steering diagnosis please?

[sodafeld1]

Hard to describe a difference in steering of late besides not feeling as nice as what it use to on 1988 troopy hj75, 285000km. She runs straight on the freeway feels ok, no wobbles, turning seems slower, especially in suburbs, possibly lower revs suggesting hydraulics. Seems a bit slower in response to take a turn. If I stop at a traffic light and there is dent in the road, my wheel turns into it, didn't feel so noticeable before, that was the first thing I noticed, tyre pressure was too high at that point. On the gravel, corrugated roads in low4 feels happy as Larry.

New tie rods and ends, checked bearing preloads, knuckles fresh packed, shocks, damper, stabilizer all seem fine not all that old. Toe in good. Everything snug, rubbers good, ubolts torqued and knuckle studs. tyre pressure correct. New springs, shackles, brake calipers.
Everything seemed very good for at least 20,000kms, made me feel I knew something!. Some heavy towing and lots of bumpy roads. Now it seems quite suddenly a steering issue

There is little to no slop in the steer wheel and responsive there without much play. I tried a bit of box adjustment but wary of it being a cure all, not wanting too over tighten it. The steering wheel returns but not like it use to.

Three things I have noticed I haven't seen before:

1: when axle is on stands the steering is stiffest in the middle when wheels are straight but there is less resistance when turned more to either left or right, engine off, using the steering wheel. This kind of makes sense to keep the wheels straight, or should it have equal resistance from all the way left to right and back again without extra resistance in the middle? (is this called bind?, if so, more box adjust)

2: Some how, atf power steer fluid has somehow expanded and sits on the lid of the reservoir, just a bit wet. never saw that before. The level seems fine, never too low, on the line when hot. Could my pump have a blockage to create that sort of expansion? It does not whine or carry on, never has.

3. Slight burning oil smell, pretty subtle. I have chased any engine oil and diesel leaks, she is pretty clean, no dribbles or leaks. I have read the burnt oil smell can signify box is on it's way out.

I shall do a fluid flush as it is due for that. If that doesn't make the steering better (which I don't think it will), rebuild the pump next, I am guessing? Or is the box binding? Maybe try rotating tyres again in case the last tyre rotation introduced unbalanced tyres with possible lugs knocked off?(but that would be more noticeable at high speeds.)

??????

 

[sodafeld1]

Ok, humbly reporting, resealed power steer pump and reinstalled, that was it.
My theory is the hydraulics assists even steering full turns and straight, the box should feel even under pressure. I was confusing the inconsistent steering resistance with the steering wheel. I am wary of adjusting or fiddling with box adjustment as it is not the sort of thing which wears suddenly. If I had a choice to bath in a motor oil, it would be atf dxiii, lovely cleaning oil stuff. There is a pressure valve in the pump which can stick, a tell tale can be some gunk grime sticks behind the pump pulley and/or power steer fluid appearing on the lid of the reservoir. This was the problem for me, stuck valve in the pump.

It is a bit of a dog job, access is poor, rhd remove coolant return bottle and air filter housing to make life easier. The fsm is not the best for installing the pump, as installing the pulley once the pump is on would be like something from harry potter. The two bolts attaching the pump to the bracket are doozies with the pulley in the way but doable, maybe removing the pump with the bracket is actualy easier, didn't try that. Just remove the tension pulley completely, it is easier, and probably go for a 15a890 belt rather than the epc 15a865 or keep the 865 size and turn the crank with two pin lever to get the belt on. Then install the tension pulley. Someone here has replaced the pump valve seal in the engine bay, wow! That circlip is difficult imo.

Then, I re-adjusted the box so it was obviously too loose, to find a definite. Then gently tightened it back to the slightest resistance was felt in the adjuster screw. Then check the play in the steer wheel. It has to be loosened first and the wheels turned so the shuttlecock shape adjuster can lift and settle before being tightened. Redo if necessary.

