Poor Brakes with Judder

[Wheelz]

It's about time I sorted this problem. I fitted all new front brakes some years ago but have always had a judder / shudder when braking hard at speed. I thought the problem was disc runout but that measures about 4 thou in total which is within spec of 6 thou.


More recently I fitted all new rear brakes, but the brakes still judder and don't inspire confidence.

[marshman]

Did you have the judder before renewing the front brakes?

Have you checked the disc thickness at several points? - not unknown for new discs to be badly machined such that the thickness varies.

[Wheelz]

Did you have the judder before renewing the front brakes?

Have you checked the disc thickness at several points? - not unknown for new discs to be badly machined such that the thickness varies.

The run-out check should show that up but I guess you can never be sure. I will check that. I have a new disc set and EBC Green pads which I might just fit to eliminate a disc problem.

Some have suggested drums might cause this, but they were renewed last year and didn't help with the judder. But one helper suggested play in rear wheel bearings ( do have some) would allow drums to wobble and cause a judder - seems plausible?

[marshman]

Reason I suggested checking disc thickness at several points is my son has a Skoda VRS, he fitted new discs and it then had judder when braking firmly at speed (on the motorway was most noticeable). We checked disc runout but only had the DTi running on the outer face of the disc, they were fine according to that. We then checked the disc thickness around the circumference using a micrometer, there was a clear variation of more than just a few thou. He got them skimmed at a local specialist who said the rear face was not "true" - same on both discs. After refitting the judder was gone. Fairly quick and easy to check so worth doing to rule it out.

[Chris01573]

If it happens at speed when braking hard I would swap out the discs and pads and see how you get on sounds like the discs are warping when hot

[KOY 23]

Hello Chris01573

Just seen your video on the correct way to assemble rear brakes, very clear thanks, to those who criticised it I suggest you look at it on a larger screen or go to specsavers.
You mention a video where the adjusters had been mounted back to front. I wonder if Wheelz followed this and maybe the shoes are not correctly seated and cause the judder?
Someone mentioned worn wheel bearing maybe a cause, I would have thought they would have to be dangerously worn to cause judder, a good reason for annual MOT tests to keep dangerous cars off the road.
I would agree with you that changing disks and pads would be the first approach, badly fitted disks can cause judder and the only cure is replacement.

[Chris01573]

Hello Chris01573

Just seen your video on the correct way to assemble rear brakes, very clear thanks, to those who criticised it I suggest you look at it on a larger screen or go to specsavers.
You mention a video where the adjusters had been mounted back to front. I wonder if Wheelz followed this and maybe the shoes are not correctly seated and cause the judder?
Someone mentioned worn wheel bearing maybe a cause, I would have thought they would have to be dangerously worn to cause judder, a good reason for annual MOT tests to keep dangerous cars off the road.
I would agree with you that changing disks and pads would be the first approach, badly fitted disks can cause judder and the only cure is replacement.

Thanks Koy, when i looked on you tube there were not many and one actually showed the adjusters being put back the wrong way !!! If they are back to front it will cause issues though not sure brake judder would be one of them. if the vibration is through the steering wheel then definately front discs and pads imo.

[Wheelz]

. if the vibration is through the steering wheel then definately front discs and pads imo.

In my case there is no vibration felt through the steering but I will probably still change the discs. And as for the rear brakes I did initially get confused and assembled the adjuster the wrong way, because that is how they were already, but I soon found that was wrong and so its now all correct and working well.

[mole42]

When I had front brake judder it turned out to be a worn wishbone which allowed the bottom ball joint to rattle. The MOT garage diagnosed a worn bottom ball joint, but replacing it didn’t fix the problem. I did a little more examination and found that the part of the wishbone that houses the ball joint had worn so the ball joint was loose in it - a replacement wishbone solved that as well as fixing the brake judder.

[KOY 23]

Thanks Koy, when i looked on you tube there were not many and one actually showed the adjusters being put back the wrong way !!! If they are back to front it will cause issues though not sure brake judder would be one of them. if the vibration is through the steering wheel then definately front discs and pads imo.

Hi Chris 01573
Just searched on YouTube and found the offending video. Oh the irony
Amazing that the video has not been edited to correct the misinformation.

[richardthestag]

I saw that video too John.

makes you wonder

[MandM]

I have seen when a disc that has been mounted to a dirty hub (disc contact surface) , this has caused run out and wobble. some people don't take enough care in this area!

ps

The end float on the rear bearings is 0.002"-0.005", which at the wheel dia of 14 inches is more than you would think, the MOT man does not always like or understand this if one of you is good at maths you could work out how much that is

[DZP]

Hi Chris,
I would say that generally speaking then:-
Vibration though the steering is worn suspension or wheel wobble caused by wheel balancing.
Vibration though the brake pedal is usually the brakes disks or drums.
It sounds like you have checked the front disks quite extensively, so take a look at the drums.
I have seen some really oval drums in my time, the giveaway is difficulty in getting the drum off, sticking as you rotate the wheel and difficulty in adjusting the handbrake and brakes to get a full pedal.
A simple test for the rear drums is to find a straight piece of quiet road and gently apply the handbrake. If the rear drums are out-of-true you will feel a gentle pulsing on the handbrake lever.
I hope that helps,
Den