Master Cylinder/Booster Swap Questions

[roachrider]

I'm swapping out the manual master cylinder in my '67 F-250 with a MC from a '71 F-350 with power booster. Couple quick questions:

1. Both trucks had drum brakes at each corner. However, the MC in the '67 had a smaller reservoir in front like you would see on a drum/disc setup. Is it possible that someone changed it at some point? When braking, the front tires would lock up before the rears even when the bed was empty. Could that be a symptom?

2. The bushing for the pedal is almost dead on both. As long as I've got it apart, where do I find new bushings?

3. The metal brakes lines snapped about a half inch from the master cylinder when removing it. I tried to get the fitting to spin on them but there was too much rust. Can I just use a grinder to cut the tip off of them so they are flat and then get a new fitting and slip it over the end? What do you call the pipe fitting that slips over the end and screws into the master cylinder?

4. Any recommendations/tips/gotchas you guys know so I can learn from your mistakes/experiences rather than repeating them?

[heep70]

Tube flaring tool

As far as the fronts locking before the rears I always had the opposite happen. Backs before the front except under load. I also did the manual/power brake swap. The front reservoir is smaller then the rear and I have drums on all four corners. If I remember right the visual differences between the drum/drum vs disk/drum MS was the height of the MC and how the lines fitting were the wrong size.

You can buy the right one (drum/drum) PB MC from an auto parts store.

I have considered installing an adjustable proportioning valve, but now that I have waited for so long I have gotten used to how to use the brakes and under loads its not a problem.

[roachrider]

Well...isn't that interesting. Learn something new every day. I never knew they actually made a tool for flaring tubing. That's gonna make everything a lot easier.

How much would be reasonable to pay at a parts store for a new MC/Booster combo? Is it worth the money over reusing the one I have? $$$ is tight at the moment, but for safety, you gotta spend what you gotta spend...

[heep70]

I bought my booster used from a junkyard and the MC was $35 I believe. I am not sure how you could easly test the used booster besides just put it on and see if it works. NAPA sells the combo, but I am not sure of the price. I could guess it at $150, but thats a guess.

[roachrider]

I guess I'll stop by the auto parts store on the way home then. Thanks so much for your help!

[roachrider]

I got the new booster and MC installed and reflared the lines. None of the auto parts stores in town had the fittings that screw into the MC to hold the lines in. I had to clean up the threads on the old set and reuse them. Does anyone know a source for new?

Once I had everything installed, I went to hook it up to the pedal and found the pushrod on this setup is about an inch longer than the last one. I could go back and pull the pedal from the truck I got the MC/booster from. How hard is it to get out? However, the wiring under the dash of my truck is SCARY! I'm sure I'd pull out a million wires while working under there. Has anyone just fabbed up a bracket to adapt the two lengths? How did it work?

Basically, does anyone have an suggestions/ideas/thoughts/quick solutions before I rip into this and break something?

[FORDification]

Use the '71 brake pedal....the '67 brake pedal (from what I understand) will only accept a '67 MC/booster.

It removes easily. On a stick-shift truck, you just remove one nut on the end of the pedal pivot to disconnect the clutch rod, and then slide the hinge pin out. The brake pedal will drop right out.

[roachrider]

I got the pedal out of the donor truck using my favorite tool(sawzall). Since the rod that the pedals pivot on is welded to the clutch pedal, I had to cut the heavy spring that connects to the clutch pedal as it wouldn't allow me to push the pedal out and I don't have the strength to remove the spring myself.

So the question is: On my "real" truck, how do I remove it? If I can't slide that spring off, and it bolts to a chunk of metal that's VERY well connected to the truck, is there a trick? If pictures would help, I can go borrow a cam and take some pics.

[FORDification]

I've never actually seen a pedal setup that had that spring...it was completely missing on all the trucks I've parted out...and from what everyone tells me too, it doesn't seem to make a difference whether it's installed or not. I think if I had the spring to replace though, I'd go ahead and do it.

However, I can't offer any advice on removing/installing it, but would definitely like to hear some tips on doing so, just for future reference.

[roachrider]

I guess it's no fun if you don't have parts leftover

I'll go see if I can get it out but I need the truck tomorrow and still have to bleed the brakes before I run out of light so if might meet the sawzall too.

You wouldn't happen to have a pic of what a normal underdash wiring bundle looks like would you?

[FORDification]

What do you need to see? I've got pics taken by just aiming up under the dash, but you're not gonna be able to use them for anything, since it's just gonna be a pic of a bunch of wires.

I've got the '67 wiring diagrams posted here to the site, which should help you out in most areas, depending on what you needed.

[roachrider]

So I got the pedal in, but the pushrod still doesn't line up. It looks like the bracket that bolts to the firewall, dash, steering column, and e-brake(in my case) that has the holes drilled for the pivot rod to pass through...has the holes in a different place than the '71.

I transfered the MC/Booster, booster mount brackets, pedal, and pushrod all over from the donor truck.

I put a pic of what I think is the culprit in the pedal attachment.

Here's my thought. What if I pull the MC/Booster off again(ugh) and fab up some spacers for the brackets that bolt to the firewall? Anyone think that would work? Anyone have a better idea?

[roachrider]

I used some washers and longer bolts to space the booster/mc out from the firewall about an inch. Looks like that solved it. It started raining so I'll finish up later and then bleed the system.

[roachrider]

Well, it's all working. It's leaking fluid at the MC a little bit. I reused the old fittings as none of the local parts shops had them and it looks like they don't seal as well as before. The brake line was so old and brittle/rusted that it kept cracking so I guess it's time to replace that. In the meantime, I'll just top off the fluid periodically.

I just wanted to thank everyone that posted and PM'ed me with suggestions. This board made the swap go a lot smoother and less frustrating than if I had run into all the problems alone.

Power brakes ROCK!

Here's a pic of how I spaced the MC.

[heep70]

Don't wait to long on the new lines. Not only do they leak, but they also suck air back into the system.