Power Steering Pump Issue

[Charlie Brown]

I have the pictured PS pump in my car. I rebuilt it about 800 miles ago. It worked fine until last week. I now have very little, if any "parking lot" assist. When the car starts to move forward, the assist returns. Increased engine rpm also helps. While driving, there are no issues. Could the use of ATF+4 as the fluid be an issue? Steering box is a Firm Feel rebuild with about 25k on it. Diagnosis welcome.

 

[493 Mike]

Did you use a new drive belt? If so it may have stretched from the originally installed tightness. They all seem to.
Mike

 

[1KoolBee]

I have that same pump and it does the exact same thing, I’ve had it apart a few times with no easy fix found. The pump slippers are probably shot and no longer available. Finding a NOS replacement is unlikely or unaffordable. If your car is not a concourse restoration, I’d swap in a 69 or later Saginaw pump. Easy to get parts and pretty reliable. Pretty much a bolt in if you find the right donor.

 

[Charlie Brown]

Did you use a new drive belt? If so it may have stretched from the originally installed tightness. They all seem to.
Mike

Belt is not new, but typically I would expect to hear belt slippage / squealing. I will check this though.

 

[RJRENTON]

I have the pictured PS pump in my car. I rebuilt it about 800 miles ago. It worked fine until last week. I now have very little, if any "parking lot" assist. When the car starts to move forward, the assist returns. Increased engine rpm also helps. While driving, there are no issues. Could the use of ATF+4 as the fluid be an issue? Steering box is a Firm Feel rebuild with about 25k on it. Diagnosis welcome.

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Most people use ATF+4, out of convenience or recommended by their "buddy". but the power steering system is a hydraulic fluid system. Usually, the FSM recommends a hydraulic fluid such as ISO-VIS #32 or #46. Hydraulic fluid has totally different characteristics such as anti wear, anti foam, additive package, and temperature ratings. But you can't go wrong with the FSM recommendation....your choice of brand names......
BOB RENTON

 

[Don Frelier]

I'd buy a bunch of regular old power steering fluid.
Pump what's in there out.
Flush with fluid.
Fill with fluid.
Ill bet it will improve.