No steering on ~78 580CK Series B

[jerbucc1]

Hi Guys,
Please help me diagnose what the problem is. The steering was okay then one day it started becoming difficult to steer and I felt back pressure on the steering wheels when the tires hit a rut,
Then a week later I started it and absolutely no steering. I replaced the power steering pump, and still nothing. When i raise the front wheels and turn them manually back and forth I hear fluid pushing back and forth and the steering wheel turns accordingly. Assuming the new pump and old pump worked, it seems like the pressurized fluid is not getting to the steering cylinders. I replaced both cylinders about a year ago.
Thanks for any troubleshooting advice,
Jerry

 

[Tinkerer]

Although the steering cylinders are only a year old one of them, or even both may be leaking internally.
Do you have the service manual ?

 

[jerbucc1]

Thanks for the reply. If there was an internal leak wouldn't at least one of the wheels at least move a little when up in the air? I have some half ass pdf manual that was called a service manual, But it doesn't say much other then how to bleed the system.

 

[Vetech63]

Thanks for the reply. If there was an internal leak wouldn't at least one of the wheels at least move a little when up in the air? I have some half ass pdf manual that was called a service manual, But it doesn't say much other then how to bleed the system.

The steering cylinders are tied together hydraulically even though they move in opposite direction. You can eliminate there being a cylinder problem and check your orbital steer valve by putting pressure gauges in both steering lines to dead head yhe pressure. If your steer pressure is correct going both directions then you have a cylinder problem. If not there is leakage in the orbital.

 

[Tinkerer]

Thanks to the good people at MinnParr Parts here is all of the manuals
https://minnpar.com/manuals5.aspx?F...) 580 SERIES PARTS MANUALS&SSSFName=CASE 580B

 

[melben]

Does the steering wheel free wheel like it isn't hooked to anything or is it hard like no power assist?, cylinder leakage should not be hard to diagnose. On several of them over the years the spool in the valve under the tank would beat out the aluminum end cap where the lines from the steering wheel connect, IRRC the replacement caps had a steel insert for the spool spring to come up against. if the wheel spins without any assist effort the cylinders can be checked by seeing if the temperature of the hoses change after continual turning for several minutes, if you have a bad cylinder the hoses to that cylinder would warm up, some may cringe at this but in 50 plus years I never had problem by using a pair of needle nose vice grips and carefully squeezing one of the cylinder hoses to stop the flow to the cylinder, you do not have to crush the hose to do this.

 

[Vetech63]

some may cringe at this but in 50 plus years I never had problem by using a pair of needle nose vice grips and carefully squeezing one of the cylinder hoses to stop the flow to the cylinder, you do not have to crush the hose to do this

I've done this myself.

 

[melben]

I've done this myself.

TYVM lol

 

[jerbucc1]

Thanks- The wheel has some resistance, but not much. In other words, it doesn't spin around in circles from one push. I'm afraid to keep turning the steering wheel multiple revolutions. Will that cause damage to the manual steering pump?
I have a 3000 PSI pressure gauge, but I don't have the fittings to connect it. There is a test port on top of the control valve, that looks like a machined 7/16 wide thread, while my pressure gauge has a pipe thread. Again, when I turn the tires while they are off the ground, I hear large amounts of fluid going up and down the lines and the steering wheel spins accordingly. When I loosen the test port on top of the control valve that has an o ring, a little fluid comes out, but not what I would expect from 1700 PSI? Maybe my original pump went bad, and the new after market pump(made in China) doesn't even work? I'd like to test it. Can I connect the gauge directly to the output of the pump? I'll also try squeezing the lines one at a time and see what happens.

 

[melben]

Thanks- The wheel has some resistance, but not much. In other words, it doesn't spin around in circles from one push. I'm afraid to keep turning the steering wheel multiple revolutions. Will that cause damage to the manual steering pump?
I have a 3000 PSI pressure gauge, but I don't have the fittings to connect it. There is a test port on top of the control valve, that looks like a machined 7/16 wide thread, while my pressure gauge has a pipe thread. Again, when I turn the tires while they are off the ground, I hear large amounts of fluid going up and down the lines and the steering wheel spins accordingly. When I loosen the test port on top of the control valve that has an o ring, a little fluid comes out, but not what I would expect from 1700 PSI? Maybe my original pump went bad, and the new after market pump(made in China) doesn't even work? I'd like to test it. Can I connect the gauge directly to the output of the pump? I'll also try squeezing the lines one at a time and see what happens.

 

[melben]

Turning the wheel will do no damage, if it turns without much resistance will it turn the wheels with the wheels off the ground? If you stop the flow to either one of the hoses on each side you take the cylinders out of the circuit and if the wheel firms up fairly solid and you hear pump relief you have isolated the cylinders as the problem. Steering hand pump failure at the steering wheel is practically unheard of so I would concentrate elsewhere unless all else fails.

