[Mk2] [Generic] Sticking brakes

[pbmr2]

Brakes are sticking quite badly after lending the car to a mate last weekend. Going to take wheels off to see what's going on.

What am I likley to find wrong?
How can I tell if a caliper needs replacing?
Anything else to look out for while in there?

Current plan is to asses discs (think 1 front is warped) and pads then order as needed. Clean up the sliders today and lube with brake grease.

It's a rev 4 UK car.

[abovetherim]

There are a number of reasons a caliper can stick.
Dry, dirty or corroded sliders or ingress of water due to torn rubber boots
Dry, dirty or corroded pistons again crap can get in if the sealing boot is torn
Hand brake cable sticking due to water ingress causing corrosion or freezing again due to torn boot.
Hand brake lever mechanism on caliper seizing.
All of these are generally obvious with an inspection. For the pistons the amount of force required to push (front) or wind (rear) in will tell you if they are seized.

Sometimes popping the piston out and cleaning and polish and clean and grease the o-ring can provide a good result. It all depends on the condition. The same applies for the sliders.

You mention brake grease and I'm hoping you mean brake grease or rubber grease and not copper grease as you shouldn't use copper slip for sliders or piston as it goes glue like with heat and deteriorates the rubber.

[Grazzy]

yes your likely to find whats not right, caliper is normally fine, its the slider pins that normally need replacing due to be pitted and corrosion. pistons will need freeing back up.

Normally I take the caliper off the hub and leave it connected to the brake line. take the pads out and put wood in the caliper to adjust max length(to prevent the piston coming out too far) and use the foot brake to push them out then wind them back in. WD40 to get them moving again. may need to repeat this a couple of times, then clean the pistons, grease them back up, wind back in. Don't forget to check the sliders & treat them also to some grease. If you have someone spare to pump the brake pedal, speeds things up a lot.

Afterwards check fluid level!

If the disc is wrapped needs replacing or you will be doing the whole lot again soon.

this is a method for front calipers sticking issues, its worked for me every time. rears are more of a pain, mine have always needed rebuilding.

[pbmr2]

yeah, it's caliper slider grease. Designed for just this job. Left over from an MX5 we used to have.

No idea what the last person to service my car used but I've got the right lube.

Looking at the cost of rebuild kits, may as well rebuild them all anyway and know they are going to stay working. May well even replace all the slider pins too. Going to finnish breakfast and go have a look at it all.

[pbmr2]

well just to buck the trend nearly all of the sliders were perfect but all the pistons were stuck.

Looks like it's been very well looked after in the brakes department but it was parked up in a garage for 3 years. seems the pistons didn't like that.

rebuild kit for all the calipers and new lower bolts/tubes for the rear as they were a bit rusty. cleaned them up for now but best to replace. Should be mint by next weekend and not too expensive.

Didn't find any warped discs or dead pads either. will swap them for new items in a couple of months as the front rotors have a bit of a lip and the rears are lightly pitted.

[pbmr2]

Where is the best place to get rebuild kits for the calipers?
Need to do all 4 due to sticking pistons and lower rear slider pins.

Car is a UK rev 4 08/96

[abovetherim]

Where is the best place to get rebuild kits for the calipers?
Need to do all 4 due to sticking pistons and lower rear slider pins.

Car is a UK rev 4 08/96

I have used biggred and very happy with their service. They can also supply new pistons but the rear ones will need the wind gubbings transferring from your old ones

[pbmr2]

thanks.

ordered everything except the rear lower slider bolts. can't find them really. only one place (mr2ben) but really expensive for 2 sliders.