Brake discs keep warping. What could be causing it?

[oneilldom]

2009 C30 2.0D Sport R-design.

When I test drove the car I noticed a fairly rapid shuddering in the steering wheel upon braking. It was very noticeable. It was obvious the break discs had warped at some stage.

Naively I assumed this would've been over a long period of time so I got the garage to change them and went on my merry way. This was in mid-August 2015 when I bought it. They have now warped AGAIN in the space of 4 months.

Braking from high speed is my only real theory as to how they could've become warped but even with that I'd have expected them to last more than four months. Is this common on C30's? What else could be causing it?

Thanks in advance.

[Proghound]

Exactly the same thing happened to me, except that my first set of discs didn't start juddering until I'd had the car a few months. Like you I changed them and then a few months later I was back where I started.

The warp is caused by the discs cooling unevenly. One thing you can do to try and avoid it is to always come off the brake pedal and use the handbrake once you have come to a standstill - especially after a hard stop or a long steep downhill. That way the hot the brake pads are not still directly applied to one section of the disc surface for a long time. It's also known that staying on the brakes at rest can cause material to transfer from the hot pad to the disc and subsequently feel like a warp, because of the extra friction as that section of the disc passes under the pad. But even if you're careful about this (and I am), the warp can still get you.

My mechanic says he sees it most often on cars of any make that have open-spoked wheel designs and relatively large brake discs - his own diesel Audi being another example. His theory is that after braking hard in the wet, water can splash through the spoke gaps when the discs are hot and hey presto, uneven cooling occurs. Unfortunately there's really not much you can do about that if you don't want steel wheels :-/

[JulianT]

Just take them back to the supplier, as long as you changed the pads and disks together they should not do that.

[oragex]

Cheap replacement disks are less rigid and will flex more under wheel lugs torque.

If the disks are of good quality or originals, make sure the caliper sliding pins are sliding easily. They have a rubber bushing that will swell if greased with some random grease. I use silicone synthetic grease on mine, but not sure about more recent models.

If all the above checks fine, there is another possible issue (read video description) related to uneven wheel lugs torque that will cause the brake disk to warp.

[RickT]

MK4 Golf - I had this issue over 12 months 4k miles and 3 sets of discs.

The answer was to replace them with OEM VW discs.

The issue went and after 9k miles never returned

http://www.vwaudiforum.co.uk/forum/s...l-judder/page3

Strange i know as you would expect the 3rd party ones to be fine... but for some reason this car didnt.

[oneilldom]

Originally Posted by Proghound

Exactly the same thing happened to me, except that my first set of discs didn't start juddering until I'd had the car a few months. Like you I changed them and then a few months later I was back where I started.

The warp is caused by the discs cooling unevenly. One thing you can do to try and avoid it is to always come off the brake pedal and use the handbrake once you have come to a standstill - especially after a hard stop or a long steep downhill. That way the hot the brake pads are not still directly applied to one section of the disc surface for a long time. It's also known that staying on the brakes at rest can cause material to transfer from the hot pad to the disc and subsequently feel like a warp, because of the extra friction as that section of the disc passes under the pad. But even if you're careful about this (and I am), the warp can still get you.

My mechanic says he sees it most often on cars of any make that have open-spoked wheel designs and relatively large brake discs - his own diesel Audi being another example. His theory is that after braking hard in the wet, water can splash through the spoke gaps when the discs are hot and hey presto, uneven cooling occurs. Unfortunately there's really not much you can do about that if you don't want steel wheels :-/

Thanks for the heads up. Now I think about it I have heard about the whole braking down a hill and keeping foot on the brake issue causing the warp where the contact is.

Judging by your reply and other replies here it seems it is likely an issue cause by cheaper brand discs/pads and this uneven cooling issue. Tempted to go back to genuine volvo pads/discs now to save re-occurrence.

[oneilldom]

Originally Posted by JulianT

Just take them back to the supplier, as long as you changed the pads and disks together they should not do that.

Wasn't me who changed them unfortunately and the garage I bought from is in Bradford. I'll call them but I suspect it'll be a waste of time, they won't want to know.

[oneilldom]

Originally Posted by oragex

Cheap replacement disks are less rigid and will flex more under wheel lugs torque.

If the disks are of good quality or originals, make sure the caliper sliding pins are sliding easily. They have a rubber bushing that will swell if greased with some random grease. I use silicone synthetic grease on mine, but not sure about more recent models.

If all the above checks fine, there is another possible issue (read video description) related to uneven wheel lugs torque that will cause the brake disk to warp.

Thanks for the video! I will look into it before I do/buy anything else. Thinking of getting them switched back to genuine volvo pads/discs to avoid re-occurrence if not a wheel lug/caliper pin issue

[oneilldom]

Originally Posted by RickT

MK4 Golf - I had this issue over 12 months 4k miles and 3 sets of discs.

The answer was to replace them with OEM VW discs.

The issue went and after 9k miles never returned

http://www.vwaudiforum.co.uk/forum/s...l-judder/page3

Strange i know as you would expect the 3rd party ones to be fine... but for some reason this car didnt.

Seems to be a fairly common problem judging by the response. Think I'll go back to volvo pads/discs if I can't find an obvious cause when I investigate further over these holidays

[Proghound]

Originally Posted by oneilldom

Thanks for the heads up. Now I think about it I have heard about the whole braking down a hill and keeping foot on the brake issue causing the warp where the contact is.

Judging by your reply and other replies here it seems it is likely an issue cause by cheaper brand discs/pads and this uneven cooling issue. Tempted to go back to genuine volvo pads/discs now to save re-occurrence.

I hope you get it sorted as it's annoying when it happens, and disappointing in an otherwise very well put-together car.

Do post back with long-term results if you go back to OEM. Reason I say that is because as far as I can see, the first set of discs that warped on mine were the factory originals. I bought it with 20k on the clock at just under 5 years old, with the itemised invoices for the full main dealer history. I don't see any discs being done in that time, and even outside of the history it's surely somewhat early for them to have been replaced - unless the first owner had a very heavy right foot, maybe?

The reason for my second set warping may be because they're non-OEM, although I'd hope my local garage where I had them done is competent enough where the sliding pins and wheel-nut torque are concerned.