'55 2nd series Disc Brakes

[Krumenauer]

I am restoring a '55 1/2 ton and have added a disc brake kit including master cylinder from Classic Performance Products. I did not bench bleed the master cylinder before installing it to my chassis and have been unable to bleed the system now that it is installed. Can this system be bled without removal from the chassis?

[Rickysnickers]

I would think you you would be able to. Just have another person pump the brake lever while the hoses from the master cylinder output are held back into the reservoirs. I'm sure others will chime in, but I think that would work.

[Krumenauer]

I have done this. In fact, I even pressurized the master cylinder using a break bleeding container and was unable to push fluid through to the wheel cylinders.

[dsraven]

you can bench bleed on the vehicle as said above. some auto stores will sell a plastic adapter set that threads into the res fittings and has a hose barb so you can use plastic tubing to go from there back into the res. they also usually come with a new master cylinder. after that little job is done you should bleed right out to the wheel cylinders though. just because there will probably be air in the system because the lines were off and the brakes were probably pumped a bit trying to bleed them. if you are by yourself on this you can use a container with some brake fluid in it, and a hose connected to the bleeder screw. start at the furthest away wheel, usually the pass rear, and work through the system from furthest away to closest. loosen the bleeder screw and put the hose onto the screw (should be a tight fit), the other end of the hose goes into the partially filled container so the end of the hose is below the fluid at all times-submerged ALWAYS. now go and make full brake applications with the pedal. the theory is the fluid goes out the tube when the pedal is depressed, then, when the pedal is released and comes back to the top (when air could get back into the system) there is no air to "suck" back up the tube because it is submerged in brake fluid. it helps to pull the pedal back so the master cylinder fills the bore with fresh fluid from the res rather than fluid from the wheel cylinder/system.
make sense? if not lyle makes a unit called a one man bleeder. it is basically the same thing only a self contained bottle with tubing and stuff already set up and some rubber fittings to fit different sizes of bleeder screws. just fill partially with fluid and (what I do) place it in a coffee can or something so you don't make a mess if it overfills or falls over. I also place a hose on the overflow of that system so it doesn't spray out the top when it overfills, just flows down the tube to where ever you place the end of the tubing, usually inside the coffee can.
google lyle tools 19200mone man bleeder for more info and youtube of how it works.
is your system disc all around or disc front and drums on the back? drums on the back means you may need a residual valve to keep some fluid back there or maybe it came already installed in the master. master cylinders are specific for what type of brakes you have front/rear. but you probably already know that.
if drum on the rear make sure to adjust the park brake after doing a normal brake adjustment. this is what adjusts the wheel cylinder end on the drum brakes so the master cylinder doesn't take 3/4 of the pedal travel to fill the wheel cylinder. the star wheel adjusts one end of the shoes to fit the drum and the park brake adjustment takes up the slack at the other end of the shoes. make sense?
have fun and remember brake fluid removes paint so be carefull.

[Krumenauer]

Thanks for the reply. I have front discs and left the rear drums. Yes I am aware that brake fluid is very aggressive on paint and even epoxy floors!

[mr48chev]

You would have to rig up your own cap for the master cylinder but you can make your own pressure bleeder for about 20 bucks if you find a small weed sprayer bottle on sale. You only want a gallon size or smaller and don't need but about 15 lbs of pressure.
An old master cylinder cap from the wrecking yard that matches your master cylinder and a couple of fittings will make a good cap for it after you trim the middle out of the gasket.

http://faculty.ccp.edu/faculty/dreed...atech/bleeder/

[1-ton of fun]

i have found that the pedal needs to be depressed some for the power bleeders to work properly.

[1-ton of fun]

on a dry system, i use a combination of the power bleeder, and a mitty-vac handheld vacuum bleeder on the wheel end of the system to help draw the fluid through the system.

also helpful tips here: http://hydratechbraking.com/braketech1.html

i used the port plugging method for bleeding a MC on a foxbody mustang that i did a brake conversion on, and it worked well.