As one can see in this picture, the burrs have cut into parts of…

As one can see in this picture, the burrs have cut into parts of this piston/seal. I also removed quite a bit of what I can only describe as dissolved rubber during cleaning. Remember that this seal handles all of the force applied when the clutch is depressed.

I think that by design this seal is intended to expand (get fatter) as pressure is applied, which again is designed to provide a better seal. Hydraulic pressure is applied from one side of it, and pressure from the spring mechanism is applied from the other direction by the finger springs in the pressure plate.

My theory for the failure of this part is as follows:
Chemical deterioration of this seal, coupled with the gouges caused by the burrs in the "piston follower", coupled with flexing of the inner and outer housing caused fluid to get past the seal. As the chemical deterioration progressed, fluid continued to gain the ability to get past the seal at the weakest point, which were the gouges.

Bottom line is that I'll never buy a cheap Chinese part again, especially when it takes so much labor to replace.

Owner caption February 2017 · Photo 13 of 76