Brake bleeding question & Nut Qestion

[mortation]

Hey guys,

Couple quick questions.

1) I pulled my calipers, lines, and front master cylinder off while doing some stuff to the bike. I put them back on and added fluid but no matter how much I squeeze it doesnt feel like its building up pressure. Is there a trick to refilling the brake system???

2)What are the chances of me finding that long brass bolt that goes on the starter cable/carbs at a hardware store???? I need one ASAP!! Mine went for a walk

[Matchless]

Hi,
This has been asked many times before and there are many different ways to kill a cat! First of all you need to "prime" you master cylinder, so that it is able to pump the brake fluid. Secondly you need to "bleed" the whole system at the furthest end (calipers) to get all the air out of the circuit.

1) I wrap a lot of rags around the bottom of the M/C to absorb spilled brakefluid and then put an old brakepipe on it with the free end into a bottle with some brake fluid covering the opening. Hold the bottle with the pipe higher than the M/C and pump the handle until no more air bubbles are seen and brake fluid is pumped out in a steady stream. If you have to top up the reservoir after a few strokes, you M/C is working and primed.
2) Carefully remove the hose and connect the proper hose going to the calipers, loosen a bleed screw and push a piece of clear pipe over it, also into a bottle with some brake fluid covering the open end. Again hold it higher than the caliper and pump the handle until no more air bubbles are coming out. Lock the screw and do the same to the second caliper.
3) Never let the reservoir get so low that it sucks in air as you will have to start over. Also preferably lock the caliper bleeding screw while holding the handle compressed and no air showing in the plastic pipe.

If you still have no pressure the rubber seals may need replacing in the M/C.

Good luck.

[Steve]

Hey, guy, couple of quick answers.

1) You likely have too much air in the system to notice any pressure build-up by using the typical "pump, hold, vent" method. The best way to evacuate the air from the system is to use a vacuum pump. A Mityvac is only about $35-40 at your favorite auto parts store. The next best method, especially for situations like yours, is to modify the technique. Loosen the bleeder so it is just snug, not real tight. Place a small amount of fluid in a small jar (baby food jars work great), suspend it near the caliper so a short hose from the bleeder sits in the fluid. Open the bleeder, squeeze the lever, close the bleeder, release the lever. Each time you do this you will move much more fluid through the system than if you squeeze several times before opening the bleeder.

2) "that long brass bolt that goes on the starter cable/carbs" I don't know of any such bolt that goes to the starter cable/carbs. In fact, the starter cable really has nothing to do with, and doesn't go anywhere near the carbs. Exactly what bolt are you talking about.

.

[Nessism]

Improvised Mitivac = long piece of tubing on the bleeder nipple so you can suck with your mouth - clear tubing advised for obvious reasons. As soon as you see the fluid level lowering in the master, it should be primed.

[waterman]

Improvised mityvac 2.0, after priming, stick end of tubing into reservoir and pump until blue. Will eliminate having to dump baby food jar and constantly refilling reservoir with brake fluid.