Frankie the Fink

If anybody has pics or measurements of where their power brake pedal is at rest (particularly on a '63) I'd appreciate it. I have everything installed on the split window now for power brakes but had to move the pedal towards the floorboard a lot to make the clevis pin engage. And, yes the pin is in the proper (lower hole) and yes I've backed the clevis adjustment out about as far as I can and keep a decent amount of threads engaged!

Thanks in advance.

MikeM

Correct pedal height is 4 5/8" measured from the floor covering (carpet) at the toe pan to the top of the pedal pod.

Frankie the Fink

If that's true (for power brakes) -- then I'm off an inch or more in height with the engine off. May not sound like much but your foot will sure feel it when stopping....and when the engine starts and the booster engages it'll drop some more...

As far as I can tell everything is original in the setup....guess I'll have to keep looking at things.

66jack

Frankie...

Did/do you have the correct length rod from PB to pedal?

Frankie the Fink

I sure hope so...this is a restored one-year-only master cylinder/power booster combo for '63. The push rod is integral to the booster so its a done deal...either its right and something else is amiss; or its wrong; and the restorer screwed the pooch..

DucatiDon

Its probably right...the PB pedal is noticeably lower than the clutch.

MikeM

If it is not right you can call Chevrolet because that height came right out of the '63 Service Manual.

Frankie the Fink

I'll try to take some pics tomorrow after I bleed the system... Right now, the pedal is uncomfortably low IMO. I'll know more once the pedal is firmed up and I can see where things set.

I can extend the booster push rod with a coupler but I shouldn't have to do that with all factory original parts...

Ol Blue

I ordered my car with the Metallic brake package and Power brakes. My brake pedal is 4 1/2" from the carpeting to the lower part of the rubber brake pad.

After a couple of drag races I put my clutch pedal on the quick throw setting and it is 5 3/8" from the floor.

Frankie the Fink

Thanks - my pedal is now exactly 4-1/2" from the carpet...it just seemed to work out that way. I adjusted and tweaked and adjusted and no matter what I tried the brakes were locked on with the engine running and my foot off the brake pedal. The only way around it was to put two bronze spacers behind the master cylinder on the mounting studs (about 1/4" in width). That did the trick and the brakes are freakin' awesome now...prob as good as it gets with all drum system.

Turned out to be more of a job than I anticipated; mainly getting the pedal engagement adjusted and bleeding the wheel cylinders. My My-T-Vac wasn't so mighty. It didn't seem to want to work until I first pressed the brake pedal 3-4 times for each wheel to get the fluid moving with the bleeder valve open; after that it went OK.

tbarb

That looks like a very nice job you did on the install. The rod from the booster front has to be to long or the piston inside the M/C is not correct. Did you purchase the complete assembly. I don't know much about these boosters but you were short on the interior and too long outside in the engine compartment, just give some thought to that.

I am curious, PM me with $$$ you spent. I am thinking about this for my 63.

Frankie the Fink

I followed the factory install precisely - even down to the rivets in the booster mounting strap support at the cowl.

As to the spacers - get this, with the clevis pin OUT of the brake pedal arm (clevis and pedal rod floating freely) AND the booster-to-M/C push rod screwed down to its shortest length (its adjustable); with the engine on, parking brake off, the brakes had the wheels locked up (so the pedal rod is eliminated in this scenario) -- brakes are properly adjusted BTW.

That only leaves the booster-to-M/C push rod in my mind. However, maybe you are on to something with the M/C piston length. Those are the only two possibilities I can think of.

Two 1/4" wide spacers under the M/C on the mounting studs make things operationally perfect; although I'll be adding a rubber spacer behind the piston to mate up to the booster front metal cup - that piece is held in by the M/C mating directly to it, it seems.

I bought the assy complete and restored from a forum member; correct M/C and correct '63 booster as a unit.

Sent you a PM -- the total cost was in line with what some of the "higher end" disc brake conversions cost but have to say this has made the all drum brakes quite acceptable now; don't think there is a disc brake conversion in my future for the '63 now.

tbarb

I agree, I would never change the drum brakes for the disc brake.

Take a break from it for now to think about the problem, something is not right in that M/C connection. Go over to the NCRS forum and do a search to see what info may turn up about the rod or M/C piston.

Did you flush and use DOT 5 fluid, if not give some thought to that also.

Frankie the Fink

Figured it out and more than a little pissed after what I paid for this setup. It turns out the booster pushrod has a nylon bushing around it firmly attached at its base inside the booster front cup (it's some little amount over 1/4" thick). The master cylinder metal tube that the pushrod goes into MUST be wide enough to go around that bushing as well as the pushrod. If it is NOT then when you tighten down that last 1/4" or so and fully seat the M/C into the booster the nylon pushrod bushing contacts the metal tube in the M/C and depresses it, effectively applying partial brake pressure.

My 1/4" bushings on the M/C mounting studs on the booster were actually keeping the two pieces from contacting which unintentionally bypassed the real problem and let the brakes work.

So it didn't matter how long or short the push rod is adjusted without the spacers the brakes were partially applied. So I suspect the booster pushrod setup should not have that nylon bushing at its base or somebody rebuilt the M/C with the wrong kit.

I'd post pictures but I'm still doing a slow burn over it. I stripped the pushrod adjustment insert (seems it was rusted in place anyway) in dealing with all this so that's FUBAR'ed so I guess the setup is off to Dewey's Boosters.

So much for buying "restored" parts from forum members.
I'm a big boy and will take my lumps on this deal but it doesn't make it any less annoying...

Blk63Vette

I feel your pain Frankie...I been burned a lot lately on professionals. I get sick thinking of the money I have wasted the past 2 months on "professional" hacks. Keep your chin up....my brother made me feel better by telling me its "only money" Yeah.... right.. Easy for him to say..

Frankie the Fink

This is what I'm talking about -- the M/C metal piston cup hole is about .457" wide. The P/B booster's nylon bushing is about .737" wide.

Tighten the M/C to the booster without spacers and the brakes are already applied with no pedal pressure....WTF ??

Ignore the sawn off push rod end - that's being replaced.

morly1963

Boy, that looks nice! You did a very nice job! I'm still waiting for my booster to come back from getting restored/rebuilt. morly1963

Frankie the Fink

Thank you - I was meticulous about the install -- to no avail...
It's all back out now until I solve my brake lock-up problem...
I'm hoping Dewey can figure out what's going on if I send him the booster and M/C...

I'll be back to non-power brakes until that happens.

Whew - that Nixon/Agnew sticker needs to go.
I was showing my daughter my Army Discharge certificate one day and she saw Nixon has signed it and said, "...wasn't he a crook ?"

Rich Yanulis

I think the bumber sticker is very cool

Don't touch it!

morly1963

I bought the car and it was on the bumper plus as a kid I read Mad magazine a drew Nixon from the magazine. morly1963