There are several reasons for the failure of a Steering Box (SB), but in the case of our trucks, the most usual one is the failure of the sector shaft seal (this was my case). The failure was so critical in my truck that it wouldn't hold the Steering Fluid for more than 5 minutes, so it was time for a rebuild.
As the title states, I'll try to explain to the best of my memory the procedure to remove the Steering Box, open it, replace the parts included in the kit (parts might vary) and finally reinstall it. Some of my procedures might not be the ones that are described by manuals, neither some of the tools. I just did what I could with what I had (actually had to buy 2 tools, which I'll point out in due time). I hope whomever might be doing this task, finds this write-up useful.
I apologize for any blurry pictures... they were all taken with my cell phone, and tired, tired, shaky hands...
One note for the most unexperienced ones: Never set a tool against the splines on any part of your car, if the metal seems shiny and unprotected (as in no paint at all) don't use any tool directly on it, unless you're removing the said part to replace it with a new one.
Tools and parts I used
(some might not be listed, I'll add them later, if you used a different size and don't see it here or if the size I stated is wrong please tell me so i can add/modify it up):
- Ford Steering Box Rebuild kit (this one had the complete set of seals, snap rings, o-rings and dust caps, but didn't have new bearings)
- 3/8 and 1/2 Socket Wrenchs (3/4, 11/16, 5/8, 9/16, 5/16, 3" ext, 1/2 - 3/8 adapter) needed (1 5/16 or 1 1/4, I'm not 100% sure)
- Wrenchs (11/16), you could also use the same sizes stated for the sockets if you wish.
- 1 12" Adjustable Wrench
- 2 Jack Stands
- 1 Jack (used the Truck's)
- 1 Center Punch
- 1 Pitman Arm Puller (KD 2289, mighty important to get a good quality puller)
- 1 3lbs Hammer
- 1 Oil Pan (any kind of pan were you can flush the entire content of the system)
- 1 Funnel (just in case you want to transfer the steering fluid from the pan)
- 1 plastic Container (for the ball bearings)
- 1 pair of Pliers
- 1 pair of Snap Ring Pliers
- A set of Allen Wrenchs (you'll only need the 3/32 one)
- 1 Knife (preferably short, slim and pointy)
- 1 Flat Screwdriver
- 1 size 10 slot screwdriver bit
- 1 plumbing Pipe (this was my substitute of a breaker bar, the handle of my 3/8 socket wrench fits nicely inside)
- 1 Vice (i didn't have one, but it would have helped a lot with the rebuild)
- 1 pair of Protective Gloves
- 1 pair of Safety Googles/Lenses
- 2 qts. of your Steering Fluid of choice.
- 1 can of Engine Cleaner
- 1 can of Penetrating Oil
- 1 Mechanic's Creeper (i used the poor man's option instead: cardboard)
Well, first off, you need to find a good working spot, of course, somewhere flat, without inclination, and keep in mind leaving enough space on the front of the truck to work comfortably. Prepare the area, set your tools near, etc... Of course, remember to use your googles and gloves. That said, let's get to the important bits:
Steering Box removal:
The first thing I did was separating the lines (High pressure and return) from the box, in order to be able to do that you'll need to take the snorkel and the rubber tubes that link the throttle body and the air box (MAF equipped models will have only one tube). Use the 5/16 socket to loose the clamps on both tubes in order to separate them from the airbox, so you can then place them out of the way. To remove the snorkel use both hands and press on the plastic pieces clipping it to the airbox while pulling the snorkel. This is how your engine bay should be looking, now you have access to the top of the SB:
(frontal view) Notice the top of the airbox to the right. The tubes should be placed in a spot where they won't interfere with your work or get bent.
Place the tray under the truck, were the lines should pour the steering fluid after being disconnected. Some might say you'll need a special wrench to remove the lines, but I found no problems doing it with the 11/16 wrench, of course, be careful not to twist the metal. If your engine bay is as dirty as mine, it's a good idea to cap both lines, I guess rubber bands and plastic should work fine. After that, move the plastic sleeve covering the joint between the steering shaft and the SB. Use the 5/8 socket to remove the bolt that holds the joint to the SB, I think I have no need to remind you to place every bolt, nut, washer, etc you take out in a safe place
. It should be easy to slide the joint out now. If you have the means, this would be a good moment to fasten and secure the SB.
