Brake Bleeding HELP!!!

[MARK2]

I recently replaced the front calipers on my 97 V6 Camry. I bled the brakes using the 2 person method but still have sponginess in the brake pedal. I bled the brakes again and still no improvement. I know that during my brake job the master cylinder was very low on fluid, maybe even empty. Do I need to bleed the master cylinder? If so, how is it done?

Thanks for your help.

[MARK2]

So far I have found this:

If the master cylinder has been disassembled or if the reservoir
becomes empty, bleed the air from the master cylinder.
(a) Disconnect the 2 brake lines from the master cylinder.
(b) Slowly depress the brake pedal and hold it.
(c) Block off the outlet plugs with your fingers, and release
the brake pedal.

(d) Repeat (b) and (c) 3 or 4 times.

My question is, in step C, after I release the brake pedal, do I remove my fingers from the outlet plugs or just keep them there? I have never bled the master before.....obviously.

Thanks

[95PimpingCamry]

I have never bled the master cylinder, but to me it sounds like you want to remove your fingers when you press the pedal (to let the air out), and plug with your fingers when you release the pedal (prevent air from entering). You should also have the reservoir full during this procedure.

[MARK2]

Originally Posted by 95PimpingCamry

I have never bled the master cylinder, but to me it sounds like you want to remove your fingers when you press the pedal (to let the air out), and plug with your fingers when you release the pedal (prevent air from entering). You should also have the reservoir full during this procedure.

I think your right, makes sense.

Thanks

[Axxis8203]

no, the instructions are correct as they are written. they state to use your fingers to plug the holes when you release the pedal so that air does not reenter the system, just as you would when bleeding the brakes at the wheels.

[Dave's]

Never actually had to bleed a master cylinder but I think you would keep your fingers on. The person pressing the pedal should have no trouble overcoming the pressure of your fingers and forcing fluid and air past them. Think of your finger as a one way valve. As the pressure from the pedal diminishes your finger(s) immediately close off air from re-entering.

[JohnGD]

+1. I use a bench bleeder kit. Basically your fingers will act like one-way valves. If there is pressurized air/fluid they'll push your fingers aside to exit the master cylinder. When there is no pressure (released pedal), then your fingers closed the ports like one-way valves close the ports.

You may also want to raised the rear of the car so the master cylinder is about level. You should be able to tell easily if there is air in there then.

I never tried this, but when the master cylinder is level, you may be able to see bubbles in the reservoir if the piston is pushed back. It's like a reverse flush, and I assume you have lines with only clean fluid by now. Might be worth a try before you remove the brake lines using flare nut wrenches.

Do you have ABS?

Originally Posted by Dave's

Never actually had to bleed a master cylinder but I think you would keep your fingers on. The person pressing the pedal should have no trouble overcoming the pressure of your fingers and forcing fluid and air past them. Think of your finger as a one way valve. As the pressure from the pedal diminishes your finger(s) immediately close off air from re-entering.

[RU2CHKN]

I used a one man bleeder kit from advance auto parts. I also had a friend press down on the pedal and hold it there til I close the bleeder screw up.

[bill buttermore]

Some auto parts stores sell brake bleeder kits (Dorman Help line?) comprising a couple of vinyl hoses about 15" long and a couple of plastic fittings to screw in the outlet ports. But the plastic fittings don't always seal properly, and as others have mentioned, you don't want to suck in air on the return stroke when the pedal is released. You can make a bleeder kit for your master cylinder that works perfectly by buying a couple of pieces of replacement metal brake line with the correct-fitting nuts for your master cylinder, or even better, use a tubing cutter to remove the nuts with about an inch of metal tubing from a donor car in a junkyard. Slide a piece of tightly-fitting vinyl tubing onto the cut metal tubes at both outlets and route them into the reservoir full of fluid. Then, pump and release the pedal slowly until no bubbles appear from the hoses.

This is usually done on a bench in a vise where the master cylinder can be kept level and the piston can be depressed by hand to the end of its run with a dowel rod or a round-end metal rod. If you go this route, be careful to clamp the cylinder in the vise by the mounting ears and not by clamping on the cylinder bore.

[MARK2]

Wow, thanks for all the help everyone. I had a friend help me bleed the master and the brake lines last night and everything seems good now. The pedal is nice and firm and the car stops on a dime.

Thanks again for all the responses.

Mark