The Stovebolt Site Forums The Parking Lot Big Bolts Hydro/Master question

Fella on IH board says with hydro-vac, you shouldn't have a check valve in Master cylinder. He didn't really say why. He was talking about IH truck and fella that rebuilt his master, couldn't bleed them. I'm having trouble with big truck, which has the smaller truck new master in it, having slow comeback for pedal and fluid. Is that then because it has the check valve in master? I can pump mine up for better pedal, and it stays all the time I'm driving, just goes down overnight. When driving, slow recovery, feel brakes drag for few seconds and can feel it come back slow in pedal or watch it rise to stop in few seconds. What ya think?

Could have an obstruction in the vent on the hydro or a problem with spring on the small diaphragm(sp?). I had bug nests clog the vent on my '49 (PO left the screen off) and had similar problems. After cleaning it I put the spring back in on the the wrong side of the small diaphragm, making the problem worse. After puting the spring back in right, it worked perfectly. I have a IH shop manual that came with my '68 Load Star. It covers several of the IH hydrovac systems. When I get back after the weekend, I could scan any pages that cover your system (is this an IH your working on?).