Brakes?

[Longhunter7]

When it rains it pours!

I just finished replacing all the wheel cylinders, brake shoes, all the seals, repacked the wheel bearings, and replaced one bad wheel bearing.

Then as luck would have it, the master cylinder went south while trying to bleed the brakes!

Now I need to find a new master cylinder, or I might try a rebuilt one that is sleeved with stainless steel. Has anyone tried the stainless route?

 

[CGarbee]

I've got a good MC that I pulled from my truck when I went with a dual circuit unit from a Chevy (forgot the actual application, but it is the one that Ray Suiter plugs on his website along with the disc brake setup that he fabricates and I have installed, Charles Talbert at M-Series Rebuild uses the same MC...).

A lot of times with an older MC, you can depress the pedel too far when bleading and it gets past a wear line and the cups get torn. You don't have this problem with a new one usually since you don't have a wear line, but the info that came with my new Chevy MC had a warning about pushing the pedel too far during bleading as well...

 

[mangus580]

I think when you push the pedal too far when bleeding, you make the cup pass over a port in the side of the bore, thus tearing the cup.

BTW.... Adirondack Dodge carries new MC's I think...

 

[Longhunter7]

Master Cylinder?

Gentlemen,

I would like to put in a dual master cylinder, but I don't have a shop to work in!

I have to do most things on the driveway, and with cold weather coming, I need something easy!

How difficult is the change over to a dual master cylinder?

 

[CGarbee]

Remove the existing MC, drill two small mouting holes (for the bolts that hold the new MC in place) on each side of the hole in the bracket where the existing MC is mounted, drill a pair of larger holes in the frame rail for the outlet lines on the new MC to pass. Cut the existing front brake line just ahead of the holes that you drilled for the MC out let lines. Run a line from the front port on the MC to the line going to the front wheels, run a line from the rear port on the MC to the t fitting where the front lines used to connect to the outlet from the old MC (this feeds the rear brakes). Relocate the stop light switch from the old MC to the t-fitting where the old MC outlet line used to pass through the frame (the fitting where the outlet line from the rear of the new MC is tied in). Shorten the front half of the pushrod that was used with the original MC about an inch and screw it into the pushrod for the new MC. Blead everthing...

You need three line adapters (available at parts stores along with the MC) since the line diameters are different. You need to either be able to do a double flair or you need to get a long enough new line for the front outlet of the new MC that you can get to the first line splice in the existing front line so that you can tie in to it.

Whole process takes and afternoon... Not real difficult if you can use hands tools and have a modest amount of mechanical abiltiy...

 

[mangus580]

Cabell, could you post the MC info for the dual? We have to rebuild ours, and it really makes sense to just do this.

 

[CGarbee]

1980 Chevy C30 1 ton, CarQuest part number is 20-1584, the Bendix part number is 1584. Got mine at the local NAPA....

This master cylinder does not have residual pressure check valves built into it. This makes it perfect for 4 wheel disc brakes which do not require residual pressure. If you have the original drum brakes on all 4 wheels, your best bet is probably to purchase a proportioning valve from either a chevy dealer for the 1980 1 ton truck that goes with this master cylinder or get one at the your favorite parts house. This should have the residual pressure check valves in it (provided that you specify to the parts man that your truck has drums on the front instead of discs).

 

[Longhunter7]

Dueling Masters!

CGarbee,

I appreciate the in depth details on the conversion!

I will have to start rounding up the parts and getting started!