Brake judder (pedal only)

[Drollic]

For the last couple of weeks my s2000 has developed what can be described as a slight judder/wobble on the brake pedal under braking. It's barely noticeable at braking from around 30mph but a lot more so at 50mph+. Nothing through the steering wheel and doesn't pull to either side. The discs all round from memory are pagid and the pads all round are stop tech. They were all changed at the same time less than 25k on them. Pads still have life left in them from the looks of the depth. Fluid was changed when the lines were done due to corrosion less than 12 months ago.

Any ideas other than sticking caliper and uneven disc?

 

[Conscript]

Usual suspect is simply a build up of pad material on the disc. I would take the car out for a drive, get the brakes nice and hot then find a nice quiet stretch of road. Get up to a decent speed, then brake as firmly as you can, and bring the car down to almost a stop (but do not stop entirely). Repeat that a few times, then drive home gently with as little brake use as possible to let the pads and discs cool.

Not saying that it definitely is the problem, but if it is, that should be enough to burn off the material causing the judder. It's worked for me before, but even if it doesn't for you, it won't have cost anything to try.

If it doesn't work, my next port of call would be checking the sliding pins of the brake calipers in case they are binding (assuming it's a floating caliper?). Should be fairly easy to remove them, clean them up and regrease them.

 

[Drollic]

Usual suspect is simply a build up of pad material on the disc. I would take the car out for a drive, get the brakes nice and hot then find a nice quiet stretch of road. Get up to a decent speed, then brake as firmly as you can, and bring the car down to almost a stop (but do not stop entirely). Repeat that a few times, then drive home gently with as little brake use as possible to let the pads and discs cool.

Not saying that it definitely is the problem, but if it is, that should be enough to burn off the material causing the judder. It's worked for me before, but even if it doesn't for you, it won't have cost anything to try.

If it doesn't work, my next port of call would be checking the sliding pins of the brake calipers in case they are binding (assuming it's a floating caliper?). Should be fairly easy to remove them, clean them up and regrease them.

The car isn't driven all that much and whilst there is no corrosion on the discs, there are marks on the discs from where the pads look to have sat with the handbrake on possibly. They don't have that clean silver disc look to them if that makes sense. No score marks or anything like that. Will try it as wasn't aware it could cause this.

 

[Conscript]

Indeed, a lot of the time what people call 'warped discs' is down to material thats been deposited on the disc. Hopefully a few good high speed stops should be enough to clean them off a bit. Best of luck!

 

[Phemo]

I had exactly the same thing on one of my other cars. Didn't notice anything below 50 but when braking from above 50 it was quite bad. I changed the discs and pads and it went away for a while before coming back again. When that happened I checked the temps of all 4 discs with an IR thermometer to see if one was massively hotter than the others but they all seemed to be fine so it didn't seem immediately obvious as a caliper issue. Just for the hell of it I took the front calipers off, pushed the pistons back in and put them back on the car with the same brake pads and the problem went away but I ended up ditching the car soon after. I never got to the bottom of it but it had to be caliper related in my situation.

 

[a1ex2001]

I had this, Beak discs and pads looked ok but it went away when they were changed. I tried the old break clean method as described in this thread with no luck.

 

[skookum]

Get a judder in my minibus when the discs are shot. Being its weight its heavy on brakes. You can solve it temporarily by hard braking. But within a short time it will come back. Replacing pads even if the discs are within wear region will only be a temporary fix. New discs and pads is the only long term fix.

 

[Drollic]

So turns out this was the rear drivers side disc. After some harder braking about 2/3 of the rotor became scored and has started to rust over with a dull surface. The other 1/3 is as it should be. I don't see what would cause this though as there is still a lot of pad life left and the discs weren't that old without much of a lip? No noises either suggesting nothing trapped. I'm hoping nothing is wrong with the caliper. It's there anything that can be done to the caliper as preventative just in case? I know refresh kits exist.

 

[MatteH Oxford]

The car is at least 10 years old? I expect the caliper seals & pistons need a thorough clean at the very least, it's normal wear and tear.

 

[Orionaut]

The car is at least 10 years old? I expect the caliper seals & pistons need a thorough clean at the very least, it's normal wear and tear.

Seals, pistons, slides, retaining pins and all sorts.

All needs a damn good clean I would think after all this time.

If they are available, cleaning up callipers and putting fresh seals in isn't that hard. (And if you are completely OCD about it, you would do it each time you change pads, especially if you only do low annual mileage) But more often than not, only service exchange callipers as complete units are available these days.

 

[Drollic]

Car is twenty years old this year, possibly never been done.

 

[Orionaut]

Car is twenty years old this year, possibly never been done.

There your answer then (Probably)

Unless I have misinterpreted this completely. Your rear callipers are the combined hydraulic/handbrake variety. These are quite complex with lots of potential wearing parts.

If you are really keen you might have a go at seeing if you can refurb them yourself. But in practice. Service exchange is really the way to go. (Do Both, like tyres/brake pads do not just do one side only)

The fronts are a different matter however, again, If I am reading the data correctly, refurbing the front callipers should be an easy job if the kits/spares are available.

If the seals/pstons are available, and you are willing to spend the time/hassle. You can strip them down and overhaul them yourself.

To disassemble calliper, leave the hydraulics connected after you have removed the calliper from its mounting and use the brake pedal to gently pump the piston out of the calliper.

Avoid pushing the brake pedal all the way to the floor when doing this. This can upset master cylinders.

If the cylinders are corroded they will need to be replaced. Often these days, seal kits are available on their own. But new cylinders not (Which is why it might just be easier to go service exchange)

In practice, if the cylinders are corroded, it would probably be less expensive just to go for service exchange

Good luck!

 

[Drumroll]

Usual suspect is simply a build up of pad material on the disc. I would take the car out for a drive, get the brakes nice and hot then find a nice quiet stretch of road. Get up to a decent speed, then brake as firmly as you can, and bring the car down to almost a stop (but do not stop entirely). Repeat that a few times, then drive home gently with as little brake use as possible to let the pads and discs cool.

Not saying that it definitely is the problem, but if it is, that should be enough to burn off the material causing the judder. It's worked for me before, but even if it doesn't for you, it won't have cost anything to try.

If it doesn't work, my next port of call would be checking the sliding pins of the brake calipers in case they are binding (assuming it's a floating caliper?). Should be fairly easy to remove them, clean them up and regrease them.

Quite possibly.
Usually rear brakes can rust quite bad this time of the year, and light breaking won't clear it.
Mine I do the same harsh break now and then, as driving everyday at the same stretch, sometimes I just use my breaks once or twice.