Removing clutch actuating arm from spline

[mangocrazy]

When I bought the gearbox that Day & White subsequently rebuilt/refurbished for me, I failed to notice that it was missing the clutch release bearing arm/levers and the external actuating lever. As a result I've been trying to liberate those components from the gearbox I removed from my Beta Spider engine prior to stripping it.

The circlip notionally holding the two parts together came off easily enough, but trying to seperate the two splined parts has proved an entirely tougher proposition. I've repeatedly doused it in Plus-Gas and tried various threatening moves with a lump hammer, but it hasn't budged. The part inside the bell housing has come out of its locating hole and is now waggling about freely, which doesn't help. Is there a suitable puller that could help me?

Also, is the nylon top hat sleeve that acts as a bearing between shaft and housing still available? Mine has seen better days. I'm thinking of giving the splined area some serious heat with a view to seperating the two halves, and that will probably finish it off.

[rossocorsa]

I can't help really as mine just came off without any problems I just lifted it off by hand.

[SanRemo78]

Two or three legged puller perhaps? That might work if there's enough room to get the puller teeth underneath the arm. You may want to centre punch the shaft and drill a locating point so it's secure first.

https://www.ebay.co.uk/itm/334014872144?hash=item4dc4d67a50:g:wFgAAOSw9RBgrfbe

If that fails my next step would be to see if any local engineering shops have a suitable hydraulic press to pop it off.

If that fails then I'd try heat, I suspect that'll kill the nylon bush pretty quickly. Maybe invest in an induction heater to localise it a bit and try to protect the nylon with a shield?

https://www.ebay.co.uk/itm/324643170235?hash=item4b963da7bb:g:BWUAAOSw7S9grO2n

And if that doesn't work then it's either time to give up or resort to violence with an angle grinder with a diamond cutter attached in an attempt to cut the arm down to the splines and a cold chisel to spread it slightly. If you go that way then please make sure everything is securely nailed down, wear proper eye protection too and choose where to make the cut carefully - I'd go for a point near the base of the lever to the left of the lever when viewed from above. That way you might be able to re-use the arm without having it welded up again, the load from the cable will try to close the cut up under operation, if it were the other side of the arm it's going to try to open it.

Guy

[SanRemo78]

Is the old gearbox/bellhousing scrap? Cutting the bell housing up with a reciprocating saw or a drill (join the dots with a chisel) would release the components and allow you to save the nylon bush? This would free the bits you need and allow you to get them into a hydraulic press.

Or a parts wanted advert?

I think that's all I've got for now!

Guy

[SanRemo78]

And if you do end up destroying the bush..

https://www.ebay.com/itm/113754335250?hash=item1a7c496812:g:zvIAAOSwLvFc4MVe

[mangocrazy]

Hi Guy,

Yes, the more I think about it a 2 or 3 legged puller should do the job. There's about 12mm of clearance behind the arm so should have enough room. And the shaft has already been centre-popped so that helps as well.

Good spot on the bush all the way from the USA, even if the part number he's quoted is not one that seems to match. Betaboyz do list these, but as out of stock, so I do need to cast my net wider. It's a bit infuriating, as if I had even a hobby lathe I could knock something like this up in a few minutes. One day...

Thanks for all the suggestions - much appreciated...

Graham

[SanRemo78]

It's not the 12mm step that's critical in choosing a 3 legged puller Graham, it's if the 3 legs will clamp together under the step without interfering with each other. If the do then you'll be pulling on potentially a smaller area that you might with a 2 legged one if you see what I mean.
I don't know where you are but if it's anywhere near Liverpool (L30 5RD) you're more than welcome to pop in and try my pullers - I think I've got two 3 legged ones of different sizes.
Chances are that it'll pull straight off if it's been soaked in plugs and suffered a beating!
Guy

[mangocrazy]

Yes, I get what you're saying. I've bought a 3" 3-legged puller, so hopefully I can get enough pressure on the arm with that to do the job. I'll be introducing it to the MAPP gas torch before using the puller, just to encourage it a little more. As with most things of this nature, it's a case of applying the right amount of force at the right point. Hopefully what I can bring to bear will be sufficient.

Thanks for the offer, it's much appreciated. Unfortunately I'm in Sheffield, so Liverpool is a bit of a trek for a puller... 

[peteracs]

Hi Graham

I should have some spares of these, so if you need anything after your efforts, let me know.

Peter

[mangocrazy]

Hi Peter,

Thanks for that. My next step would have been a 'parts wanted' call. I'll see how it all goes, but I may well need to take you up on your kind offer. It all depends on the state of parts if and when I can get them disassembled and inspected.

Graham

[mangocrazy]

Well, this is proving to be a real annnoyance. I've tried to remove the arm from the spline with both a 3 legged and a 2 legged puller (but not at the same time...) and neither has any effect. I have to admit that both pullers were at the cheap end of the price scale (ebay specials), but neither could get a good enough grip behind the arm to be effective. In particular the 2 legged puller (which I though would be the best bet) had very shallow hooks on the leg ends and slipped off when any serious pressure was applied. On thinking about it, I may take it to my welder friends and see if they can eadd some metal to the area in question and build it up so there is more meat where it's needed.

