Nice thread, I will have to do some reading later.

I dont know anything about steering boxes. What does that spanner nut cap the shaft goes through look like? Is there a bushing in it? If its tightened to spec and still sloppy, theres only so many things it can be... Worn bushing, worn shaft, or a bad bearing somewhere.

Next time no teflon tape. It should be used on plumbing only, and even that is kinda iffy IMO, we have better options now. On tractor hydraulic NPT ports I just use regular cheap *** non hardening pipe dope for like 2 bucks at the hardware store. Another option is some type of anaerobic sealer. Dissolved pipe dope is gonna cause way less problems in a system vs pieces of teflon.

 

Good for you for not trying to just fix that with your wallet. I probably would have just bought a new pre-tapped box from PSC haha.

 

yeah, you're probably right about the tape. The last time I put it back together, I was very cautious that the depth of the tape did not get near the fluid port. I did also use pipe dope on it as well. Belt and suspenders.

There's a roller bearing in the box that the shaft rides on. Just a little guy. The spanner nut cap is an adjustment which sets the preload on a thrust bearing. There is an adjustment procedure for the box, I just marked where the cap was and put it back to the same spot.

If there's anything I'm good at, its doing stuff myself so it takes longer, is more expensive, and comes out worse lol. The PSC drop-in replacement is like $1200. That hurts just a bit too much when there are other options.

 

So the power steering saga is still not going well




Blew the sector shaft seal out again. I'm obviously doing something wrong. I still was feeling like there was something weird with the way the steering felt while bleeding. Felt like it was building pressure in the system while turning. Like the return line was blocked or something.

After contemplating burning my garage down, I pulled everything back apart again. I blew air through everything on the return side including the hoses, filter, cooler, and pump reservoir to make sure there wasn't a blockage somewhere. I disassembled the box again to see if I could identify an issue, which I couldn't.

At this point, I don't know what I'm doing wrong, but I'm trying something else. I ordered a Durango box on eBay, along with a rebuild kit. I plan on tearing the Durango box down to tap for hydro assist and rebuilding, like I did on the XJ box. Just hopefully this time it works.

While going through the system, I pulled the pump bypass apart again. I could hear the pump bypassing while bleeding when I turned full lock, but wanted to do it for good measure. When apart, I laid the XJ and WJ parts next to each other to closely evaluate any differences.





The notable piece here is the spring inside the bypass valve. The rate of this spring sets the pressure at which fluid will flow through the bypass rather than through the steering box. Stiffer spring means higher pressure in the system.

The springs are pretty close, but the WJ spring is beefier. Both springs have the same wire thickness and outer diameter, but the WJ spring is about 0.055" longer and has 0.5 less coils. I've read numbers stating the WJ spring is good for about 1900 psi whereas the XJ spring is more like 1400 psi. More pressure equals more turning power, but also puts more demand on the seals.

During all of this, I was able to finish a smaller project that I'm pretty happy about: I moved my windshield washer fluid reservoir to under the hood. I used a reservoir from a ZJ (Mopar PN 55155360). It fit pretty good and did not take a ton of effort to get it installed.

First step was to undress the hoses and wires out of the harness. This was the most tedious part of the whole ordeal.





I mounted the tank utilizing 2 existing holes on the side of the fender, and drilled a 3rd. It almost fits perfect, but the rearward hole did need a small mounting tab to gain another inch. I had to play with this mount a bit because the tank is very close to the hood. First time around the hood touched it, so I had to rework the position a bit to gain another 1/2".















I drilled a hole into the reservoir to reuse my low washer fluid sensor







Plenty of room for activities now! Pretty happy with how this came out.

 

That's a really good idea on moving the windshield washer reservoir to inside the engine bay. I've smacked my reservoir a few times and had to plastic glue/weld it a few times.

Edit:
for the wiring, did you have to rewire/switch wires or did you just need to pull the necessary wires from the loom to redirect them?

 

I just pulled the wires from the loom and redirected them. The ZJ tank uses the same pumps, so the connectors worked. I didn't even shorten the wires, just tied the slack back.

