried a bypass pipe for the brake adjuster aswell.....and have spend an embarrassing amount of money on brake fluid as well as a reverse bleeder and also a pressure bleeder. I have zero confidence that a specialist will do anything that I havent done already and I could end up with a bill for thousands with no result.

Anyway,enough of the sob story...

I did have a thought that the symptoms that exist could well be caused by the MC somehow still having air in one of the circuits despite me having bled this on the bench twice. One thing that ocurred to me is when bleeding the brakes uing the 2 man method, the pedal travels all the way to the floor when I open just one of the nipples. Surely this duplex system is a safety feature which still provides braking if one curcuit fails. In this case then I would expect and open circuit to result on the pedal travelling further but still able to operate and stop the car without the pedal going to the floor.

Could it be that there is in fact air still in the front circuit that I wasnt able to purge via bench bleeding ?

Is there a procedure for bench bleeding the MC. I am thinking of leaving the mixed circuit open and dry such that I can put all the effort into fully bleeding the front...

Any advice greatly appreciated....

Hi

You should not need to bench bleed it. I replaced all items on mine incl hard lines and simply filled with fluid, pressure bled (as on my own) and not had to do anything to them since. Did you ever try isolating individual circuits to establish where the problem is? It may be you have a faulty new MC of course….

As Peter suggested, the MC may be faulty.

Does your current one match up to either 82293524 or 82369266?

Both these part numbers appear to be exact matches, the latter number
succeeding the former,  and are 22.2mm bore.

The Beta braking system didn't change throughout the years and models so
you can be reassured these numbers are ok.

Nigel

Hi Peter, I got as far as making some capping adaptors to isolate all of the circuits but didnt attempt anything as I realised that i could not bleed the curcuit. However, I have since thought better of this and decided it will bleed ok by loosening the cap and closing it when under pressure. It was about this time my Mojo disappeared !

Need to resume the crusade.

One thing that was curious was that I decided a while ago to securely attach pipes the both bleed nipples on the nearside front and pump the brake pedal with the aim of cycling the fluid around the shortest circuit and then back into the reservoir. The mixed circuit worked fine and the returning fluid was clear and no bubbles whatsoever but the Front circuit had almost a constant stream of tiny bubbles (almost froth like). I took this to be simply air being drawn into the system from the bleed nipple thread.....hmmmm

Hi Nigel,
The part supplied to me by Betaboyz was LM29584 (Delphi) and I have seen that this cross references to the Lancia part number 82369266. The Delphi MC was slightly different to the original Lancia MC that I removed in the respect that it did not have a "piston stop screw" to limit the movement of the piston in the front circuit. I just assumed that the part had been superceeded by a better design maybe ? . The rest of the MC was externally exactly the same as the original. I didnt dismantle the new one as...why would I ?

Hi Guys,

question still stands ....

Using the 2 man bleeding method, the pedal travels all the way to the floor when I open just one of the front nipples. Surely this duplex system is a safety feature which still provides braking if one curcuit fails. In this case then I would expect the open circuit here to result in the pedal travelling further but still able to operate and stop the car without the pedal going to the floor.....On my car, the pedal goes to the floor every time and so not saved by the other entirely seperate circuit......what am I missing ?

I do hear you all and your feedback about a faulty new master cylinder but the brakes actually do operate albeit they are spongy, not responsive and the pedal travel is too long....as in it is not leaking fluid out of the cylinder nor is the pedal sinking to the floor....

Another thing to add is that when I got the car in the first place the brakes were every bit the same as they are now, even after all the work I have done. The oly thing I have not done anything with is the calipers themselves (all operate and the pistons are not seized or leaking)

I can hear Peter screaming at his PC (and I live in Australia) telling me to isolate everything as he suggested.....gotcha...on it

Cheers,

Steve
Cheers,

Steve

Is this the case no matter which nipple is open front or rear?

Yes, when bleeding the brakes, the rear brake nipples and both the front cause the pedal to go to the floor when open. I would have thought that with this super duplex system that the pedal should never go to the floor regardless of which nipple / circuit is open unless one nipple from both circuits was open.

Hypothetically, if either circuit fails then the pedal should travel further resulting in a mechanical stop for the MC piston in the failed circuit allowing a hydraulic action in the good circuit to apply the brakes. In my situation, the symptoms of long pedal travel and weaker brakes suggest that one of the circuits isnt working which could possibly be be air in just one of the chambers in the master cylinder, rendering it inoperable.

Given the bodges you found elsewhere has the PO tried to refurbish the front calipers and cocked it up?  I think I'd focus on them  - not least as it's the only part you haven't replaced!

