Post Number: 464
|Posted on Monday, 09 October, 2017 - 07:12 am: |
When braking for the first couple of miles from cold, there is a very slight brake judder from the N/S/F wheel I am fairly sure. As the journey progresses this judder gets very much worse, and at low speed gentle braking, the pulsing can be felt distinctly. This has got worse over the last 500 miles. I have checked wheel bearing adjustment an disc run out with a DTI. Brake pads are 50% , genuine and there is no contamination. Hot spots on the disc or distortion only when hot have been suggested. Any thoughts welcome.
Post Number: 1889
|Posted on Monday, 09 October, 2017 - 07:56 am: |
It sounds like the surface of the discs have been damaged.
Most often by sitting for a long time or possibly washing the wheels, getting the pads wet and then leaving it parked.
If you spin the disk and shine a light on the disk at about 45 degrees and watch the reflection you may see deeper embedded marks that are not noticeable looking straight at it.
Chat up your local MOT station and get them to put it on the brake tester and apply the brakes slowly and watch for pulses.
If this is the problem and there is enough thickness left we would do a light on the car disk skim.
Post Number: 1550
|Posted on Monday, 09 October, 2017 - 08:03 am: |
Or wheel balance or tyre run out if the car has been stood in one position for weeks.
Post Number: 2686
|Posted on Monday, 09 October, 2017 - 03:03 pm: |
Check for tyre tread delamination especially if the tyres are past "middle age" - just feel for bulging on the tread while you rotate the jacked up wheel.
A give-away can be a faster-than-normal loss of tyre pressure if the tread is aged and cracking. The pressure build-up as the tyres heat up can accelerate the bulging which then decreases when the car is stationary and the tyre cools down.
Post Number: 187
|Posted on Monday, 09 October, 2017 - 07:09 pm: |
Mine did this very thing, I was convinced (?) it had a warped disc and tried to get them skimmed - even offering to buy the adaptors required to fit our cars for one specialist, they refused! Anyway, after more use, it simply went away of its own accord! I knew the braking system was in good order (it was all bloody new!) just an annoying vibration above certain speeds. I suspected it was just pad contamination from washing the car and then leaving it for weeks unused but my hated brain would not shut up.
It is most likely, pad contamination and if you are near Paul, then go get them on the car skimmed.
Post Number: 465
|Posted on Wednesday, 11 October, 2017 - 06:14 am: |
Thanks for the suggestions, I will have the wheels off again when work subsides and get the discs skimmed if all else fails ( the biggest pain is removing the calliper bolts without snapping them).Once they are off the car, my son can skim them.Unfortunately Paul is rather a long way from me.
Post Number: 45
|Posted on Thursday, 12 October, 2017 - 04:10 pm: |
Hello Mark....perhaps you would also like to check the condition of your upper and lower ball joints.
Is the pulsing felt through your braking foot?
Post Number: 9
|Posted on Tuesday, 21 November, 2017 - 09:06 pm: |
The pins that hold the pads in place can be worn and need to be replaced after time .This is hopeful answer but worth checking as pads can move around .More than likely imperfections in Rotors.
Post Number: 473
|Posted on Tuesday, 21 November, 2017 - 11:47 pm: |
Car is presently at Colbrooks in Stilton having Discs,genuine Crewe pads and Accumulators changed, as due to business commitments I don't have time to play with it myself at present. The surging showed very clearly when I put the front brakes on a roller tester.
Post Number: 114
|Posted on Wednesday, 22 November, 2017 - 07:52 pm: |
If your nitrogen is depleted cam brake pump pulses can be felt via the brakes at half engine speed. Do the pump down test etc
Post Number: 476
|Posted on Thursday, 23 November, 2017 - 02:23 am: |
Just collected the car, new discs have completely cured the problem and pressure reserves are restored. Excellent job.
Post Number: 105
|Posted on Thursday, 23 November, 2017 - 11:52 am: |
Mark...good to hear...it's usually the simplest things that are the root cause.
Post Number: 17
|Posted on Monday, 11 December, 2017 - 11:29 am: |
I had the same problem. I had the disc's machined and fitted new pads and all is good now. Incidentally I got the pads, complete kit from IntroCar. Very good service and quick delivery to Australia