Steering judder

[espritmania]

Hi has any body had this before.I seem to be getting a judder through the steering wheel on braking at speed.Also I get a judder on the motorways when traveling at a constant speed.( the wheels have been balanced)

Any help appreciated ,cheers Paul G.

[andydclements]

I still have to sort the former on the S3, although it only occurs when instigated by hard braking.

Assuming they're both the same problem on your car (please tell us if the symptoms started at completely different times), I'd guess wheel bearings not correctly tightened or on the way out.

[Sparky]

Runout on the front discs.

[FRANTIC FRANC]

I had a really bad steering wheel wobble, especially on breaking.

I found the front disks to be warped - so bought a new set from SJ's (not cheap!) and it has been perfect ever since.

[andydclements]

I was thinking discs, but so bad that it impacts wheel stability at high speed? that's a heck of a lot of run-out.

[Sparky]

Yeah, seen it a few times. It can get really violent!

[andydclements]

You should take my S3 out, take it to the 70 limit, and brake hard. If you have any dental fillings that are not 100% you need to pre-book an appointment.

It's had discs skimmed, new discs, new bearings, new bushes (twice), discs checked for run-out.

When I next get time to do something on it, there will be a review of the rear braking system as I wonder if a warped rear disc could cause the braking judder to transfer to the fronts and cause me to have misdiagnosed it as front problem. But that's for a different month.

[molemot]

Mine does it too...fine if you brake HARD but the gentle stuff makes the steering oscillate! No run out on the discs, checked that...wheel bearings are new and properly adjusted..no play in the linkage that I can detect..I'm still twiddling with it from time to time when I've nothing more urgent to do!!

[peteyg]

Paul,

If you haven't already, check the REAR wheel balancing. Not being funny but it was the answer to the vibration I've been trying to fix for about 4 years! Changed wheel bearings, steering rack, rebuilt front suspension, brakes, steering u/j, steering column....and a few other things but it was the chuffing rear wheels all along!!!!!

Pete

[espritmania]

Cheers Pete,I will get some new rear tyres this weekend and I will let you know.

[braziers]

have you spun the wheels up to see if your tyres are out of shape ie side wall structure failed ? also check the rears although it seems on the front it can have some wierd effects that make it seem like fronts. just a thought !

[Geeman]

My 'LHD 84 Turbo has a very bad steering judder, braking from any speed.  It had a slight judder before I did the following work, and now its even worse.

New front and rear brake pads

Front wheel bearings re-greased

Both front discs skimmed

New front and rear tyres fitted and balanced.

I checked all the suspension bushes and steering and everything looked and felt good

The car tracks straight and no steering wobble at any speed, except under braking.

I have searched the forum and found similar but not identical cases.  Despite having the front discs skimmed, I am strongly suspecting this is the root cause, out of true discs still, especially after reading a few similar topics.

How sensitive are the cars to the wheel bearing set up?  I am not hearing or feeling anything wrong in the hubs/bearings when turning.  I screwed on the castellated spindle nut to hand tight and a then a bit more then backed it off to the first cotter pin hole.  No play in rocking the wheel top to bottom and spins freely.

Thoughts?

 

[andydclements]

Get a dti on the discs, hubs can distort, dust/rust can get between the surfaces.

[Geeman]

13 hours ago, andydclements said:

Get a dti on the discs, hubs can distort, dust/rust can get between the surfaces.

Thanks Andy.  I'm going to retrace my steps tonight and see if I did anything stupid.

[Geeman]

When I had the discs re-faced, I had them done removed from the hub.  I am hearing I should have had them done with the hub attached.  Anyone concur with this?

[andydclements]

Technically both on and off should get the same result, but only if the hub, bearings etc are all spot-on.On -the-car skimming can eliminate these other potential problems by masking them. Think of a metal car and repainting it, you can paint it but if the surface below is distorted it will be apparent after a nice coat of paint, but if the surface below is fine then the top will be fine.

If the hubs etc are not fine then you may have to have those machined to true.

 

Just because you feel the vibration at the front, don't assume it's front brakes, they do most braking so any pulsing in the pressure system will show there. Check that ALL calipers move freely, all pistons move freely, all discs are free of distortion/ within limits.

 

 

[molemot]

I doubt very much that it is the discs. Change the anti roll bar bushes...this bar also locates the lower link. If the bushes are defective..;and it's difficult to see by inspecting them in situ...then the lower link moves under braking and you get the judder. That's what mine turned out to be; I only found it whilst fitting one of PNM's uprated four pot caliper brake systems. I had changed the bushes before, which is why I hadn't thought of them.

[Geeman]

Just a quick update.  The discs and hubs were re-checked and machined together and this has solved the steering judder under braking. Thanks for everyone's input.

[andydclements]

At least you found it,and it didn't take too long to find and resolve.