bench bleed Master Cylinder
Team Owner
Joined: Apr 2002
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From: Zionsville, PA NRA Life Member
St. Jude '03-'04-'05-'06-'07-'08-'09-'10
When I purchased my new master cylinder for my '77, it came with two plastic fittings and short tubing to bench bleed it.
You could purchase a short piece of brake line and bend it to suit.
Jeff
You could purchase a short piece of brake line and bend it to suit.
Jeff
Instructor
Joined: Sep 2004
Posts: 193
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I suppose you probably COULD bench bleed the master cylinder in the car; however, it requires a lot of pushes on the brake pedal and someone to make sure the brake fluid doesn't splash all over. I did mine on the bench using a phillips screwdriver - got a sore arm because I just couldn't believe it when all the bubbles stopped coming up and kept depressing the thing. My new master cylinder also came with plastic fittings and hoses to go back up into the cylinder.
Safety Car
Joined: Aug 2001
Posts: 4,883
Likes: 11
From: North Easton Mass
I don't trust the plastic fittings and plastic hoses because they always seem to leak fluid, and the hoses tend to fall out ot the reservoir. If they are leaking fluid they are also letting air in. Someone on the forum made a bleeder setup using metal fittings and lines. That setup, while being more time-consuming to fabricate and specific to one fitting size, looks like a much better way to bench bleed the MC. Just MHO.
Rick B.
Rick B.
Thread Starter
Instructor
Joined: Apr 2005
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I got the MC from VBP and the only thing that came with it was 2 plastic plugs covering the brake line holes. I see no way of using them.
Another question is does any one know the hole size. so I can pic up 2 brake lines.
Another question is does any one know the hole size. so I can pic up 2 brake lines.
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Team Owner
Joined: Jun 2004
Posts: 20,216
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From: Smile, it's just the internet.
I just bought to short steel brake lines from Advance Auto. They were already flared and had fittings installed. I just cut off one end and installed them on the MC, then bent them to where I wanted them.
I agree about the bench versus in-car. Clamp it in a vice and be patient. There's a LOT of air in there!
I agree about the bench versus in-car. Clamp it in a vice and be patient. There's a LOT of air in there!
Intermediate
Joined: Nov 2005
Posts: 40
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From: Kent WA
One other thing you might try that has worked well for me....
After you tire your arm out by pumping the piston on the bench,
if you have time (don't need to drive the car the next day) and/or
can excercise a little patience, just leave the master cylinder there
on the bench for 24-48 hours or more and occaisonally walk by and
give it a few pumps. Left on it's own, any air bubbles should "gather"
over time and make it easier to evacuate them by excercising
the piston several times.
Bela P. Havasreti
After you tire your arm out by pumping the piston on the bench,
if you have time (don't need to drive the car the next day) and/or
can excercise a little patience, just leave the master cylinder there
on the bench for 24-48 hours or more and occaisonally walk by and
give it a few pumps. Left on it's own, any air bubbles should "gather"
over time and make it easier to evacuate them by excercising
the piston several times.
Bela P. Havasreti
Team Owner
Joined: Jun 2004
Posts: 20,216
Likes: 4
From: Smile, it's just the internet.
Originally Posted by kodaclr
Hey one more question, The rubber boot on the end, do I need to take this off the MC before I bench bleed and even install?
Burning Brakes
Joined: Apr 2004
Posts: 847
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From: Des Allemands LA
Originally Posted by kodaclr
I got the MC from VBP and the only thing that came with it was 2 plastic plugs covering the brake line holes. I see no way of using them.
Another question is does any one know the hole size. so I can pic up 2 brake lines.
Another question is does any one know the hole size. so I can pic up 2 brake lines.
ltlevil
Team Owner
Joined: Jul 2004
Posts: 40,368
Likes: 787
From: Redondo Beach, California
Originally Posted by LIQUIDDRAGON
i have a question about bench bleeding a MC. can you bench bleed it after you bolt it on the car if you can get it level by jacking the rear of the car up?
These bleeders appear to be added to the MC to bleed the MC hydraulic chambers. Actually since the MC is positioned in the car with an upward tildt, it appears that these bleeders will remove air from the MC just as it is bolted in the car. That's what I've done.
Yes... I think that if you have a MC without the 1968 bleeders I've described, you can "bench" bleed your MC by jacking up the car so that the MC is horizontal. I think this is the way to go. If you've renewed eveything with your brake system and tighened up everythink to see you it fits, you probably don't want to remove yuor MC just to bleed it. If you can do it in the car, this is best.
I did ther MC bleed procedure on my 68 Corvette with the MC installed. I used the 68 MC bleeders to remove air. Later MC's will not have these bleeders in the Mastr Cylinder. :
Last edited by 68/70Vette; Feb 13, 2006 at 10:04 PM.