One very stupid question  - you do have all four calipers mounted with the bleed screws at the top? People occasionally mix them side to side and you end up with the nipples at the bottom.

First things first...... I can confirm that all the calipers are mounted correctly with the bleed screws at the top (refer to included pic).

You are so right about all the other awful, awful bodges and yes, the calipers themselves are the only bits I havent replaced so far. I did note when I got the car that the front calipers were quite clean, indicating that someone had maybe done something with them but the piston dust seals didnt look very new and so I just assumed someone had just cleaned the calipers. Maybe there is something worth investigating there to pull them apart to see if anything is untoward.
The symptoms of long pedal travel and spongy brakes could also be indicative of air stuck in the caliper somehow. However, there are no leaks in either front calipers and all bleed screws seem to bleed normally.....

As per Peters post, the simplest thing to do would be to isolate both front calipers by capping off the 4x flexi lines and seeing what happens. this would determine if the problem was with the MC or at the calipers. My only issue with this capping thing is being able to get all the air out of the line in the absence of being able to bleed the brakes. I think that this may not be such an issue if I let the brake fluid run out under gravity and then apply the cap.

Added a pic of the front caliper for no real reason other than to liven up the thread which is mostly text...we all like a pic eh

You can get remote brake bleed nipples for not much but I agree you can just most likley gravity bleed them.

Stupid question No.2  - Are the front hoses connected the right way around? The two piston diameters in the caliper are quite differnent with one designed to work at lower pressure.

Another diagnostic method which takes me back to the 80's.....

Clamp all the hoses shut using either the correct tool or vice grips
and see if anything changes. If the pedal is still spongy you'll know it's the MC.
 There after, remove clamps in turn until
the problem appears.
 
I acknowledge that you have braided hoses but doing this carefully shouldn't
cause any damage.

Nigel

Nope...Not a stupid question at all but I checked this was all connected correctly already.

On the bleed screw front, I didnt know there was such a thing as a remote bleeder but google came to the rescue. Wonder if I will find one with M10 X1.25 connection though. I had previously made 4x "Heath Robinson" capping mechanisms to isolate the banjo ends of the pipe connections to the calipers...will take a pic once attached.

Another recollection I had was I remeber finding the odd small "blue crumbs"" in the brake fluid when bleeding at first and I thought that this might be thread locker that a PO had applied to the bleed screw threads to stop them drawing air when bleeding. I found myself that vacuum bleeding did seem to draw air past the threads even with the smallest opening of the screw.....I abandoned this method in favour of the pressure bleeder, or the reverse bleeder or the tried and tested 2 man approach.

I paid such a stupidly high price for this car thinking I would be getting a well maintained example in good order......closer inspection, which isnt really permissible when buying, has unvovered loads of astonishing hidden  horrors......buyer beware. However, I am 95% there in recovering this thing but for this one last brake issue that is preventing me getting a road worthiness certificate (or MOT for you guys on the UK)

Doh....soooo close, surely !...Keep the ideas coming please

Hi Nigel,  The braided lines cannot be crimped without damaging them as far as I am aware. I could I suppose re-install the original rubber hoses which I now know to be OK as the new braided ones didnt solve my problem or make any difference .

Isolating the front caliper is probably the only cost effective way to check the integrity of the MC installation. I will also cap off the single rear pipe where it attaches to the brake force distributor

Cheers,

I think you are quite right that logially the clip should be on the back of the caliper as the braking action would naturally draw the caliper block inward. I will change this round as you say when I next take the calipers off.

I will say though that the calipers slide as smooth as a buttered dolphin as all the surfaces have been cleaned and polished and then well lubricated with copper slip.

Cheers

From your picture the wedges and clips look correct to me. Much easier to pull out the pin at the front, not the back. The 'spring' keeps the wedge in place more than the clip. Either way this wouldn't impact air in the system....

Hi

I agree with Nigel, all the caliper wedges I have removed have the spring on the outside, then if the wedges are stiff on removing you can easily knock them out.

Personally not a great fan of distorting flexible brake lines using pinch clamps, I would always worry if any damage has been made to them, not something I want to worry about….. Coolant hoses I would worry about less!

Peter

Clamping hoses to service the calipers was an accepted method
back in the day and very little squeeze is required to close the relatively small
inside diameter.
Jasper has a 'long'
problem needing, perhaps, old-school methods.

As he said, fitting the old flex lines and doing this check may well isolate
the issue he's having.

Good luck Jasper!

Nigel