I'm not intending to use the bell housing/gearbox again, but it would be sheer vandalism to cut it up just to remove the operating arm. It doesn't help that the bell housing is on my cellar floor and not in the easiest place to work on.

So Peter, I may yet be taking you up on your offer to look through your spares stash...  I'll see what my welder friends can offer, but failing that I may have to concede.

[mangocrazy]

I went to see Nick and Chris (the local welders), and they came up with a solution in about 10 minutes. I haven't tried it out yet, but if this doesn't work I shall probably resort to explosives and ultra-violence. Nick found a suitable thickness disc with the right sized hole in the middle (20 mm ish) and then carefully TIG welded it to the puller legs, running beads all round both feet. I've since split the base in two with slitting disc in the angry grinder and so it's now ready to give it a go.

Tomorrow, perhaps...

[mangocrazy]

Well, the 'special tool' did the trick, but it still put up a fight and the tool has not been unchanged by the experience. Anyway the two parts are now separate and I can degrease and de-rust them prior to plating. The top hat nylon bearing suffered some collateral damage, and they are NLA from every source I've tried, but I have A Plan for that. Onwards and downwards...

[Nigel]

Hi Graham,

Is there a similar bush/bearing at the other end of the fork inside the bellhousing?

Regards
Nigel

[mangocrazy]

Hi Graham,

Is there a similar bush/bearing at the other end of the fork inside the bellhousing?

Regards
Nigel

Not that I could see. It would seem to be a logical thing to do, but it seems that the actuating arm extension just runs in the aluminium casting of the bell housing. Not exactly ideal...

[WestonE]

Yes the arm runs in the casting making it even more important to have the top nylon bearing in good shape.

[mangocrazy]

Yes the arm runs in the casting making it even more important to have the top nylon bearing in good shape.

During the process of removing the lever arm from the actuating arm the top nylon bearing suffered what can be best termed as collateral damage, so a replacement will need to be found. Having missed out on a NOS one on US Ebay, and drawing a blank from other source I decided that the simplest way of squaring the circle would be to get a replacement made - after all, it's not exactly a complex shape to get machined up.

I took the various bits (excluding the bell housing) round to the local engineering firm and asked them how easy (or difficult) it would be to replicate the original. They reckoned that it would be a trivial amount of work, but with one caveat. The OE bush has a small raised notch on the top surface which mates with an indent in the bell housing casing to positively locate the bush and stop it rotating. Replicating this notch would turn a simple, single stage process into a more complex, multi-stage process. The OE bush was doubtless injection moulded with a production run probably going into the hundreds of thousands. I'm thinking of single or low double figures for my 'production run'.

There was also the question of the most suitable material to use as a bush/bearing material. Plastics technology has advanced hugely in the (nearly 50) years since that nylon part was designed. There is now a bewildering choice of plastics available, but I narrowed the choice down to two types of material available form a local plastics firm; Acetal and UHMWPE (Ultra High Molecular Weight Poly Ethylene). Acetal is the better known of the two, but certain characteristics of UHMWPE really appealed to me. Here is a brief run down of the pluses and minuses of the two materials:

Acetal

Probably the easiest of all engineering plastics to machine
Very low friction characteristics (i.e. 'slippery')
Very suitable for to high speed automated machining processes such as CNC lathes
Short term (<2 hours) upper temp limit of 140 deg C. Long term limit  105 deg C. Lower temp limit -40 deg C.
High stiffness, tensile strength and surface hardness

UHMWPE

Extremely low moisture absorption
Extremely low coefficient of friction (similar to Teflon/PTFE)
Self-lubricating and is highly resistant to abrasion.
Very resistant to water, moisture, most chemicals
Only becomes brittle at temperatures below −150°C (!)
Not advisable to use UHMWPE at temperatures exceeding 80°C to 100°C for extended periods of time.
Maybe not suitable for high load applications
Very high resistance to wear

So, based on the above I'd welcome people's opinions on two points:

1) Would the omission of the locating notch be a deal breaker if you were considering purchase of a part machined from either of these materials? I would be looking to accurately specify the internal and external diameters such that the part would be a light press fit in the bell housing, and run tighter clearance internally than the OE part for better location.

2) Which would be your preferred material? For me UHMWPE wins on most grounds except that of temperature tolerance. How hot does a bell housing get? Bear in mind that 'extended periods of time' in engineering terms is 5000 to 20000 hours.

Lastly, here's a link to an article about UHMWPE:

https://www.directplastics.co.uk/about-plastics/uhmwpe-a-fantastic-plastic-you-can-t-pronounce

[Nigel]

Very interesting Graham.

In a previous life I was using UHMW-PE extensively in the manufacture of in-flight
openable doors for skydiving. I was always amazed by its ability. The manner of my use
didn't require machining though.
That said, I'm fairly biased in favour.

And yes, a light press fit would remove the need for the notch.
Perhaps the notch was designed in to aid a speedy assembly process.

Nigel

[squiglyzigly]

I think the notch was to ensure the only rotation was between the hardened steel clutch rod and the nylon bush rather than the bush versus the soft alloy bell housing.

Ian

[WestonE]

If the notch was made as a brass part with a round peg on the end a simple round hole in the bush could take the peg end on hold the bush from rotating?

Eric