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May 8, 2005 | 07:30 PM

51fordrodder

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Joined: Feb 2005

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need to stop

I purchased a power brake unit off ebay and its a disc/drum master cylinder. I want to leave the drums up front because everything is brand new in them. My question is can I use that master cylinder if i put a 10lb check valve to the front and rear?

May 8, 2005 | 08:25 PM

Earl

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From: Waynesville, OH

I think you prolly can. From previous discussions, the master cylinder difference from disc to drum is that the disc reservoir is larger as the disks take more fluid volume to actuate. You shouldn't run into a problem provided the master cylinder doesn't already have built-in residual pressure valves and/or a proportioning valve. You didn't mention it but you'll also need a proportioning valve if you want to reduce nose dive and get the rear and front to hit maximum stopping power before breaking loose at the same time.

May 8, 2005 | 08:48 PM

Madathlon

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Joined: Dec 2004

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From: Shasta Lake, Ca.

No you cant.. That master can not supply the amount of fluid needed to work the front drums.. you will be over working the rear brakes to stop the truck.. This is not a good idea... Id would save that master and just get theone for a drum/drum set up that will fit your booster..

May 9, 2005 | 06:28 AM

GreatNorthWoods

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From: Littleton, New Hampshire

I agree with Earl. Depending on which MC you have it may or may not have an internal residual valve to the rear so to be safe I'd use a 10 pounder on both the front AND rear unless you want to dissassemble the MC to find out. Even if it does have an internal residual valve, putting a second one inline will not hurt anything. I'd try it without the proportioning valve first and then add one to the rear if you find you need it.

Vern

May 9, 2005 | 12:02 PM

AXracer

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Joined: Oct 2004

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From: Durham NC

Discs require more fluid volume than drums so there won't be a capacity problem with the disc/drum MC being used for drum/drum I am using a Disc/disc MC for Disc/drum on my truck.

May 9, 2005 | 12:04 PM

tgregoire

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From: chicopee us

I accidently (didn't know any better, was only 15) put a disk/drum in my 53 and I would just tap the brakes and I thought I would go through the windsheild. I put in a drum/drum and it was 100% better. Added an adjustable proportioning valve and it is fine now.

May 9, 2005 | 12:15 PM

imlowr2

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Joined: Apr 2004

Posts: 3,005

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From: Santa Clarita

I'm doing my brakes and lines right now. Since I'm replacing the drums in the front with disc, I had to go with the dual chamber MC. I'm running the same as AX which is disc/disc and using a proportioning valve to the rear brakes. It's my understanding the 10 lb residual valves are usually recommended if the MC is mounted on the frame. You don't need them for the firewall mount. It has to do with backflow of the fluid. I was told you can run the disc/ drum MC and it's actually recommended with the drums up front. I would recommend a proportioning valve in the rear just for the fact that you can adjust it, which is nice. With the master cylinder you have, you can have a leak or loss of brakes and either side or chamber will still allow you to stop. The single chamber, when you loose fluid, that's it. Time to do the Flintstones routine and put your feet out the door to stop. I'd stick with the dual MC...