Vibration when braking

[jot_ie]

Getting a fairly sever vibration/judder when braking
I am presuming this means the discs are warped?
Its just got new front pads last week

John

[GeordieBoyKel]

How much of a lip do your discs have?

[Pete]

How much of a lip do your discs have?
Whoever installed the pads ought to have noticed if the discs needed doing too as it's a waste of time fitting the pads otherwise.

[jot_ie]

lip not too big
but then again to be honest I wouldnt know what constitutes a big lip :blink:
maybe about 0.5-1mm

The guy that put the pads on said nothing at all about the discs. And he is very good. Sorted my suspension problem quite quickly.:)

If its not the discs causing the vibrations in the steering, what could it be?
Really only seems to happen under braking.

John

[Ian C]

Oh, it'll be the discs I'd think. The lip is irrelevant really, they are warped. You need a caliper gauge to measure the runout on them, you'll probably find one quarter of the disk is wider than the rest of it, and that's what causes the judder.

-Ian

[absxxxx]

normally with warped disc's you can feel vibrations through the brake pedal, check to make sure the pads and calipers are secure as i tke it this only started after new pads were fitted.:rolleyes:

[Nic]

A knackered wheel bearing will also cause vibration when braking, can you feel which side the vibration is coming from? Jack car up, support on axle stands and see if there is any side to side play in the wheel.

Nearside bearings are usually the ones to go first, due to curbing.

[Need4Speed]

Most likely warped discs. They don't have to be old to warp, I warped mine when they were 1 week old. You can't see a warp.

[MizTheWiz]

had the same thing replaced front discs all good now..................:)

[SkyJawa]

Yeah - if you have new pads fitted - especially uprated and don't bed them in properly its well easy to warp the discs.........

[andrew7]

If your discs are still quite meaty you can have them skimmed on the car to rectify the problem.
So called "warped disc" are usually just friction material buildup on the disc. This can be made worst by the tendency to sit on the brake whilst stationary after a couple of heavy uses of the brakes (hot). The friction material burns on to the disc and provides a platform for exaggerated buildup.
Nearly all the main dealers have an on car disc skimming machine (Pro Cut is the best) purely for sorting these kinds of problems.
Toyota Bristol quoted me £135 to skim all four discs last year, so it is a big saving on disc replacement and labour costs..and if you only need the fronts doing it isn't too bad.. :)

[b'have]

If your discs are still quite meaty you can have them skimmed on the car to rectify the problem.
So called "warped disc" are usually just friction material buildup on the disc. This can be made worst by the tendency to sit on the brake whilst stationary after a couple of heavy uses of the brakes (hot). The friction material burns on to the disc and provides a platform for exaggerated buildup.
Nearly all the main dealers have an on car disc skimming machine (Pro Cut is the best) purely for sorting these kinds of problems.
Toyota Bristol quoted me £135 to skim all four discs last year, so it is a big saving on disc replacement and labour costs..and if you only need the fronts doing it isn't too bad.. :)


Thats interesting, always wondered why people don't do this. I've replaced my front discs three times now through warping (usually after track days) but there is always no visible sign of wear.
Anyone know how much material can be removed from a stock disc? My runout was fairly small so guess a re-cut might be feasable?

[andrew7]

There you go. Your discs get hot on track days eh?.....
Even if you fit brand new discs you can get runout due to mismatch between the disc and hub, which is why the main dealers keep the on car lathes. The lathe will work to a tighter tolerance than the disc is manufactured to.....

[jot_ie]

Going to have a look into getting them skimmed
Other than that, its new discs.

the vibrations really only started since I got the suspension adjusted and the new pads on. They are standard toyota ones.
The harder I press the brake pedal the stronger the steering vibrates..

Its got the uk spec bigger brakes as well, apparently fitted as standard, or maybe they were an option on the vvti's

If I need to replace the discs , are the aftermarket drilled/slotted ones better, i.e. brembos. Or is it better to stick with stock.
I dont forsee any track days.
John

[Nic]

Best to stick with genuine stock Toyota discs, unless you want to spend big money on a set of 2 piece discs such as the Project Mu or Endless ones pictured.

http://img159.imageshack.us/img159/5075/scrproslitfs2mx.jpg (http://imageshack.us)
http://img164.imageshack.us/img164/6167/rotorracing13dx.jpg (http://imageshack.us)