Re:brake caliper sliders

[Dinger1962]

Am ready to re assemble my calipers not sure what to lube slider plates with --am guessing copperslip or a graphite based grease any info welcome --thanks in advance Stu--

[HFStuart]

I've always used coppaslip and not had any problems

[rossocorsa]

There's a line of thinking these days that says copper grease can cause issues on some calipers, I haven't tried it yet but ceramic grease is what some recommend.

https://textar-professional.com/textar-training-center/the-use-of-copper-grease-on-modern-brakes/

[mangocrazy]

If copper grease migrates to the seals, it may damage them. It all depends on how much you use, I guess. Also copper grease is not particularly slippery, although it does persist very well - swings and roundabouts I guess. If I was staying with standard Beta brakes, I would get the caliper carriers, sliders and cast iron mounts all plated in electroless nickel. It's very corrosion resistant and very lubricious (i.e. slippy). I think that would give minimum friction on the sliding surfaces, which is basically what you want.

[squiglyzigly]

I have been using copperslip on Beta calipers for years without problem. I dont see where the Galvanic reaction can take place on the Beta caliper sliding faces because the brake pad cage is cast iron, the sliding blocks with securing pins the same and so is the caliper sliding cage. I have never experienced corrosion between these three components all of which are iron. The hydraulic piston housing is alloy but that is on the end of the iron sliding cage away from the area to be lubricated for sliding. I have often seen a Galvanic reaction between the alloy piston housing and the iron sliding cage as a result of road salt/grime etc but that is to be expected as they are assembled in the factory dry without any anti-corrosive barrier.

If you look at many fiat calipers such as 128, x1/9 front, 131 and so on, they do have a problem with Galvanic reaction because the whole hydraulic piston and slider assembly is one-piece cast alloy sliding against iron sliding blocks and iron pad carrier, bolted to the iron hub carrier. That is a problem for sure.

But the Beta has never had a problem with copperslip from my experience.

[squiglyzigly]

Just to add to that, am I correct in thinking the Montecarlo front calipers are one piece cast alloy? If so, add them to the list of calipers that can suffer galvanic reaction.

[mangocrazy]

It wasn't so much the possibility of galvanic corrosion that was behind my suggestion, more a case of trying to a) reduce the possibility of general surface corrosion and b) give the surfaces that need to slide across each other a low-friction coating. It's only a suggestion and not one that I've tried (yet), so it doesn't have the weight of practical experience behind it.

As you say, copperslip has been used successfully for years in this application, and provided it's not slathered on shouldn't cause a problem. If there was enough applied to migrate and attack seals, realistically it would wind up on the pad surface as well, with interesting results...

[rossocorsa]

Probably applies more to modern cars but having said that beta brakes are pretty modern in design really. I have an Abarth 595 and they suffer from squeaky brakes, if people complain under warranty a lot of dealers seem to copperslip them but it makes it worse!

[squiglyzigly]

I don’t believe the beta calipers slide very much under braking. Probably less than 1mm and quite slowly. The sliding mechanism is as much for pad wear compensation as it is to facilitate even pad application during braking. The brake calipers probably flex more than 1mm under medium application. Greasing the sliders is probably more about resisting corrosion and seizing than it is for brake performance.

Just a thought.

[mangocrazy]

I don’t believe the beta calipers slide very much under braking. Probably less than 1mm and quite slowly. The sliding mechanism is as much for pad wear compensation as it is to facilitate even pad application during braking. The brake calipers probably flex more than 1mm under medium application. Greasing the sliders is probably more about resisting corrosion and seizing than it is for brake performance.

Just a thought.

I agree there won't be much movement, although I wouldn't like to put a figure on it. But single piston sliding caliper designs rely on the caliper being able to slide (the clue is in the name) to equalise pressure between the pads. It also equalises wear between pads when it's working correctly but when the mechanism binds then braking force is reduced, and as a consequence only one pad wears. I'm of the opinion that anything that allows free sliding movement of the caliper is beneficial, and grease facilitates that, surely? I'd say that maintaining performance, and keeping the mechanism corrosion-free are inextricably linked.

[rossocorsa]

As ceramic grease isn't all that expensive it seems pointless to stick with copper grease purely on grounds of tradition.

[squiglyzigly]

Why stop there? (Did you see what I’ve done there?)
Proslip make a triple lubrication kit. Pad, clip and slider.
If you don’t like copperslip and want to do it properly.

[rossocorsa]

Why stop there? (Did you see what I’ve done there?)
Proslip make a triple lubrication kit. Pad, clip and slider.
If you don’t like copperslip and want to do it properly.

Yes that looks interesting, it's not that I don't like copper slip is just there seems too be strong evidence not to use it for brakes etc.

[mangocrazy]

That looks very interesting stuff - I'd use that in preference to copperslip. Most of the types of copperslip I've seen are quite thick and not ideal for caliper pins or sliders, even without the dangers of seal or boot damage. The best I've used is made by Wurth, but even that will not be friendly to rubber components.

[squiglyzigly]

It’s worth remembering that caliper seal attack is more often caused by split/leaky driveshaft boots than copperslip usage. When a cv boot lets go, there’s a large amount of grease thrown at the back side of the caliper and the seal usually cops it.

[mangocrazy]

True. And the quantities of grease involved are much larger.