It took a mere four hours to bleed the brakes on my 750

So I rebuilt the calipers on my 750 Seca. When I bought the bike several years ago they were froze up but I worked them and played with them until they functioned but they never fully released so that it was a real pain to back up (as many on this forum have already said). But they seemed to work fine other than that.

I removed both pistons, cleaned and polished them, cleaned and polished the bores and o-ring grooves and put new seals in. Then I re-installed the calipers and got out my trusty Harbor Freight knock off Mighty Vac and started to go to town - nothing! I couldn't get fluid to move to save my life.

Ok on to plan "B". I happened to have a syringe. I hooked it up to a piece of clear hose and bled the calipers side to side just to see if I could get fluid to flow. I did. I repeated that procedure until there were no bubbles then switched back to the Mighty Vac. It started to pull fluid and I thought I would be finished in no time until the little plunger/piston fell out of the Mighty Vac. Nuts.

Called momma out and had her work the brake lever. Bless her heart, she was on her way to the grocery store and kindly delayed her trip in order to pitch in and pull on that doggone lever for an hour while I went back and forth from one side to the other.

Bottom line, I have good brakes and no more drag in reverse. I also wonder how much drag I was getting going forward. Maybe I picked up a few horsepower to boot.

Think Spring!

 

I had a similar problem, could NOT get the "hidden" master to bleed out, ended up taping 3 feet of clear hose to the resivoir inlet, to add some pressure, with a funnel at the top, and sucking the air/brake fluid out the bottom, with clear tubing- in my mouth !!

Later I ran across the trick of using the vacuum of a car engine, hooked to a jar, then to the bleed nibbie. Much more convenient.

Get a pickle jar, poke 2 holes in the lid, get some clear 1/4 inch tubing.

 

I just zip tied the brake lever to the handlebar...

 

TrR - does the car vacuum pull more than a shop vac? Cause I tried using my shop vac and had zero results.

Schooter - I have heard of people using that method. How long did it take and how did you keep the reservoir from going dry again? It seems to me that it would take three people working in shifts to use that method.

 

At a reading of 21 inches of Hg, an idling engine is giving about 10 PSI of vacuum. by mouth - about 2 PSI. I don't know what a shop vac pulls, but I'd guess 3 ?? PSI

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On another note - If there was a little bit of air in the brake lines, and you carefully pried the pads away from the rotors, you would force quite a bit of brake fluid back upstream into the reservoir, assuming you don't over-top it. Pump it up and repeat a couple times. You would get rid of air bubbles in an otherwise sealed system.
Tapping on the calipers also helps dislodge tiny air bubbles.