Saginaw power steering pump advice

[cb_13]

I’ve got a Saginaw power steering pump that will stop giving assist if the engine is lugged to below idle conditions. In order to get it functioning again I can rev the engine to like 2k and assist returns as it should. To me this sounds like a sticking control valve.

My issue is finding the correct control valve. Will they all be the same? Have the pumps really changed? This pump may have been original to an early 70s Ford or Lincoln car, it could have been swapped from a 90s model GM truck outta a scrap yard. Really makes makes for an adventure.

If anyone knows a lot about these I’d appreciate any insight. I’d also prefer to replace a valve assembly with a GM or other known good part as opposed to swapping the whole pump out for an A1 Cardone reman.

 

[TheLastWord]

And your car is ??

 

[cb_13]

And your car is ??

78 Ford F250. Which did not come equipped with a Saginaw pump originally or the 460 that’s in it currently either. The 460 is a car engine with front sump oil pan and timing cover dipstick. So it’s highly likely the ps pump is the correct one for the engine but not the truck.

 

[PontiacHO]

May also have the mismatched power steering pump pulley.

 

[meep]

I’m not aware of any valve that would prevent the pump from grabbing fluid and pushing it. How much fluid is in the reservoir? Is the system somehow burping air?

 

[GSCJR]

What fluid are you using @cb_13 ?

 

[cb_13]

I’m not aware of any valve that would prevent the pump from grabbing fluid and pushing it. How much fluid is in the reservoir? Is the system somehow burping air?

Pressure Relief Valve Troubleshooting

Power steering pumps have a built-in spring-loaded pressure relief valve. This valve is designed to lower or stop hydraulic pump pressure when pressure reaches a preset value. You can observe this by steering to a full-turn of the vehicle’s steering limits or by attempting to turn the tire from...

benchworksteering.com

It’s full and quiet. Works good until rpm drop substantially, like lugging it(manual trans)in granny low pulling into the garage. After which it will continue not working until I rev it to like 1500-2000 rpm.

 

[cb_13]

What fluid are you using @cb_13 ?

I’d assume Dex3, potentially type F but it’s definitely a trans fluid.

I’m gonna throw a new pressure relief valve in it, some fresh fluid and see where that gets me.

I don’t suspect the pulley as I’d expect it to have weak output at low rpm consistently not just intermittent no output. I may be wrong

 

[GSCJR]

Sounds like a good plan, keep us posted.

 

[clinebarger]

Most GM Saginaw Type 1 pump are set to 1425-1525 PSI except "Remote Ram" systems used on C2/C3 Corvettes & pre '65 B-Bodies.....These produce around 1100 PSI.

There are aftermarket PR Valves that produce @ 800 PSI meant for Aftermarket/Mustang II Racks.

Then there's the Volume side of the equation, This is controlled by the Orifice in the Discharge Nut (1" Hex Fitting)

Orifice size & approximate flow (GPM)
*0.114 inch diameter = 2.0 gpm
*0.130 inch diameter = 2.5 gpm
*0.145 inch diameter = 3 gpm

Opening the Orifice by .016" will result in a @ 1/2 GPM increase.

GM# 15246463 will come with a 1425-1525 PSI PR Valve, Spring & a 3.5-3.9 GPM Discharge Nut.

Older Type 1 pumps had shims in/on the PR Valve, Removing shims increases pressure, Newer PR Valves are preset using threadlocker. Without using a pressure gauge.....I don't like fooling with the setting.

 

[clinebarger]

Does the pump have a -6AN/JIC Male Discharge Fitting?.....If so you'll need a 16mm O-ring to -6AN adaptor fitting to use the Discharge Fitting in the GM 15246463 kit.

 

[cb_13]

No the pump has a female fitting on the output. The pressure line has a male flare fitting.

Sounds like the part number you listed should be just what I’m looking for and should fall in the specified pressure range. As the original Ford pump was spec’d for 1400-1500 psi.

I’ll compare the discharge fittings when I’ve got it apart to make sure there are no major discrepancies there.

 

[someonesomewhere]

78 Ford F250. Which did not come equipped with a Saginaw pump originally or the 460 that’s in it currently either. The 460 is a car engine with front sump oil pan and timing cover dipstick. So it’s highly likely the ps pump is the correct one for the engine but not the truck.

Possibly from an early 70s Lincoln. There was a Hot Rod magazine article series ("Torque Monster" iirc) for this swap that my father and I did in the 90s. Used all dealer parts and fit right in. Made a heck of a hot rod truck, got horrible mileage. A lot more potent than the worn out 302 it replaced. Lol

Yours could be one of those transplants, as well. Worth looking into the numbers and all so you at least know what you have, moving forward. Good luck!

 

[dumkid]

Some power steering pumps use fluid pressure to seal the vanes to the housing. Maybe if the pressure drops from low rpm, the vanes loose their seal and it has a hard time building pressure until you rev it.
When you first start it does it not have assist until you rev the engine a little bit?

 

[cb_13]

Some power steering pumps use fluid pressure to seal the vanes to the housing. Maybe if the pressure drops from low rpm, the vanes loose their seal and it has a hard time building pressure until you rev it.
When you first start it does it not have assist until you rev the engine a little bit?

Assist on startup is intermittent. Sometimes it works like it should, others it needs reved up to build any pressure.

If this wasn’t my personal vehicle I’d definitely be putting a reman pump in it which would have a new valve in it already. Being mine I’m willing to experiment a little more. I may still end up having to put a pump in it even after replacing the valve. The valve is a pretty quick swap and reman pump quality is hit or miss anymore. So IF I can keep this pump and not have to spend the time replacing it that would be great.

 

[meep]

I hope I’m wrong, but I don’t think the valve is going to help. It deals with too much pressure, not enough…. Unless for some reason it’s just totally shot and the spring is goners….

 

[Chris142]

I think the pump is dead internally and needs to be spinning fast in order to put out enough pressure.

 

[FastLane]

I bet the vanes are worn out. I just changed my pump. Way better pressure at idle. Back like the truck was when it was new.

 

[cb_13]

To update this thread…

I removed the pressure relief valve. The valve and the bore itself did have excessive scoring and it actually was stuck in place upon disassembly. The discharge nut has permanently attached itself to the pressure line. Also the bottom of the reservoir was full of black sludge.

After a few changes of fluid and a bottle of Bars Leak PS fluid conditioner it is currently working. It will not last though. That sludge is almost certainly from wear on the vanes. I’ve just put a bandaid over a bullet wound. I was gonna need a new discharge nut anyway which comes as with the valve assembly, so this just bought me a little time. Currently I’ve got a new pump, pressure line and a return line filter on the shelf waiting for when I get a chance to mess with the truck again.