A slack steering wheel is obvious, inconsistent pressure from the pump is not so obvious and there is lots of factors involved with steering.

It is has been one of the few jobs I have found as after thought on the 2h (besides 5th gear, which I have not done), and pump resealing is actually easier on a 1984 w123 merc in my little experience. Which is rare imo, tojo is ace.

I would recommend resealing your pump before playing with the adjusting screw on your box if your steering feels funny. No harm done resealing the pump, fairly cheap entertainment, change the fluid and belt at the same time. Adjusting the box can damage if approached heavy handed.

I just topped up the fluid without the engine running and turned the wheels back and forth a few times, then kept topping up with little increments until the level is reached once engine running. I have bled the fluid before per fsm but that is very messy. Sure, hypothetically I have some old fluid in the system still, but the majority is fresh.

Back to cruising!

 

[Felde]

I found the steering pump to turn over quite a lot of volume; basically the entire reservoir in less than 6sec.
This means, the fluid ages quite significantly, also suffering quite some heat stress.
Changing the fluid regularly will help avoiding that gunk that mighty make that valve stick.

I however wonder on the steering box itself. I did the steering pump, but didn't dare digging into the box.
I understood, the power-assisted box is lubricated by the ATF pumped through by the steering pump? So no extra oil (like in the non-powered box)?
Are there similar guts that, which may age or collect gunk?
With my steering, going straight or turning right is no issue, but when moving left, even just a tiny bit, I can like feel the power steering kick in: A very little vibration on the steering column.
Cheers Ralf

 

[sodafeld1]

Yes the box is lubed by the atf, as far as I can see. Don't know why the fsm says to check fluid level in the box as you would have to drain most of the system to have a look, but I guess if there is a leak in the box perhaps, but then the reservoir would deplete of fluid.
I pulled apart my spare box, not too complex a thing, just the parts are exy. I don't think they would wear much if not over tightened and kept lubed, serious bits of hard steel in there.

Interestingly the merc w123 pump is much simpler than the toyota pump, but the box in the merc is way more complex than the toyota. I wouldn't take on a merc box,(paid a pro $500aud, score!) but not too scared of the toyota one as it looks, but the cost of bits. I rather a more complex pump. Grand scheme, vane pump is not all that complex.

Felde, sounds like a gremlin there, only one side. Takes some hunting. First stop is check torque of your knuckle bolts holding your king pins and pitman arm!!! Common for them to work loose, there are upgrades and extensive posts on them here on mud. Also sounds like your column shall get worse if it vibrates, it shouldn't be at all. Front bearings? Tyres balanced? Front 40psi? Tie rod ends? Springs torqued? I have seen spring perches slopped out from under torqued spring ubolts, that would make your steering pull for sure. Even slopped out rear springs can effect your front steering. Worth doing thoroughly.

You should be able to eat a burger with one hand whilst on the freeway, minimum. No expert tho.

 

[JuanJ]

I found the steering pump to turn over quite a lot of volume; basically the entire reservoir in less than 6sec.
This means, the fluid ages quite significantly, also suffering quite some heat stress.
Changing the fluid regularly will help avoiding that gunk that mighty make that valve stick.

I however wonder on the steering box itself. I did the steering pump, but didn't dare digging into the box.
I understood, the power-assisted box is lubricated by the ATF pumped through by the steering pump? So no extra oil (like in the non-powered box)?
Are there similar guts that, which may age or collect gunk?
With my steering, going straight or turning right is no issue, but when moving left, even just a tiny bit, I can like feel the power steering kick in: A very little vibration on the steering column.
Cheers Ralf

Hello,

The power steering fluid is sensitive to emulsification on contact with air. This happens when there is not enough fluid in the reservoir. Heat, pressure and oxygen do affect any fluid over time.

I have not observed gunk on ATF/power steering fluid but I have observed emulsification. Emulsions can be a pain to pump over a high-pressure circuit, especially one designed for liquids. I guess emulsions affect control valves as well.







