Bad Master Cylinder?

[pctahlequah]

I have a plastic resevior master from an 83 1/2 ton on my 66. I'm having trouble getting the brakes to bleed and firm up.

When I push the brake pedal it goes to the floor and I can see and hear the fluid agitating in the resevior, and the pedal never firms up.

What do I need to check? I get fluid with no air bubbles at all four corners. Is the master bad? It was working fine on the 83 when I drove it to the shop to strip it.


Thanks,

[onequickchevy]

Might want to check the rod length. When I changed mine over to disc, I had to lengthen the rod a bit. It should have adjustment left from the factory, just loosen the jam nut and turn it out some. Be careful not to adjust it out too far or you could damage the master. I also would put on a new master, it is cheap insurance in my book.

[pctahlequah]

I used the master, booster and rod from the 83. So, you mean adjust the length at the brake pedal or the rod in the booster?

[Captainfab]

The rod from the booster to the pedal will likely need to be lengthened.

[pctahlequah]

Well, I had to lengthen the rod to begin with because the original rod and the 83 rod were both to short to put the pedal up against the bump stop. I used a theaded coupler and a piece of all thead to lengthen it 2 1/2 inches.
It has roughly 1/4 to 3/8 free travel before the rod starts pushing in the piston

[mbgmike]

Did you plug off the MC to see if it even works? Disconnect the outlets and install a plug. If it holds a firm pedal it should be fine. if not junk it