 

oh that's awesome! My next mod! haha

 

So, I will say that I have had some ideas brewing for air intake setups and I'm now looking at this washer reservoir thinking I could've done better. The issue I am seeing is the reservoir sits in front of the brake master cylinder by about 4 inches. There is room to move the reservoir back about 4 inches, but its too wide to sit next to the brake booster. It has to be in front of it. If it was about 2 inches narrower, I could move the reservoir back closer to the firewall, leaving much more room for an airbox.

I literally just finished this mod and haven't even put fluid in the tank yet, but I'm already eyeballing it for rework. I'm looking at some more universal tanks that are smaller but will package better. Honestly, the same reservoir I use for my coolant overflow could be a great candidate.

I currently cannot fit the OEM airbox because of where my coolant overflow tank sits. Last year, I moved the tank to where the washer reservoir currently sits so I could use the OEM airbox. I just zip tied the coolant reservoir in place. It was a very crude setup to get me through the year. While I do really like how the coolant reservoir packages in its current location next to the radiator, I need an airbox solution. Yes, I could just use a simple elbow tube and cone filter, and I might for the short term, but I would very much like a more proper airbox. While the OEM piece is fine, I would like to move the intake higher. Plus, I eventually see myself going to high clearance inner fenders and possibly raising the shock mounts up into the engine bay. I have been looking at filter housings from Donaldson. They have some great options that have pre-cleaners that eject particles from the airbox before they reach the filter integrated in, which would be great. Similar setup to the UMP filters that a lot of the desert guys run. I've been taking some measurements and looking at CFM/restriction numbers. The filter housings are large and expensive, so we'll see if anything happens with that.

So, long story longer, I might redo the washer reservoir setup to prioritize room for an airbox.

 

haha, thanks for the incite! I did come across some other posts and on naxja one person mentioned using an s10 reservoir. They didn't say which year, or anything else about it.

 

Things have happened on the Jeep! Took me all winter long to resolve an issue that could've been fixed in a weekend, but I've learned some things.

First, I did end up reworking the washer fluid reservoir like I discussed in the last post. I replaced the ZJ tank with a Dorman 603-001. This is the same bottle I use for my coolant reservoir.

Made up this funky bracket to mount the bottle off of the brake master cylinder mount:






This setup takes up much less room than the previous one. The tank doesn't hold quite as much, but that's a compromise I'm okay with. I like this much more.












With this setup I am still using both my front and rear pumps as well as the washer fluid level sensor. A small detail that I addressed is that the cover on the reservoir says "engine coolant only". I didn't want this confusion on there with the actual coolant overflow showing the same thing, so I 3D printed a part to go over the cover which shows "washer fluid only". Came out nice.



Continuing the steering saga...



Received my 99 Durango gear box and tore it down for rebuild. This is a Saginaw 808 gear box which is very similar to the XJ's Saginaw 800. The primary difference is this box uses a 3-1/8" piston whereas the XJ's is 2-3/4". With all else equal, installing a Durango box will result in a 29% steering force increase because there is 29% more piston area for the pressure to push on.






These housings can be identified by the "055" cast into the bottom where the Saginaw 800's have "025".






Another notable difference with the gears is that the Durango box is a variable ratio from 16:1 to 13:1, whereas the XJ has a fixed 14:1 ratio. This translates to the Durango box is easier to turn near the center of the steering throw compared to the extremes of either side. There is some debate over which is preferable for different situations, but I feel they're similar enough that it doesn't make a huge difference. It was interesting to see the difference in the way the teeth are cut into the gears on both the pistons and the sector shafts. After doing a thorough comparison of all internal components on the two steering gears, this was the most notable difference.






The third difference to discuss on these two steering boxes is the difference in steering throw. The XJ box has 79 degrees of throw and the Durango has 72. This was a big deal to me as I've put in a good amount of effort to maximize my steering throw, so I modified the Durango box to maximize its range.

These steering boxes have a spacer at the bottom of the bore which can be removed to increase travel in one direction. The spacer at the bottom of the Durango box is 1/8" thick. Interestingly, I noticed the XJ boxes also have a spacer at the bottom. I measured this to be 0.055" thick.









