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Steering Gear Pressure Port Check Valves
There are millions of Saginaw power gears with check valves in the pressure port (the inboard port, closest to the aluminum top cover.) The check valve is needed on some vehicles because it prevents annoying harsh hydraulic pulses back into the steering wheel when making moderate high speed turns. If your gear has a check valve you will be able to look down into the port and see a small spring loaded plate blocking the fluid enterance to the gear valve. You will be able to easily depress the small plate and open the check valve by probing with a thin screwdriver or probe.

The check valve does cause the power steering pump to work against slight additional backpressure in the system. Additional backpressure does cause additional heat to be generated by the power steering pump, but typically not enough to cause any problems.

There were a series curves with of chatter bumps on the Ride & Handling Road Course at the General Motors Proving Grounds. Every prototype new model GM vehicle was aggressively driven over the bumps to determine if the car (or truck) needed a valve.

On gears that were manufactured before 1980, the check valve was installed underneath the 45 degree brass seat that seals the pressure hose pipe. You would need to run a short screw or easy out into the brass seat and pull it straight out to get at the spring and plate. Unless you have a replacement seat you probably should just leave the check valve in place since you will effectively distort and probably destroy the seat when removing it.

On gears manufactured 1980 and later (with metric o-ring ports) the check valve was contained in a capsule down inside the pressure port. You will be able to thread a short screw or easy out into the capsule and pull it straight out to remove it as a unit. By the way, you do not have to remove the check valve capsule in order to use the Tom Lee aluminum adapters. The adapter will press into the port above the capsule.

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