D

damlimey

New Member
Hi all,

Time to pick your brains on the subject of juddering which occurs on application of brakes. It is quite severe when braking from 60-50mph and not so bad 40-30mph etc. The vibration comes up through the steering column.

This began before a recently scheduled replacement of discs and pads to both front and rear. The problem seemed to resolve itself after the replacements but it has crept up again in just under 1000 miles. I think I can rule out a distorted disc on these grounds.

A previous thread did mention the pads slipping against the clip springs and I haven't checked for that as I wouldn't know how. Another thread mentions stuck calipers. Bearings, shocks and springs etc all seem good.

Any suggestions on how I should proceed?

As a second related question; since the removal of asbestos in brake pads, am I the only one who thinks the variation in pad quality has increased?

Anyone recommend a particular pad?

Ta in advance,

D
 
No reason to discount a warped disc, heavy application when new can easily result in warping.
EBC for quality pads, Mintex are cheaper.
 
Hi Datatek,

Thanks for the quick reply. So I could have warped the new discs already? Never thought of that!

Is there a non standard disc that doesn't warp so easily?

Thanks for the EBC tip.

D
 
Some discs can warp if not OEM spec.
Only ever changed discs once the cheap way, lasted few hundred miles, replaced with OEM spec. done 15K since no problem. (BMW still in the family)
 
Okay, accepting that I've managed to warp my new discs 'cause I bought badly and braked too firmly, I'm now wondering how not to warp the next set.

Should I go for the EBC vented type discs and EBC pads?

D
 
Standard discs and standard pads are fine. On fitting new pads and discs no harsh braking for first 250 miles unless an emergency.
 
As said, standard discs & pads are fine, just be gentle with the brakes for the first 250+ miles. EBC are good but expensive.
 
Whats your braking style like?

The likelyhood is discs may not be warped...stay with me...

As the majority of these are auto a lot of people will tend to rest their foot on the brake pedal when at junctions or in traffic. After heavy stops such as down hill, motorways, emergency stops (+binding pads/siezed calipers) the pads and discs will become hot. As the material on the pads heat it leaves a layer on the disc. If after a heavy stop you come to a busy junction and rest your foot on the brake pedal the hot pad sticks to the disc causing a hot spot. This transfer spot is then difficult to remove under normal braking and would require "high temp bedding" at the risk of warping cheaper discs.

This hotspot can cause the thickness variation on the surface of the disc, whether you have quality discs or cheapy discs. I found this out after replacing my front with Brembo and 500 miles later the juddering returned as before. On the disc there was a high temp glaze and a very distinct pad mark where it had stuck. Replacing them again the juddering went away.

Now I stop on the handbrake and haven't had issues since. Brakes are small for a heavy machine so I reckon under normal use they get hot anyway.
 
Check for disc run out and disc thickness in several places

If the problem went when new brakes etc fitted and then returned I would expect it to be the parts that where change asking as all the.other components are straight and true

If.you really want to find out which particular disc it is there is a way but it is highly danger.and not advisable unless.you know what.you.are doing

I can explain if you wish to find out what disc.it could be
 
Thanks guys,

It looks like I'm going to have to swap out the front discs and bed them in gently!

It's strange that I've been driving vehicles with front discs for three decades and it's only in the last couple of months that I've heard anything about warping discs.

Everything I've read here or heard elsewhere keeps coming back to that very diagnosis though so thanks all...

Anyone want a pair of nearly new front discs? Going cheap? May make good door stops.

G
 
Thanks for all this guys,

It all makes sense so I guess I'm going to be buying yet more discs! At least swapping them out will be quicker this time!

D
 
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