(top view, driver's side) From left to right: High pressure line, return line, joint bolt, plastic sleeve (slided up the steering shaft to reveal the joint)
Now would be a great time to use the pitman arm puller... but since I did it backwards I'll explain it later. Since I made the mistake of taking down the SB first, here is the procedure of how I did it: Take a jack stand and place it supporting the drag link, this should prevent the SB from falling out once you take the bolts that hold it against the chassis. These bolts should be easy to find, watch from under the truck into the driver's side front wheel well. You'll see 3 bolt heads going through the chassis and into the SB, use the 11/16 socket and drive them out. The best way to do this is loosing them some turns and cycling between them, you don't want only one bolt holding the SB at a given time, so the faster the better. Once you reached the last bolt, be careful not to be in the path of the SB (the drag link/pitman arm should hold it in place, but you never know), take out the last bolt. Now the only link between the SB and the truck is the pitman arm, so go grab your puller and get ready for a struggle...
Just a picture of the jack stand holding the drag link (and SB). Let's ignore the puller for now...
On several procedures I checked, the authors said that you should free both sides of the pitman arm, but I found that to be unnecessary. Using the pliers, take the safety pin out of the castle nut, and then remove the nut (as I didn't have the right socket I used my adjustable wrench). This should leave you free to rotate the pitman arm/SB.
Now we're finally ready for the worst part of the removal: pulling the pitman arm out of the sector shaft. Rotate the SB counter clock wise until it's almost touching the drag link. If you have the 1 5/16 socket, use it to remove the nut and washer from the sector shaft (again, I used the adjustable wrench). Then, set the puller in such manner that one of the sides is placed flat against the drag link, it will serve as a stop when you start applying any important torque. If by any chance there isn't enough space between the SB case and the pitman arm to fit the puller you'll need to fiddle with the sector shaft adjust screw, this should move the pitman arm away from the case of the SB. If you do move the adjust screw take a picture or take note or how it was before so you can adjust it back later on. Placing the puller is fairly easy, unscrew the bolt (lubbing it before using the puller is a must) it has until you have enough clearance to slide the tool's arms over the pitman arm; then, center the bolt with the sector shaft and tighten by hand until you find enough resistance (remember, one of the sides of the tool should be flat against the drag link).
The puller I bought (actually, by far, the most expensive part of this rebuild), KD 2289, is US made and even though I managed to mangle it a little, it survived (unlike the Chinese .... I tried at first). The principle behind the puller is rather simple, turn the darn thing's bolt until whatever you're trying to pull pops off. This one had a bolt with a 3/4 head, so I placed my pipe-wrench combo (substitute for a breaker bar) and applied torque until it came out, the pitman arm was loose and the SB was finally free!. I know, writting it makes it sound like it's quite easy. For a more detailed impression on the process check out this thread: https://www.ford-trucks.com/forums/1...ing-box-2.html
Here you can see the puller set, side against the drag link, and with the pipe-wrench in place.
A closer look at the puller, sector shaft, and pitman arm, this was after the arm was released, notice the sector shaft's splines.
Anyway, this is how I removed the SB from the truck, as I stated before it probably would have been easier to disconnect the pitman arm while the SB was still in the chassis, but this worked out just fine for me.
Steering Box Rebuild:
You probably want somewhere as clean and comfortable as possible. A good friend let me use a table in his house, which ended up being a perfect place to work on the SB, I even was able to set a laptop with internet to check the step by step instructions from this site whenever I felt the need: 4x4.forensick.net: '88 bronco: steering box rebuild
Since I used only the 3/4, 5/8, 9/16 sockets (And a larger one you could use to take out the bearings, which I didn't, as my kit had none, and later, to insert the seal and push them in place) the Allen wrench set, a knife, a size 10 slot screwdriver bit, the center punch and the hammer, I won't be stating the socket sizes each time for the sake of a simpler explanation.
This is the layout of my workspace for this part of the project, I had even more space to work on the left side of the table.
Ok, before anything else, I have to make a comment here: you can take appart the SB in several ways, but for the sake of keeping things simple, I'll follow the procedure in the site afore mentioned, even though this wasn't exactly the order in which I did it.
Place the SB in or above the pan, with the inlets for the lines (high press. and return) facing down, and start turning the input shaft (the one that joined the SB with the steering shaft) several times Clock Wise (CW) and Counter Clock Wise (CCW). This will pour all the steering fluid out.
You can now start disassembling the SB, the first step should be taking the two bolts that are at each side of the sector shaft adjusting screw and stop nut. In the image of the workspace the socket wrench is placed on the stop nut and the bolts are to the left and right. After that, you'll need to center the box in order to be able to pull the sector shaft out, to do so, turn the input shaft CW until it hits the stop, then turn it CCW 1/2 turn, the sector shaft should be centered now. If you have a rubber mallet you could hit the sector shaft directly, this should unseat it, it you don't have the mallet, use the hammer and hit softly the part of the case where the bolts were, this should work too. If the sector shaft still seems to be stuck, do little corrections to the input shaft while trying to pull the sector shaft (this is how I managed to do it...).
