Rebuilding hydraulics

[Arizona_928]

Rebuilding a motorcycle master cylinder.
On reassembly, should one go with silicon grease or just use brake fluid?

[1990C4S]

Brake fluid, bleed it in the car.

[cjh]

I was always taught Silgel or brake fluid due to the compatibility with the rubber and the fluid.

[Baz]

Originally Posted by Arizona_928

Rebuilding a motorcycle master cylinder.
On reassembly, should one go with silicon grease or just use brake fluid?

I've used both but over time elected to just stay with brake fluid, if at all possible. Just simplifies things.....

[E Sully]

I had quite a project on the '72 H2 I got 2 years ago that had been sitting since '77. It was a bit crusty in there. Make sure that tiny orifice is clear.
I used brake fluid and it came out great. I was a bit nervous and extra careful when filling and bleeding to make sure no fluid spilled on my new paint. Worst part was finding the brake light switch was bad and had to replace it afterwards. It sits right over the freshly painted front fender.

[Rusty Heap]

I've heard of people bench bleeding the Master Cylinder first.

[1990C4S]

Originally Posted by Rusty Heap

I've heard of people bench bleeding the Master Cylinder first.

They are easy to do in the car, just bend a tube/hose from the output side and submerge it in the reservoir, it will self-bleed as you pump the brakes.

[Arizona_928]

The ole piston is stuck inside the cylinder.

Need to find an adapter for my grease gun to the banjo bolt to force that bad boy out.

[Tobra]

Cover any stuff that is painted and in the line of fire

[E Sully]

I put the handlebars in a vice, and then bled master and hose on the bench into a container. Then I connected the caliper to it and managed to push out the cylinder.
My fear of the brake fluid on the paint was after I installed it and found the brake light sender was bad, then changed the sender mounted on the bike.

[Arizona_928]

Went to the hardware store and bought a zerk fitting for the grease. Turned out pretty well. I'll get a mason jar of diesel to degrease the master cylinder.

[E Sully]

So what motorcycle are you dealing with?

[Arizona_928]

A Frankenstein…

Steel frame swapped zx6r with dirt bike handlebars and I’m thinking about a cafe racer front end.