manual brake conversion?

[sixgun86gn]

I am thinking of converting to manual brakes.I have vacuum brakes at this time and they are just not strong enough with the bigger cam in my 4.1.I was wondering if anyone here has swapped to manual brakes and how they did it and how well they seem to work.I do not want to go back to the powermaster brakes because I think they are junk.Any help is greatly appreciated.

 

[Ormand]

It has been done. (By Bruce, I believe) But, the car is very heavy, and the brakes are small. If you go to bigger discs and drums, then it would be a better swap. Otherwise, you will be getting lots of exercise for your braking foot. You could get a vacuum pump (diesels use them) to help out the power brakes, and make sure the check valve in the line to the booster is in good shape. Or maybe get a milder cam?

 

[sixgun86gn]

This is pretty much a track only car now so the milder cam is not the option for me.Otherwise I would have left the shortblock with the 206 cam in it.The brakes were gettting kind of hard to apply already...probably the check valve like you say.The vacuum pump is an option I guess but they are expensive.

 

[bruce]

There are lots of cars running manual brakes.
Cal Hartline, Odell, just to name a few.

The 81 El Caminos had manual brakes as an option, so it's not like the right M/C isn't available. And some guys are using the Wilwood/Mopar ones.

Email me if you want the pattern for the block off plate to do it.

Just using a brake pedal from a Vac Boosted car gives you a pedal with the pivot hole for the actuating rod. You have to make up a push rod from the pedal to the M/C. Be sure to include something so the rod can't fall out of the back of the M/C.

The lines can be moved to reach the M/C so that's not a problem.

It does increase the pedal effort. Which IMO is totally a moot point.

 

[sixgun86gn]

Bruce,what about the prop valve?Did you just use the same one?Also what about the piston size in the M/C?

 

[bruce]

Originally posted by sixgun86gn
Bruce,what about the prop valve?Did you just use the same one?Also what about the piston size in the M/C?

Technically it's actually a combination valve. It affords some delay to the hydralic pressures, and senses a pressure lose. Initially no change.

When and as I changed to larger brakes, I did plug off it's delay area, and then the pressure failure section.

Beings it's GM manual system, yes it is smaller. Which seems a typical practice in everything other then in some early vettes.