Here it is... the SB... in this one you can see the stop nut and the two bolts that hold the sector shaft against the rest of the SB.
With the sector shaft gone you can see the splines over the piston, these were the ones preventing the sector shaft to be pulled easily, they should be centered like this when you assemble the SB again.
This is the dreaded sector shaft, the rugged looking top is part of the case, you can tap here gently with the hammer when you're unseating the sector shaft.
Remove the four bolts holding the valve housing, they are the ones around the input shaft.
Not much to say here... nice pic huh?.
Pull the piston/worm drive out of the SB case, which right now should be an empty shell
From left to right: Piston, worm drive (inside the valve housing) and input shaft.
What's left of the SB: an empty, empty, sad shell... Notice the little o-ring there, we'll deal with it later.
A picture of all the parts scattered on the table.
Ok, take the case and turn it so you can access the seals of the sector shaft. First, take out the snap ring (if you have any trouble grabbing the snap ring, it will probably be the dust seal seating against it, use the screwdriver and hammer to push it back a little), this way you'll have access to the roller-bearing, pressure seal and dust seal. I won't be taking out any bearings but you can do it using the large socket (whichever one you have that fits the best) or a puller. Now, turn the case again and use the screwdriver to pry on the seals, you can use the hammer to tap on it, just be careful not to hit the bearing if you plan to reuse it nor scratch the internal walls of the case. Pay attention to the order and position the seals had, as you will be placing the new parts in the same order (bearing, pressure seal, dust seal, snap ring). Use the large socket again along with the hammer to drive in the new parts, do this slowly and gently (I used a piece of cloth over the socket to further soften the hits) so they are driven in evenly, take special care with the seals as they will get deformed easily (don't ask...). Do NOT let the seals seat against the bearing, this will shorten their life, just drive them in enough to place the snap ring back "Do not seat the seal directly up against the bearing or it wont seal properly. Instead, set it in so that it is just past the groove for the snap-ring"
Here the seals are already out, and all is left is the roller bearing. Notice the snap ring groove half way down to the bearing.
This is how the new seals of the sector shaft should look like in place.
Now let's turn our attention to the piston and worm drive. You'll need a container of some sort, so keep one at hand. Near the piston, there is an u-shaped rail held in place by a strap. Remove the 2 bolts holding the strap, and then, very carefully, remove both halves of the rail (it actually has 2 parts). Some ball bearings should fall, store all of these in the container, there should be anywhere between 27 - 29 (28 in my case). To take them all out you should move the worm drive back and forth. In my case I just placed the piston with the holes where the rail halves fit facing down over the container. Count the bearings and store them safely. You should be able to unscrew the worm drive out of the piston now.
The two big holes in the piston are where the rail's halves fit, the smaller ones are were the bolts for the strap go. Notice the teflon ring near the top of the piston, that one was replaced with a new one later on.
Care to count? there are 28 ball bearings in this container. Just don't lose any of them or you'll be in trouble.
Piston and worm drive separated...
Now lets take the worm drive and valve housing apart. This is where a vice would have helped, but you'll manage without it, as I did. There is a very small screw that press against the worm drive, use your Allen wrench to remove it. Keep it somewhere safe, you could lose track of this one very easily. Next is the ring that holds the valve housing and worm drive together (it's concentric to the last one). This one is very similar to the ones used in the Bronco's hubs. If you have the proper tool now is the right time to use it. If you don't, use the center punch and hammer and tap very gently CCW until it comes out.
The worm drive, with the new teflon rings already in place. To the bottom left is the ring that held it in the valve housing.
A closer (if blurry) look at the teflon rings.
The new seals of the input shaft inside the valve housing. The procedure is almost the same as the one used to replace the seals in the sector shaft so just follow those instructions again.
This is all the disassembling I needed to replace the parts included in my kit, if your kit brings other bits you might need to take apart some other pieces (check the exploded view the kit brought).