Only removing this spacer would've resulted in an increase in steering travel on one side of center but not the other. To increase my steering range equally, I removed the same amount of material from the standoffs on the bore end cap to allow the piston to travel further on the opposite side. However, I did not make these changes without thoroughly understanding what I was doing and any potential consequences. I've read reports of many people successfully making these changes on these steering boxes, but I wasn't overly comfortable doing them.

When the spacer at the bottom of the bore is removed, the piston travels further into the bore. This puts the teflon seal on the piston very close to the edge of the sealing surface on the housing.









At the other end of travel, the piston comes very close to covering the small port which directs fluid to the far end of the piston. This is the port which all of the pressurized fluid flows through to push the piston in the opposite direction.











With some creative use of calipers, I got a very good understanding of exactly how far the seal was from the end of the bore at one extreme direction and how much the piston covers the port in the other direction. While I'm not completely in love with these mods, I decided I feel it is safe to make these changes to maximize the steering throw and it will minimally compromise the reliability of the gear box. I figured the only time these changes are affecting anything is at the extreme ends of the travel, which only happen when driving slow. So worst case if anything catastrophic were to happen, at least it wouldn't be while I'm doing 65mph.


I guess I don't have a picture of the end cap with the standoffs removed. I chucked up in a lathe and turned down 0.123" off of it to match the spacer on the other end. This left the stand offs 0.015"-0.020" tall, which I felt better about than going all the way smooth because it leaves a small space for fluid to get into rather than the piston essentially sealing itself against the end cap.

Got the box put back together with these changes and achieved 83 degrees of throw. Very nice! This changed the number of total input revolutions from lock to lock from 2-7/8 to 3-5/16. For comparison, the XJ box has 3-1/8 turns lock to lock. However, I saw something here that validated something I've seen before but never understood why: The XJ box has more travel in one direction than the other from the factory. I've always noticed that if you count the turns lock to lock then return halfway back to the center of travel (with the drag link disconnected), the steering wheel is not straight. I still don't understand why, but now with the modified Durango box my steering throw is equal in both directions.


During all of this, I sprung for a PSC underdrive pulley to match up with the Durango box and be better prepared for potential future hydro-assist. Figured while I'm in here might as well increase the scope of the project to cause as many headache and expenses as possible.






The new pulley is 4.5" in diameter compared to the OEM 5.5". This requires a shorter belt than the OEM 95.0". I tried a 92.3" but found that to be too short. 93.5" (K060935) is perfect.

Also found the OEM power steering pump hardware doesn't work with the PSC pulley. The head of the bolts are too large to fit. I ended up buying some M8x1.25x85 SHCS's which worked good, but I still had to grind the head on one of them down slightly to get it to fit.









Installing the Durango box was pretty easy. It did require adding some washers in to space it further out from the frame to clear the larger diameter housing. Could probably use some 4.5" long bolts too, but its only missing 1 thread. My steering box brace fit up perfectly, just had to pull one of the spacers out. The pitman arm brace did not fit, but I also found the whole setup to be in rough shape. I've removed it for now, but have some parts on hand to change it up a bit. Coming soon, hopefully.








So, excited that I had finally done everything correctly and gotten it all figured out, I tried out the new setup, aaaaannndddd:







*****.


Convinced the box rebuild was fine, I investigated power steering pressures thinking the relief valve might not be operating correctly or something. I rented a power steering gauge from the parts store and dove down this rabbit hole.







Its a good thing that I did this, because turns out the eBay WJ pump I installed was not putting out the pressure it was supposed to be. The system is spec'd to produce 1900 psi, but I was only reading about 950 with this gauge. Whether it was bad when I got it or if I damaged it from multiple rounds of bleeding and probably accidentally running it dry, I don't know.






Regardless, I was able to see that not only was the pressure relief valve not the problem, but I was actually dead-heading the pump every time I turned to lock because it wasn't producing enough pressure to open the relief valve.

Luckily, I had a friend who was parting out a V8 WJ who gave me another pump. I swapped this one on and hooked the gauge up to it. This one read 1900 psi, so I was able to measure the pump was working properly.

