FSJ steering box mods?

I just bought a J10-J20 steering box for my 90 XJ and was wondering if I NEED to upgrade the pump or lines or anything else. Will the stock pump produce enough pressure for the FSJ box? I read a while back about how to increase the pressure of the stock pump but would rather just purchase a new better pump. Reason being it is old and has been run low on fluid more times than I would like to admit.( steering box has a BAD leak..) Are there any pumps that bolt on without too much hassle?

TIA

Tim

What year J10 did the box come from? If it's a Saginaw box, the guts are the same as your XJ box and the stock pump will run it just fine. AFAIK the only difference is whether it has three or four mounting ears on the outside of the box.

The box is for a '87 J10. The one I got has 4 mounts instead of 3 like the XJ. I have *heard* that it will still work fine. I have also heard that the j10 box has bigger valves for the heavier vehicle.

Tim

By "bigger valves," I believe they are referring to the stiffness of the torsion bar in the spool valve. That's what controls how much the orifice opens and thus how much boost you actually get from the steering. A Z-28 Camaro, for example, uses the same box as a Jeep, but feels a lot stiffer because they reduce to boost to give the driver more road feel ("tactile feedback").

If there is a difference, I'd guess that the J trucks just have a looser spool valve to allow more boost. I've always hated the way AMC vehicles, including the early XJs, steer, because they have waaaaaaay too much boost and no road feel. The last couple or three years of the XJ were much better in that regard.

Slap it in -- it'll be fine.

Eagle, the J-box is larger in many respects, including the piston area. It is a much heavier duty box, and reduces turning to a nearly effortless event.

www.westtexasofforad.com has a tech page on how to boost the output of your OEM pump. Just get a new or rebuilt pump and give it a little tweaking. You'll be amazed at the power difference.

The J boxes have a larger cap on the end of the piston, by about 1/4 inch, so they are easy to identify.

CRASH

Cool!

Are the AGR boxes the same as the larger J trucj boxes?

Eagle said:

Cool!

Are the AGR boxes the same as the larger J trucj boxes?

Click to expand...

AGR takes the larger J10 boxes and messes with them.

Hmmmm I believe the J10 steering box is the same as the XJ, not heavy duty. It's the J20 box that is a "heavy duty" upgrade for XJs...