Hot Rods 62 Chevy Truck Clutch Master issues, help?

Hey guys, I got a 27 Ford with one of those 60's Chevrolet truck duel master that uses a hydrolic clutch. The owner brought it in, can't get the clutch to work, no pressure out of the master. I've pulled the master apart, it has a new rebuild kit in it and I'm not seeing anything wrong except when I pull up images of rebuild kits there is a part I don't have. I don't have the brass thing with the hex in the picture below. What is it (check valve?) and where does it go? Maybe what's wrong?

 

The piece that looks like the top of an old salt shaker is the residual valve that goes on the brake side of the master. It helps to bench bleed both sides of the master before installing

 

It's steel, not brass, and that is used on the brake bore. One other part that goes with it, is a very thick black rubber washer (like a garden hose washer), that sits in the deepest part of the bore, for that valve to seal against. That valve sits on the front of the spring.

That valve is a residual, and if you did use it on the clutch side, it will impede the fluid returning to the reservoir, when you let the clutch pedal come back up.

Just to clear things up. In the 60-62 chevys, their pedals are strange, in that the clutch pedal uses the bore closest to the center of the car/truck. When you buy a new master, but use it with "normal acting" hotrod pedals like old Ansen pedals, you swap the guts to the opposite bores.

if you read up on that switchover for hotrod type normal pedals, some say that you need to drill a tiny hole in the cast iron reservoir bottom for proper fluid movement. In other words, look in the bowl and compare the holes that are already there, then make the other side the same. I have never needed to do that....but I don't know why, though.

ok, if the piston is not coming ALL the way back against the snap ring when installed in the car, that would cause it to not pick up fluid to push the slave.

Put it together, in a vise, then hold your finger over the outlet, and shove the piston to see if it will give pressure. It should, as it is such a simple device when used for a slave. You are just shoving fluid from that bore to the slave bore.




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OK, I thought maybe it was a residual valve. I'm assuming the kit works for both sides and the clutch doesn't use it?

 

Hey Frank, I have the above set up on my Model A and it works great! How ya been?

 

Back in the day, EIS made two kits for that master, one for the clutch, one for the brake bore.

yes, the clutch bore does not use it.

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Same one in my 32, but found in stuck condition with 'old chrome", so I rebuilt it, works great. When some keyboard wizard says you need dual circuit master to be safe? I say, "ya, I got me a dual master, but one side's da clutch".

I.m ok, but lost so much weight after getting Lyme treatments. My neighbor works at the casket factory, claims he is saving scraps of wood leftovers to make me a verrrry skinny box. Lol.

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I built the pedals for this thing several years ago with a bell crank type setup so the master does work opposite the pedals, just like on the original truck. Everything worked till the owner pulled it apart and had the master chromed. Never worked since, either with the original parts or a rebuild kit he put in. Now that I have it apart I can't find a reason I have no pressure coming out. Knew I was reaching with the residual valve thing but I'm at a lost why it don't work, it's too simple. I guess the only thing now I can come up with is he over honed the bore cleaning out the residue left from the chromer.

 

Bench test it, and you should know. And while you are putting the piston back in, you honestly should be able to "feel" if the bore is way oversize by how the rubber fits/feels.(resistance)


I always tell people to not think too far out of common sense... I doubt someone could sit there with a simple hone for a long, long time and make it so far oversize? JMO
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The rubber feels tight. Like I said, I'm reaching. I don't see any reason this thing won't pump.

 

That's what SHE said....

 

Yeah, I thought about that after I read what I wrote!
FWIW it was the master. Leaking out the back of the bore, would not bench bleed. Maybe too many rebuilds in it's 50+years. Shame, it was pretty in chrome. Put the new parts into another master and the clutch works.