daniel77350

My power steering has gone to the pits. Its gotten bad quickly, and now i believe its worse then manual steering, so Im going to rebuild it. my question is, do you think its the pump? I guy i talked to said something about, becuase it sat so long, the seals gummed up, and all I need to do is take it apart and clean it up. Is this true? I can't remember all of what the guy told me, it may not have even been the pump, I don't know.

Where should I look first? And how involved is the job?

Daniel

RUSTY79L82

clean up all the oil with degreaser i found that the oring that seals the pump to the resovor on mine was leaking got a rebuild kit at local gm parts store about 15 bucks i think it was a ease job

Jim Shea

Rebuilding your power steering pump is not a real difficult job. Zip Products has a pretty complete description of the procedure on line.

Go to http://www.Zip-corvette.com. The only area that they are not real clear about is removing the pulley. All pumps until 1975 had a pulley the had a keyway, a woodroff key, and a nut to hold the pulley to the pump driveshaft. In 1975 all GM power steering pumps went to an interference fit of the pulley to the pump driveshaft. For the later pumps you must have a special puller to remove the pulley. You must also have a 3/8-16 UNC bolt, nut, and washer to draw the pulley onto the driveshaft when you are done. Do NOT under any circumstances press the pulley directly onto the pump shaft.

The Chevrolet or Corvette shop manuals also have pretty complete instructions as well.

Also, I strongly recommend that you use General Motors power steering fluid to refill your system. It is available from any GM dealer.

Tom454

The internal pump parts do not have any seals that would cause your pump to stop pumping. The actual pump consists of all metal parts- an obround chamber with a central set of vanes held in slots that use centrifugal force to scrape the sides of the chamber to produce pressure. The seals are only to seal between the shaft and the pump, and between the pump and the reservoir. Even with a bad shaft seal, or with seeping reservoir seals, if there is fluid in the reservoir (and the pump itself is not damaged), you will still get some hydraulic pressure.

If your pump is leaking, of course, you need to "rebuild" it... or more acurately... replace the seals.

More likely, the slave cylinder is leaking/has failed... unless the pump reservoir is empty due to leaks anywhere in the system.

If/when you do take it apart, try not to let the pump itself come apart because the vanes will fall out. They develop a "wear pattern" and should be kept in their current wear position if possible. Once they fall out, it's almost impossible to determine how they were oriented. Also, there are two pins that hold the pump internals in the correct orientation to each other... these can be installed wrong and this will damage the pump. They also just fall out like the vanes.

Running an engine when the reservoir is empty causes the vanes to scrape the chamber with no lubrication... this is what actually kills the pump unless someone drops dirt in the reservoir.

Jim Shea

Another possible reason that your pump would suddenly stop putting out fluid is that the flow control valve could be stuck. Years of use could cause a buildup of varnish from the fluid that could be causing the valve to stick in a by-pass mode. The valve is located just behind the discharge fitting where the power steering pressure hose connects to the pump.

Unscrew the hose, then unscrew the fitting from the back of the pump. You should be able to take a small screw driver and reach inside the pump and press on the flow control valve. It should easily slide back and forth inside the pump and you shoud be able to feel it depressing a spring behind it. You should be able to remove the flow control valve and spring with a magnetic probe. Check the valve for varnish, burrs, etc that could be causing it to hang up.

Otherwise, (assuming you are not low on fluid) a pump rebuild is probably in order.

JIML82@aol.com