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Old 06-13-2016, 08:17 AM   #1
pgnavy
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Bendix Hydravac w/Dual Master

Hi all, I have a factory installed Bendix Hydravac on a 59 chevy 3100, with single master cyl. I am installing a new dual master cyl from Performance Online and wondering how to connect the factory hydravac. Or do I need to buy a booster/master already setup? Enclosed is a pic of the factory HydraVac and the new master cyl I plan on installing. Any help is greatly appreciated. thx
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Old 06-13-2016, 10:34 AM   #2
dwcsr
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Re: Bendix Hydravac w/Dual Master

You can not use the hydravac with a dual master cylinder. You need a 7" dual diaphragm booster that will bolt to that bracket. depending on whether you are converting to disc front and or want under cab fill or remote fill on the firewall will determine which kit you should get. The bracket you have pictured above will not accept a booster. Its for a master cylinder only
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Old 06-13-2016, 02:46 PM   #3
1project2many
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Re: Bendix Hydravac w/Dual Master

Dodge motorhomes and many medium duty trucks with dual chamber master cylinders used dual Hydrovac boosters. Alternatively you might find a tandem HV such as this one:


Last week I was looking at a remote booster that used an hydraulic slave cylinder from a single master to actuate a vacuum assist dual chamber master. An interesting exercise that one...


BTW, I'd love to get pictures, copies, or whatever of your brackets and lines to help with the HV installation in my own truck.
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Old 06-13-2016, 03:37 PM   #4
pgnavy
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Re: Bendix Hydrovac w/Dual Master

Well, I bought the wrong item, thank you for the advice. So I am returning the manual master/bracket to Performance Online. My plan is to pull out the factory HydroVac (I realize some of you consider that a "crime") and plumping and keep if for "another day".
Here is the new setup I purchased today. Its for a disc/drum system with 7" booster (from Performance Online). I also bought the residual pressure valves to maintain a small amount of pressure in the system which is needed when the master is below the level of the calipers and wheel cylinders. This installs to the existing brake bracket which is riveted on the frame, also pictured below (from an online parts photo).
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Old 06-13-2016, 11:13 PM   #5
Softpatch
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Re: Bendix Hydravac w/Dual Master

Quote:
Originally Posted by 1project2many View Post
Dodge motorhomes and many medium duty trucks with dual chamber master cylinders used dual Hydrovac boosters. Alternatively you might find a tandem HV such as this one:

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Old 06-13-2016, 04:23 PM   #6
dwcsr
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Re: Bendix Hydravac w/Dual Master

Unless your slamming the truck the valve won't be needed, But the kit is correct for what you want to do.
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Old 06-14-2016, 06:41 AM   #7
1project2many
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Re: Bendix Hydravac w/Dual Master

No, you're not the only one. There was a guy selling them a few years ago for not too much $$. I don't know where to find one now.
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Old 06-14-2016, 09:55 PM   #8
_Ogre
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Re: Bendix Hydravac w/Dual Master

Quote:
My plan is to pull out the factory HydroVac (I realize some of you consider that a "crime")
not upgrading the brakes on any old truck is what i consider a crime

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