As for the brake material ....
that Ben is talking about in Reply# 46,
I noticed in the multimatics the brake material GM used was cotton based.
What lead me to believe that this is a cotton material is the fact that 3 of the 5 multimatic transmissions I've rebuilt had water in them. Every brake assembly I took out had a tremendous amount of rust, evenly across both sides of this brake material, to the point the brake assemblies were not able to separate. Only after prying the metal plates apart would it release and tearing the cotton friction material. Even though the original cotton material was submerged in oil, the oil was totally replaced by the water.
BTW ..... one important lesson to take away from this! If you ever get your hands on a multimatic do not power it up. The very first thing to do is drain the oil and check for water. WHY? If water got into the transmission, the brake will be fused together with rust because of this cotton material. Operating it will destroy the transmission when it goes from spin to stop. It will agitate and spin just fine .... but when the machine goes from full spin to stop when the motor is no longer in spin mode, the clutch is forced past neutral and into agitate. At this point the spinning mass slams the brake assembly on the spin tube and rips the 6 clips that hold the brake assembly together and strips the inner brake cup teeth on the spin tube. A very ugly and violent death! pic #3. After removing this brake, it was found the brake plates were totally bonded together with rust with the cotton in the middle again.
If you drain the oil and find water, you can almost guarantee the brake will be corroded together. Even a small amount of rust between the brake plates, it may still work as it should, but the rust will tear up the cotton friction material in no time. When the brake doesn't work, you will get agitation in spin mode.
I was able to acquire 2 NOS brake assemblies. Both of them still in boxes but one had gotten wet. This one had again held water and the plates rusted together. The other was pristine and showed the cotton cloth that GM had originally used. After some research I found an article that talked about a hydraulic brake built in the 50's that used a heavy weave cotton as a friction material constantly saturated in oil.
I ordered a very heavy cotton sail cloth or also known as oil cloth and used an oil resistant contact cement (pic #1) to bond the cotton to the brake cup as seen in the pic #2. I have reman'ed 3 brake assemblies using this material and it has worked very well. If you wanted to get really slick you could order "kevlar tape" that is 3.5" or wider by the foot on ebay. The thickness of the sail cloth is about .055" and the kevlar is about .065" The extra thickness will make no difference, but the added benefit of the kevlar is that it will not absorb and hold water .... if water ever got into the transmission.
Bud - Atlanta
