is brake pad paste necessary

[tom-320iS]

I'm installing some PBR pads on an 82 320i and they came with brake pad paste from BMW, any body know if this is important and where to apply it ? Thanks

[glotman]

Hi, the brake pad stuff is supposed to prevent sqeaking from the pads, which is actually caused by the pads vibrating at a high frequency rate. the "stuff" is supposed to prevent that. along with proper break in procedure of the new pads. especially, no panic stops till the pads are bedded in.
Put a thin layer on the back of the pad where the metal piston contacts it. when this stuff comes in a small tube, I just sqeeze a 1/8 inch wide bead of the stuff across the back of the pad.
a proper break in consists of going about 35 mph, then slow your car briskly, but not panic, to about 5 mph, but NOT full stop.
Do this about 10 times, and your pads should be bedded in enough for regular use.
Geoff
ps- dont break in your brakes in traffic-find a big empty parking lot or a back road with no other cars behind you

[tom-320iS]

Thanks Geoff ! Well of coarse like all "simple" jobs on this 28 year old rig this one is more involved than I had hoped. The pads on the drivers side went on without a hitch but my attempts to compress the pistons on the right side have failed. I have the caliper pulled away and hanging to give me more access. Most of the caliper spreading tools seem to be made for a caliper that is not as enclosed or ones having a single piston with space opposite the piston to place the stem of the tool. Anybody have any tricks to do this or perhaps they are seized and I should rebuild. Just not sure how much muscle to apply to these.

[glotman]

I use large channel-lock type pliers, and the old pad in place, sqeeze down hard and piston should move in. If not, open bleeder screw, cover with rag, and sqeeze again. Piston should move, and some fluid will spray out if it does. If still no joy, you have a seized caliper, which can be rebuilt, or replaced. I have had fairly seized up calipers come loose and be useable again. If it does come loose, but is still stiff, bribe a pal with beer, and get him/her to step on brake while you hold lightly with the pliers. Piston moves out under pressure, then you sqeeze it in with pliers. Do this several times to "exercise" caliper, then bleed system, as the rust is caused by moisture in your brake fluid. And dont forget to have fun, and drink some of the beer yourself, and have one for me if all this works
Geoff

[tom-320iS]

Yah I'm celebrating ! I was using channel pliers to compress and could only apply pressure to one edge of the piston and caused it to bind up within the cylinder. It was getting dark so I quit and slept on it. Next morning I pressed it in evenly from the center of the piston by placing a small wood shim in the cup of the piston and used a c-clamp to easily push both piston out of the way to accept the new pads. Brakes feel great. Thanks for the support. Next up - R&R Clutch Master Cylinder

[glotman]

Nice!
G