67-72 power vs. manual brake pedal

[MikeB]

I converted my 69 to power brakes back in the dark ages (mid-90s) using a master cylinder, booster, and brackets from a scrapped 71-72. It's always bothered me that the pedal sits up so high off the floor (5" from back of pedal to the toe plate), when all it takes is around 2" travel to stop the truck.

Did power brake trucks have a pedal that sat closer to the toe plate like cars with power brakes? And did the pushrod hole sit lower on the pedal arm for less leverage?

Thanks.

[Steeveedee]

From what I've seen, the brake pedal heights are the same. When you went to power brakes, did you use the "bell crank" mechanism? My understanding is that that mechanism removes the need for repositioning the push rod on the brake lever. I looked at my brake lever, and it only has one hole for the push rod clevis.

[MikeB]

Yes, there is a bell crank. I just realized it does the same thing (reduce pedal travel and leverage) as a lower hole on the pedal. But I can see why lowering the hole would not be a good way to go.

Also, looking under the dash I can feel there are some threads exposed on the pushrod, which means I should be able to shorten it. However, I suspect the under-dash return spring would still want to pull the pedal all the way back up against the rubber stop. I'll have to play with that. I may have to look into welding a steel pad onto the pedal arm, and/or using a thicker rubber stop.

I'll be pulling the instrument panel this fall to rewire the truck, and will probably pull the seat, too, which should give me better access to all things under the dash. I'll pull the steering column if necessary, but it's a PITA to reconnect it to the intermediate shaft.

[Steeveedee]

You can lower it that way. You'll have to relocate the stop light switch, as well. No seat and no dash would ease the pain. I had to adjust the pushrod when I went to front disc brakes. I'm an old man, and I did not enjoy those contortions.

[72SB]

FWIW, 72, I converted my stock manual disc brakes to power using the CPP MC/Booster kit. Used the same hole on brake pedal for the new threaded pushrod. Brake pedal is same height as clutch pedal. Don't have a second hole on pedal arm

[kwmech]

Just bolted everything from a power brake truck and called it good. Got everything from the wrecking yard on the firewall including the prop valve and lines. Bolted it up spliced the brake lines and never had any issues. This was about 40 years ago. Boggles my mind that every now and then this issue comes up with guys having all these issues. GM trucks 50 years ago were incredibly simple. GM made practically everything interchangeable for ease of assembly. Years a go I had a 69 short step that was a bare bones truck---all it had was a small block, T350 and AC. I put everything on it. I converted to big block, power disc brakes, power steering, tilt, tach. All the goodies I could round up. ALL OE parts and ALL BOLTED IN and worked without problems

[MikeB]

Originally Posted by kwmech

Just bolted everything from a power brake truck and called it good. Got everything from the wrecking yard on the firewall including the prop valve and lines. Bolted it up spliced the brake lines and never had any issues. This was about 40 years ago.

I did the same to my 69 in the mid-90s. I still use the 71-72 factory booster, which got a new diaphragm back then.

Originally Posted by kwmech

Boggles my mind that every now and then this issue comes up with guys having all these issues.

I've had my truck for 30+ years and was simply looking for a way to lower the pedal height a little, just as GM did with power brake cars back then.

Being 6'2" tall, my right knee is already bent quite a bit with my foot on the accelerator pedal. And I have to pull that leg up even more to step on the brake pedal. A couple years ago I was able to shorten the steering column by 1-inch to move it farther away from my body. Even that little bit helped, so now I'm looking to do the same with the brake pedal.

If that "boggles your mind", then move on to the next thread! Maybe you can find one where no mods are involved.