MC bench bleeding

[65-72 chevytoys]

Anyone here have any tips on bench bleeding when replacing a MC. How much fluid does it take and then to bleed the whole system? What tools to use to bleed the fluid from the ports back into the MC? Plastic tubing, or old lines? Can the MC be bleed after mounting in the truck before the lines are hooked up to use the pedal to do the bleed? I have never done this before so simple instructions would help. Once I hook up the actual lines what order do you bleed the wheels? Thanks for the help.

[flatheadnut0]

You can sure do it with the brake pedal or you can follow some of the threads here. That is a better solution. The brake pedal method takes a partner. One of you pushes the pedal and holds pressure while the other opens the bleeder. When the pedal pushes to the floor the bleeder needs to be closed. Repeat until you have all the air and bubbles out of the lines. Start with the wheel that is farthest from the master cylinder.

[pissonNOS]

just bench bled my master cyl on the 92 chev the other night i got some fitting to fit into the two holes and just used some rubber hose which goes from the fittings back into the reservoir. Fill the reservoir full and use a blunted off screw driver to push on the cylinder dot go all the way with the pushing it might wreck seals and just keep pushing and letting off slowly till you dont see any air bubbles in the lines anymore then you should be ok. If someone can simplify my instructions go ahead I some times hae a hard time explaining my self

[AR15DEFENSE]

Originally Posted by pissonNOS

just bench bled my master cyl on the 92 chev the other night i got some fitting to fit into the two holes and just used some rubber hose which goes from the fittings back into the reservoir. Fill the reservoir full and use a blunted off screw driver to push on the cylinder dot go all the way with the pushing it might wreck seals and just keep pushing and letting off slowly till you dont see any air bubbles in the lines anymore then you should be ok. If someone can simplify my instructions go ahead I some times hae a hard time explaining my self

[65-72 chevytoys]

Well NAPA didn't have any fittings to put in the outlet holes. I did get some plugs to put in the holes and the instructions with the MC said you can do it this way by pushing in the pistion until you get good pressure. Anyone done it this way before?

[Eichorst69]

Where did you buy the MC, it should have came with plactic fittings & rubber lines??? Every one I ever bought has!
Once you have those, run each line into each reservior and push in the piston until the air is out, 10-12 times should usually do it.
Then bolt it to the truck, attach and tighten the brake lines, and then bleed the master again by having someone pump & hold the brake pedal while you release each line a few times. That will get the air out of the lines too.
As far as I know, I don't think they sell those plastic fittings seperately, check wit where you bought it.

Rob

[65-72 chevytoys]

I got a new MC at NAPA. Nothing in the box except MC and instruction sheet. I have bleed the line before, but this is the first time I have replaced a MC. I will check the instruction for the parts list and see if they should come in the box.

[Fred T]

I have a different approach on bench bleeding, which has never failed me. Install the m/c, hook up the lines, and fill with fluid. Then hold a rag under the fittings where the lines exit the m/c, and crack open the fitting until fluid drips out. Tighten the fitting and you're ready to bleed the system.

When bleeding the system, I use a helper to pump the pedal. I also use a piece of clear plastic tubing about 2' that fits over the bleeder nipple. Put the end in a pop or water bottle and position the tube so the fluid has to run uphill from the fitting before it drops down. That way the first part of the tube stays filled with fluid. Makes it easier to watch for air bubbles. You can also know when you have new fluid coming out, so the system is flushed, a very important step.

Complete flushing usually takes two of the small cans of fluid. Be sure you don't let the m/c run dry during the bleeding, or you will have to start over again.

[65-72 chevytoys]

Cool Fred thanks for the info I will try that.

[truckdude239]

alot of mc company's have come up with a new way of bleed a mc they give you 2 plugs that you screw in the fill it dot 3 brake fluid pump the mc untill no bubbles are seen in the resavior

[WorkinLonghorn]

They have MC bleeding kits at the parts stores. I bought one last century and am still using what's left of it. Just some tubes,various sized threaded adapters and some clips that hold the tubes into the reservoir(s).
I've heard there is a product called quick bleeder or something that you can put on the wheel bleed port that make bleeding easier. I just put a hose into a jar of brake fluid.

[BobbyK]

How I did mine.
Just bent up some brake line I had allready.

[65-72 chevytoys]

Bobby that brings up a good question do I need to do the prop valve at the same time or will that be taken care of when I bleed each line at the wheels?

[Yukon Jack]

I use a power bleeder that I made - check this thread for information on how to build one. I just used it on my 70 K5 and it took care of the master cylinder without me bench bleeding it. Sure works fast to and doesn't take a helper.