Master cylinder installation
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 2,337
Likes: 14
From: Norfolk VA
Master cylinder installation
Can someone explain the bench bleeding process (how it's done) I have a reman MC and I would like to install it. Does the MC kit come with screw type plugs? If not, where can I get them? I understand that there are two resivors. My question is how do you know which piston for which resivor you are pushing the air out of? What do you use to push on the back end on the MC?
Instructor
Joined: Oct 2005
Posts: 147
Likes: 0
From: Lafayette IN
Just did my first brake job a few months back...and they still work 
I'm not familiar with any other MC's, so I don't know how you have more than one cylinder to pump for both reservoirs...Mine had one "piston" to pump both reservoirs and 2 brake lines coming out the sides, one for the front, one for the rear.
To bleed the MC, I put it into a vice then ran some old brake lines up out of the cylinder and back into the reservoir. Front line goes to the front reservoir, back line goes to the back. I basically bent the lines into a big loop until they were submerged in the brake fluid in the reservoir.
I don't remember exactly what I used, something with a long skinny handle and a blunt end (screwdriver, but not the end with the bit, or a socket wrench handle), but I pumped the cylinder til I didn't see any air bubbles coming out of the reservoirs. I took my time, wanted to do a good job and make sure I didn't screw up. I spent about 30min pumping the cylinder til I was completely satisfied.
Then I put the cap back on, installed the MC on the car, bled the brakes, and drove.
I am far from an expert, but I hope this helps.
I'm not familiar with any other MC's, so I don't know how you have more than one cylinder to pump for both reservoirs...Mine had one "piston" to pump both reservoirs and 2 brake lines coming out the sides, one for the front, one for the rear.
To bleed the MC, I put it into a vice then ran some old brake lines up out of the cylinder and back into the reservoir. Front line goes to the front reservoir, back line goes to the back. I basically bent the lines into a big loop until they were submerged in the brake fluid in the reservoir.
I don't remember exactly what I used, something with a long skinny handle and a blunt end (screwdriver, but not the end with the bit, or a socket wrench handle), but I pumped the cylinder til I didn't see any air bubbles coming out of the reservoirs. I took my time, wanted to do a good job and make sure I didn't screw up. I spent about 30min pumping the cylinder til I was completely satisfied.
Then I put the cap back on, installed the MC on the car, bled the brakes, and drove.
I am far from an expert, but I hope this helps.
Drifting
Joined: Apr 2002
Posts: 1,716
Likes: 4
From: New Baden Illinois
I agree with ceweaver's method. However, they also make plastic adapters with rubber hoses to return the fluid back into the reservior. You basically keep pumping until there are no more bubbles coming out of the return lines.
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
A picture is worth 1000 words.
Use a Phillips screw driver to push the piston until it stops. It will move an inch or so. Release and push again. Continue until no air bubbles are coming from the tubes. It is IMPORTANT that the resorvior is filled with clean brake fluid and the tubes are submerged in it (the one in the pic has no fluid). Otherwise you'll just suck in more air when you release the piston.
Use a Phillips screw driver to push the piston until it stops. It will move an inch or so. Release and push again. Continue until no air bubbles are coming from the tubes. It is IMPORTANT that the resorvior is filled with clean brake fluid and the tubes are submerged in it (the one in the pic has no fluid). Otherwise you'll just suck in more air when you release the piston.
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
Originally Posted by Oldguard 7
Good piv. BTW, are those brake lines or copper tubing of the appropriate diameter to allow fitting into the MC.
Burning Brakes
Joined: Feb 2002
Posts: 752
Likes: 31
From: Melbourne Australia
I like to leave the tubes on the master cylinder, install it on the car then remove one tube and refit the brake line. Repeat for the second tube.
Use a shop rag under the master cylinder so the brake fluid doesn't make a mess when you remove the bleeding tube and make sure the fluid level is full in the master cylinder so there is no chance it can drain out completely or you will have to start again.
Hope this helps,
Joe
Use a shop rag under the master cylinder so the brake fluid doesn't make a mess when you remove the bleeding tube and make sure the fluid level is full in the master cylinder so there is no chance it can drain out completely or you will have to start again.
Hope this helps,
Joe
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Drifting
Joined: Feb 2005
Posts: 1,738
Likes: 2
From: San diego ca
I just replaced my MC about 3 weeks ago... and imagine my surprise when the enclosed instructions indicated you can bench bleed the the MC without the arrangement shown above, but instead with the port plugs still in the outlet ports....
basicly this involved VERY SLOWLY pushing on the piston with your phillips screwdriver and watching for air bubbles out of the feed hole in each well.
Though skeptical I tried it and lo and behold it worked great...
basicly this involved VERY SLOWLY pushing on the piston with your phillips screwdriver and watching for air bubbles out of the feed hole in each well.
Though skeptical I tried it and lo and behold it worked great...
Safety Car
Joined: Jun 2002
Posts: 4,757
Likes: 2,506
From: Buckeye, AZ
St. Jude Donor '12-'13
Originally Posted by Dick72LT1
I have to do this soon. I'm told auto parts stores sell a kit with plastic fittings and hoses just for this purpose. In fact, I believe some MCs come with the kit. Mine didn't. FWIW. 
The kit works nice and I only paid a few bucks for it. Threaded fittings, etc. Install per instructions and push the piston in and out with screwdriver.
Safety Car
Joined: Aug 2001
Posts: 4,883
Likes: 11
From: North Easton Mass
Originally Posted by fauxrs2
I just replaced my MC about 3 weeks ago... and imagine my surprise when the enclosed instructions indicated you can bench bleed the the MC without the arrangement shown above, but instead with the port plugs still in the outlet ports....
basicly this involved VERY SLOWLY pushing on the piston with your phillips screwdriver and watching for air bubbles out of the feed hole in each well.
Though skeptical I tried it and lo and behold it worked great...
basicly this involved VERY SLOWLY pushing on the piston with your phillips screwdriver and watching for air bubbles out of the feed hole in each well.
Though skeptical I tried it and lo and behold it worked great...
I did the same thing a few weeks ago. MC was from Advance Auto. i had never heard of the closed plug bleeding method before but it did indeed work. Too bad my son didn't tighten the brake hose to the front caliper more carefully. Now I get to bleed everything again this weekend.
Rick B.