Through all of this, I learned a ton about the WJ pump swap. Per the manuals, the WJ pump produces 1900 +/- 50 psi and 2.4 - 2.8 GPM flow at 1100 RPM. In comparison, the XJ manual states the pump puts out 1400 +/- 50 psi and 2.4 - 2.8 GPM flow at 1500 RPM. So many people on the forums say to swap the WJ pump in to boost system pressure and all is good, but that's not the whole story.

The hydraulic systems on the V8 WJ is not only a pump and a steering box, they also use hydraulic pressure to drive the engine cooling fan. The system first sends fluid to the fan, and is then divided into two paths. One path going to the steering box, and the other returning directly to the pump reservoir. This means that the steering box on WJ's does not see 1900 psi. In fact, the manual gives a separate pressure spec of 1450 +/- psi at the inlet of the steering box.

With that information, I was uncomfortable sending the full 1900 psi to the steering box. I had also seen people state their steering was twitchy after this swap. Makes sense seeing as the box was not intended to operate at that pressure. Also the seals were not designed for that pressure. It felt like asking for trouble sending 1900 psi to the box. However, knowing many people had been successful doing this in the past, I pushed the envelope slightly.

I used the power steering pressure gauge to tune in the relief pressure that I wanted from the system. I experimented with different thickness shims on the valve to achieve 1600-1650 psi relief pressure. I found this sweet spot at 0.040" of shim with the WJ flow control valve and pressure relief valve. I chose 1600-1650 psi because I felt it was a good balance of increasing system pressure without going too far.








During the pump pressure investigation, after I learned the first pump was only putting out 950 psi, I was able to safely say the steering box was the problem. At that point, I threw in the towel of trying to do it myself and sent my box to Blue Top for them to rebuild it.





From talking with them, I learned the root of my problems was that I did not understand how the seal on the sector shaft works.

These use a single lip seal to hold ~1500 psi. The seal is positioned in between the bearing and a snap ring. For whatever reason, I had been working under the assumption the seal needed to be compressed between the bearing and the snap ring. In my head, the compression of the seal was the force which would make it squeeze outward to hold pressure against the bore in the housing and the pitman shaft. Turns out that was wrong.

What I really needed to do was drive the bearing in deeper and leave a gap between the bearing and the seal to allow the fluid to push against the seal. The pressure of the fluid against the seal is what actually is producing the force to make the seal expand against the wall of the bore and the pitman shaft, and thus hold pressure.

This could've been avoided had I paid better attention to the depth of the bearing upon disassembly. I should've taken a measurement. With the OEM bearing having a flange to drive the bearing down onto and the aftermarket bearings not, the exact position of the bearing was something that I was uncertain about.

Expensive lesson to learn. I wasted a lot of time on this. In hindsight I really should've put more thought into what I was doing with that assembly step and how it was affecting the performance, but here we are.

Upon receiving the box, I measured the rotating torque and found it to be quite high compared to the spec's from the manual. Took 20-25 in-lb to rotate, and was maxing my torque wrench out at 30 in-lb to go over-center. I found that to be odd, but didn't think too much about it because they're the experts.


To get the rig back to operating state, I hacked a corner off the OEM airbox to get it to fit with the coolant reservoir. Wasn't stoked about this, but I just had to do something for now. It works, but its still on the list of things to change.






Wrapped this up at about 9:30 PM last Friday night. Took it for a run down to the gas station for its maiden voyage of the year. About 20 minutes to get there and back. All was going well until I was about 30 seconds from returning home. Climbing the hill at ~3500 RPM, I blew the power steering hose off of the filter inlet. It was pretty spectacular because it was right out in front of me and with it being dark out the headlight really made it look like quite the burst. Rolled the thing into the garage leaving a snail trail of oil all the way up the driveway.

I quickly was able to diagnose the issue. I had been cheap and lazy and used one of the OEM style spring-clamps on that connection. Should've known better. I replaced it with a worm clamp, and everything was fine. Everything was also covered in power steering fluid. My engine bay is a mess, the whole grill and even down the side of the vehicle was covered in oil. What a mess.

