Sticking caliper?

[benm3evo]

Hi all.

I have an R53 Mini with R56 calipers (second-hand) & discs pads (new) on the front.

We did a track day, my first one, at Blyton Park yesteday. At the end of it the near side pad was down to metal! The off-side is about 50%.

Any likely causes for this? I presume sticking caliper is one but it doesn't seem to be stuck all the time, i.e. wheel moves freely but I am wondering if once it gets hot it is sticking??

Also, a long shot, when we fitted the discs they aren't directional, the cooling fins were straight so we understand they can go on either side but, to me, it looked like the near side grooves & slots were going the 'wrong' way' & just didn't look right so wondered if we had 2 near side discs. I've been told I'm mental & it looks fine, so probably is just me but wondering if a disc is rotating the 'wrong' way if it could cause the increased wear??

Thanks,
Ben

[E-bmw]

benm3evo said:

Hi all.

I have an R53 Mini with R56 calipers (second-hand) & discs pads (new) on the front.

We did a track day, my first one, at Blyton Park yesteday. At the end of it the near side pad was down to metal! The off-side is about 50%.

Any likely causes for this? I presume sticking caliper is one but it doesn't seem to be stuck all the time, i.e. wheel moves freely but I am wondering if once it gets hot it is sticking??

It pretty much has to be the caliper/slider sticking, whether it is doing it all the time or not, but obviously heat will exacerbate any wear.

benm3evo said:

Also, a long shot, when we fitted the discs they aren't directional, the cooling fins were straight so we understand they can go on either side but, to me, it looked like the near side grooves & slots were going the 'wrong' way' & just didn't look right so wondered if we had 2 near side discs. I've been told I'm mental & it looks fine, so probably is just me but wondering if a disc is rotating the 'wrong' way if it could cause the increased wear??

Thanks,
Ben

IIRC grooves are supposed to sweep inside to out with respect to the pad in the normal direction of rotation, but I very much doubt that would be a factor at all.

[benm3evo]

Thanks, we'll whip the caliper off on the weekend & see what we can do.

Just checked & it's actually the off-side disc that looks 'wrong' to me, not the near-side in question....but I'm still not convinced I trust my eyes!

We'll investigate the caliper as prime suspect for now.

Thanks.

[Panamax]

I'd just replace the callipers with new - they're not exactly expensive and braking is high on my list of priorities.

If you bought stuff second hand are you absolutely sure you've got a matched pair?

If a calliper has been sticking enough to quickly erode a brake pad I'm surprised you didn't have serious brake overheating, with its associated smell.

[benm3evo]

Panamax said:

I'd just replace the callipers with new - they're not exactly expensive and braking is high on my list of priorities.

If you bought stuff second hand are you absolutely sure you've got a matched pair?

If a calliper has been sticking enough to quickly erode a brake pad I'm surprised you didn't have serious brake overheating, with its associated smell.

That will be what we'll end up doing, I just wanted to make sure it was the caliper....but I couldn't think what else would cause it to be fair.

Fair point about the matching pair, I didn't get them myself but my mate said he saw them on the previous car. Not sure if there's any way to tell for definite if they are a pair?

That's the thing, everything seemed fine up until lunchtime at the track. We're presuming the couple of runs after lunch is when the problem must have started as that's when it went to metal, but even leading up to that we weren't get any fade or smoke/smell when we got back in.

Thanks,
Ben

[Pastor Of Muppets]

If you have one of the commonest issues with Mini brakes Ive found over the years then there's a chance that replacing the calipers may
well be unnecessary.
I've done hundreds of them and the most common problem is the rubber insert on the caliper, the alloy behind it corrodes and swells
causing the rubber to tighten and grip the slider pin so tight you can struggle to remove it.

Remove the sliders and prise out the rubbers, clean the corrosion away, clean up the rubber, grease them both and insert the rubbers
back in the caliper, the sliders will then do what they are meant to...slide. Try that before spending any money, you might be surprised
just how well they work after it.

Edited by Pastor Of Muppets on Friday 30th September 11:40