Technical warped discs

Currently reading:
Technical warped discs

Joined
Dec 29, 2009
Messages
377
Points
167
Location
bradford
Hello folks, I've got a 2004 1.2 8v panda that suffers fromwarped discs that judder under braking. It has been a problem for some timenow. I have gone through 3 sets of discs in 30k over the past 2 years. I’ve hadthem skimmed around a year ago but still have problems and they are getting worse.



Also over the past few months, under moderate breaking thecar pulls to the left. I have examined the callipers and have decided they needto be renewed.



I was just wondering if there could also potentially be aproblem with front hubs causing excessive run-out, as the discs have beenwarped before it started pulling to the left.



I’ve always thoroughly cleaned the hub flange surface beforeinstalling the discs.



If the hubs are at fault is it possible just to replace the hub flange as opposed to the wheel bearing as well?



Many thanks, Adam
 
I had a FIAT Coupe that constantly suffered from warped discs. The problem was down to long hard braking and leaving foot on the pedal. (Traffic lights / junctions..) The heat build up on pads / calipers caused excessive heat on one side of the disc. Conscious of this now and tend to come off the pedal after stopping.
 
As Gilbie says, keeping foot on brake with hot discs will lead to warping. "When a pause becomes a wait, use the handbrake." So assess your technique.

If they were skimmed on the car, that would have trued any run-out of the hubs. Sticking calipers can cause discs to run hot, so that may be a cause.

1. Check run-out of the hubs, then the discs. Run out does not cause judder directly, as the caliper moves with the disc. But the run-out causes certain points to keep rubbing the pads, leading to localised heating. This then leads to uneven wear, or heat distortion, causing a thickness variation, which causes the judder. Run-out will push the pads further back than normal, leading to longer pedal travel to apply the brakes.

2. Measure the thickness of the discs at 4 points or more. A variation in thickness will cause judder.

3. Ensure all caliper pistons move easily.

4. Use a good brand name pad.

5. Brake over longer distances, but lightly, release pedal once stopped.
 
I would say more likely a sticky caliper or two. A 1.2 isn't going to heat up the brakes to the point where holding the car on the brakes for a while is going to warp the discs. What brand of pads and discs are you using?

Brembo's can be had from nextdaybrakes for only 45 pounds or so, I've had 41k out of mine so far and still about 50% of the pads and brakes left :)
 
I would say more likely a sticky caliper or two. A 1.2 isn't going to heat up the brakes to the point where holding the car on the brakes for a while is going to warp the discs.
:yeahthat:

If you can get the brakes hot enough to warp the discs on a 1.2 Panda, please never, ever drive anywhere near me or anyone I know haha :p. A sticking caliper does sound more likely, and is still a relatively easy fix.
 
They must smell terrible. Surely you must get the smell of burning brakes when you get out of the car?

I'd say sticking calipers are to blame too.
 
Thanks for all the replies!


The latest set of pads and discs I have been using are EBC.


I have learned that long hard braking and holding your foot on the brakes at lights is bad, every time I come to a stop I put the handbrake. I always use the gears to slow down too.


I've got a 2012 panda which I drive exactly the same and have no problems with the discs!


Considering they've already been skimmed once, they should have checked the hubs, but its worth while checking them again.


What I have noticed is, firstly, the juddering is more pronounced when the brakes are warmer. Also, when I first installed the discs, they were fine for a couple of weeks, that's when the juddering started.


As for the callipers, on the left hand side, the rubber boot on the slider pin has a spilt, no doubt letting dirt in. The right hand side calliper, isn't as free as I'd like. This must be why the car is pulling to the left under braking.
 
Read this post - the 1.2 Panda brakes are almost identical to the 1.2 500's.

It's more likely that one of the pads has seized in the reaction frames than the sliding caliper bolt has seized, though if the caliper bolt's rubber boot has split, then the caliper may also seize on the bolt and it should either be dismantled, cleaned and the boot replaced (if you can source one separately) or a new caliper fitted.

Either way, if the braking force is not distributed approximately equally across both pads, rapid, uneven pad wear and disc warping will likely occur.

Strip the brakes, repair or replace what's worn or seized, and clean & lubricate what needs to be cleaned & lubricated.

Properly lubricated (this isn't done on new cars in the factory), the 1.2 500/Panda brakes will give many thousands of miles of trouble free service.

If assembled dry and used in the UK, one decent winter will quite likely ruin them.

3 sets of discs in 30000 miles is a sure sign of an underlying problem that hasn't been fixed.
 
Last edited:
Back
Top