I have fabricated an old master cylinder cover to be used to apply pressure to the brake system in order to bleed the system. How much air pressure should I use?
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Re: Pressure Bleeding the Corvette Brake System
Bryan, since a system can gravity bleed you need very little pressure. I'd say a pound or two. Why, if your using DOT 3 you do not want it spraying on any paint as a result of high pressure. Say good by to the paint.
Not a problem with DOT 5. If your using DOT 5, about $10.00 a small container, you probably want to waste as little as possible.
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Re: Pressure Bleeding the Corvette Brake System
Thank you Harry. I'm still using the DOT 3 fluid.Comment
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Re: Pressure Bleeding the Corvette Brake System
If memory serves me correctly I believe 10 psi will work.
DavidComment
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Re: Pressure Bleeding the Corvette Brake System
Five psi is fine - no more than 10.
DukeComment
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Re: Pressure Bleeding the Corvette Brake System
Like Harry said don't get it on your paint, or say good-bye. What I do is take a spray bottle with water in it and spray a water mist around any area thar "may" get DOT 3 on it. The water will help reduce any chance of the brake fluid doing damage as long as you can get at it right away.Comment
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Re: Pressure Bleeding the Corvette Brake System
On a C1, there's a welch plug on the front of the master cylinder reservoir. The reservoir is not under pressure in service. The plug is probably inserted in there pretty good. But over the years, who knows what happened.
On my C1, I filled the master cylinder with brake fluid; hooked up the pressure bleeded; and, had pumped just a few times, got to maybe 5-10 psi, when that welch plug let go spewing brake fluid all over the engine compartment, engine, and some of the fender. Thank God it was DOT5, silicone brake fluid. But there was still a mess to clean.
If your master cylinder contains plugs or fittings that can let go, you may wish to bleed some other way, or to drape towels over the master cylinder.Comment
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Re: Pressure Bleeding the Corvette Brake System
Hi Harry,
Since you mentioned gravity bleeding could you please describe the procedure for that method. Time I have plenty of.
Thanks very much. Merry Christmas!
Regards,
Alan71 Coupe, 350/270, 4 speed
Mason Dixon Chapter
Chapter Top Flight October 2011Comment
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Re: Pressure Bleeding the Corvette Brake System
Alan, this is for my drum brake 63. I just open the wheel cylinder attach a drain tube, then remove the master cylinder cover and let it bleed out. Since I'm using DOT 5, I just wait for nice clean purple fluid without air bubbles then close it up.
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Re: Pressure Bleeding the Corvette Brake System
I used some green garbage bags and filled the area around the master cyl. with them and taped the bags and some old rags to make suire nothing would get on any paint. The pressure cap for the bleeder leak a little , glad I had everything covered up. Also had a can of blake cleaner to spray things. Once I tighten down the cover everything went good. Just keep the pressure around 5 lb. to 8 ilbs. works great.Comment
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Re: Pressure Bleeding the Corvette Brake System
All,
Thanks for the words of caution. I'm going to use a small electric air pump. I'll be sure to keep things covered, prepare for the unexpected and keep the pressure low.Comment
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Re: Pressure Bleeding the Corvette Brake System
Bryan-----
If you want to pressure bleed, I recommend purchasing a Motive Products pressure bleeder. This is a very economical unit that will save you from a lot of "jury rigging" and will get the job done. The only thing you will need to fabricate is a clamp to retain the master cylinder adapter to the master cylinder. The "chain set-up" provided with the adapter is totally inadequate.
If you do it the way you're talking about, you may very well deplete the fluid in the master cylinder while bleeding. Then, you have to start all over again.
It's also available from several of the Corvette parts vendors.In Appreciation of John HinckleyComment
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Re: Pressure Bleeding the Corvette Brake System
I have been using a hand vacume diaphram tool from snap on that has worked quite well for bleeding brakes. The tool has a cup so there is no mess. Start with most distant caliper r.r.,l.r.,r.f.,l.f. this tool has vac, guage and is great for testing distributor vac. advance, t.c.s., auto vac. modulator,ect.Comment
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Re: Pressure Bleeding the Corvette Brake System
John,
I chuckle every time I see this picture. That has to be the mother of all C clamps. One things for sure, that baby ain't going nowhere. 100 psi won't even make it sweat. Hope you had something under the bottle so the valve cover didn't get a scuff mark.
WayneComment
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