Juan

 

[Felde]

Yes the box is lubed by the atf, as far as I can see. Don't know why the fsm says to check fluid level in the box as you would have to drain most of the system to have a look, but I guess if there is a leak in the box perhaps, but then the reservoir would deplete of fluid.
I pulled apart my spare box, not too complex a thing, just the parts are exy. I don't think they would wear much if not over tightened and kept lubed, serious bits of hard steel in there.

Interestingly the merc w123 pump is much simpler than the toyota pump, but the box in the merc is way more complex than the toyota. I wouldn't take on a merc box,(paid a pro $500aud, score!) but not too scared of the toyota one as it looks, but the cost of bits. I rather a more complex pump. Grand scheme, vane pump is not all that complex.

Felde, sounds like a gremlin there, only one side. Takes some hunting. First stop is check torque of your knuckle bolts holding your king pins and pitman arm!!! Common for them to work loose, there are upgrades and extensive posts on them here on mud. Also sounds like your column shall get worse if it vibrates, it shouldn't be at all. Front bearings? Tyres balanced? Front 40psi? Tie rod ends? Springs torqued? I have seen spring perches slopped out from under torqued spring ubolts, that would make your steering pull for sure. Even slopped out rear springs can effect your front steering. Worth doing thoroughly.

You should be able to eat a burger with one hand whilst on the freeway, minimum. No expert tho.

Thank you for the extended reply.
The front knuckles will be like perfect on Monday: I'm over The Knuckle Job right now. All bolts and guts on the knuckles will be addressed. New bearings all over.
But there was no issue when took it apart.
Steering linkage was done with new OEM parts little over a year ago. Regular inspection. I doubt any of thst is the issue.
Yes, my steering column has a little play. Buts not the point.
This vibration feels a bit similar to touching a device with a worn bearing, where you like feel the single bearing balls. No notable malefunction, though. It also was there since I own the truck (2y) and didn't get worse. Monitoring it.
I'll study how that powerbox actually works. Maybe that gives me an idea where that comes from.
Good to know it's likely not a lubrication issue. My servo ATF gets regularly inspected, and changed once a year.
Thanks Ralf

 

[sodafeld1]

Thank you for the extended reply.
The front knuckles will be like perfect on Monday: I'm over The Knuckle Job right now. All bolts and guts on the knuckles will be addressed. New bearings all over.
But there was no issue when took it apart.
Steering linkage was done with new OEM parts little over a year ago. Regular inspection. I doubt any of thst is the issue.
Yes, my steering column has a little play. Buts not the point.
This vibration feels a bit similar to touching a device with a worn bearing, where you like feel the single bearing balls. No notable malefunction, though. It also was there since I own the truck (2y) and didn't get worse. Monitoring it.
I'll study how that powerbox actually works. Maybe that gives me an idea where that comes from.
Good to know it's likely not a lubrication issue. My servo ATF gets regularly inspected, and changed once a year.
Thanks Ralf

Strange only to the left, not sure if boxes can wear unevenly unless turning left most of life. Let us Know what you find. If not the knuckle, then tyre balance, bearing or spring mounts maybe. Pull happens without braking I assume.
Once I broke off my bolt from a front shock in the bush, I could limp home at up to 80kmh for 200km without issue or very noticeable pull.

 

[sodafeld1]

Just another little thing I found whilst checking any play in rear bearings. I recently adjusted and backed off my rear drums when installing new front calipers, so I thought they were ok. But about 2000km later, I noticed one of the rear drums binding a tad with the handbrake released, which would also effect steering . Backed it off a tad again, they need to be kept in check those rear drums, fairly regularly. Steering can be subtle stuff.

 

[sodafeld1]

Here is a youtubby which explains the adjustment screw on the box a bit better, you don't just tighten willynilly. Not toyota I don't think but same principal.