Master cylinder operation question

I rebuilt the MC on my 550 Maxim last year and just finished rebuilding the one on my 650 Maxim. The parts for these two are slightly different, in particular the rubber cap on the end of the spring in the 650. The way mine was assembled was with the small end of the spring and the cap at the bottom of the cylinder against the outlet port where the brake line connects.

Right now the seal being made by that cap (with the spring pushing behind it) is very tight. I can't really move any air past it when I suck or blow in the threaded hole. So my question is, how exactly does it operate? Is there enough pressure behind it when the lever is pulled that it just forces fluid past the end cap despite the spring pressure?

 

Your spring and rubber cap are backward. That cap goes against the piston, not the outlet.

The parts might be a bit different, but overall it should be very similar to the one on the 550.

 

That makes more sense. I'm surprised the brake was working with it assembled backwards.

Now the question is, will I be able to get the boot pulled off the other end of the piston without tearing it to pieces...

Thanks.

 

Sure.

Take the Rubber Tip off from a Butler Stimulator.
File the Knob to be a Flat, Pointed Wedge.

Pull the Boot away from the Top of the Plunger.
Fish the Boot Tool down-in and slide the wedge under the Boot.

Badda-bing; Badda-boom.

 

I doubt I can get my wife to give up her Butler Stimulator, especially if I tell her I'm going to file the knob off.


OK, I give. What's a Butler Stimulator?

 

http://www.amazon.com/Butler-G-U-M-Gum- ... B000GFZPWM

Just fine something like a retired Dental Instrument to reach down-in and lift up the Boot.