Hi all,

 

A few weeks ago I had to make an emergency stop due to a young school boy running into the road whilst I was coming down a steep hill. The car stopped fine, I felt the ABS cut in and the car came to a halt in a straight line without skidding. Ever since then if I brake from high speed, say 50 or 60mph I get a very strong juddering through the steering wheel, I have had a look at the discs (Pagid less than six months old) and can fine nothing wrong, no discoloration or signs of warping as far as I can tell. The brakes have not lost any of their efficiency just judder like mad when braking from high speed.

would love to hear any Ideas.

 

Skoda Octavia VRS MK1 1.8T

 

Thanks in anticipation

 

 

   

Sounds like a warped disc

Warped disks, You can't see the warping by the naked eye.

Pad residue contamination on the discs, which people frequently confuse with warping (because the symptoms are the same).

 

Find a quiet road and do about half a dozen half-G (estimated) brakes from 70 to 30, accelerate hard back to 70 and repeat. Now treat the brakes very gently until they cool back off and do not hold the car on the footbrake when it's stopped. This should burn the contamination off.

Pad residue contamination on the discs, which people frequently confuse with warping (because the symptoms are the same).

Find a quiet road and do about half a dozen half-G (estimated) brakes from 70 to 30, accelerate hard back to 70 and repeat. Now treat the brakes very gently until they cool back off and do not hold the car on the footbrake when it's stopped. This should burn the contamination off.

Great advice. It could be warped discs but this is definitely worth doing before replacing your discs. Also, check if all your suspension bushes are ok as this can cause juddering.

Discs don't just warp after one hard-ish stop.

 

I had an Impreza Turbo once with standard 4-pots. Following any hard braking episode, the steering wheel would wobble/judder on the next few applications of the brakes. Turns out that four of the eight pistons at the front were seizing up. Would be worth checking the piston and sliders on our single-pot calipers.

Discs don't just warp after one hard-ish stop.

 

I had an Impreza Turbo once with standard 4-pots. Following any hard braking episode, the steering wheel would wobble/judder on the next few applications of the brakes. Turns out that four of the eight pistons at the front were seizing up. Would be worth checking the piston and sliders on our single-pot calipers.

Looking at your sig, you're that guy from PPC magazine, yes?

 

My thought on the Pretzel would be that the seized pistons led to uneven pressure across the pad surface, and I don't see that happening with single-pot sliding calipers (it they seize you either get "stuck on" (caliper stuck on slides) or "stuck off" (piston seized in caliper)).

Yep that's me.

 

Here's another suggestion to go with the others. The Caterham had a wobbly steering wheel under moderate braking recently. The pads (DS3000s) were shot and fresh pads eradicated the problem.

You will normally feel warped disc's through the brake pedal when braking hard as well as through the steering wheel. 

It would be worth checking bushes and track rod ends and wheel balance as it is not unknown for balance weights to come off.

Edited 28 November, 201411 yr by ruffday

Unbalanced wheels would cause juddering all the time not just under braking. I've recently had to do all four wheels due to weights coming off. But the car was fine up to certain speeds then it got quite noisy!!

Unbalanced wheels would cause juddering all the time not just under braking.

Not true a wheel out of balance can cause judder at certain speeds and not others.

It can also cause judder when braking hard.

Unbalanced wheels wouldn't just judder under braking. That's what i meant to say. They might judder under braking but at certain speeds you would know that was the problem. Mine was alright up to motorway speeds then it was juddering.

Yep that's me.

 

Here's another suggestion to go with the others. The Caterham had a wobbly steering wheel under moderate braking recently. The pads (DS3000s) were shot and fresh pads eradicated the problem.

Hiya then.

 

I'd agree that shot pads are a possible issue.

Unbalanced wheels would cause juddering all the time not just under braking. I've recently had to do all four wheels due to weights coming off. But the car was fine up to certain speeds then it got quite noisy!!

 

 

Not true a wheel out of balance can cause judder at certain speeds and not others.

It can also cause judder when braking hard.

What you're both saying "sort of" makes sense.

 

IME unbalanced wheels cause vibration through the steering in a certain speed range (or above a certain speed; depends on the size and nature of the imbalance and harmonic frequencies) irrespective of whether you're accelerating, braking, or cruising.

Yeah that's what i meant to say!!

Thanks for all that great info, will take everything on board and get back to you...

Dti Guage on the disc measure the run out any more than 0.02mm than then it's warped also hub's if more than 0.03 mm replace bearing's.