master cylinder bolt in swap(?)

[pj's64F250&66F600]

Folks, I know we've written about putting in a dual master at length. Two questions:


1) I drive a lot of old cars that have had brake line rust and when I step on the pedal when, unbeknownst to me that there is a rusted line, it goes right to the floor - this is on dual master cylinder equipped cars. I've experienced this sort of brake failure a number of times (no problem on any of the multiple occasions, thankfully). So, the advantage of a dual master cylinder is...??

2) I've been a member of this discussion group way since back when it was an msn group and I don't recall a single post that discussed a retrofit of a dual master cylinder that didn't involve rod modification. Is there a direct swap?

I did a rather exhaustive search on the topic this morning, so I don't believe I'm simply being lazy and asking an oft-repeated answer here.
Thx.

[Brian Taylor]

I had to modify the rod I used. It is a simple process and if you wish not to modify one I have a spare I can cut down for you.
You can run a single pot or dual just be sure that all the components of the brake system are in good working order, this is one part of any vehicle that lives depend on.

[DV65CustomCab]

The dual circuit will provide at least limited braking on 2 wheels when the other circuit fails. You don't have this luxury with a single line system.

For simplicity of replacement parts I used a Ford pickup master cylinder that does require the rod be cut down to install. I've read but have not personally used a Mustang master cylinder which allegedly bolts right in and is the proper length...I think the year needed is 1969(?). Remember, you MUST get one designed for your system (disc or drum front brakes). My how-to illustrates using the truck master and cutting down the pushrod: http://www.mongrelmotorsports.homestead ... discs.html

[pj's64F250&66F600]

Great...1969 Mustang perhaps. Can anyone confirm? It seems that the most efficient way to do this would be to get one that doesn't automatically require the extra work/trial and error given that one that is a bolt in evidently exists and I'm sure would be approx the same price as would units requiring modification.

Of course, in '64, my F250 setup is drum brakes all around.

Can anyone confirm the year?

[65 66 Ford]

Use a master cylinder from a 67 F100, F250. It will bolt right in without any modification needed. The 68 and later trucks have the longer push rod.

[64shortbed]

Thank you! I've been looking for an answer to this one for a while.

[matt2491]

I used a 1974 Maverick master cylinder with a 15/16" bore. I did have to lengthen my pedal rod by about an inch. However it works great for manual disc/drum brakes. Almost feels like power brakes.

[jacobd]

Use a master cylinder from a 67 F100, F250. It will bolt right in without any modification needed. The 68 and later trucks have the longer push rod.

Is this official honest and for true? Will it work on Cheryl's 66.
She is going under the knife today. Having surgery on her decellerating system. If this is at simple as sounds. I'll be a happy boy.

[slickmainer]

I have have read that 67 will bolt direct, never did it, but have read it many other places

[69supercj]

I just bought a dual res M/C for my '66 and I went with one for a '68 Mustang with front disc, non-power. It came with two rods. One was real close and all I had to do was grind the end off of it, 'bout 3/16ths or so. I'm fairly certain that my truck has the stock pedals. One tip, these new M/C's come with a spring steel keeper that clips onto the end of the rod. Don't install it untill your absolutely sure that you've got the rod the correct length because if you put it on the end of the rod and then try to test fit the rod into the M/C to check for correct length, you wont be able to remove it if you have to do any further mods. I plan on leaving mine off completely as unless your M/C falls off the firewall, the rod can't come out.

[samdog1966]

I used a M/C from a 68 Mustang from NAPPA. Bolts right up. I did have to modify the rod.

[DukeRoche]

I personally don't mind the repeated questions on the master cylinder. Every time someone asks I learn something new

[DukeRoche]

And to add to that I have a question of my own. Last year for Christmas my wife bought me a master cylinder for my Slick but its not the duel one. It is the swap for the original one thats about to rust apart in my Slick now. I will have to redo the whole brake system (or someone will). In the event of a complete new system, will this master cylinder work okay? I hate to tell my wife that all that all that effort she put into purchasing a Slick part went for not

[slickmainer]

well as my dad would say, the single pot master cylinder never failed him hauling beans out of the field and down the road, so id put that new one on and go with it. I had to relearn how to drive correctly (planning, slowing down, etc), but my single never failed me, and with new lines, it should be good for another 20 years.

["Whitey Ford"]

I have a single pot with disc up front and it works just fine. It is getting a little rusty so I plan on changing mine out as well but i think changing the pot to an original one should be just fine. I think it looks better anyway.

[Obsa]

The way that I understand it is a single pot MC works fine in the sense that hydraulic pressure is provided to all four wheel cylinders from the one chamber. Loss of pressure at any point causes a loss of all braking (except for cable operated patking brakes). A dual chamber MC splits the system into front and rear sections so if you lose pressure at one wheel you still have some braking power. Really just a safty factor.

[69supercj]

Hey whitey, are you running any type of a residual valve for your front disc brakes? Reason I ask is I had the same setup on mine but with the stock M/C which puts out 10 or so lbs. of residual pressure, my front pads were staying pressed against my front rotors, which was causing excessive brake dust and probably robbing me of some gas mileage. Might want to check yours.

["Whitey Ford"]

69super...im not sure. they were on when I got them but I did change the pads and all seemed ok. Where would the residual valve be located? Im assuming at the brake itself correct?

[69supercj]

Should be plummed in the front brake line somewhere. Have you noticed your front wheels being hard to spin when you've got it jacked up?

["Whitey Ford"]

No not really...hell i can push the truck with one leg sticking out the door...all is well but i will check anyway. I need to rebalance my driveshaft so when I do that and have the jack out I will try it out.