Dual Master Cylinder HELP!!!!!

I have a 1968 non power brake MC on my '35 and I wanted to know if I am going to need the Residual Valves that Wilwood supplies to keep fluid at the cylinders when it's lower then the brake (ie under the frame).

How can I tell if I have built in residual valves in my MC? THe part number for my MC is NAPA 10-1485 which is the one most of you recommended. I don't want to waste the $40 on these residual valves if I don't have to.


Thanks, JJ

 

Buy the brass valves from ECI, the Wilwood ones suck. You will find several threads discussing this.

 

Jeffrey,
If it has built in residuals, you will see a ball blocking each of the outlet ports on the M/C. If they are just open holes into the cylinder, there are no valves. And yes, you should run them if the M/C is lower than the wheel cylinders.

 

Ok I'll look into those. Damn that's the last time I trust Chris. He told me to get the Wilwood hahah!!!!

 

Yes. If the Master is mounted lower than the wheel cylinders, you need a residual valve (to keep the juice from running all the way back to MC from the wheel cylinders)

 

Even if they are built in? SHould I another set?

 

Damn. You guys are fast.

 

No, if they are built in that's all you will need...BUT, I'm not sure if the factory used different pressures for disc and drum, so I'd make sure the M/C matched the type of brake you are running at each end. RIIIGHT....

 

I bought the same one and had to run resdidual valves, did not see the ball blocking the ports

 

I run them.

 

The easiest way to determine if there is an RPV inthe m/cyl. is to take a paper clip, straighten it out and insert it into the hole in the seat in the m/cyl. where the brake tube attaches. If you feel something rubbery immediately behind the seat, that's an RPV (10 psi). Deeper than a 1/2 inch or so is the piston seal. It can be removed by removing the seat, take out the valve and spring, and reinstall the seat. That by no means assures you that the cylinder has adequate displacement to make the system function correctly with the brakes that you are using, it just takes care of the valve.
The best bet is to replace the cylinder with a 4 wheel disc one of the CORRECT BORE SIZE, one size does not fit all. There are no OEM masters that use an rpv on the disc brake side of the cylinder. Some of the aftermarket "oriental boat product" that is out there may have, no telling.