I finally got around to bench bleeding my new Baer master cylinder. I have the tubes running out of the ports going back into the master and pushed the cylinder bore in about 3/4" for 20- 30 times. On the front reservoir (which are the rear brakes on this Baer master) you could easily see fluid gushing up from the small orifice in the bottom of the reservoir, but on the rear port, (for the front brakes) you do not see any fluid movement from the orifice. So I decided to remove the fiitting from the rear port (front brakes) and fluid does slowly drip out, but when I push in the bore no fluid squirts out. I did the same on the front port (rear brakes) and fluid squirts out like its suppose to.
I called Baer and explained the situation and they said to mount it and try to bleed the brakes on the car. I think this is a total waste of time since it doesn't seem to be working correctly on the bench, what do you guys think? Am I missing something here?

Thanks!
Mike

There are two springs inside the master cyl, one in front of each piston, one is a bit weaker than the other one. The with the master cyl not plumbed into anything, the softest spring will compress first, THEN the other spring will begin to compress. Since you aren't stroking the master cyl it's full available stroke, the softest spring is doing all the pumping. Full stroke should be 1 1/8" or 1 1/4" sometimes more depending on the master cyl.
David

So David, should I go head and push the bore in all the way and see if I get any fluid to shoot out of the rear port? If I still can't should I assume I have a defective master and not bother trying it on the car?

Thanks!
Mike

Yes, you have to go full stroke to see if both pistons are working. If you still get no fluid I don't see how putting it on the car would make it any better.

David, thanks again for helping me out. It turns out that when I pushed the piston all the way in, fluid did squirt out of both ports. The reason I didn't push it in all the way to begin with was after reading many posts about bench bleeding many said don't push it in no more than 3/4 inch or so because you man damage the master cylinder. Anyway, It looks like I'm all set and I can go ahead and mount it and feel a lot better :D.


Mike

Mike,
Most warnings of limiting travel have to do with used master cyls that have some corrosion in the bore. The normal stroke area is pretty clean, but beyond that area can be corrosion, and if you push the pistons into that area, they can pick up crud and the piston seals can be damaged. That is not a problem with a new master cyl.
David