Odd power steering problem on new engine

[41woodie]

Finally managed to stick with the job of finishing the woodie long enough to get the engine started for the first time.  The engine had been sitting for 12 years + but I took it back apart and relubed everything and it started up immediately and ran smooth and cool.
I ran it at 2000 rpm for 20 minutes, no leaks no problems.  I then took it up to 2500 for 5 minutes still no problem.  Took it up to 3000 and was going to hold it for maybe five minutes but about 1 minute into that rpm I smelled something and looked down to see power steering boiling up out of the pump.
This is a GM Saginaw power steering box with a matching GM integral reservoir pump.  I had installed a rebuild kit in the pump while everything was apart.  I filled it up to the cold fill mark with GM factory PS fluid a couple of weeks ago and no leaks etc.
The pump puked up enough fluid to make an 18" puddle under the car plus some extra to blow down the side of the engine and frame.  The fluid was extremely hot when it came out.  I'm positive I didn't overfill the pump and I'm at a loss to explain what happened.  Any thoughts?

[Digger]

Hoses reversed?

[41woodie]

Anythings possible, one hose runs from the steering box to the pressure valve on the backside of the pump.  The other hose connects from the steering box to the hose fitting that is merely a slip-on nipple and the hose is secured by hose clamps.
The two fittings on the steering box are different sizes but it's possible that I had the hoses made up backwards.  Does anyone know which of the two steering box fittings matchup to which pump fitting?

[enjenjo]

The most forward line on the box goes to the pressure side of the pump

[41woodie]

Well assuming that the pressure side is the connection to the valve rather than the hose barb  fitting that's how mine is plumbed.  Now that things have cooled down I just looked in the pump and there is no fluid visible at all.  I knew it had puked out quite a bit but didn't think it was enough to empty the reservoir. I checked for any leaks that I might have missed and there are no leaks in the pump, hoses or steering box.

[enjenjo]

The way a GM box and pump functions, the oil circulates through the box, and back to the pump all the time. When you turn the steering wheel it opens a valve in the box, redirecting the oil to the top or bottom of a piston, depending on the direction you are turning to provide power assist.  So to creat the problem you are having, there are a couple possibilities. One of the lines, or the box, may have an obstruction in it that prevents the oil from circulating. There may be water in either the pump or the box that creates a steam pocket when it gets hot enough and pushes the fluid out. Or, the pressure relief valve may be stuck in the closed position. To check for water in the oil, drop a drop onto a hot plate, or hot exhaust manifold. If it sizzles, there is water in the oil. To check the pressure valve, remove the pressure  line from the pump, and screw the whole valve assembly out of the pump. inside you will find a valve and spring. The valve should not have any rust on it, and move freely in the bore.

[41woodie]

Great information, I'll pull the valve out tomorrow and give it a good hard look.  Rust might be a concern, when I first tried to start the engine this morning the starter gave me a problem with the bendix not throwing out.  I turned a bit by hand and hit it with a bit of Gibbs and was good.

[BFS57]

Hello;
As you said you have a power steering pump, I am guessing you have power steering. Did the power steering get bled? You have to bleed power steering to get all the bubbles out.
This involves running the motor and turning the steering wheel back and forth until the fluid doesn't have any foam or bubbles.

Bruce

[41woodie]

Hello;
As you said you have a power steering pump, I am guessing you have power steering. Did the power steering get bled? You have to bleed power steering to get all the bubbles out.
This involves running the motor and turning the steering wheel back and forth until the fluid doesn't have any foam or bubbles.

Bruce

Bruce when I added the fluid to the pump initially I turned the steering back and forth repeatedly but since this was the first start of a fresh engine the pump was not running at the time.  During the first fireup I was bouncing around monitoring everything at once and the steering was not cranked back and forth at that time.  
Now that I have the engine up and running I'll add some fluid and crank the wheel while the pump is running.  Hopefully I'll find a cure for the problem.  I've never seen this problem before but compared to all of the things that can go wrong on an initial fireup this is pretty mild.

[BFS57]

Hello;
I'm sure you will solve this problem whatever it is.
I like your car. Hope it gives you hours of driving pleasure for a long time to come!

Bruce

[41woodie]

Hello;
I'm sure you will solve this problem whatever it is.
I like your car. Hope it gives you hours of driving pleasure for a long time to come!

Bruce

Thanks for the good words Bruce.  I took the hoses off the pump today, blew through the return hose to make sure it wasn't obstructed in any way.  
I then removed the fitting from the rear of the pump and removed the flow valve and spring.  Everything appears to be ok EXCEPT when I rebuilt it I inserted the flow control valve, then the spring, then the pressure fitting.  After looking at the exploded view that came with the kit it looks like I should have inserted the spring first, then the flow valve, then the fitting.
I hate to resort to reading instructions, somehow it seems unmanly or something.  Hopefully this and a careful bleeding with the engine running will be the fix. Mike

[kb426]

Hope you found the answer!