J20 Steering Box plumbed for assist and rebuilt

[Elliott]

There are a few things missing in every set of instructions I've read (including my own write up I'm working on ;) ). It's done, I'll install a filter in the return line and run it to flush it good before I drain it down and refill the system prior to use to get wheel bearing grease out of the fluid (gotta use that to get the last four balls in the tube fitted to the piston. Oh, when you load the balls into the piston: There are two different sizes which need to be replaced in an alternating pattern. The black ones measure 0.280" and the chrome ones measure 0.281". Save 4 out for the tube, then split the remainder and install them evenly between the front and back holes (maintaining the alternating small/large pattern)... using a piece of clear tubing helps to drop them in without fumbling.

Loading the balls (http://www.fullsizejeeps.com/jeeps/files/Users/Elliott/InsertBalls.JPG) (if they don't go in perfectly alternated from large to small your box will bind near full extension) I believe there is supposed to be a way to install the balls from the end of the piston with the piston cap nut removed and this may be the best way to ensure they go back in alternating.

Sure helps to build one of these before you even start:
Spanner Wrench 1 (http://www.fullsizejeeps.com/jeeps/files/Users/Elliott/Spanner1.JPG)
Spanner Wrench 2 (http://www.fullsizejeeps.com/jeeps/files/Users/Elliott/Spanner2.JPG)

Pick up the correct torque wrench, KD2955 Beam Torque Wrench 0-60inchLbs (it's 1/4" drive and you will need an adaptor to drive the 3/8" 12pt 17mm deep socket that you fit to the splined input):KD Torque Wrench (http://www.fullsizejeeps.com/jeeps/files/Users/Elliott/KD2955BeamTorqueWrench0-60inchLbs.jpg)

Adjusted to spec and finished:
J20 Box 1 (http://www.fullsizejeeps.com/jeeps/files/Users/Elliott/CompleteBox1.JPG)
J20 Box 2 (http://www.fullsizejeeps.com/jeeps/files/Users/Elliott/CompletedBox2.JPG)

Steering Box Diagram (http://www.fullsizejeeps.com/jeeps/files/Technical/SteeringBoxDiagram.JPG)

[ January 27, 2006, 02:29 PM: Message edited by: Elliott ]

[luckypabst]

You may want to make note of how the balls are two different sizes and need to be staggered in the race. One set has a light black finish, the other set is chrome. The black ones are .005" smaller than the chrome ones.

Chris

[Elliott]

Arrg, are you serious? Is this for later Jeeps or all of them? Have to get my calipers out and check the balls from my spare box.

Thank you very much! The black ones measure 0.280" and the chrome ones measure 0.281".

[ September 05, 2005, 11:47 AM: Message edited by: Elliott ]

[luckypabst]

That was from a mid-70's GM factory service manual. Same basic box so I assume it's the same across the board.

Chris

[luckypabst]

OK, verification:

'74 Chevy passenger cars & light trucks manual

"IMPORTANT: The black balls are .0005" (OK so I was off by a factor of 10, but you get the picture) smaller than the silver balls. The black and silver valls must be installed alternately into the rack-piston and return guide."

Chris

[Elliott]

I appreciate the info on that. Unfortunately for Jeep owners the ball tube on the Jeep boxes don't have a return guide. The tube has to be removed. I wasn't certain the balls should all go in one hole so I split them between the holes, then put four in the tube, held them in place with a stick magnet and inserted the tube halves back in the piston with needle nose pliars. It's a lil tricky keeping the alternating pattern going while keeping the piston centered so that when it was all buttoned up it would actually cycle fully from one side to the other... if I didn't get things just right it wanted to bind up when turned hard to the right.

[Dmntxn77]

More great info...

[mark]

thanks elliot
ive got a box tapped and ready to go in but i did not dissasemble it because of the scary 2 size ball deal.maybe now i will tackle it while i still have it out.did you buy just one rebuild kit for the box?i remember the one on my montecarlo had 2 seal kits an upper and a lower.

[mark]

Thank you very much! The black ones measure 0.280" and the chrome ones measure 0.281".
thats because all the chrome wore off! :rolleyes: lol

is your j 20 box the one with the 3.5 piston

[Elliott]

just one kit did it and yes it's the 3.5" piston

I have more info if you want to see it, but I don't have it completely edited just yet.

[Dmntxn77]

I got your email, did you mean to send that to me or mark? Either way, its great info, and I plan to do the conversion soon too..

[Elliott]

Doh, glad you could use it... let me know how it goes. :D

[Elliott]

Write up goes something like this:

(links to TSM at the bottom)

WWW.Rockauto.com (http://WWW.Rockauto.com)

1979 J20 (large box) rebuild kit # GAA 350440
Wagon and J10 boxes will use a different kit as they have a smaller rack piston (the worm gear and stub shaft/adjuster plug are interchangeable).

