Vibrations under braking, before and after KADs

[Beastlee]

As many of you know I upgraded my brakes to KAD because I was fed up of the brakes fading. The old brakes gave heavy vibration under braking as well which had led me to belive I had disc issues.
Having fitted the original KADs and still getting vibration I had assumed an issue with the second-hand discs which had been tracked. After replacing them discs it was still the same and I also found out I needed new calipers. I have now replaced everything replaced I still suffer the vibrations. I can now only determine that the vibration is not actually my brakes.
I've checked for bearing issues and play in the joints and I have new lateral and curved arms to fit I do have bad wear on the inside edge of the driver's side tyre with the same but to a lesser extent on the passenger side.
Can anyone suggest anything? I'm guessing the vibrations could be due to bad tracking which will be done straight after I fit the arms.

I tell you, my car must be worth £10k the amount I seem to be spending on it. I think I'm at about £100/mile in the last 6 months!

[Gly]

wheel balance/alignment

i had vibration issues when i lowered the vr, and changed a rack end.
that and the tires were stuffed


new tires, balance and alignment, sorted

[Beastlee]

Carsten,
prior to fitting the new brakes, but after the wobbling started, I replaced the wheels with brand-new Rota Torques and Eagle F1s. Everything was balanced but I didn't get the tracking done as the old tyres were not showing signs of uneven wear. The wobble was still present but not to the same extent.
As far as I am aware the car is not lowered but the suspension is quite firm, much firmer than the previous car. It's still comfortable but on the autbahns it causes a little too much undulation for my passengers LOL

Once I get eh new arms on I'll get both the tracking and balancing re-done. I'm also going to rotate the wheels again as unfortunately I've never done it. In reality I don't want either of the front tyres to remain on the front as they will continue to wear unevenly.

[Gly]

yep id take it in for a check, asap

doesn't take much to screw up the handling.

you say you changed everything brakes wise, does this include pads??

[HJM]

I never had any problem with vibrations from tracking those brakes - they were always spot on red hot or stone cold

Good luck sorting a fix.

H

[Beastlee]

Front has had new wheels tyres, calipers (twice), pads (twice), discs(twice), hoses, brake bells, fluid (three or four times), caliper mountings (twice) and all associated bolts. At least one side had a new wheel bearing just before I bought it too, I just can't tell which it was and it's not a handed part.

I'm sure the vibration is on the driver's side which is where the wear is worst. Hopefully getting the tracking done will sort it.

[Roberto]

One idea from left field.

Any chance the ABS is acting up.
Maybe pulseing only one wheel???

Just throwing then thought out there.

[Beastlee]

Roberto, thanks for the suggestion. I have run Evoscan on the car with the ABS selected and no DTCs were flagged, they aren't coming up on the dash either when tested. Everything seems to be functioning correctly but I can take another look at it tonight.

[White Lightning]

Tracking and balancing do definately sound like the next things to check out, Lee.

Have you checked to make sure there is no play in either of the front wheels in case there is a bearing on it's way out?

[Davezj]

here is a possible try and it cost nothing to check and fix.

take the wheel off and check the disk bell for flatness (e.g. no rust uneven paint, bumps in the metal) as this would cause the wheel to not sit correctly on the disk and cause wobble.
check also the disk to hub mating surface for the same, this would cause wobble on the brakes.
i know you said you have got lots of new parts but it might be worth checking them all the same.

one other thing is did you do the correct bedding procedure when changing the disk and pads. i believe this can cause problems if you don't do it properly. the sort of 60mph to 20mph slow downs repated many time there should be a procedure on the manufactures web site the do differ though for manufacturer to manufacturer.

[Beastlee]

Wayne, yep, tried that three times yesterday just to make sure I wasn't doing it wrong. All seems sound there, doesn't budge at all and is smooth spinning by hand but I'd like to find out which one was changed in July 07.

Dave, I have checked the outer surface but you may well be right with the mating of the floating bell to the hub. I did clean them before fitting the new ones but there may still be an issue, I'll check that tonight. I did the bedidng in correctly and gave it some good hard stops from high speed. There may have been issues due to the first set of KAD calipers being faulty but as this has been so persistant I would think it's unlikely.

I'll do a few other checks whilst I'm under there but I'm almost certain that it's a tracking issue. It's the only thing that hasn't be done throughout my ownership of the car. If it wasn't so expensive I'd get it checked now before I do the arms or at least get the lateral arms done then test it. I'll be blowed if I'm getting it done twice for the sake of a week waiting for the curved arms to arrive!

I'm just getting frustrated because I've spent so much already but the car still isn't quite right. I've exhausted (excuse the pun) my savings and I still need to get a complete cat-back exhaust! I have two rather large holes in the standard one right now. Add to that I need spark plugs to complete the service items and a few other bits. Grrr.

[Beastlee]

OK, I did the all the front arms the other day including the two new lateral ones. So far the outlook is good, there's no clunk on bumps turning left and the wobble doesn't appear to be present when braking. Haven't fully tested it yet as there's another 2" of snow on the ground.
One quick Q for those that have changed the arms, the workshop is slightly higher than the road surface outside and as the front dropped off there was a single loud clunk, nothing after that, anything I should worry about?

[steelie600]

i missed this before but judder when braking is mainly discs warped followed by lower ball joints, followed by bearings (order of popularity)

[Beastlee]

Kev, it definitely wasn't the discs as this has been present with 3 sets, one of which were brand new.
Looks like lower ball joints (driver's side in particular, also had bad inner edge wear on the tyre) were the cause but it is still possible it's a wheel bearing. One side has been replaced already but I don't know which. Both sides felt solid when attempting to feel for play and there is no tell-tale rumble when driving.
Interestingly enough there was no play to be felt in any of the ball-joints of the removed parts but it definitely felt tighter on the way home.
Will be booking in for the tracking and wheel balancing to be done this week.

[taupodrifta]

I had the same issue when I replcaed my front pads and discs took it to a brake specialist to find the new disks needed skimming also he had to skim my hub surface slightly as it was out of allignment

[stuartturbo]

don't ignore the rear wheel
I have had a similar on the old womans fiesta. I swore it was a front axel issue done similar thing disks swapped side balanced etc. I had a rear wheel knackered

[peter thomson]

I often have a clunk after the car has been in the air

[Beastlee]

Why can't the German workshop employees just do what you ask of them? I took the car down for tracking and they tell me that they won't do it becuase the tyres are already too badly worn. I asked them to just check and see how bad the tracking is but they still refused, only willing to do it with new tyres on. As I see it if the values were excessively out then it would be clearly a tracking issue wheras if they are even remotely near the expected values it could be something else.
As it happens they want 480€ (that's tax free) for 4 replacement tyres. The rears have only done about 6000 miles and are still perfect! Oh and they could get me a set of part worns but expect to wait 1-2 months for them!

I really don't know where to go from here as they insisit that the balancing and/or tracking will not be affecting the braking. I'm just completely fed up with it now, I wish I had never even conidered the KADs.

[Beastlee]

Tracking done, total toe was -0o04' with +0o04' and -0o08'
Now it's total +0o00' but +0o02' and -0o02'

Not sure I'm happy with the 0o02' readings but when I was watiching it was dead on and I'm not sure how bad 2 rads would be.


Have now determined I still have a knock turning left over uneven surfaces and the wobble is still there. That's with the orignal rear wheels on the front too so I can only assume it's either an upper joint or one of the shocks/springs. This is getting beyond a joke now.

[raph]

^^^KAD caliper hitting something on full lock?^^ like touching the track rod?

wobble coming from shot discs/stuffed rear caliper?