Front Master Cylinder Q?

My freshly rebuilt front master cylinder wont pump... Question is, should both holes in the bottom of the reserve be open? Only the one closest to the brake lever is open, the other does not go through to the piston. On the inside of the cylinder, I cant see any sign that it ever went all the way through.  But she no pumpy!
 

Sorry for putting it in the wrong forum......
Steve

Yes, it needs to be open. It is a really tiny hole. 

Yes, tiny.

When you pull the hand lever, with the lid off, a stream of fluid will shoot out of that hole, so consider this your warning!  The regular wrenchers are no doubt laughing after reading that, since many of us have managed to squirt ourselves, and the bike, learning (the hard way) this nugget of wisdom.

Thanks Fellas, I just used a Torch tio cleaner to clean the hole. It measured out to be .0017" or .4318mm.

Nessism wrote:

Yes, tiny.

When you pull the hand lever, with the lid off, a stream of fluid will shoot out of that hole, so consider this your warning!  The regular wrenchers are no doubt laughing after reading that, since many of us have managed to squirt ourselves, and the bike, learning (the hard way) this nugget of wisdom.

Also don't forget brake fluid is an incredibly effective "paint stripper" especially when it gets were you don't want it (another lesson learned the hard way many years ago !!!!!)

Next question, do the piston cups go in the same direction or face each other? I ask because there is no squirt out of the freshly opened "little hole".
Thanks you guys are Awesome!

The piston rubber gaskets should face the same direction.
Small OD to the leveler, big OD to the brake line/banjo bolt.
See animation made by Lou D, R.I.P......

 
 
 
 
 

Scirocco, Thanks. Thats the way they are. For some reason the master isnt building pressure. I got this master from ebay for my barn find because it was missiing.  There is some corrosian that I tried to hone out , I must not have done a good enough job. I will give it another shot tomorrow.
 Steve

Sometimes bleeding a brake sytem could be a pain in the a**.
Reverse bleeding with a syringe or hanging up the caliper in the air over the MC level is the only option.

saltroni wrote:

Scirocco, Thanks. Thats the way they are. For some reason the master isnt building pressure. I got this master from ebay for my barn find because it was missiing.  There is some corrosian that I tried to hone out , I must not have done a good enough job. I will give it another shot tomorrow.
 Steve

If the bore is corroded, the master is junk.  Get a new one.

5/8" bore (16mm) for a dual disc bike, or 14mm bore master for a single disc bike.  I used a rectangular reservoir EX650 master for my bike and it works great.

You may not of noticed but some of those Tokiko masters had a metal sleeved bore, a real propensity to rust/rot out. I've tossed soo many of those over the years could fill a dumpster. If you somehow ended-up with a good metal bore one, crack the line banjo at the master after pumping lever and holding it. Repeat several times, you'll feel it priming. Like Wookie said, keep some rags underneath it to capture the sweet sweet fluid. What you're doing is filling both chambers of master and starting the bleeding process.

Forgot to mention. If this bike is a rescue and has been sitting a long time, the lines/splitter could be clogged-up too. This will hamper any bleeding. Ya might pull the pull the caliper banjos off and verify fluid presence. This is if you don't have any brake vacuum equipment.