I'm running a Chevy G-van power steering setup (95-back type). A while ago it started acting up - power ***ist would come and go, it sometimes didn't like to return to center, the ***ist never completely went away but it was very erratic as to just how much ***ist it would give me. No real rhyme or reason or predictability to it. So, I changed the pump with a good used one I had around. The pump had been sitting a while and had some dings in the bottom from the clowns I had pull that engine out manhandling it, but it's the same pump otherwise. Unfortunately that hasn't solved the problem - it's no different than it was before. What am I looking at here, some kind of issue in the box? It doesn't have any obvious signs of trouble otherwise, no leaks, fluid level is right and I cycled it lock to lock a couple times and checked again after the swap. Which, I can turn it lock to lock while parked okay - but sometimes going down the road it almost like hangs up, then once I get past that point it's got normal ***ist. I haven't noticed if it's only turning in one direction. Then sometimes it acts like there's almost no ***ist. I'm not looking forward to going and pulling a used one, since we weren't smart enough to keep a spare, and then doing an R&R on it. Mostly because it's a pain in the *** to get to it, and around here pulling used means all kinds of **** dropping in your face as you do it, too. And the pump swap was enough trouble, it wanted to fight me every step of the way. It's strange to me too because usually these things are reliable for way more miles than this one has on it. (around 115K). The only other possibility I can think of is if the high pressure hose itself is bad and has collapsed inside like a brake hose sometimes does. That wouldn't be obvious from the outside, but might explain why it almost wants to stick, then the pump pushes through whatever's collapsing and I've got ***ist again.
Might have some trash in it - have you tried flushing it out? Remove the return hose from the pump reservoir and block off the fitting on the reservoir. Then rig your return hose to dump into a bucket or something - start the engine and have someone work the steering while you feed the reservoir with clean, new fluid. Run a quart or two through it and put it back together. This may help.
Well, I can try that, but this came on all of a sudden after several thousand miles with the cap not even opened on the reservoir - there shouldn't be trash in it. And now most of the fluid is clean and new. That said, stranger things have happened, a beater years ago I thought the fuel filter was clogged, so I changed it to find a skinny brown leaf on the inlet side partly blocking it - no clue how it could have gotten in there since it was an electric pump with a screeen on it.
We go around and around on these p/s issues. It looks like a slamdunk but somehow we thrash. One thing we've seen is the power steering hoses develop a flap, usually the pressure side. This really makes things fun on hydroboost. BEFORE you go crazy with three pumps and two steering boxes stop and evaluate. It's time to make sure that tie rod ends, ball joints, drag links, idler arms pitman arms are all lubricated (where possible) and happy and aren't WIPED. I can close my eyes and see ** jobs in our shop gone wrong because no one wanted to think outside the box. A water pump intermittently leaking coolant ( or anything leaking) on your belt can cause a momentary slip of the belt and loss of ***ist. How that would cause steering not want to return to center I don't know. The front end geometry tries to force the wheels straight with vehicle moving so if they don't want to go back straight sounds like a front end steering component locking. Not good. But before it gets another steering box (or a second or third) you gotta check everything else involved.
It puzzles me because there's nothing obvious. I changed the rotors and bearings on the front end not that long ago and it all seemed tight then, nothing moving how it shouldn't, and the tire wear is normal. I can't get it to bind when it's on a jack or lift so I can see what's going on; even in park sitting I can crank it back and forth fine. It's hard to describe accurately what it does when it "sticks" - it's almost like it gets a high spot you have to turn past, or like the centering adjustment in the box is off by like 1/4 turn of the wheel. I could see where that could be a mechanical bind, but it's strange that it's intermittent. I agree a wear part is more likely the cause, the pump and gear in these things I've seen go 300,000 miles without a problem. And there's been no leaks or drips out of it that I've ever found except the old P/S pump had signs of it on the bottom. But it never marked it's territory either.
Does this system have the slave cylinder? I had one like this had that symptom. It had air in it. Jack it up and turn all the way to one side break line at cylinder repeat in both directions a few times.
Sounds like Air trapped or a partially clogged Power Steering Check Valve.. However; "The only other possibility I can think of is if the high pressure hose itself is bad and has collapsed inside like a brake hose sometimes does. That wouldn't be obvious from the outside, but might explain why it almost wants to stick, then the pump pushes through whatever's collapsing and I've got ***ist agan" Correct,internal hose delamination could cause an " Internal Check Valve" .. Things to look for: *Contaminated Fluid (You did flush ENTIRELY correct?) That old pump you had laying around could have had corrosion and deposits that could quickly contaminate the system (or you could have deposits and contaminants suspended in the fluid) *Use the RECOMMENDED P/S fluid, incorrect fluid can damage the system (non compatible chemistry/heat transfer,etc) *if P/S fluid is the wrong viscosity. (can also break-down like oil) or too thick and will slow down/increase the pressure of fluid. *I would replace ALL the RUBBER HOSES and make sure that the steel lines dont have pin-holes or are contaminated (a small pinhole due to rust or a metal line rubbing can **** air) Rubber hoses can deteriorate without any visible damage to the naked eye. *Slipping belt/damaged belt *MAKE SURE THAT the ORIFICE on the P/S Check Valve is not CLOGGED!This orifice is super tiny,if dirt or contaminants block the flow you can lose pressure hence that "flat spot" on your steering feel. I would do a quick check of the system and bleed it properly to make sure you have all air evacuated as well as to bleed the entire system properly.. You can rent a vacuum pump at your local AutoZone for free,go to you tube and look for a Power Steering System Bleed video/diagnosis how to) showing how to use the pump or go to A1 Cardone's website. Hope you sort it out! Best, Jon
Low side hose is new and I did burp it on the new pump install. Symptoms are the same as before I changed anything, which leads me to believe either the box has a problem or there's a mechanical bind somewhere. No slave cylinder.
