KLR

I'm getting ready to replace the pads and rear rotors on the 951 for the (well, my) first time this weekend. I bought a set of zimmerman rear rotors and metal master pads for both axles from Paragon, but want to make sure that I have everything I'll need before I start, as I'm going to be stranded if I don't.

So... do I need anything special besides:

1. A can of brake cleaner
2. Antiseize or similar to lubricate the edges of the pad backing (where they slide in the caliper)
3. The rotors and pads

Other quick questions:

In the factory manual, there is much talk of various vibration supressors. What are these and do I need them with the metal master pads?

How hard is it to retract the pistons? I was going to bleed the brakes anyway, so if I open the bleeders, how much effort is required to retract the pistons?

Are there any gotcha's to this job that the factory manual or clark's garage don't cover?

theedge

Its fairly easy to push the pistons back. Leave the pad in and squeeze the pad tab and the caliper with pliers, dont use a screwdriver between the pad and rotor. You can also move the pistons back by hand using the pad.

Get "Flare Nut Wrenches" for the bleeder bolts, makes it lots easier.

I always try to have two cans of brake cleaner on hand, but thats usually cause I go all kung fu on cleaning stuff.

Vibration dampers you heard about are thin metal shims that go between the pad and pistons to cut down on noises and squeeling. You can also buy silicon like stuff at most car part places that does the same thing.

Keep in mind that new pads are usually quite noisy for a while, then quiet down. Be prepared for questions if you pull into a police road block with loud screeches to let them know about you... Been there, done that. Obviously I was sober, but they still asked me.

sm

You've got it mostly covered. Only items I can recommend is a long ratchet or a pipe to put over your ratchet. Those bolts can be mighty tight and stubborn. Also, get a pair of channel locks or a C-clamp to retract the pistons. A thick pad or cloth would be useful to prevent marring up the calipers, too.

83na944

I had trouble removing the Phillips head screw that holds the rear disc on the hub. I just couldn't get enough leverage with a screwdriver. I went out and got a large Phillips head socket to use with a long ratchet handle and they backed right out.

Also, you might want chamfer the leading edges of the new pads so they don't drag during break-in.

I don't know if you need to "bed-in" the metal-masters.

I use the anti-sieze in the backs of the pads, the pins, and the parts of the calipers that slide.

xsboost90

i put in rear metal masters, didnt take long to break in at all! I use the screwdriver between the pad/rotor method, just dont scratch the rotor. I always take a file and take the edge off the sides off the pads to keep them from squeeking.

Zero10

Stupid question time, what are flare nut wrenches?
I have always used the box end of a wrench on bleeder screws so I don't strip them, is this a safe thing to do?

Retracting the pistons is easy, I have done it by hand on my car. I just put metal masters in the front, and they were quiet for a few days after I bedded them in, but after the first solo II event they were squealing like mad, and they still haven't quit. I am going to try some anti-squeal shims/grease to try and stop this terrible racket they are making.

Dave in Chicago

Channel locks are handy for squeazing the little pad retainer together and getting it to flip out.

Needle-nose pliers are handy for pulling the pad sensors out, if you still have them. They can be reused if you are careful.

I use the old pad to lever the pistons back in, usually positioned on end. Press them back in SLOWLY. Once in, you have about 3 seconds to utilize the space you've openned up. The little pistons like to come back out, so pry them in gently and drop the pad into the slot.

Leave the system and bleeders all closed up until you've replaced the pads. The hot set-up is to replace pads and then bleed them. I have done both at the same time (driver side all, then passenger side all). Works okay, but I still prefer to change all, then bleed. By the way, you only need to bleed if you NEED to bleed. Pad change does not dictate the bleeding of the system.

I use a bit of antiseize on the back of the rotor mating surface only. I've never used it on the backs of pads and such. 'Course, I don't mind pads rattling or screeching. Heck, it's a Porsche, not a Caddy.

The adventure with these calipers is when the spring plates located at the ends of the pad slot get corroded with gunk (aluminum + steel + time = gunk) and the bloody pads won't fit in properly. The only TRUE fix is replacing those spring plates and GENTLY removing the corrosion from the aluminum calipers. This may lead to the use of torches, drills, and much foul language. Good news - Once you've done it right, you're all set for some years. Poor man's remedy is to grind the pads down at the ends to fit (not easy with today's rock-hard pad materials).

Time - Allow about 2X the time you think you'll need. With practice, you can change these pads all the way around the car in any parking lot, paddock, etc... in about 20 minutes including wheel removal and install (it's amazing how quickly you can work when you are about to lose critical track time).

Dave in Chicago

I forgot, breaking in MM's. I usually find a lonely road and make repetitive threshold stops from about 60 mph. MM's will SMOKE (it's not tire smoke) as they burn off the gases from stuff in the pads. Usually 10 good stops will do it. Drive home gently (hopefully NOT escorted by local law enforcement) and let that baby cool overnight. THIS is actually the best time to do the bleeding (next day, bedded, etc.) from my perspective.

Good luck!