Product by: Gates Rubber Company
Denver, CO 80217
# 350440

Notes:
• Remove the pitman arm while the box is still bolted in the vehicle. This isn’t mandatory, but likely a lot easier.
• Clean the box prior to disassembly. Use only brake cleaner to clean internal parts and blow out fluid passages.
• It is easiest to drive out the end plug by removing the retaining ring (using a punch) and then pushing the end plug out by cycling the steering to full extension using deep 12pt 17mm socket and ratchet. The ball bearings will drop out, don’t lose them.
• Note/mark where the adjuster plug is seated at and how many turns used to remove it in order to return it to approximately the same place (11 inch/lb max preload). If you forget to do this I list how to set preload later.
• Remove the pitman shaft cover. With the piston centered, remove the pitman shaft, pry out the pitman shaft seals, drive out the bearing using a socket reversed on a 1/2 extension.
• Reinstall the pitman shaft bearing and then drive the seals up one at a time w/washers until they just leave enough room for the retaining clip
• Replace o-rings and seals using an o-ring pick. Remove Teflon rings from valve body, being careful not to damage or nick grooves. Note: To aid in installing teflon rings, they may be heated in boiling water fro 5-10 minutes. Dry completely and lubricate before installation. There are 0-rings are under the Teflon rings.
• ***There were two o-rings left over in my kit. The only things I did not fully disassemble were the rack piston plug and the adjuster plug which instructions did not show it had any internal 0-rings inside of it, only one external one which I replaced along with the two end seals. The diagram did not show a total of more then 8 o-rings.
• ***Reassembly should be done with power steering fluid.
• To assemble the valve body to the stub shaft, insert the smaller section into the larger section with the hole for the pin on the input shaft at 3 o’clock from the slot on the larger section which should be at 12 o’clock. Install the stub shaft so that it’s pin locates into the hole on the smaller section of the valve body, push in while locating it correctly with the slot cut in the large section of the valve body.
(the small section of the body is easiest to install in the larger section coming from the back side or end which would be respective to the adjuster plug.
• Install the worm gear with washers and bearings into the box housing/piston.
• Leaving the adjuster plug off of the stub shaft, insert the o-ring into the worm gear end of the shaft and locate it to the worm gear lining up the pin on the worm gear to the slot on the stub shaft. {***If you screw this up and break the pin because you didn’t have it oriented correctly when you tightened the adjuster plug then get another box to use for parts or replace the pin. You can interchange the worm gear from a smaller Saginaw box out of a Cherokee, Wagon, or J10. To replace the pin you can try this: it measures .140 and can be replaced with a cut down #28 drill bit if you can drill the old pin out with an undersize cobalt drill, a 5/64 cobalt drill bit and then use a #1 screw extractor or just re-drill to .136 with a #29 drill bit. Taper one end of the cut down drill bit and drive it in, trim to correct height in respect to the input shaft dimension. If the fit is difficult, boil the worm gear and freeze the cut down drill bit and retry.}
• If you assembled the stub shaft correctly the return fluid port at the top of the inside of the box should be visible before you install the adjuster plug, if you can’t see the port then work to the stub shaft to fit together prior to installing the adjuster plug.
• Then install the adjuster plug returning to the original marks. If you did not take the steps to mark the adjuster plug orientation prior to disassembly then turn the plug in with a spanner, tighten the plug to 20 ft/lbs if you can attach a torque wrench to your spanner (I approximated 20 ft/lbs with my homemade spanner). Make a mark respective of a spanner hole and then another 1/4-3/16” counter clockwise from that mark and back off the plug to match the mark. From there start testing for the thrust preload.
• Set thrust bearing preload: turn the input (using a 12pt deep socket size 17mm). Using a 50 inch/lb maximum torque wrench (it’s ¼ drive so you will need an adaptor up to the 3/8 socket drive). Use directions on page 404-405 of Chilton’s or 2L32-36 of the TSM (1979).. Set preload not to exceed 11inch/lbs. Install lock ring and retest preload to be sure it has not been disturbed.
• Center the piston in the housing, turn the input until the flat on the shaft is facing up (centered position). With the piston centered, the flat portion of the splined input should be straight up in relation to the box.
• Remove the ball tube from the piston by rotating the piston until you can access the two bolts holding the strap down. If you left the piston cap off then you can put a socket on the end of the piston which helps to rotate the piston into what ever position you need it to access the holes in the piston and to access the tube retainer bolts. There are 24 ball bearings total. The ball tube removes in two halves, load 20 ball bearings into the piston/worm gear through both holes in the piston (equal number of bearings in each hole). It’s easiest to cut a 4” section of clear tubing to drop the ball bearings through. You have to turn the input back and forth to wiggle in the last of 20 ball bearings. Load the last four bearings into one half of the bearing tube and smear in some wheel bearing grease at each end of the tube to hold the balls in place for reassembly (or you might try a stick magnet on the tube to hold the balls and you can prevent using grease that you will need to filter out later). Assemble the other half of the tube and carefully insert the assembly into the holes in the piston (using needle nose pliers) and reattach the strap. Straighten the piston in the housing and be sure it is centered for installation of the pitman shaft.
• With the piston centered place one wrap of tape around the splines on the pitman shaft (to protect the seals on installation) and install it in the box.
• Reinstall the piston cap and lock ring.
• Screw the allen screw in the top of the pitman shaft counter clockwise (using a 3/16” allen wrench) as far as it will go. Reinstall the aluminum top cover.
• Turn the pitman slack adjuster (allen screw) to set the over center drag torque per the manual. Use directions on page 404-405 of Chilton’s or 2L32-36 of the TSM (1979). Tighten the set nut.
• Temporarily attach the pitman arm and cycle it through it’s arc to be sure of full range of motion.
• Torque set nut to 35ftlbs.
• Install pitman arm and torque nut to 185ft.lbs. (it’s probably easiest to do this when it’s back in the vehicle).
• Fill and bleed steering system, run it and then drain/flush to remove wheel bearing lube if you used any.

From the TSM (1979):
http://www.fullsizejeeps.com/jeeps/files/Users/Elliott/TSM1.JPG
http://www.fullsizejeeps.com/jeeps/files/Users/Elliott/TSM2.JPG
http://www.fullsizejeeps.com/jeeps/files/Users/Elliott/TSM3.JPG
http://www.fullsizejeeps.com/jeeps/files/Users/Elliott/TSM4.JPG
http://www.fullsizejeeps.com/jeeps/files/Users/Elliott/TSM5.JPG