Manual Brake Conversion on a 1980 El Camino

[Streetbu]

 

[drb930]

That looks like a Corvette Master Cylinder?
What is it off of?

 

[Streetbu]

Right hand drive postal van

 

[drb930]

Did those RHD Postal Trucks have rear disc brakes?
Or do I need to remove some valve for a 4-wheel disc setup?

Thanks,
Dave

 

[Streetbu]

No, drum, but the residual pressure valve is located in the proportioning block anyways. So yes, you should also get a 4 wheel disc proportioning valve.

 

[drb930]

Thanks!
I changed that already.
So I guess I just now need the larger 1" MC.

 

[64nailhead]

There are other options as well. Early '80 full size wagon such as a 82 Buick Estate wagon for the '81 and later large bore booster. For the pre '81 booster that needs a smaller bore MC one from an 80 Riviera for the disc/disc car works great.

I'm not sure of the rear C5 caliper piston diameter. I will assume that it's larger than the Seville rear discs. But for the Seville rear discs the stock proportioning valve worked great for me with the '80 Riv MC. We swapped prop valves several times and could not tell any difference. We used the Seville rear setup so that we could still fit a 15x8 or 15x10 wheel on the car. Ill guess that the C5 brakes won't allow for that size wheel.

 

[drb930]

Thanks,

Maybe the 82 wagon is a better way to go as I believe I have the larger booster.
I’m sure the seville and LS1/C5 rear caliper pistons ave very similar in size.
Yes, you need a minimum of 17” wheels for the LS1 or C5 rear discs brakes as the brake discs are 12” diameter.

 

[64nailhead]

Thanks,

Maybe the 82 wagon is a better way to go as I believe I have the larger booster.
I’m sure the seville and LS1/C5 rear caliper pistons ave very similar in size.
Yes, you need a minimum of 17” wheels for the LS1 or C5 rear discs brakes as the brake discs are 12” diameter.

I've posted many times about the conversion we did with the C5 fronts and Seville rears. 285's on the rear and 275's on the front - fargin' yikes would that thing stop easily. The low profile tires put handle into the term handling as well. I'm sure you'll be happy once you get it dialed in/completed.

 

[drb930]

So it looks like the Blazer MC is P/n 18M974 which is a 1" bore.
The MC that you tried according to your thread is P/n RAYBESTOS MC39328 which is a 1-1/8" bore, but was too big for your booster.
So you went with at the end the 18M974?