fiftyfive

I have pad knock when stopping my '86 951 in reverse; car's a fairly recent purchase. Yesterday I pulled the wheels and here's what I saw.

The gap between the pad retaining clip and the slot in the pad's backing plate is about 0.20", same on all four wheels. That'd seem to explain the knock.

Is this amount of backing plate gap normal? If not, what brands of pads reduce it? These are recent OEM pads.

If I change pads, a performance street one with more bite and higher friction coefficient would improve pedal response; the OEM's stop well but are kind of dead-feeling. I'm willing to put up with reasonable noise and some extra dust in return. Any suggestions welcomed.

Thanks

Luis de Prat

Porsche specifies brake pad dampeners for the 951 brakes. They're adhesive and stick to the backing plates limiting front-to-back movement of the pads in the calipers. You can buy them from your local dealer.

If your pads are knocking inside the calipers, I suppose the pads were not fitted with the dampeners. A non-M030 brake set up takes a total of 16 dampeners 8 front and 8 back in 4 different sizes.

I also noticed you have the single-tab brake pad wear sensors. It's possible that your calipers are meant for use with dual tab sensors, which hold down the pads somewhat, since the wire is clipped to the locking pin. Fitting some dual-tab sensors just might eliminate the knocking. HTH

xsboost90

ive got metalmaster Ultimate ceramic pads- not too expensive and they stop and wear pretty well.

Rich Sandor

I do not run backing plates on my pads - but I do use a copper based anti-seize compound on the edges and back of the pads and I do not get any squeal or pad knock whatsoever. I run Ferodo DS2500's.

fiftyfive

Really appreciate the answers and suggestions.

Are Metalmaster Ultimate pads made by Axxis? A few months ago I put Axxis ULT's (Ultimates) on my M5, replacing the OEM's. Significantly better bite and modulation. The ULT's are also Kevlar ceramic.

shiners780

We're supposed to use shims behind the pads???

Luis de Prat

On non-M030 front and rear brakes, Porsche specifies 16 adhesive brake dampeners.

On M030 front brakes, Porsche specifies damping plates and adhesive dampeners on the rears.

shiners780

Wow, funky. I never knew that.

My pads are such a tight fit that I never would have thought they were needed.

hosrom_951

I use Mintex Orange pads, love them.

They don't squeal nor have i ever complained from brake dust.

However, i do always add some copper grease/anti seize to the BACK of the pads before installation. I do that on any brake pads for any car, it is an old trick.

Luis de Prat

I grease the sides of the pads to make it easier to remove them later, but the stock dampeners work great to eliminate brake squeal.

GreyDog

Mine make a big clunk when braking forward to reverse or the opposite, though I don't think its the retaining clip at issue. I believe the issue is backing plate length-to-caliper housing that effects this, as the pad is sliding side to side.

Also notice there is a flat metal part that lays on the caliper body where the end of the backing plate hits the caliper (near where the retainer clips into the caliper body) ? Not sure what that is, perhaps its replaceable as well ?