| madcsl |
24-06-2011 12:34 PM |
Had the same problem - a clunk from the rear pads - here is the helpful response from AP
The mechanic is correct it is the clearance of pad to caliper (approx 1mm on length) that can cause pad knock as the car rolls forward or is reversed and the pad gets rocked back and forth producing a metallic click. It causes no harm but can be intrusive but if this clearance wasn’t there then the pads would expand and jam in the caliper! The anti rattle clip is there to arrest the rotational momentum of the pad and is normally enough to eliminate the clicking sound on take off, although it can’t overcome the loads applied during reversing so it can click then and once more as the car moves off. If yours are clicking constantly but the A/R clip is fitted correctly i.e. in contact with the top of the pad steel backing plate, then there are 2 other possibilities: -
1)
The pads are to short in length (Nom = 113.47mm / 5.20”) producing more clearance than required. But if the pads are as supplied with the brake kit it’s highly unlikely!
2)
The pads or discs are worn producing a wear lip that is causing the pad drag in free condition.
Solution: - Clean off any wear lip on pad or disc with a file, but don’t touch the braking faces!
If that’s not a cure then we can provide self-adhesive rubberised shims to attach to the calipers lower wear plates (2off only per caliper). To fit these shims dampers, the Pads need to come out and the calipers wear plates wiped clean of dust and grease.
It’s Very unusual to have to do this on the M3, but it will affect a cure. I’ll send the Agent in Sydney a set for you to try in their next shipment arriving with them early next week marked for your attention.
Part # CP5119-113
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