Das vierundvierundzwei

In the process of converting from power disc/drum to manual in my 1971 442 due to low manifold vacuum.

What is all required for this conversion?

I picked up a pushrod assembly from inline tube as well as a firewall reinforcing plate.

The master cylinder I have is the OEM style Disc/Drum with 1 1/8 bore diameter. From other threads, I am assuming I need a 1" diameter disc/drum cylinder, however I cannot seem to find this part. Rockauto and other distributers I have checked seem to carry two types: drum/drum and the shallow piston disc/drum for power brakes like mine.

Also, I have also seen mention of a brake pedal return spring for manual brakes. Where does this mount and where can I find the correct spring?

Thanks,

Steve

Run to Rund

make sure to get the "derby hat" pushrod retainer from Inline Tube as well, INL12439

VC455

Unless you are married to this course of action, the easiest solution to the problem is to install a GM vacuum pump to augment the low vacuum.

I found one from an 80s Cavalier in the junk yard and it has worked perfectly for 10 years. It only comes on when I start the car, or if I brake a few times when engine revs haven't been above 1500.

You need a source of switched power and you plumb the pump between the engine and the booster.

I put it under the driver-side fender, completely out of sight. You wouldn't get any point deduction in a show.

joe_padavano

I have factory manual discs in my 1970 W-30. The car stops fine and pedal pressure is not excessive. Use a 1" master cylinder. Be sure to use the upper hole in the pedal arm for the manual M/C pushrod.