Hello all - I had some brake work done to my '62, to the tune of adding a power boost to my truck. Drums still on front and rear. The power boost came off an (ahem) S-10, with the original master cylinder attached to that. It works well, actually almost too well, as the truck is very responsive to slowing/stopping now. It really pulls to the left on hard braking also (it always has.) Brake pads are new and clean. I know I need to replace the front hubs (worn out of spec) and have the new rubber brake hoses to install. Too cold in the garage now for that and the truck's parked for the winter anyway. Just wondering if I did a bad thing, or is there some way to adjust the pressure? If it matters, the engine is a stock 5.0 with a 390 Holley carb. Thanks for you inputs!

 

I have not done this conversion yet myself. I have the MC out of a 72 F250 4x4 that was drum at all 4 corners. It will go in my 65 4x4. My question is did you or the person that installed your MC and booster get the proportioning valve to go with that MC. This my be the problem if it was not used. Pulling to one side may be more due to the hoses, brakes out of adjustment, grease or fluid leak onto the break shoes. The hard braking may be more to no proportioning valve. Sounds like you put new shoes on it but did you rebuild or replace the brake cylinders at all for corners you could have some of those that are only partially working and that can cause some hard pulling.

Hey welcome to this forum. I took a look at your truck. Looks like a nice little flairside slick. Look for Jhooch he is another Spokane boy that chimes in on this forum from time to time. Im glad to see you here Im north of town up in the Colbert area.

 

Are you using the original single pot master cylinder on the booster?

 

Run the shoes all the way out on all four corners then back off. It pulls due to one of the drums activating before the others. Nothing wrong with using other brands of parts as they all function the same way and preform the same job.

Garbz

 

So lets say that the (ahem S-10 mc/booster is[ wrong] or different) and we add to that the (ahem S-10 proportioning valve[ wrong] or different) to a Ford vehical. Keeping in mind my definition of wrong is adding Chevy parts to a Ford. Or vice versa Ford to Chevy. Would this then be a case of two wrongs making a right? Im just wondering.

 

jhooch: The original single pot m/c was retained, just added to the power boost.

My truck didn't have a proportioning valve originally, at least I don't think it did, but I do know that the modification did not include the p/valve from the S10. I've been under the impression the proportioning valve was for disc/drum set ups; really don't know if it would work on drum/drum brakes, but old vehicles worked that way didn't they?

 

Are you sure you want to stay with the single pot?
If it fails it's an e ticket.
Ask me how I know.
If you switch to a dual reservoir you will not need a p valve either if you stay drum/drum.

 

Agreed Marc... dual with the power is the only way to go... You don't need the Proportioning valve on a Drum/drum set up.. but it is a good idea anyway to get optimal braking, and even brake wear... I went without the P-valve and the rear's seem to wear out much faster than the front... SO I would suggest the P-valve to get a better brake Bias... And yes with a single piston set up.. if it ever fails.... your heart will almost assuredly fail about 1/2 second later...... and that unique fluid colored something like brake fluid will magically on the front seat , right where you happen to sit.. if you have a child with you.. take the safe route and use the dual Master Cylinder...

 

On that subject Paul.
I had always understood that if you plumbed the rear set into the rear of the m/c the it would start operating a split second before the fronts thereby eliminating the need for a p valve. Thoughts?

 

I have tried it both ways, it seems not to make much difference.. I got better braking with the fronts plumbed to the rear, and vice versa, My next conversion is changing the single piston front drums to dual piston, that should help a lot...

 

Well guys I have to tell ya. I got my power MC out of a F250 4x4 that had drum brakes at all 4 corners. There is a distribution valve in the system with internal valving. I dont think the Ford engineers just put it there for looks. You are probably going to have problems with the proper amount of pressure being applied to the front and the rear brakes. Just my 2cents. Braking is not something you want to take chances with. The easy part is getting them going the hard part is getting them stopped.

 

I'm in the process of adding a power booster and 2-circuit master to my '65 F-350 dually. It needs brake work anyway (pulls hard left, and after removing the right front drum and inspecting the parts I believe the wheel cylinder is frozen)... I am embarrassed to admit it but I have just realized I haven't changed the brake fluid since I got the truck and redid the front brakes and all three flex hoses... in '00

Anyhow, about five or six years ago I bought a rebuilt booster complete with master cylinder from NAPA. I'd have to look for the invoice but it should be for a later F-truck. The bolt pattern doesn't match the old master, which is why I've put it off so long. Original pattern is 5" wide by 2-3/4" tall, bolts, and the new booster is 3-3/4" wide by 3-1/2", studs. The booster pushrod will need to be shortened but that's less of a problem.

I'm going to leave the front plumbing intact (assuming it flushes clean) and connect it to the rear (closer to the firewall) port on the new master cyl. After plugging off the original rear port on the frame-mounted distribution block (which also has a pressure switch to operate the brake lights), I will run a new hardline from the rear frame bracket all the way to the forward port on the master.

Today I removed the old single master, rusty inside and out although still working, and the pedal assembly from under the dash (that was some fun with a rigid steering column in the way). Now I need a small 4x6" piece of 1/8" steel plate to modify the pedal bracket for the new bolt pattern, and also make some clearance reliefs for the new studs/nuts before welding it in place. After that it should bolt right in and determining the new pushrod length will be simple.

I'll post as the project progresses.

 

The distribution valve from 67 up in a drum drum is a safety device. It has an internal shunt that if one circuit fails pressure seals it off. The integral switch also activates the lamp on the lower left hand corner of the dash.

Pressures are not regulated in the drum drum valve.

A Disc Proportioning valve has the same shunt valve and additional flow limiting to prevent rear drum lockup. The integral switch activates the brake warning lamp.

The s10 booster produces the same vacuum leverage as a ford unit. Everything works off the same PSI to activate brakes. GM master cylinders are the same internal design as fords.

Garbz

 

Thanks for that Garbz learned something new. Not sure where maybe over on Fordification I thought I had read that it was valved for proper distribution but I may be getting the two confused. Wouldnt be the first time. Oh well carry on all you Chevy lovers. Oh by the way thats humor in case you didnt know.. Or is this the CTE????

 

Thanks for all the replies! I asked about using a dual pot, the mechanic said it wasn't necessary, so we stayed with with the original m/c. I wanted to swap it out someday anyway, now I will. I suppose to make it easier would be another (ahem) S10 m/c. Thanks for the comment on my picture Buzz...it's totally primered in gray now.