 

[jerbucc1]

Thanks- When I raise the wheels off the ground, and turn the steering wheel either direction, the wheels don't move at all, but with the wheels in the air and I physically turn them from end to end the steering wheel spins back and forth?

 

[Vetech63]

Thanks- When I raise the wheels off the ground, and turn the steering wheel either direction, the wheels don't move at all, but with the wheels in the air and I physically turn them from end to end the steering wheel spins back and forth?

You have one of 2 possibilities as I see this currently. Either the commutator in the orbital isn't dispersing the fluid correctly, or there is no fluid pressure for it to work with. Your best bet is to still put gauges in the steering hose ends from the orbital and see what you have for pressure. With the steering hose ends plugged with gauges there is no where for the orbital to port the oil when the steering wheel is turned. The wheel should be fairly stiff with little movement in both directions and run over relief pressure which you should see on both gauges steering to left and right. Without oil flow and pressure, the system will not work. One other possibility is the steering shaft that goes into the top of the orbital has rusted and worn the splines bad enough it no longer will move the orbital commutator under a pressurized load.

 

[melben]

The flow from the steering hand pump goes to the steering valve spool end caps right behind the engine, when the steering wheel is moved the pressure created flows into the end caps and shifts the spool end to end to supply flow to the cylinders. Have you taken the end caps off that valve and checked for free spool movement and damage to the end caps from the spool coming against it. That has happened to me enough that I would at least look at them. Later designs of hydrostatic steerings contained all the functions in the orbital control valve and there were just lines to the orbital pump and lines out to the cylinders and a supply and return. Yours uses a separate valve. If your wheel just spins with no effort since the steering wheel splines directly to the steering hand pump and there are no couplers in play the problem is either a failed hand pump (rare) , (the hand pump is simply a pump, no valving) or a steering vale problem or trapped air, they can be difficult to bleed, if you could get some #8 JIC plugs and plug the lines from the steering hand pump to the valve end caps to see if it firms up when plugged that may aid you in diagnosis also.

 

[jerbucc1]

Thanks guys. What you say makes a lot of sense. I'll try to check these things today. The problem I have is I don't have plugs and fittings to plug or test lines. The gauge I have is an old gauge that my dad left me, pic attached. He was a diesel mechanic by trade. It looks like a 1/4 inch(about 1/2 inch wide pipe thread. Is there a reasonable price fitting set that I should purchase?

 

[Vetech63]

Thanks guys. What you say makes a lot of sense. I'll try to check these things today. The problem I have is I don't have plugs and fittings to plug or test lines. The gauge I have is an old gauge that my dad left me, pic attached. He was a diesel mechanic by trade. It looks like a 1/4 inch(about 1/2 inch wide pipe thread. Is there a reasonable price fitting set that I should purchase?

That gauge will work. It has a male 1/4 pipe thread in which any hydraulic hose place can fix you up with a couple of adapters to fit your steering hose. They will need to know the fitting size of the female hose end which assume is JIC.

 

[melben]

A hydraulic shop should be able to get you what you need. the plugs are reasonable. I would still like to know if the steering wheel completely free wheels or if you can feel some resistance in it, does it turn but firm up a little and feel spongy or completely spin free? Have you tried bleeding it at the fittings that go straight down into the steering valve under the front of the fuel tank, loosen them slightly and start the engine and see if you have any oil flow there, also turning the wheel with those fittings loose should show oil flow.

 

[jerbucc1]

I didn't get a chance to go to a hydraulic supply shop to get a fitting for the gauge, but, what I did was first take off the left side line from the manual pump. It seems like there wasn't much fluid in the line. When I turn the wheel it gargled like it has air in it. So, I thought maybe it just needs bleeding.
I then loosened the line from the pump output(top connection). I then started the engine, and hardly any fluid came out. Wouldn't the fluid be squirting out if the hose connection is loose? Now I'm suspecting the aftermarket pump I bought doesn't work?
BTW, when I turn the steering wheel one revolution there is not much resistance, but when I let it go, it spins back about 1/8 to 1/4 turn.

 

[melben]

That would indicate a problem with the pump. the pump should gush oil out under high pressure if you loosen the high pressure line, Make sure that when you get ready to install the new pump that you put oil in the reservoir and turn the pump by hand till oil comes out the port to avoid a dry start.

 

[jerbucc1]

Unless the oil is just going around in circles, to the valve and right back? I need to get a fitting and check the pressure without a hose? I'm assuming it's okay to do because of the internal relief valve in the pump?