Pneumatic Brake Bleeder with Dual MC
- Ronald I. Maciejewski
- 356 Fan
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Pneumatic Brake Bleeder with Dual MC
A smoking brake incident required a total rebuild of both fronts on my '58 A. Everything new except for turned in-spec drums and Zims dual MC. Now ready to bleed.
I was gifted, but never used, a HF pneumatic brake bleeder. Instructions are pretty straight forward.
Any reason not to use with dual MC?
Any concerns with 90 lbs compressor pressure?
Planned bleeding sequence; RR, LR, RF, LF. OK?
As always, any and all guidance is appreciated.
Thank you.
I was gifted, but never used, a HF pneumatic brake bleeder. Instructions are pretty straight forward.
Any reason not to use with dual MC?
Any concerns with 90 lbs compressor pressure?
Planned bleeding sequence; RR, LR, RF, LF. OK?
As always, any and all guidance is appreciated.
Thank you.
Ron
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- 356 Fan
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Re: Pneumatic Brake Bleeder with Dual MC
I use one but only with 10psi, anything higher pressure makes the fluid shoot out of the bleeders in a spray. I have the manual pump up type, homemade but just like the Motive, make sure when done you suck a little bit of fluid out of the reservoir to leave an air space.
- Phil Planck
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Re: Pneumatic Brake Bleeder with Dual MC
It helps to bench bleed the m/c before installing. If already It installed you can still bleed it in situ before starting with right rear.
Phil Planck
- David Jones
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Re: Pneumatic Brake Bleeder with Dual MC
One small correction here Phil. The right rear is not the furthest away from the MC if you are assuming that it is so. In a straight line it is but in reality the rear brake lane splits on the right side of the trans and then runs over to the left brake so that one is slightly longer than the route to the right side. I know I am nitpicking as it probably does not make one iota of difference in practical brake bleeding operation.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715
Cymru am byth
David Jones #9715
- Glen Getchell
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Re: Pneumatic Brake Bleeder with Dual MC
You are going to be more specific as to what a HF brake bleeder is.
You have two types of pneumatic bleeders. The Pushers, and the suckers. I have both, and much prefer the pusher for a good bleed. The pushers attach to your reservoir and push fluid through. If you have a duel system with one reservoir, then you are good to go, but you should only used no more than 15lbs of pressure. If you have two reservoirs, then you will have to do the front and rear separately.
If you are using a sucker kind (I.E. vacuum) then you are still good to go with the duel system. But in my opinion 90lbs is insanely high. Maybe 40lbs or less. Personally I have not had very good luck with the vacuum style. Seems like you can pour gallons of fluid and always have bubbles. But they are good to get the system up and running so you can do an old fashion wife in the driver seat pumping bleed to finish the job off right. I can usually get a good bleed with the pusher.
Just remember to start at the wheel furthest from the MC and work towards it.
Glen
64Cx2
You have two types of pneumatic bleeders. The Pushers, and the suckers. I have both, and much prefer the pusher for a good bleed. The pushers attach to your reservoir and push fluid through. If you have a duel system with one reservoir, then you are good to go, but you should only used no more than 15lbs of pressure. If you have two reservoirs, then you will have to do the front and rear separately.
If you are using a sucker kind (I.E. vacuum) then you are still good to go with the duel system. But in my opinion 90lbs is insanely high. Maybe 40lbs or less. Personally I have not had very good luck with the vacuum style. Seems like you can pour gallons of fluid and always have bubbles. But they are good to get the system up and running so you can do an old fashion wife in the driver seat pumping bleed to finish the job off right. I can usually get a good bleed with the pusher.
Just remember to start at the wheel furthest from the MC and work towards it.
Glen
64Cx2
- Doug McDonnell
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Re: Pneumatic Brake Bleeder with Dual MC
Like Steve I also use a pusher type and use 7-10 Lbs of pressure. It is important to remember that you are not trying to push fluid through. You are creating a pressure and want the air to come out. I think very minimal opening of the bleeder allows time for the air bubble to move and come out.
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.
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Re: Pneumatic Brake Bleeder with Dual MC
I use the Motive Power Bleeder from Zims on my single circuit. It makes bleeding a JOY !!!
- David Jones
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Re: Pneumatic Brake Bleeder with Dual MC
I'm cheap, I put a spare Schrader valve in a spare MC cap and pressurize it with my compressor set at 10 psig.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715
Cymru am byth
David Jones #9715
- Ronald I. Maciejewski
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Re: Pneumatic Brake Bleeder with Dual MC
Hi,
Thanks to all.
To clear up a few things.
HF is Harbor Freight. The specific brand is Pittsburgh Central Pneumatic Brake Bleeder. It is the vacuum/suction style.
I'm assuming (hate that word) that the 90 psi at the compressor is somehow adjusted by the bleeder. Having said that I will start with a lower pressure of 40 lbs as recommended and work my way up if needed.
I have the dual system with one reservoir so I should be okay.
I've read David's comment before of RR vs LR being furthest from the MC and will modify my bleeding sequence accordingly; LR, RR, RF, LF.
Probably be a week or so before I get to it as my back is still recovering from multiple excursions under the car. Sorry now that I was talked out of a lift purchase a few years. back.
Thanks again to all.
Thanks to all.
To clear up a few things.
HF is Harbor Freight. The specific brand is Pittsburgh Central Pneumatic Brake Bleeder. It is the vacuum/suction style.
I'm assuming (hate that word) that the 90 psi at the compressor is somehow adjusted by the bleeder. Having said that I will start with a lower pressure of 40 lbs as recommended and work my way up if needed.
I have the dual system with one reservoir so I should be okay.
I've read David's comment before of RR vs LR being furthest from the MC and will modify my bleeding sequence accordingly; LR, RR, RF, LF.
Probably be a week or so before I get to it as my back is still recovering from multiple excursions under the car. Sorry now that I was talked out of a lift purchase a few years. back.
Thanks again to all.
Ron
- David Jones
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Re: Pneumatic Brake Bleeder with Dual MC
Rin, the 90 psi of air at the compressor is required to be able to generate the vacumn suction needed by the eductor in the bleeder can. 40 psi will be unlikely to produce any useful suction.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715
Cymru am byth
David Jones #9715
- Ronald I. Maciejewski
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- Al Zim
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Re: Pneumatic Brake Bleeder with Dual MC
I posted about brake bleeding using gravity rather than a pressure bleeder. With the dual master cylinder you must use a pressure bleeder. I apologize for being misleading.
Last edited by Al Zim on Fri Nov 19, 2021 2:39 pm, edited 1 time in total.
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- Wes Bender
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Re: Pneumatic Brake Bleeder with Dual MC
Ronald, that vacuum bleeder will be a bit harder to use because it will try to suck air in past the bleeder screw threads. It will work once you get the hang of it, but I found the pressure bleeder to be much better. In Al's method, they are using gravity as the sole force to bleed the brakes. That works too. I bleed mine once a year and keep removing fluid at each caliper until it comes out fresh. Check the reservoir and don't let it run out or you'll just be letting more air in.
Some days it's just not worth chewing through the restraints.....
- Ronald I. Maciejewski
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Re: Pneumatic Brake Bleeder with Dual MC
Thanks AL and Wes. Like the Eveready Bunny the good advice just keeps on coming.
Thanks again. Love this Forum.
Ron
Thanks again. Love this Forum.
Ron
Ron
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Re: Pneumatic Brake Bleeder with Dual MC
Another suggestion: get a piece of clear tubing that fits over the bleeder valve, so you can see the bubbles and avoid making a mess with the fluid coming out.