master cylinder swap

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Feb 3, 2004 | 09:23 AM

onelowzuki

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From: Central PA

master cylinder swap

I got a master cylinder assembly that would fit great in my 56 f250, the deal is it is for disk/drum setup. I want to keep it all drums for now and swap it to disks later on this year. If i put a 10 lb residual valve inline on the disk outlet on the master cylinder it should work, right ? I know it would be easier to do it all at once, but it is not an option right now due to money. If you guys have any ideas or opinions let me know if it will work or not.

Feb 4, 2004 | 07:41 AM

GreatNorthWoods

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From: Littleton, New Hampshire

Re: master cylinder swap

Quote:

Originally posted by onelowzuki
I got a master cylinder assembly that would fit great in my 56 f250, the deal is it is for disk/drum setup. I want to keep it all drums for now and swap it to disks later on this year. If i put a 10 lb residual valve inline on the disk outlet on the master cylinder it should work, right ? I know it would be easier to do it all at once, but it is not an option right now due to money. If you guys have any ideas or opinions let me know if it will work or not.

A 10 lb residual valve placed inline between the front MC compartment (disc outlet) and before it splits to the front drums should work just ducky...

Feb 4, 2004 | 08:48 AM

onelowzuki

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From: Central PA

Thats what i thought, i just wanted to be 100% sure, i am always willing to guess when it comes to going forward, i never guess when it comes time to stop.

Feb 5, 2004 | 04:52 AM

GreatNorthWoods

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From: Littleton, New Hampshire

Quote:

Originally posted by onelowzuki
Thats what i thought, i just wanted to be 100% sure, i am always willing to guess when it comes to going forward, i never guess when it comes time to stop.

Good advice for anyone! I went through all that residual valve stuff on a 29 Ford a few years ago. I didn't think I'd ever get the brakes working right. Eventually I did, but no more under the floor master cylinders with disc brakes for me. I'm putting mine on the firewall from now on.

Feb 5, 2004 | 07:25 AM

onelowzuki

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From: Central PA

Yeah, I am going to do the firewall mount also, the floor pedals are cool but it is easier and cheaper to do the firewall mount when going with power brakes

Feb 5, 2004 | 11:42 AM

tgregoire

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From: chicopee us

I thought the residual valve was to hold a small amount of pressure on the brakes?? I had a disc/drum master in my 53 and just tapping the brake pedal would put you through the windshield. I swapped it for a drum/drum master and it is much better. I still had to use a proportioning valve to get them how they should be.
I was always told the masters are not the same for disk/drum versus drum/drum. I assumed different orifice sizes.

Feb 5, 2004 | 05:29 PM

onelowzuki

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From: Central PA

From what i understand the valve will hold pressure against the wheel cylinders so they won't collapse, a valve is not needed if the line is going to disk brakes and if it is higher then the calipers. They usually made disk/drum master cylinders a larger bore to get more fluid to the calipers, but the larger the bore the less pressure. That is probably why when you pressed the pedal on the disk/drum setup it grab quickly (lots of fluid) The one i have is from an import car (small bore) but it is a power brake unit and it is a small unit altogether and it pushs enough fluid for drum brakes on a large vehicle but not enough for disks on a large vehicle.