Sandeep_19

The vette was leaking out all the power steering fluid over night so I just rebuilt the control valve and ram and bought a rebuilt pump. New lines. Now the return line blows off the back of the pump even with the hose clamp tightened down real tight. I can run the motor for a few minutes while trying to balance the control valve but then the return line just blows off and leaks out all the fluid. The fluid in the tank is foamy when I run the motor so Im not sure if Im bleeding the system right. The ram goes in and out but when its centered its really hard to turn the wheel. Whats causing my return hose to blow off the back of the pump?

wombvette

Sounds like you have something wrong in the valve.

Peterbuilt

Are you sure the hoses are not crossed?


Here's a how to...
http://www.corvettemagazine.com/stee...g-rebuild.html

Sandeep_19

Yeap hoses are criss crossed from the control valve to the ram like they should be. What should I look for in the control valve that would cause pressure build up in the return line to blow it off?

rdroe

OR is it being yanked off as you turn the wheel? Just a thought ...

Jim Shea

Only two things come to mind.
The only real obvious one is that the hose is being pulled off of the spout on the pump reservoir. Have someone turn the steering wheel full right and left and note the motion of the return line.

The only way the hose could blow off of the reservoir spout would be some type of blockage inside the pump reservoir and inside the spout itself. Did you reuse the reservoir from your original pump? If you reused the original reservoir, then you would think that it was not the problem.

If you obtained a new reservoir with the pump then this is all I can offer. The only reservoir problem that I remember relative blockage of the return spout was a brazing problem. Parts of the pump reservoir, including the spout, are furnace brazed together. A glob or brazing flux got stuck inside the spout and restricted flow. That would cause high pressure in the return line and possibly a blow off.

There is usually a round magnet inside the pump. It should be sticking against the pump housing. Is it possible that somehow it got trapped between the pump reservoir and the pump housing and is restricting the return flow coming back to the pump?

You can see the magnet (Z) in the above drawing at about the 4 o'clock position, just above the stud. It should not even be close to the area where the spout attaches to the pump reservoir (in the center.)
Jim

Sandeep_19

Checked the return hose for clearance already and it shoots the return hose off even without turning the steering wheel. I'll dig into the pump on friday to see if I can find any restrictions. Should I look for anything else? Im tired of pulling the pump off to get the hose clamp tightened down again after the return hose shoots off.

7T1vette

It's a "return" line and shouldn't have much pressure on it at all. You have something wrong in the control valve. Somehow, the incoming line pressure is being transferred to the return line. The main valve must be stuck or installed wrong.

72LS1Vette

So it sounds like you have not been able to balance the control valve after the rebuild. I'd guess that a seal in the control valve may have been damaged during the rebuild. Easy to do. I went through 2 seal kits when I rebuilt my control valve.



Rick B.

Jim Shea

If the hose is blowing off of the spout on the reservoir, the pressure to blow it off has to be created on the reservoir side of the hose. The control valve cannot create pressure in the return hose.

Jim

7T1vette

Jim,
The control valve has high pressure going to it. Why can't that pressure be directed to the return line directly, if the valving is not installed properly?

Sandeep_19

Jim I did get a rebuilt pump with reservoir so I will check out the pump. I can turn the adjusting nut on the control valve and have the ram go in and out but its real hard to move the ram in and out by hand once its centered. Is there a way to check and see if the control valve is working like pull the hoses off the ram and see if fluid shoots out of one of the hoses with the engine on?

Jim Shea

The only way a return line hose can build any kind of pressure is to restrict the fluid from going into the reservoir. The control valve only directs fluid to the assist cylinder or back to the pump reservoir.

I would think that if you disconnected the assist cylinder rod from the frame, you would find that the rod was rather difficult to move even in a correctly operating Corvette steering. Pushing and pulling on the rod makes the assist cylinder become a pump. Moving quantities of fluid back and forth through the system.

Jim

noonie

Did you try running the pump with the cap off or loose.
There is a very, very, very remote possibility that the pump is leaking pressure into the reservoir and with a very full tank it could build up some pressure after a few minutes. In and out oil volume of the pump should be the same, but with some expansion heat and aeration it could be possible.
I've seen housings crack on hyd gear pumps, but never vane pumps.

You could always rig one of your old pressure lines directly from the pressure port to the return port and test.

69 Chevy

My return line blew off the fitting of a chromed replacement PS pump. Yet I did nothing except replace the pump. It turned out that the fitting was straight, that is, it had no flare on the end. Plus the chrome plating made it extra slick. Once I flared the end of the return line fitting and replaced with a heavy duty worm drive hose clamp, I thought my problem was solved. It turned out that the old, hardened flex hose was part of the problem. I replaced it with a new, supple hose and problem solved.

Sandeep_19

I took the pump off today and noticed there was some rattling coming from inside the pump as I was moving it around to get it off the engine. Its under warranty so a replacement pump will be here on the 6th.

Sandeep_19

jim you had it right it was the pump. put the replacement on it and bleed it and no more hose flying off. put 10 miles on it so far. gonna check it for leaks in the morning. thank you