Regardless, I had the system bled and back together the next morning. We had some friends over to camp and they wanted to go wheeling. It was about an hour between the time I had these problems resolved to when we were headed out to the woods lol. We just putted around some easy local trails on Saturday, but then went out all day Sunday on some fairly aggressive stuff in the pouring rain. Smart? Debatable lol.

It went great though! The rig didn't explode and we had an awesome day.












So, I'm feeling good about it! The rig does seem to not be running great. It’s fine under ~3000 rpm, but stumbles up higher. Gonna need some diag, but still made it the whole day and drove an hour home!

Impressions of the steering: meh, not as strong as I had hoped. With the larger piston diameter of the Durango box and higher system pressure, it should produce about 1.6x the steering force of the previous setup. It probably is that much stronger, but it needs more. Still doesn’t want to turn 37’s at 10 psi. Hydro-assist still on the list.

edit: oh also, forgot. Through all this I dialed in my steering stops on the knuckles. I'm using most of the available travel from the box, paired with my longer pitman arm, and now I have steering stops on both the forward and rear sides of both knuckles. Should be a very safe setup for the RCV's moving forward.

 

nice work! I did the WJ power steering pump swap and it is one of the best things that helped off road.

 

Wow, this is some serious tech work you did on that steering box. I love to see people documenting and sharing their lessons learned along the way rather than just repeating decades old forum wisdom ad nauseum.

Great post!

 

I can't help but feel my steering system is still lacking. I did a u-turn the other day and was severely disappointed in the performance. Made me think it might be worse than before. I'll have to pay more attention to it as I get more seat time. Gotta remind myself I started this whole endeavor to set myself up for hydro-assist, but I did get my hopes up that the Durango box and WJ pump combo might make assist unnecessary.

edit: I just looked at the Durango manual and can see it's power steering system is spec'd for 1500 +/- 50 psi and 2.4-2.8 GPM at 1500 RPM. Quite close to the XJ's. I should be slightly above both of those specs.

Thank you! I like being able to contribute some tech and spice things up a bit. I see the same questions recycled over and over again. Nice to dig into something a bit more. I took a ton of pictures and measurements of the XJ and Durango boxes torn down side by side. Hoping to do a thorough write-up comparing the two. That should dispel some myths.



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The other day I did an alignment to adjust the toe angle. I was thinking the Jeep was feeling pretty darty. I found the toe was right at 0 - 0.05 degrees. I adjusted it to ~0.30 degrees. It seemed to settle everything down. Rig tracks much better now.



Today I replaced my clock spring. I damaged it at some point in the steering saga. I feel a bit satisfied by this because years ago I replaced this with a non-cruise control version, and this time I replaced it with a cruise control version. Not that I have the other parts for cruise installed anymore or its anywhere near a priority. But hey, one step closer to the Jeep not being a hot mess anymore.

 

Drove the Jeep into work today. The power steering still sucks. I can barely turn the wheel while sitting still in a parking spot. I wish I had a better comparison to how it was before all of this work, but it still needs lots of help.

Its still drivable and wheelable as it is, so not in a huge rush right now.

 

Dang. Did you have them rebuild the xj box of the durango box? Sounds like you're having a little bout of my luck on this proj lol. Sucks when people tout some of these upgrades as bolt on such as the WJ and it doesn't work out that way but I've honestly heard so many instances of it not working well for enough people for me to not to attempt it again. Rn my psc pump feels like it's doing alright with the hydro assist. The HA really changes the characteristic of the driving experience a lot. I personally like it but there are some cons currently with my set up. 1. When I first start it takes a while to build pressure at idle for it to want to do well backing out my driveway and turning while stationary. 2. Making quick turns specifically U-turns like you said. Generally when you're making a U turn you're trying to get TF out of whatever situation you're currently in so you tend to try to steer faster and it doesn't like that so much. This quick steering does NOT allude to like making a quick small adjustment to avoid a pot hole or your neighbors kid in the street. Anyway I feel for ya. If you're working with the durango box and the wj pump you're kind of far enough off the beaten path of things that are designed to work together you might consider reeling it back in a bit on the pump side IMO that's where I would start.