Brake pad really tight in CP6600 Cerbera calliper

[Montauge]

I’ve just changed the front brake pads on my late Cerbera which has the CP6600 callipers (with TVR written in yellow on them). Pads were Ferrodo DS2500 and the discs are in good nick having only done c.6000 miles.

The old pads came off fine and the 4 pistons all pushed back easily. My issue was getting one of the pads back in. I had to gently tap it – it was in effect an interference fit. The sliding pins all went in easily. I didn't remove the calliper btw.

With the wheels back on the car, and brakes pumped, the wheel that I had no issues with spins relatively freely, but the one with the awkward pad will not spin freely and takes some effort to rotate.

Is it just a case of bedding the pads in and all will be ok or might I be overlooking something? I’ve not yet driven the car.

[mac315p]

I've had this on a few different cars and pads lately. I just run the leading and trailing edge of the pad backing (not the friction material!) over the stone disc on the bench grinder (don't get too carried away). Obviously if the pad needs pushing into the caliper when its stone cold this won't work well, never mind when things get hot, it needs to move freely whilst not being too loose. . .

[Montauge]

mac315p said:

I've had this on a few different cars and pads lately. I just run the leading and trailing edge of the pad backing (not the friction material!) over the stone disc on the bench grinder (don't get too carried away). Obviously if the pad needs pushing into the caliper when its stone cold this won't work well, never mind when things get hot, it needs to move freely whilst not being too loose. . .

That sounds like sound advice. I'll take it apart again and try it. Hope I can get the pad back out!

[Brithunter]

If these are alloy AP calipers then check if they have wear plates inside the caliper that are retained by a domed headed allen bolt. If so then chances are that brake dust has crept under the plates and forced them to curve up at teh edges and it is this that is making the brake pads a tight fit.

if they are not cleaned out then they will begin to corrode the alloy of the caliper body under the plates.





Those are soem 4 pot AP Racing MG branded ones that I serviced for the MGF:-







The finished job.

Those 6mm dome headed screws are a real PITA to get out. Had to drill out and retap the threads on several.

[Montauge]

Thanks for the heads up on that one. I think they do have wear plates like those from memory. I'll take the calliper off and have a good nosey.

[Poopdog]

I can second this as I've stripped my calipers for powdercoating and those plates are a right pain but when I took them off there was layer of brake dust behind each one which had gone hard

[ukkid35]

This is probably due to corrosion between the ally body and the stainless steel plates. Brembo calipers have a very similar design and suffer the same fate, and there was a very good article in 911 Porsche World March 2003 explaining the repair process. Let me know if you would like me to email you a copy, don't really want to post it publicly due to copyright.

[Poopdog]

Yes your probably right as stainless and aluminium aren't best buddies

[Montauge]

Thanks for all your advice. It turns out that the problem was indeed a build up of crud (a mixture of brake dust and corrosion) behind the stainless steel plates. Mine came off easily enough with an allen key so were easy to clean up. Here's a before and after for anyone else reading this post in the future.

[Montauge]

And after