Steering Shaking under breaking

Under light to medium breaking I'm getting rather a large amount of vibration / shaking throught the steering wheel
Is this common and normal? Or does perhaps my tracking have an effect on this?

Going to get tracing sort on the weekend but untill then wondering if anyone has any other suggestions or is this usual?

David

Warped discs??

MarkyMark wrote:

Warped discs??

Almost certainly!

If it was under all conditions (i.e. not only under braking) I would suggest wheel balancing / alignment.

This is due to uneven transfer of pad material on discs...

Mostly a problem of improper bedding in procedure... but also, this happens over time on an FRP when using 'track' pads and not driving the brakes hard enough... the alcons do take a lot of warming up...once they are bedded in properly you still need to drive the car hard now and again and give the brakes a real good spanking to keep them working and more to the point...coated evenly... this is the key..

I'd remove the discs...scrub the hub flanges, scrub the discs with Garnet paper... clean off with brake fluid... and ideally, re-bed with a NEW set of pads... if you re-use the old pads, scrub them down too vigorously with Garnet paper also....

then re-bed more carefully...

Regards

Chris
453

New front discs and pads

El dude wrote:

I'd remove the discs...scrub the hub flanges, scrub the discs with Garnet paper... clean off with brake fluid... and ideally, re-bed with a NEW set of pads... if you re-use the old pads, scrub them down too vigorously with Garnet paper also....

this is what we're about to do with Phoebs.... I pretty much constantly have problems with juddering under braking. We think it's down to the fact that she isn't driven much (maybe 3000 miles a year) but when she IS driven it tends to be at meets etc so the driving can be quite hard, lol.... the disks get 'very' cold cos she sits on the drive most of the time, then 'very' hot if driven at a meet... and then the disks warp! I've had mine skimmed twice now and it did solve the problem, albeit it a temporary fix. So... going to be looking for new pads in the next week or so, and then it's over to Dunk to do the oily / dusty / dirty work

If that doesn't fix it, new disks will be on the shopping list....

thanks for the info all.

Think I've just found out what I'm doing over this bank holiday then

Disks and pads are pretty new and loads left on them so I'll be trying what Chris suggested (thanks for the info)

Recieved my 12" x 3" reg plate today so I'll upload some photos on Saturday night and you can let me k ow what you think
David

PussCat wrote:

El dude wrote:

the disks get 'very' cold cos she sits on the drive most of the time, then 'very' hot if driven at a meet... and then the disks warp! I've had mine skimmed twice now and it did solve the problem, albeit it a temporary fix. So...

Just to clarify again... the judder you feel is not 'warping' of the disc... this is ALWAYS a mis-diagnosis... and sadly mechanics still widely use this mis-diagnosis too...

Its the uneven layer of pad material transfered to the disc.... actually warping an alcon disc i woud think would be extremely unlikely!...

If the judder is severe and has been on-going for a while it may be difficult to cure with a new skim..however... iv'e experienced the same judder early on in my FRP days.. and always managed to recify it without the need for being ripped off with a £100 skim..(mentioning no mames.. ) Skimming the disc and not changing driving habits will only see a quick return of the problem....

I recommend every FRP have a good read here... http://www.stoptech.com/tech_info/wp_wa ... disk.shtml this gave me some great advice and ideas years ago... and putting some of these in practice really has worked...

My 'basic' explanation of how i bed in the brakes is this...

Warm up the setup gradually doing 60-10mph stops...not hard braking but enough to give the discs a firm even contact of pad!

When warmed up, the pads should now START to transmit material to the disc in a uniform fashion....this is the important bit..

Then i take the car to high speed 80+ lol and brake long and hard down to 5mph...as the car slows ...press harder and harder to give the discs and proper good scrub round... do this a couple of times till the discs are really quite hot (FAR too hot to touch ideally...lol)

now take a steady drive back home...your done...

once thats been done a couple of times...an ocassional enthusiastic drive is all that is need to keep them tip top... it's all about getting it right from the start thats the key....just make sure it's on a dry day on a good quality road surface as you don't want ABS intervention ideally... ....always in a dead straight line too

Also, patience is needed with immature pads.... not to drive them too hard on the first bedding in session.... but don't be afraid of them smelling...thats a perfectly normal proccess of the moulding resins burning off... keep going... The best way and easiest BY FAR of bedding in new discs is to use a matured pad...maybe several weeks old for example.... that way, you can go straight into bedding as enthusiastic as you like.... all this is explained in the link.....iv'e tried it all... and it does work for sure....

Regards

Chris

[lisafrp]

Nice in-depth info Chris - thanks

[W4FRP]

Great info Chris - mine is doing the judder thing so I will clean them up and follow your advice - many thanks

No probs...

I remember in the first year or two... this topic would be cropping up on a weekly basis..

I think the more 'track orientated' the pad is, the more difficult it is to keep at optimal performance when only using the car as a road car.....

after saying that, i drove Vas's car last year after doing his brakes... and it really put a smile on my face how good the oem setup is...

Chris

Thanks again Chris looks as tho the car will be getting a little bit of use / abuse this weekend

David

answer to davids question get your tires balanced and tracked that usually fixes the jugder front ones usually rear ones shouldnt make a differance.

Thanks for the info Chris. Having a similar problem so will use your sound advice.