I will be interseted to know what fixes this in your situation, I have a similar issue with one of my cars with a common saginaw 800 series box. I have never had one of these boxes fail, leak sure but not fail. Seems like sometimes I hit a hard spot when steering and then it works fine, not the same place everytime when turning the wheel. I have never had it on any car before, and the only thing I can think of is I am running actual power steering fluid in the car, normally I run ATF with no issue. This time I said "lets put the right stuff in this time" and I think that may be the problem. I am going to drain mine and go back to ATF and see what happens.
I'm a member on IATN did a quick search. There are some variable ***ist systems out there, maybe your van is too old for that? The variable ***ist models have a steering angle switch on the steering column. Whenever I'm in doubt I call our GM dealer with the vin and see if the van came with this system. Anyway, variable ***ist or EVO or whatever it's called takes a different p/s pump? Saw the weeping waterpump thing. Also saw metal shavings in the pump. Like I said, this is where you put on the brakes and check everything possible. Wiring diagrams. Alldata. Mitchell on Demand. Call the dealer. ( and then I call every other mechanic still talking to me for a consensus).
Are there u joints in the sector coupling? If there is I would take a good hard look at them.They can do just what you are talking about if they are bad (loose or froze)-----Bob 6bt
One other thing,if you have a slip coupler in the steering shaft that is bound up or not sliding it can cause the problem you have. Bob
No variable ***ist on this old clunker. I changed all four tie rod ends and all four ball joints and it still does it. When centered it's stiff to turn either way, then it's fine, then it's stiff again if you turn far enough. Coming back to center it gets stiff again. The column is broken where the shifter mounts (top part of mount is gone, bottom is still there), I would change the whole thing right off but the one I have on hand is for a cable shift and this one has a mechanical linkage. Right now the closest place for used parts has no vans I can pull one from - either another column, or a cable and the connections. This column does have two U-joints in it so it can bend about 50' or so into the box. But beyond that all that's left to change is the pitman arm, idler arm and the box itself.
You'll need to determine if it is actually loosing ***ist, a hydraulic problem, or a mechanical issue causing a bind. That's the first thing, not throwing parts at it. Since you changed the pump and have the same problem I'd imagine its a mechanical issue. But beyond that all that's left to change is the pitman arm, idler arm and the box itself. ... And the steering column components - bearings, the steering shaft u joints , rag joint, intermediate shaft supports,
As far as "throwing parts" did you find anything loose or marginal in the parts that were replaced? Then you didn't "throw parts", you did preventative maintenance.
You say it only happens when the vehicle is moving down the road, but wont happen for you when sitting still in the driveway? When you get it to one of those "tough spots" does it feel like the steering wheel is trying to push against you or it just gets a little tough then you muscle through it? I didnt see where you mentioned what vehicle this is in, stock suspension, lowered, etc? Is there any sort of noise that occurs when you get to the tough spots? Whine from the pump, strange clunking sounds, etc? Since you say it came out of the blue, and changing your PS pump had no effect on the problem I would definitely say it is something mechanical happening. On these old rides you have to jack the suspension up under the lower control arm in order to accurately check for radial and axial play in the ball joints. Unloading the suspension by jacking under the frame can very easily hide a bad ball joint from you. Chasing down gremlines like this can be a pain in the ***, especially over the interwebs where I cant get my hands on the car LOL
if its not returning to center everytime its a internal issue with the valving, sounds like the spool valve is worn and not gripping the torsion bar allowing the ports to remain open , or the valve body is loose in the housing . only way to repair it is have it professionally rebuilt .
In the end the lower of two cardan joints - a small U-joint - was just about frozen up on one axis. I swapped another column in - the shifter mount was partly broken anyways - and cured the problem. It's worth noting if guys are going to use these joints as a low buck alternative to your Speedway or other joints, that you want to pick from a 92-93 through 95 van. Somewhere between 91 and 95 they changed these from an open, exposed design to one where the intermediate shaft - the one with the joints on it - sits inside a rubber tube, sealing it from the elements. The tube bolts to the firewall on one end with like 7mm bolts and seems to be pressed on the top of the steering box on the other end. I wasn't sure if the first donor I pulled would work, so I got enough parts to use another one I had on hand if necessary and pulled a '95 intermediate shaft - it was like new inside the tube. The biggest problem with pulling these is one of the bolts on the firewall for the rubber tube is a pain in the *** to access, it's under the power brake booster. I had some trouble getting the tube off the steering box, too. But at least the design lets you pull the top end right out once the column is loose. The 95 intermediate shaft also offers the option of being able to be shortened, and you could run it a tad longer if you needed to - it's two pieces and slides together in the middle. Otherwise it's not much different than the older ones. And yes, while changing the ball joints and tie rod ends was kind of throwing parts at it, they did need to be done. It actually sits about an inch higher in front after the change, the ones in it were original to the suspension and pretty worn.
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