No brake fluid movement in MC

[Guest]

Hi all,
I'm rebuilding a suzuki GSX 400.
Iv'e rebuilt the front caliper and the master cylinder (all with suzuki OEM parts)
i wanted to bleed the system and ran into a problem, no matter for how long i pump the handle no pressure is being built and the fluid doesn't go down from the "cup" to the pump body.
I left the handle "pulled" for couple of hours but it didn't made any difference
i feel no resistance when pumping and the surface of the liquid does not move.

Any ideas?

and just as an option, can i fit a GSXR master cylinder to my bike but stay with my caliper?

Thanks
Eran

[hampshirehog]

Have you got all your brake lines plugged in or are you just testing the MC?

The GSXR MC will fit but you'll have to figure out a bracket to hold the reservoir.

[eran_k]

Yes it's all fitted, new SS hose as well

[tkent02]

Remove the brake line from the MC. Squeeze the lever, block the port with your finger, release the lever. Squeeze it again, keeping you finger blocking the port, but if any fluid moves against the finger let it out, repeat as needed. You are basiclly using your finger as a one way valve to let fluid come out but not back in.

[azr]

If you had a syringe and a hose handy you could draw the brake fluid thru the lines from the bleeder and overcome this problem.

[hampshirehog]

Remove the brake line from the MC. Squeeze the lever, block the port with your finger, release the lever. Squeeze it again, keeping you finger blocking the port, but if any fluid moves against the finger let it out, repeat as needed. You are basiclly using your finger as a one way valve to let fluid come out but not back in.

That's the ticket. Make sure you cover your paintwork up to avoid splashing with fluid.

[eran_k]

Tried that, i got little fluid at the MC exit but not a "Flow"
My MC is a one piece unit and there are two holes at the bottom of the reservoir.
thru one i can see the piston moving and that's where the bubbles came from, i guess the other hole is where the fluid is drawn into the cylinder,could it be blocked?

[tkent02]

It can, and it common is. That's the compensation port, the one that can kill you if it clogs up..

You said you rebuilt the MC???

[eran_k]

Rebuilding: cleaned it as best as i could inside and out and installed new internals (piston,spring and seals)
i might have missed that hole,is it tiny? (like a very small pinhole)

[tkent02]

Yes, very tiny.

[eran_k]

any good method to make sure it's open?
should a hair from a wire wheel go thru the hole?

[Chris G]

Easiest method I've found is to use a syringe connected to a clear hose, if you have only changed the hose I assume you still have fluid in the caliper, fill the syringe and push out any air bubbles connect to the bleed nipple and undo the nipple (note anymore than half a turn on a bleed nipple can let air back in the system and you'll be at it forever and a day) slowly syringe fluid into the caliper and up in to the MC you will see how much air is pushed up into the MC, repeat a few times, then bleed as normal from the caliper.
This method worked perfectly on my XJR last weekend after changing the hoses.

As stated cover any previous paint work, and don't on mad using the syringe all you'll have brake fluid all over the place.

[Steve]

any good method to make sure it's open?
should a hair from a wire wheel go thru the hole?

A hair from a wire wheel is probably WAY too big.

You can examine some of your electrical wire to see if any of them have fine strands. Poking one of them down the hole might do the trick.

One more tip: Before re-connecting the brake line or the handle, use a screwdriver to push the plunger as far as it will go. Sometimes there is a pesky bubble of air that stays at the top of the bore, just inside the outlet to the hose. The piston usually is not pushed very far into the bore, using a screwdriver will push it farther, usually expelling that pesky bubble.

.

[hampshirehog]

5 amp fuse wire fits that little hole. It's a bit soft but does the job.

[Gorminrider]

any good method to make sure it's open?
should a hair from a wire wheel go thru the hole?

There are different sizes of wire on different "wire wheels"....
I used a strand from a very-common cheapo wood-handled wire brush. These Wire brushes are good because the wire is stiff and the right size....even a strand from a brass barbecue cleaner brush would not work for me.