Brake issues

[Khristian B.]

I have a 82 CB750F and I bought a repair kit for the master cylinder along with the fluid cup, gaskets, cover, ect. The main reason being, I had a small leak I couldn't track down and the cup was yellowed and looked (possibly?) cracked. The repair went fairly easily with the cause of the leak: an improperly seated snap ring in the master cylinder itself.

I also pulled apart the calipers and replaced the gaskets and boots around the pistons; very minimal pitting with what I'd describe as brake fluid sludge behind both - about the consistency of wet Vaseline.
Both calipers were cleaned out and replaced on the bike. I've heard the front brakes on these cb's are not
overly grabby and with a single piston I can see why, although my repair manual and every parts website
I go to show me a dual piston caliper for this model and year. Strange.

My Problem : the brake lines have been thoroughly bled but I can't seem to build up any pressure unless I pump the handle 4 to 5 times.  And, I'm getting this water fountain / old faithful jet of fluid only,  (no bubbles) back up into the brake fluid cup which seems to be coming from the small (return?) hole. I'm wondering if anyone has had a similar problem or if one repair kit is better than another. I bought these parts, among others, from a company in Indiana and haven't experienced any problems thus far. Thanks in advance for any info on this.

[Re-run]

AHHH Brakes! Everyone loves brakes!

Provided that fluid is not leaking out at all, sounds like air is still trapped.
There are different ways to do this though.

You can get a speed bleeder which goes in where the old bleed nipple went. These work great usually. You put a tube on it to go to a container like normal. Open the bleeder about 1/4 turn or so and pump away just making sure the master does not run dry. Many have luck with this.

Another option is a mityvac. Makes the job very fast usually.

Third is the old fashioned finesse way., which is also a dirty way! A hose on the bleed nipple. A long arm or helper to pump the lever. You squeeze the lever just a bit, open the bleeder a bit to pass fluid without everything leaking around the threads, then squeeze the handle to the grip. Hold and tighten the nipple. Release the lever. Repeat. Stop ever few times to refill the master, it must not run out of fluid.

once things are pretty decent, take the master cap off and squeeze the lever slowly about half way and tie it that way and let it sit for a while with the cap loosely on to keep dirt out. This allows bubbles to slowly come up and out over time.

Others will have their methods which will most likely work just as well. One thing they all require is time to do it right.

[CB750 Winger]

  To add one more to rerun, what works good for me is when you think you have it bled, wrap a rag around the banjo bolt up top (so you don't spill on anything), pump the brake slowly a few times, hold it in and crack the banjo bolt quickly. It might burp air out there. Try this 2 or 3 times. Make sure you don't spill brake fluid on anything, it will eat plastic, paint, etc.         Paul