Topic: Air in brake lines

[BikerTrash]

OK, replaced my wheel cylinders and Now can get all the air out of my lines. Already did a search and didn't find anything quite like this.

Cant find anything leaking, it almost clears up and then I get a huge surge of air through the line. I am not running the MC out of fluid,  my little brother is working the brake pedal.

At one point we thought we had it, the pedal was firm, got it it with the  rear tires off the ground, put it in first spun the rear tires. and stood on the pedal and the rear tires kept on spinning, the Emergency brake works though. Followed the instructions in the Chilton's manual on adjusting everyting in the rear drums(first time working on drum brakes, not first time bleeding brakes).

I would just keep going but I have already put two large bottles of brake fluid through just the brake lines in the back axle. the only place I am not getting air is to the proportioning valve on the frame, just getting a good supply of fluid.

Any help will be very appreciated.

[79coyotefrg]

it sounds like he is lifting his foot off the pedal befor you tighten the bleeder

he has to mash the pedal down and then hold firm,  you crack the bleeder  then  tighten it back down then say OK  befor he moves his foot from the floor

[BikerTrash [OP]]

Wow, quick reply.

Actually that is what we are doing. My brother pumps three times and holds, says "OK". I crack them until I stop getting air and then shut again. Using a length of  clear hose so I can watch, the first section headding uphill for about three inches so that it keeps  some fluid near the bleeder and I can tell just how much air I am getting and just encase it tries to suck something back into the bleeder all it can get is brake fluid. Except for the fact that the system in not bled, I think we have a good system working  .

My brother will be in school allday tomorrow so I will probably go and buy one of those little handpumps to bleed it by my self tomorrow, had had good results with them in the past but I think I forgot it in the toolbox of a truck I sold a few years back.

[jimbo74]

if you can, they are liek $50 and are called motive power bkleeders, they are the best around, period

[RustyToy]

Just get the five dolar one with the magnet on it... works great just make shure you get the can above the breaks.

[Shamb]

can you continously bleed them to validate when it does happen that it is infact air in the lines and not something else?


could be your MC going bad...

[Duffil]

I always gravity bleed mine..just break the bleeder and walk away.

[Marlin]

Quit pumping the brakes three times. Do not do this.
If you are using an old master cylinder, it could be sucking air into the system past the seals at the back of the master cylinder.

1. Push down on the brake pedal.
2. Open the bleeder until the pressure pushes out the fluid.
3. Close the bleeder.
4. Release the brake pedal and let it return to the top of the stroke.
5. WAIT at least 15 seconds for the master cylinder to draw fluid from the resevoir thur the compensating port and fill the bore of the cylinder.

SLOW DOWN and give time for the fluid to fill the master cylinder.

In most cases, I simply gravity bleed the brakes.

[BikerTrash [OP]]

Well, sorry for the long time between posts,  got everything working about half an hour after I got home with the little vacuum bleeder, the only thing I can figure is that my little brother was waiting for the master cylinder to run dry before adding more fluid because it would almost clear up and then I would get a huge slug of air.

  Well, thanks everybody for your help!

[Hottrod81]

Marlin, you are da man.