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Brake master cylinder overhaul #4

I disassembled the brake master cylinder again I repaired on the other day because the behavior of the piston seemed to be not smooth enough. 


When I removed the piston at the last time, I checked the condition of the rubber and it looked good.  Therefore, I reassembled it without replacing the rubber.
However, again I disassembled the brake master cylinders piston and checked its condition carefully in order to reassure myself.


I disassembled and cleaned the piston and the spring.


The condition of the original rubber was not bad, but I replaced it once with the rubber part of the repair kit.


Again, however, I felt that the quality of the rubber parts of the repair kit (left one) seemed to be poor….


I also assembled the piston into the cylinder as a trial, however, the tight contacting feeling was not enough.

As my conclusion, I judged the condition of the original rubber parts were good enough and decided to reuse them.
So, I reassembled with the original rubber parts again.

When I was reassembling the brake master cylinder, I felt very slight resistance in the movement of the piston.
I checked the inside wall of the cylinder with my finger very carefully and found there was a very small step in the smooth surface.
I honed the inside of the cylinder again and polished with #2000 sand paper to make the surface flat.  Then, the movement of the piston became very smooth.


I thought now it should be okay.  I would try a test drive with this, if it would be not good, I would replace it with a new part at that time.


(My original blog was written on 25th Jun 2009)

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