Menu toggle

Brake judder problem

P

Paul Fraser

New member
OK, bear with me on this one.

Car failed MOT today because of (among one or two others): "offisde front brake juddering severely" (this giving a 36% imbalance). Examiner said that the disc was warped/corroded.
Got home, wheel off, caliper off, looked at the disc, gave it a spin and it seemed fine to me: no particular corrosion other than some pitting/edging and it didn't seem to be warped (looked fine from above, spinning).
Tried freeing off the caliper, as I thought this might be the problem, also put new brake pad pins in (too let them move freely if required, old ones were rusted) and also greased the grooves the floating part of the caliper move on.
Out for a spin and there is still marked judder braking from 70 to 60 and at maximum braking the left hand wheel locks up and the right hand one doesn't.

Now... have new discs and pads I can fit and will happily do so, but is there anything else that could be causing this before I do, rubber brake hose for instance?
Thanks.
P.S. Advisory for slight play in steering rack.
 
yes I would check the track rod end for play and especially check the other end of the track arm where it joins the rack inside the gaitor. I would bet a fiver your problem lies at the rack to rod arm swivel joint.
you will need to use considerable force to find the play like a long iron break out bar .

Get someone to turn the wheel back and forth whilst you put your hand on the trackrod arm see if you can` feel 'the play
 
I'll have a look at this at the weekend -- would the tester not have picked this up when he was looking at the steering rack, though? And why is it brake related rather than say, speed or turning related..?
 
the tester in a MOT station cannot really replicate driving at 50mph and braking sharply in the workshop. Any movement in any part of the steering or suspension will move under heavy breaking due to the enormous forces acting on the entire system.

judder occurs because that small movemenat there sets up an occilation which rapidly increases. We feel it at the steering wheel and because it only happens when we brake we assume that it is to do with the braking system.
It is possible that you have a loose wheel bearing or the there is something wrong with the braking system more likely to be the suspension strut fixings or wishbone inserts or bottom ball joint worn but my money is still with the steering rack/track arms joint .
 
I hate to get too technical, as this may not be the case, but from memery your brake lines are all conected through the same master cylinder this is maybe model specific, do-not rule out a problem with the rear brakes when looking at pulling, judder or weakness as everything is connected through your hydralic lines i have had problems with judder at 60mph badly through the streeing NOT under braking and it` been a sticking handbrake cable, keep your options open chek all your braking system you may have a rear brake caliper binding or alike.... i hope this helps good luck...
 
Ok, had a look at this yesterday.
Needed to replace the offside gaiter so unscrewed the track rod arm. While I was doing this noticed that there was a couple of mm play at the track rod ball joint. The track rod end seemed to be solid, but I couldn't work out a way to putting any load on it really. Had also noticed a bit of wheel bearing play when the wheel was off. Thought this might be the problem so tightened it up a bit. Test drive still gave me the problem.
Next, freed off the caliper (second time, it seems to be moving fine, as is the floating part). Replaced the front disc and brake pads. Test drive showed problem was cured so it was the disc or disc/pad combination. Bit surprised actually, as I've said already the disc didn't look that bad compared with some I've taken off cars :) Must have been on for some time though as the bolts holding the hub to the disc were surrounded by heavy corrosion. Fearing a problem with rounding the bolt heads I cleaned the area with a drill driven wire brush, heated them with my propane burner, WD40ed them and then used a small breaker bar to shock load them into cracking. Worked out fine actually.
I find with jobs like these I never seem to remember to order the small niff naff bits like bolts and nuts and washers which make the job easier -- you don't have to worry about rounding bolts or stripping threads etc. To my credit I did have a set of brake pad springs, pins and brake warning cables lying in the box.
Shouldn't count my chickens though as I have the other side to do today. :(
Thanks to you all for your suggestions.
 
well done . glad you seem to have found the cause.
Don't do as I did though and shoot off down my drive and find I had zero brakes at the bottom. narrowly missed my neighbours car .It takes a few pumps and a bit of use before the pads bite properly. That episode certainly woke me up I can tell you[:D]
 
You must log in or register to reply here.

Posts made and opinions expressed are those of the individual forum members

Use of the Forum is subject to the Terms and Conditions

Disclaimer

The opinions expressed on this site are not necessarily those of the Club, who shall have no liability in respect of them or the accuracy of the content. The Club assumes no responsibility for any effects arising from errors or omissions.

Porsche Club Great Britain gives no warranties, guarantees or assurances and makes no representations or recommendations regarding any goods or services advertised on this site. It is the responsibility of visitors to satisfy themselves that goods and/or services supplied by any advertiser are bona fide and in no instance can the Porsche Club Great Britain be held responsible.

When responding to advertisements please ensure that you satisfy yourself of any applicable call charges on numbers not prefixed by usual "landline" STD Codes. Information can be obtained from the operator or the white pages. Before giving out ANY information regarding cars, or any other items for sale, please satisfy yourself that any potential purchaser is bona fide.

Directors of the Board of Porsche Club GB, Club Office Staff, Register Secretaries and Regional Organisers are often requested by Club members to provide information on matters connected with their cars and other matters referred to in the Club Rules. Such information, advice and assistance provided by such persons is given in good faith and is based on the personal experience and knowledge of the individual concerned.

Neither Porsche Club GB, nor any of the aforementioned, shall be under any liability in respect of any such information, advice or assistance given to members. Members are advised to consult qualified specialists for information, advice and assistance on matters connected with their cars at all times.

Porsche
Lockton
Pirelli
Officially approved
Oracle Finance
WEX Esso
Collecting Cars
Archant Dialogue
Back
Top