Persistent Power Steering Problems (1 Viewer)

[RexTreks]

Hey guys,

I've been working on a front end refresh for my '94 FZJ-80 and I've been running into some walls with the power steering system.

Originally, I was dealing with the loud whine and aerated P/S fluid, knowing that I would be swapping out components and that I would likely fixed the problems by replacing the pump assembly as well as the pressure hose from pump->rack. After going ahead and replacing both the pump and hose I'm still running into issues of very bubbly fluid and whining pump.

I followed the FSM for the component replacement, as well as the bleed methods, however some strange things have me scratching my head.

For example, when I received the pump from the parts store, it was completely filled with gear oil instead of an ATF or similar. Found that to be very strange, but I drained it of gear oil and installed it onto the truck along with all new crush washers, rubber o-rings, etc.

I've ran through a gallon of ATF of using the hose-barb method of utilizing the return line to fill a catch bottle of ATF as you turn the wheel slowly lock to lock, as well as a few engine bumps for 2s with the ignition coil disconnected.

The next step in the FSM is to let the truck idle under 1000rpm while you slowly turn lock to lock, stopping just shortly before lock, and holding for 2-3s, then returning to the other side, holding again for 2-3s.

When I hold it there, I hear a sharp hiss and the pump immediately gets loud again, and the fluid becomes aerated. I can only assume that either my steering stops are too far and I'm over turning the system or that my steering rack/valves are old and air is slipping in at max lock.

Thanks for taking a look at this and offering your guidance, I'm so close to having this truck back on the road!

Stay tuned for a video of the sounds the pump makes as I follow the bleeding instructions.

/R

 

[RexTreks]

Here's a clip of the aforementioned noises. Thanks again!

/R

 

[BILT4ME]

Yes, sounds like you still have air in the system.

I did this with the front axle on jack stands to take the pressure off the tires and let the pump work easier.

You are actually turning the steering wheel pretty quickly. I did approximately 100 back and forth with the engine OFF first, filling it after every few cycles until the level got better. Then I did 100 cycles with the engine RUNNING at idle, but I took about 8 seconds to turn EACH WAY for each cycle. I have not had a squeal or a grind since. Do not hold the wheel against the stop at the end, as this will cause the pump to cavitate. Just touch the stop, then move away from it slightly, pause, then slowly go back the other direction.

Doing this with the tires off the ground makes it easier to do that many cycles and it easier on the front end parts.

 

[RexTreks]

Roger that, I still have the truck up on stands so I will get out there right now and get busy (but much more slowly!!)

Thanks!

 

[Tools R Us]

Any leak or restriction on the suction side will cause fluid aeration. Restriction is most commonly from the screen/filter in the reservoir being clogged. In my experience, power steering or hydraulic fluid runs cleaner and is less likely to aerate, than ATF. If the reservoir is kept at the proper level, the system should self bleed in a few drive cycles, if it's making air there is a problem that bleeding isn't going to help.

 

[george_tlc]

I had ATF in my power steering and it would make the groaning type noise and you could sorta/kinda feel it in the steering wheel when turning into a side street - not always but often enough.

Went to hydraulic fluid and the groaning went away, but after a little while had a leak in the rear power steering pump assembly. Figured I'd put a tablespoon or two of brake fluid in and that stopped the leak 100% and has been that way for several months.

I have all the seals etc for an R&R when I get around to it...

cheers,
george.

 

[richardlillard1]

Good god that sounds like a lot of work for nothing.

I’ve never understood the fascination with “bleeding” the system on these. You fill it up, you start it and turn it off immediately a few times, topping off each time, then start and let it run for a while. It takes like ten minutes. Even with the hydro assist ram.

Though I will confess I turned the steering back and forth a few times to force fluid into the ram when it was empty.

I just don’t understand the hours of work mud insists is necessary for these simple machines.

 

[jonheld]

I hate to agree with Richard, but I R/R everything on my PS system last year. New reservoir, all new soft hoses, all new OEM high pressure hoses, which required removing the pump.
I put everything back, filled the system with ATF, started the engine and topped off the reservoir. Turned the wheel lock to lock once or twice and checked the level again.
Done.

 

[RexTreks]

Given this information, something is still wrong then... Might be time to pull the reservoir cap open and clean out that filter.

The only other thing I can think of would be the steering box itself has bad seals?

Would any of the other hoses (the non-pressure hoses) be potentially responsible in this case?)

I went out and did the bleeding process far more slowly and I'm still getting lots of air in the system.

 

[richardlillard1]

I hate to agree with Richard, but I R/R everything on my PS system last year. New reservoir, all new soft hoses, all new OEM high pressure hoses, which required removing the pump.
I put everything back, filled the system with ATF, started the engine and topped off the reservoir. Turned the wheel lock to lock once or twice and checked the level again.
Done.

Goooooood.

All joking aside, the only thing I would do differently is not running the ATF, but that obviously works so it’s not the end of the world. Out here in AZ I’ve found the stuff I run from Napa makes less noise when at angles and doesn’t seem to pump out the cap as much. But anyone else’s mileage may vary on that one.