Dry master cylinder, dry rear caliper

[bdfinally]

I'm starting with new components, both MC and caliper. What's the best way to get the system up to stuff, should I prime both by pouring dot 3 in each and then start the bleed? Easier on the bike or on the bench? I've got a mityvac also. Thanks

[ducpainter]

I'd do it on the bike.

I wouldn't mount the caliper...keep a wedge in there to prevent the pistons from leaving the bore.

Bleed keeping the caliper bleed screw above the level of the master.

Priming is not a bad idea.

You may have to re bleed as tiny air bubbles often form on the inner surface of the line in a dry system.

As they converge they'll make larger bubbles and affect braking performance.

I'd use DOT 4 if you can find it.

[bdfinally]

It's a '00 M750 dark compnents, still dot 4?

[ducpainter]

Yes.

Castrol makes a fluid that is priced like DOT 3 and meets DOT 4.

[bdfinally]

Cool, Thanks DP.

[printman]

with out getting to technical, DOT 4 is pretty much the same as DOT 3. They are 100% compatable even when flushing older systems. DOT 4 has a higher temp rating usually. Look at the bottle for manufacturers specs, not all Brake fluid have the same specs. Seen DOT 4 with high dry temps, but really low wet temps. Go with something better than Auto store quality.


A side note, brake fluid is hydroscopic, meaning it absorbs water out of the air, hence look for good wet numbers also not just dry, and don't use an old bottle (it will have sucked in water)