Chevy Al 1 1/16" bore
 

Installing disc on front of 66 Chevy2 with drums on rear. Brake tech stated I needed 1 1/16" mc bore and 10lb residue valve for rears. I seem to remember there was a Chevy Al mc with 1 1/16" bore, but can't remember all details. Hoping someone can help my memory out. Thanks.

Ed
SS2266

Re: Chevy Al 1 1/16" bore
 

I got one from a early 80's S-10 pickup It had a flatter plastic tank on top .

Re: Chevy Al 1 1/16" bore
 

Don't think anyone made an aluminium master cylinder that looks "stockish". I'm going to try a stock master from a 69 Nova on my Chevy II with the distribution block and prop. valve attached on the brackets that bolt to the mounting of the master. Won't know how it works out till next summer.

Re: Chevy Al 1 1/16" bore
 

Ed, is this a drag race car and is the MC mounted in stock location?

Re: Chevy Al 1 1/16" bore
 

Is this for a manual brake set up? For an aluminum GM master cylinder I'd look at an S-10 with manual brakes. I've used a GM MC from an early 80's fullsize pickup before but they are cast iron. Most GM aluminum master cylinders were made for power assist and the problem with them is they are made to mount at an angle, the resevoir is the problem.
I wouldn't worry about a residual ck valve unless the MC is lower than the brakes.

Re: Chevy Al 1 1/16" bore
 

NAPA part number M2456, This might be a bolt in for what you are doing

Re: Chevy Al 1 1/16" bore
 

The s-10 one is the way to go. bolts right up, is level and has enough volume to work with disc brake setup.

Re: Chevy Al 1 1/16" bore
 

Yes, this is a full drag car and yes the MC is mounted in the stock location.

Re: Chevy Al 1 1/16" bore
 

If you don't run the residual valve you wont have a good pedal and the rear drum brakes won't apply with the correct bias. I'd go with the Strange master that has ports set up for 3/16 brake lines. i think its 1" 1/8. That's what I installed on my Firebird and it works and fits great.

Re: Chevy Al 1 1/16" bore
 

Thanks Todd. I can use the 1 1/8" MC. The strange looks like the ticket and priced very reasonable.

Re: Chevy Al 1 1/16" bore
 

I used to work for an aftermarket brake manufacturer as their tech adviser. With MC on firewall, you do not need residual pressure valves, they are only used when the MC is mounted lower than caliper/ wheel cylinders ( as on a Hot Rod) to avoid fluid drain back to MC. A 1 1/8 inch bore is for power assist brakes, use an aluminum Corvette style MC with one inch bore, and an adjustable proportioning valve in the line to rear drums. It will allow you to regulate pressure to the drums and avoid rear brake lock up. Just my two cents.

Re: Chevy Al 1 1/16" bore
 

https://www.dragstuff.com/techarticl...sterCylPN.html
Here's a list of sizes and part #'s for Mopar style aluminum MC's.
No matter what MC you use be sure you have a way to retain the pushrod so it cannot drop out of the rear of the MC. A good top pedal stop and a guide for the rod is important. Last year a racer at a local track in a car that was bullt and raced for years had an incident. His foot caught under the brake pedal and he pulled up hard enough to get the rod to drop out. He went off roading and was lucky.

Re: Chevy Al 1 1/16" bore
 

I know this is a popular opinion among racers and street guys. I found different results. When I bought my Firebird I replaced and replumbed the whole car. I called a few aftermarket brake manufacturers about the proper way to go about it. Mark Williams and Strange’s opinion was adjustable valve in the front lines and the residual valve to the rear line. Some of the others had the opposite opinion.

You have a greater chance of locking up the fronts because of less tire footprint to the ground. The reason of the residual valve in the back with drums , is because you need quite a bit of pedal travel and fluid flow to get the rear brakes to activate, compared to the fronts with aftermarket calipers. What happens is the front calipers seat the pads hard and the pedal stops traveling. When this happens the rear shoes lack holding pressure and you have an extreme bias to the front. This makes it hard to hold on the starting line.
I can foot brake my car to 4000+ on the starting line and when I hit the brakes hard on the other end it almost never locks them and if it did it was the front doing it. The pedal is high and firm and the brakes seem to wear evenly. Just reporting my results and opinion.
4 wheel disc systems doesn’t need any of it. Just the drum setup. Do what you feel is right.

Re: Chevy Al 1 1/16" bore
 

The problem with the stock Mopar MC’s is you have to use different size line bushings to hook your lines up. With the Strange it takes the standard and comes with a pushrod

Re: Chevy Al 1 1/16" bore
 

If you can flare tubing you can buy the line nuts and not use any adapters if the adapters bothered you. I used a new replacement MC for an 85 Chrysler and made the rod. I removed my pedal support and welded in a plate with a hole to guide the rod and it cannot drop as the MC has a shallow hole in the piston.

I have disc/drum and no residual valve in the rear and have plumbed others and never used a residual valve if the MC is on the firewall. I have an adjustable proportioning valve in the frt. line but it's wide open and don't have any problems holding the car at 4k. If you want more rear pressure applied to your brake shoes simply increase the diameter of your rear wheel cylinders.

Re: Chevy Al 1 1/16" bore
 

Sounds like your deal works pretty good. Lots of different ways to get the same place. Race on