1985 3/4 ton suburban steering issue

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travis
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1985 3/4 ton suburban steering issue

Post by travis »

A friend of mine has a 1985 2wd 3/4 ton suburban. It's a high mileage truck and all the suspension and steering components was worn out. He had new ball joints installed as well as everything in the steering replaced except the steering box and had it aligned. It drove much better but still had excessive slop in the steering wheel. We replaced the steering box with a parts store replacement, and now it has a new and interesting issue. The steering slop is gone, but now the steering is twitchy feeling. Going down the road, the steering is quick and responsive turning to the left (like changing lanes or just traversing a turn) but slow and lazy turning to the right. The response is so different left to right it's actually hard to stay in your lane in anything other than a perfectly straight road. Slight adjustments to the box either tighter or looser doesn't help. Tires and shocks are fairly new.

Any ideas?
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Re: 1985 3/4 ton suburban steering issue

Post by SupStk »

Probably the spool valve, which is up where the steering shaft connects. Inside there is a torsion bar that determines the steering rate. If that bar is broken, has a loose pin or is too light for the application steering will be twitchy.

The difference between right and left turns I would associate with a hydraulic problem, possibly an internal leak?
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travis
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Re: 1985 3/4 ton suburban steering issue

Post by travis »

SupStk wrote: Sun Mar 12, 2023 2:40 pm Probably the spool valve, which is up where the steering shaft connects. Inside there is a torsion bar that determines the steering rate. If that bar is broken, has a loose pin or is too light for the application steering will be twitchy.

The difference between right and left turns I would associate with a hydraulic problem, possibly an internal leak?
This is a hydro boost system... maybe something going on there?
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mt-engines
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Re: 1985 3/4 ton suburban steering issue

Post by mt-engines »

I'm surprised the box was bad. Usually its the worn out rag joint that causes slop.

I'd make sure the steering box was clocked dead center. If not that can cause the issue you are having
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Re: 1985 3/4 ton suburban steering issue

Post by BillK »

Travis,
When the original box in my 99 Tahoe wore out at about 220K miles I bough an AC Delco reman replacement. It had similar issues to what you have so I replaced it under warranty. The second one never really felt right and went about 25K and started leaking like crazy. That was a few months ago. I ended up finding a 99 Tahoe in a local junk yard with only 30K miles on it. Put that box in and everything is back like new.

The fact that the issue started after you replaced the box leads me to think that is the problem. I did a bunch of research the second time with mine and pretty much decided that there are no good reman boxes. I did find one company after the fact that sounds like they might do a better job. I think I have a link at the shop. Will check in the morning.
Bill Koustenis
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travis
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Re: 1985 3/4 ton suburban steering issue

Post by travis »

The rag joint was replaced when all the other steering components was replaced.
We didn't take measurements last night, but just a quick eyeball on the pitman arm it looks like it isn't dead center...it doesn't appear to be off much at all (less than 5*). We'll see if we can tweak that a bit sometime this week.

Bill, after doing some research myself there are 2 brands that seem to have much better reviews (at least in the Ford truck world)...Red Head and Blue Top. I think that will be the next step if tweaking the pitman arm alignment doesn't help
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