Power steering not working

[Reenie_B]

We bought our son a 1975 k10. Truck was a farm vehicle, lots of cobbled things and ignored maintenance and repairs. Power steering worked when bought, however there was no cap on reservoir, and pump was leaking extensively, fluid was disgusting. Replaced pump, as well as rag joint, and lines. Was very difficult to burp it, however after replacement and flushing the power steering no longer works. Replaced steering gear box, no change. We replaced pump again as it was presumed to be not functioning. Please share any helpful hints you may have in troubleshooting this.

 

[Grit dog]

Did you bleed the whole system?
Jack up front wheels. Start engine and turn steering lock to lock about 20-30 times.

 

[Reenie_B]

We did, for pump and steering box.

 

[AuroraGirl]

We did, for pump and steering box.

is the belt turning the pump, it sounds dumb to ask but yeah.. did you swap the fitting or did you use one that came on the pump. and how big is the pulley on the pump diameter wise, hows your belt condition, and did you notice any debris in the fluid you removed from the system like chunks or anything. are those hoses both replaced. id replace the pressure hose and at least pull off and verify the return is not an issue or replace as well. is the pump being tensioned into the belt

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This may not match the location, the shape of the lines, or the color of the reservoir, but does this look similar to what your truck has going on? The cap is the same design, the pulley is about that diameter give or take, it runs on the inner groove if two grooves, etc..

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This picture is of that 305 in the foreground but the green sbc in the background in the upper left, that has a factory pump. its from a 77 k25. It also had an AC compressor, so the sizing of the pulleys may not be directly comparable if you have a non-AC truck but its a guide to what generally it should look like. also, if your pump is turning, and has fluid, you should be getting something even if low amount of assist, but check those tire pressures, belt tension, belt condition, pulley sizes... a pic would help...

otherwise something that would make sense to me, is just your high pressure hose is either blocked by debris or collapsed on itself. And the pump is running in relief


The reason I asked about the valve is this:
"In the event a valve is fully stuck, all power steering will be lost and the vehicle’s steering will act as if the engine is off. GM Saginaw pumps see this problem far more frequent than other manufactured pumps."

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Source: https://benchworksteering.com/tech-talk/pressure-relief-valve/

Based on the debris and wear in the pump on the right(that it came out of) I think it was blockages and lesser so sticking valve but your new pump may be stuck. Ive had a brand new pump(different pump but the valve is the same exact as the saginaw P pump you have, that I just discussed) with it overtorqued and it scored in the bore from something in its previous life or something and it worked but it was very worked and then didnt no in between. you could have debris from old fluid, maybe some funky rebuild, maybe this or that......

Check the externals, if you still dont see the issue, check your fitting and the thing under it. Should unscrew and pop out with ~9 pounds of force from that spring.


just note your pump is probably a "banjo" shape vs the teardrop shape of my pump shown and the steering gear/pump use inverted flare not metric o ring to seal(different design ends than what I would have, your fitting on the pump would match those pre-1980 lines)

 

[Reenie_B]

Thanks for the info. We'll have to look further into it tonight. Lines were replaced, pump replaced 2 times, and steering box now. I'm wondering if a new line could be a source of failure internally?

 

[AuroraGirl]

Thanks for the info. We'll have to look further into it tonight. Lines were replaced, pump replaced 2 times, and steering box now. I'm wondering if a new line could be a source of failure internally?

possible but the short length would make me think not likely unless it was binding up or kinked on install.

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here is my old pump, the new line is already on here but you see they dont travel far for most squares. a pic when you check would help too. If your new pump had a valve installed on the back or you needed to transfer would tell a lot i think too for diagnossi. a smashed line, too. beings the cap was missing i would not be surprised if a debris or material blockage was not removed and founds it way upstream somewhere etc. are ball joints greased. if you jack the truck off the ground when checking everything that would help eliminate any concern about the pump being "overworked" since the steering has way less to assist. but i dont think thats likely the big thing here.

also what kind of fluid was used?

 

[Grit dog]

Thanks for the info. We'll have to look further into it tonight. Lines were replaced, pump replaced 2 times, and steering box now. I'm wondering if a new line could be a source of failure internally?

Possible, but not probable.
Easy to check though.
I’m fairly stumped, otherwise.
One off the wall suggestion. Does it have a cooler that the return line is plumbed through? Possible blockage in the cooler?

Or more detailed description of “not working”. May help diagnose. Not out of the question that you received bad “new” parts either. Heck I went through 3 alternators in an hour in a Napa parking lot because they were junk remans.
Certainly not normal but?
Describe symptoms. Pump whining like it’s trying? Does it work better in one direction than the other? (Shuttle valve in steering gear box could be stuck)
With low fluid level in the pump can you see the fluid circulating if you look in the reservoir?
Just some suggestions

 

[Reenie_B]

No cooler in the system. I didn't get home until way late, so needless to say I never got out there. This has me baffled. The truck was an ac equipped build originally, but someone's removed that before it came to us. There are only so many things in the system, and I'm baffled. The power steering only kicks in when you really step on the gas to rev the engine more, and then it responds for only a quick second, then it's gone and you're trying to steer with all the strength you can muster. Pulley is clean and shows no sign of belt slippage, belts are new, all hoses are new, this truck was a "neglected farm truck " so many items had to be replaced, radiator, water pump, alternator, battery, pitman, tie rods, steering stabilizer, carburetor, blower motor, heater core, brakes are new all around, the list just goes on and on. (The parts guy is my new best friend) The steering gear was replaced, power steering pump was replaced twice (had to transfer reservoir to new pump), the lines were replaced. When I say it's not working, it's like trying to steer the non running continental grandpa had, that had power steering and did great as long as engine was running, but no power steering help at all when trying to drive after the engine died and you're trying to shove it into the shop. The fluid was all replaced, I'd have to look at the bottle to see what brand it is. The tires are stock sized, mud and snow.

 

[AuroraGirl]

sounds like a valve issue or a fluid blockage or a power transfer. is your pulley turning a belt which is tensioner with the pump bracket and not just loose or anything.

 

[AuroraGirl]

No cooler in the system. I didn't get home until way late, so needless to say I never got out there. This has me baffled. The truck was an ac equipped build originally, but someone's removed that before it came to us. There are only so many things in the system, and I'm baffled. The power steering only kicks in when you really step on the gas to rev the engine more, and then it responds for only a quick second, then it's gone and you're trying to steer with all the strength you can muster. Pulley is clean and shows no sign of belt slippage, belts are new, all hoses are new, this truck was a "neglected farm truck " so many items had to be replaced, radiator, water pump, alternator, battery, pitman, tie rods, steering stabilizer, carburetor, blower motor, heater core, brakes are new all around, the list just goes on and on. (The parts guy is my new best friend) The steering gear was replaced, power steering pump was replaced twice (had to transfer reservoir to new pump), the lines were replaced. When I say it's not working, it's like trying to steer the non running continental grandpa had, that had power steering and did great as long as engine was running, but no power steering help at all when trying to drive after the engine died and you're trying to shove it into the shop. The fluid was all replaced, I'd have to look at the bottle to see what brand it is. The tires are stock sized, mud and snow.

whats the torque on these replaced steering components, and are they in the rigiht planes. i have a feeling something is not moving right.

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Heres an example of a couple steering geometrys