I should also say, I've already installed four new Monroe HD shocks and a new Monroe steering stabilizer/damper. I haven't studied the drag link or pitman arm. I shouldn't assume it's the box but I believe it is. I plan to throw parts at it until I find the problem.

 

Saginaw 800 or 808, probably the latter. You can tell by measuring the outside of the piston.

A 1987 would have the later metric o ring hose connections. This is a useful website for researching the different gearboxes

Saginaw 800 Power Steering Gearbox For GM Classic Cars - 3-bolt 12:1 (leepowersteering.com)

 

Thanks guys.

Saginaw 800 or 808, probably the latter. You can tell by measuring the outside of the piston.

Is that 800 vs 808 mm? On the piston itself or the case?

If you box has a lot of steering wheel play you should try to adjust it before you swap it.

I'm thinking about that. Can I do the adjustments with the box on the truck? Or is that ridiculous?

However I'm pretty sure I'll just replace the box, and the rag joint too while I'm in there.

On the rag joint. Best to replace the whole steering coupler or just the rag joint itself?

 

If you box has a lot of steering wheel play you should try to adjust it before you swap it.

I would also check my tie rods and ball joints.

 

 

And what the heck size are the hydraulic hose flare nuts on the steering gear box? I've tried every wrench I own. Too small for 3/4 or 19mm. Too big for 11/16 and 17mm. Is this 18mm? Who owns an 18mm flare wrench??

Edit: ok, I got them off with a 3/4" flare nut wrench. It wasn't snug but it did the job without stripping.

 

it’s an 18mm. I’ve never had an issue with getting them off using a standard wrench.

 

So my only remaining questions (so far), are:

* Should completely replace the flexible steering shaft coupler, or just the rag part?

* What other parts should I replace while I'm in there? Bagusjeep, you mentioned o rings. I'll have to look for those.

I've decided to get a redhead unit from BJs which is just down the road from me. Plus whatever else I need.

 

So my only remaining questions (so far), are:

* Should completely replace the flexible steering shaft coupler, or just the rag part?

* What other parts should I replace while I'm in there? Bagusjeep, you mentioned 16mm o rings. I'll have to look for those.

I've decided to get a redhead unit from BJs which is just down the road from me. Plus whatever else I need.

the rag joint is normally the only thing that needs replaced. I would also look at the rear steering column bearing and see if it needs to be changed.

 

The Saginaw 800 or 808 is the model number.

Small Bore 800 is “70mm piston” and a Big Bore 808 is “80mm piston”. just measure across the slightly domed end and you will get an idea of how large the piston is. My J20 has the 808.

Check you have:

• 18mm Metric O-ring pressure fitting
• 16mm Metric O-ring return fitting
• 3/4-30 input shaft

You could use new o rings, I have not bothered changing them in the past.

They come in 3 bolt and 4 bolt mounting, either will work as the J trucks only used the 3 mounting holes.

You COULD try adjusting the preload on the shaft which will close up any gaps between the input shaft and the rack and remove steering wheel play. Slacken the nut, adjust with a big screwdriver until you feel it touch, back off a little, fasten nut. Then work gearbox back and forth, it should be smooth the whole way and not bind at all. the problem is that the shaft can wear a point in the straight ahead position, so it binds left and right. This is a factory adjustment, so whilst possible it can lead to progressive failure if you do not get it right. I would give it a go anyway.

As said it could equally be play in joints, loose bolts holding the gearbox and even frame flex from a cracked frame. isolating the exact cause requires some careful examination with a pry bar. Replacing a gearbox is my last resort as they are darn expensive.

 

They come in 3 bolt and 4 bolt mounting, either will work as the J trucks only used the 3 mounting holes.

Mine measures 3" across the piston cap. I think it's the 800. It was mounted to the frame with four mounting bolts.

Replacing a gearbox is my last resort as they are darn expensive.

Yes they are. But that's the route I'm taking. As I understand it, that locking screw on the sector shaft is only one of the two necessary adjustments. The other is behind the locking nut on the output shaft. I don't know how to set the lash correctly and I don't want to screw it up. Plus, a major int'l steering gear box remanufacturer is only 60 miles away from me. They don't have any 4 bolt 800s in stock so I'm having them do a custom rebuild. If the steering is still loose with the new box, then I know it's something else.

I have a feeling, however, after pulling the steering box yesterday, that most of my issue is in the rag joint...

 

Get a replacement box for an 87 J10 remanufactured by Lares (high quality) and you don't have to worry about what model it has. They will know which one fits your Jeep.

 

You can use 4 bolt or 3 bolt, the Jeep only has three fasteners but either will fit over them.

3 inches is 76mm.

 

Redhead did a custom rebuild on my original box. I picked up and delivered. Took about a week.

Still waiting on one caliper banjo bolt and one brake hose. I should have everything reassembled in a few days.

 

Looks very nice.

 

Newly rebuilt steering box, new Lares 200 rag joint, new brake hoses, calipers and pads, new power steering hoses, and new brake hoses.

Plus one new driver's side steel brake line, to replace the one I destroyed. I didn't make that same mistake on the passenger side.

Remaining to do:
attach the new PS hoses, attach the rag joint to the steering column, attach the pitman arm, torque everything down, and bleed the steering.

I already replaced 4 shocks and the steering damper, and greased the steering zircs. Next are new tires and alignment.

If all that doesn't address my problem, I guess I'll have to keep trying.

 

All done with the Jeep. Test drove, no leaks, steering is pretty tight. I hope it loosens up a bit.

Thanks everyone for your help.