640 GC shudder under heavy braking

[anonymous-user]

Dino D said:

CSK423 said:

I checked both fronts and the OSF (refurbed wheel) drags on the pad when spun, the NSF (original finish) does not. It's not able to dissipate enough heat which results in the disc warping, this has been after circa 5k miles and generally braking from motorway speeds, it's taken a while and high speed braking to warp it. I have no doubt someone tootling around town probably won't see this level of heat build up and will never suffer the same consequences or it'll take a lot more mileage.

I would challenge your dealer and see what response you get, you don't ask you don't get.

I'm trying to work out how the wheel/paint can cause the pad to drag on the disc?
Or have I missed something?
It's the dragging that causes the heat regardless of what wheel is on that side if have thought?

I think the theory is that the paint caused the warping and the warps disc now rubs on the pads at some point in its rotation, which is understandable.

Thing is,this is a very common problem with the F10, I doubt there are that many refurbished wheels involved.

[CSK423]

REALIST123 said:

Dino D said:

CSK423 said:

I checked both fronts and the OSF (refurbed wheel) drags on the pad when spun, the NSF (original finish) does not. It's not able to dissipate enough heat which results in the disc warping, this has been after circa 5k miles and generally braking from motorway speeds, it's taken a while and high speed braking to warp it. I have no doubt someone tootling around town probably won't see this level of heat build up and will never suffer the same consequences or it'll take a lot more mileage.

I would challenge your dealer and see what response you get, you don't ask you don't get.

I'm trying to work out how the wheel/paint can cause the pad to drag on the disc?
Or have I missed something?
It's the dragging that causes the heat regardless of what wheel is on that side if have thought?

I think the theory is that the paint caused the warping and the warps disc now rubs on the pads at some point in its rotation, which is understandable.

Thing is,this is a very common problem with the F10, I doubt there are that many refurbished wheels involved.

Dino - it's as REALIST has said.

[Dino D]

This painted alloy theory of BMW just doesn't stack up for me.
A bit of a search for painted alloys and heat transfer and warped discs only brings up results for BMW...
http://www.bimmerfest.com/forums/showthread.php?t=...
Over here a guy was fobbed off with the excuse but turns out his refurbished allot was down properly (i.e. No paint on the surface).
Some mention of the 'dry' braking feature that pulses the brakes to keep the discs dry.

You could try checking this heat dissipating theory by getting a infra red temperature reader and check the temps of the wheels / discs to see if there is in fact heating serious amounts of heat building up.

[PhilRS]

On my 640d,I eliminated brake shudder by applying very strong braking from about 90 mph, perhaps 7 or 8 times in a row. By very strong, I mean literally emergency, full pressure braking from 100 mph to 20mph (obviously went to Germany), letting the brakes to cool down following each application. If shudder has reduced, but is not eliminated after 7/8 applications, repeat. If it has not reduced at all it could be a bucked wheel. If it worsens, it could be a warped disk. I experienced both, with other cars.

[CSK423]

DinoD - If this had been a set of discs I would agree and contest further but as it's only one and is mounted to the refurb wheel I don't have anywhere to go with it but to accept this is the cause. If it was a pair I would be having a different conversation with the dealer.

I had both the front dics skimmed (only the OSF was warped) at a cost of £99. No more shudder and it's only after this has been done I can tell how bad the shudder was previously, I must have been growing use to it as it gradually got worse.

I know the disc will always have a slight imperfection from where it previously warped but hopefully it won't heat up the way had previously for the warp to return. Time will tell.

[IATM]

PhilRS said:

On my 640d,I eliminated brake shudder by applying very strong braking from about 90 mph, perhaps 7 or 8 times in a row. By very strong, I mean literally emergency, full pressure braking from 100 mph to 20mph (obviously went to Germany), letting the brakes to cool down following each application. If shudder has reduced, but is not eliminated after 7/8 applications, repeat. If it has not reduced at all it could be a bucked wheel. If it worsens, it could be a warped disk. I experienced both, with other cars.

That actually sounds like a very good test: particularly the "If it worsens, it could be a warped disk"