It was not difficult and really fun. I had watched some videos previously and found them a bit confusing. The service manual has more complete instructions than i will list here. In my case, i did not disassemble any further than necessary to reseal and adjust it. The problem I aimed to address was a very loose feeling on center. I remember driving my Dad’s ‘86 4wd extra cab brand new and loved the steering feel so i was trying to achieve that feeling. All other moving parts including the rag joint on my truck have been replaced during the last 20k miles. I had swapped the steering box for another one and that one has been leaking so i decided to rebuild the original and swap it back in.

 

Working in a clean, shallow tub helps control the mess and parts. No special tools other than a pair of snap ring pliers.

Remove top 4 bolts and one nut. Turning the screw clockwise will push the top cover off.

 

After the cover is off, stand the box up in mounted position with its own weight bearing down on the sector shaft(part where pitman arm bolts up) and slightly turn the input shaft. The sector shaft will pop up and out.

 

Remove 4 bolts on the valve body and turn the inpt shaft to separate. Prepare for about 44 ball bearings to come falling out.

 

Unscrew the input shaft from the power piston. Bearings will fall out! Clean everything. Spray thru the valve control with Brakleen and make sure movement is smooth and not loose. If yours is leaking around the input shaft you will need to disassemble further to change the seal.

 

I used a Gates kit from Rock Auto. About $30. They sell two cheaper kits but all appear to contain the same parts, mostly seals.

 

Replace the rubber o-ring on the top cover, then the parts in this photo. Put the worm gear into the power piston and get ready to load bearings.

Easy to miss this little one!

 

As you load the bearings in each hole about three at a time, apply pressure with your thumb and turn the input shaft to get them to move in. Put grease in the ends of half the bearing shell, then 11 or 12 bearings and then put the top half on. After all other bearings are in the power piston, put the bearing shell on and apply some pressure with your thumb. Again turning the input shaft back and forth see that it moves smoothly. Screw the bearing shell keeper down. Be cautious, the bearings can fall out again if you turn too far.

 

Now remove the rubber seal that seals the sector shaft with a hook, seal puller or screwdriver. Below it is a snap ring and then these other parts.


All these parts except the snap ring come in the kit.

Gotta reuse this snap ring!

Cleaned up on wire wheel.

 

Reassemble the seal stack in reverse order.

Teflon seal is easier to place if you bend it into a cardioid shape.

Teflon seal goes inside o-ring.

1 1/4 socket is good for pushing down the seal. I also cleaned the sector shaft surface where this seal contacts it using a scuff pad and Wd40.

 

Lightly grease the power piston cylinder and o-rings and use two bolts to pull it until is seats. Then use the input shaft to center the gear teeth on the piston to the middle of its travel. The input shaft turns about 4.5 rotations so put it at 2.25 and you should be right about there. The flattend area on the input splines will be on the bottom if looking at the box in mounted position.

 

Grease the teeth on the power piston and sector shaft and where the seal rides on the shaft. Now center the sector shaft teeth and drop it in. Turn the box upside down and allow its own weight to push it in.

 

Grease the o-ring on the top cover. Turn the adjustment screw on the sector shaft counter-clockwise to seat the top cover. (If you are British, turn it anti-clockwise) Put the 4 top cover bolts tightly. I adjusted the screw to take up all the slop between input shaft and sector shaft movement and ran it through the full range several times to confirm smooth operation.

 

Yes, I had to take the power piston out and bearing shell off again. Grrrr.

 

There are two caged roller bearings on the sector shaft that I did not remove from the housing but did clean them with Brakleen. They are not part of the seal kit and would probably have to be gotten from the dealership. I doubt what you can buy as a “rebuilt” box would include new bearings unless they were clearly toast. Mine with 180k miles seemed just fine. If there is slop between your sector shaft and the box the while turning, then you would need to replace those bearings

The rebuilt box is in and feels great. I have no more leaks and approx 1.5” of movement of the wheel on center.

I have some tips for swapping in a box:
* You need a pitman arm puller.
* Disconnect the rag joint bolts leaving the coupler attached to the input shaft. It’s easier to realign this way.
* the bottom of the sector shaft and Toyota pitman arms have alignment marks stamped into them. Cheapo $8 pitman arms do not.
* When you swap in a box, you will lose a lot of fluid out the pump after disconnecting the high pressure line. Use an appropriate sized fitting with a plug or glob of rtv on it screwed into the pump to hold back the fluid while you work on the box.
*I could not easily disconnect the high pressure hose fitting at the box so i just removed the box with the hose attached and then dealt with it off the truck.
* You can probably replace the sector shaft seal on the truck if that's all you need. Mine was leaking and i later discovered it had become cocked on the shaft. Maybe I could have stopped the leak by reseating it squarely. Rock auto sells the seal. You’ll need a pitman arm puller.

 

See this video for additional guidance. Not exactly the same box, but close. It helped me a lot.

 

Nice Job! Great photos and write-up. My '89 2wd manual box started to leak. Nasty stuff that gear lube. I explored options. Rebuilts are in the $250-300 range. Used boxes are not abundant and generally run around $100 here in CA. I took the cheaper/easier way out and obtained a used box from one of our members. I had it swapped in at a local truck frame shop. Its working fine. I'll probably have the original re-manufactured by Cardone and stick it back in. Since I have determined that I will never sell my old beater, I figure its worth spending a few bucks to fix stuff right as it pops up. The deal with Cardone is you ship it to them, and they determine if its a good candidate. If so, they do the work and ship it back to you, or just ship it back if not. Anybody have experience with Cardone?

 

How in the world did you take this piece off?? i struggled for 2 days before I gave up, put it back together and used it as a core for a reman.

I could not for the life of me figure out how to get that piece off without a SST

(piece highlighted in red)

 

i suspect mel didn't take that apart, as he notes:

 

Yes, Wally is correct. I didn’t have to, and your photo is different than my box.
But, if i was to attempt it on yours, my strategy would probably be to grind the staked areas with a Dremel tool,
Then fab some kind of spanner to fit that large hex. Then maybe use a couple tack welds instead of staking on reassembly.