If you have done everything following the instructions in this write-up, you should have the seals of both the sector and input shaft ready. Now we will replace some o-rings and teflon rings (remember to clean off any dirt and debris in the grooves or seating place of every seal/o-ring/teflon ring). Now just follow this check list:
- Big o-ring (flat) between the sector shaft and SB case
- Small o-ring in the SB case
- Big o-ring (flat) between the valve housing/worm drive and the SB case
- Big o-ring (round) under the big teflon ring near the top of the piston (you will need to remove the teflon ring first in order to be able to see this one)
- Big teflon ring near the top of the piston (just use the knife to cut this and any other old teflon rings)
- 4 small teflon rings in the worm drive
Installation of the new teflon rings can be tricky, so be very careful. The teflon rings aren't very flexible, if you put too much tension on them you'll break them (as in if you stretch them too much). When you're replacing the small ones, I recommend starting from the one closer to the worm drive, sliding in the new rings one at a time before cutting any of the old ones (you can help yourself do this using the knife), this way you'll have less grooves to take the new rings over, as they will be filled by the old rings.
Having done this, we are ready to assemble the SB and finish the rebuild. As you have probably noticed already, this is quite more easy than it looked like at the start, so let's get to it:
First off, let's join the worm drive and valve housing again. Slide the worm drive into the housing (be careful with the teflon), then screw the ring in until it feels tight, then use the center punch and hammer CW to finish tightening it. Don't forget to put back the little Allen screw!. Now insert the worm drive into the piston, and turn it until it lines up with the ball bearing holes. Insert both halves of the ball bearing guide (rail), there should be a hole in top of it, use it to insert the ball bearings, moving the worm drive every now and then to make space for the new ones, until you have inserted them all (did I say 28 already? that was my case). Once you have done that, re-attach the strap that keeps the guide in place using the two bolts it has. Now slide the piston inside the SB case, keeping the teeth facing up and try to center them with the sector shaft's tunnel (check the third picture of the rebuild procedure). Now insert back and tighten the 4 bolts that hold the valve housing against the SB case.
The teeth on the body of the piston facing the right side while being centered.
Having done this, you should be ready to put the sector shaft back in place. Slide it inside the SB case, again, very carefully, matching the teeth (splines) to the ones in the piston's body, if everything is in place, it should slide right up, if it doesn't, try doing little corrections turning the input shaft until it does. Now insert and tighten the 2 bolts holding the sector shaft against the SB case. Now is a good time to set the adjusting screw and the locking nut, retrieve that picture you took (or remember the threads you counted, check the mark you made... wichever method you used). You will need to hold the screw or the locking nut in place while you turn the other. I'm sure there is a special tool to do so, but since i don't own it... I found out that using a wrench on the nut and a socket wrench with a screwdriver bit in the screw i could do just that (having a friend helping you with this would be nice too)... You should be feeling very proud now (that is... if you didn't broke/lost anything) you just rebuilt your Steering Box!.
Steering Box Installation:
The installation of the SB is quite easy as I did it, except for the struggle I had as I did lift the box with one hand as I tried to slide the bolts to the chassis back in (so I will describe another procedure that will make it easier on you if you're having trouble).
Well, let's start with this... The first thing I did was to hang the SB from the chassis once again. To do so, I was recommended to use a board from fender to fender along with a couple of ratchet straps to hold the SB's weight while lining up the box's holes with the 3 bolts that hold it to the chassis. Once again, tighten them up cycling between bolts and making them turn a couple turns each time to keep them even, until they're properly tight. Now you can re-attach the lines and the steering column, just be careful not to bend any of the lines. About the column, get in the cabin and make sure the steering wheel is centered before sliding the joint over the input shaft and placing the bolt back in. Slide back the plastic shield to protect the joint.
Now lift the truck's front axle (sort of speech, it's a TTB) and place both jack stands to hold the weight of the wheels. Doing this will make it a piece of cake to fit the pitman arm back into the splines of the sector shaft. Once this is done, you can re-install the nut and washer and the castle nut, tighten them by hand and then take the truck down of the jack stands to finish tightening them, remember to put the safety pin back in the castle nut and to set the proper torque on the sector shaft's nut.
The Bronco on jackstands, ready to receive the rebuilt SB.
This is how the pitman arm should look set in the sector shaft.
A closer look, ready to be tightened.
With this, we're done reinstalling the Steering Box
. The only thing left to do is to refill it with fresh steering fluid. There is no need to bleed the system, as the system will bleed itself. You just need to top the fluid, start the truck a couple of seconds and turn it off, top the fluid again, start the truck again and turn it off, refill again... and so on until the system doesn't require any more fluid. In the following days just keep refilling the fluid when needed. You could also grease up the steering system since you're at it already...
Congrats! now you're really done! go for a drive now! send me a beer!
I hope this write-up helps anyone willing to try and rebuild their own steering boxes.
(special thanks to the fellas in the Big Bronco section of FTE for their help and support)