Category: Process Improvement

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Replacing the Rear Drive Shaft in a Jeep Cherokee

Replacing the Rear Drive Shaft in a Jeep Cherokee

After installing a Slip Yoke Eliminator kit in her NP231 transfer case, Jenny needed a different drive shaft in the rear of her Jeep Cherokee. The SYE requires a CV shaft like the one used in the front of the Cherokee. In fact, with her set up, a front shaft actually fit.

However the front drive shaft was at its fullest extension to connect up in the rear. So, if there was any pay at all in the splines, the drive shaft would vibrate. Finding a used shaft in good enough condition to run smooth was proving to be a challenge. Also the added abuse from off road driving made the choice of a stock front shaft no so good in the rear.

After much research, she decided to try a custom made shaft from Adam’s Drive Shaft. She also liked their skull themed logo.

There was no measuring involved. She simply sent them the specs of her Jeep along with the Pay Pal payment. A few days later the shaft arrived.

To remove the old shaft, I removed the four bolts at the rear diff and the four at the transfer case. These all use 8mm hex heads. I have found that the Craftsman 8mm hex wrench is the only one in my tool box that fits the bolts properly. My local Sears store rarely stocks these however. I bought Jenny one and made it into a necklace for her to take when she goes off road.

The Adam’s shaft is much heavier than the stock shaft indicating that it is made form stronger material. It was also just a tad longer. I did not measure it, I just set it in place and tested that it fit perfectly.

I elected not to use the 12 point bolts they sent since I have standardized on the six pint bolts. I will at a later time swap to the twelve pint bolts on both ends so that it will be easier to find a wrench that fits.

With the bolts tight, I took it for a short test run. It seems to turn freely and smoothly. I will have to wait until I can get it up to speed to evaluate the balance. I saw a couple of small weights welded to the shaft so I expect it to run smooth.

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Installing Sway Bar Disconnects on a Jeep Cherokee

Installing Sway Bar Disconnects on a Jeep Cherokee


One of the simplest ways to increase the off road traction on a Jeep Cherokee is to remove or disconnect the sway bars. While the rear bar can be removed entirely and never missed, having a front sway bar greatly improves on road handling. It feels unsafe to drive one on a curvy road without the front bar.

Therefore, a quick and simple method of disconnecting and reconnecting the front bar is needed. The sway bar is connected to the axle by end link bars. The end links can be unbolted from the axle to disconnect but since the axle is normally covered in dirt and mud, the bolts can be stubborn to deal with.

One very simple way to make a cheap disconnect is to replace the axle end bolt with a pin from a tractor supply place. This trick works well but does allow some slop and will eventually degrade the rubber in the end link.

For a more advanced disconnect method, Jenny chose the JKS disconnects. These mount to the swap bar with a bolt and hinge mechanism. The axle end bolt is replaced with a large pin that the link slips over. It is help in place by a clip.

To install the JKS links, first remove the Jeep end links. Start at the sway bar and remove the two 15mm nuts. The rubber grommets will likely be compressed into the threads so they will be difficult to remove. Use a hammer or pry bar to pull the bar up and of the end links.

Next remove the 18mm nuts from the bolts holding the axle end of the links. The other end of the bolt has a torx head but you seldom have to hold it as on most axles, this bolt is pressed into the axle tab. Once the end links are out of the way, drive the old bolt out of the axle tab. Use a back up while pressing the bolt out so as not to bend the tab. If you do bend it, straighten it back into position before proceeding.

Assemble the U section to the end of the sway bar putting the washer in the hole of the sway bar and the U section on top of the bar. Tighten the bolt securely and align the bracket. Make sure it is aligned and tight as you can’t access the hex drive on the screw after it is installed on the link. Connect the U to the top of the link and tighten the bolt.

Install the pin in the axle tab paying attention to where you want the pin hole to be. Slip on the spacer and the end link. Then set the clip in place. Do the same on both sides.

When running disconnected, you will need some way to secure the end links to the bar and the bar needs to be flipped up into the highest position to keep it form hitting the springs as the axle moves around.

To reconnect for the drive home, find a flat place to park the Jeep. If one side is higher, it will be difficult to get both links connected. Have someone press on the bumper to move the Jeep around if need to get the pins to line up. Set the clips and you are good to go. It is a good idea to have some spare clips in case these get lost or damaged.

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Regearing the Jeep 8.25

Regearing the Jeep 8.25
How to set back lash and pinon pre load on the Jeep 8.25

I recently put 4.10 gears in Jenny’s XJ. Her Jeep has a Chrysler 8.25 rear end. There seems to be very little info available on the 8.25 compared to what is on the web for the Dana 35 and Dana 44. So here is how I did it.

I began by removing the rear end from the Jeep and replacing it with our spare 8.25. That gave me the opportunity to take my time and not be in a rush to find parts. We got parts from our Crown Distributor as well as Advance Auto and Ebay.

With the axle out and mounted on my work stand, I removed the cover. Since this cover will be replaced with a Blue Torch Fabworks Kryptonite cover, I set the original aside.

Next, I disassembled her Lock Right locker so I could remove the axle shafts. The 8.25 uses the same length axle shafts on both sides so I did not have to keep track of where they went.

Next, I used a punch to mark the bearing caps so I could keep track of where they went. I could not see any factory marks like the Danas have. I removed the two small bolts that hold the keepers and then removed the keepers. I then removed the bearing cap bolts and the caps. I set all the parts in a box in order so that I could easily put them back where they came from.

Next, I slipped out the threaded preload plates and set them in the box. Then I was able to lift out the carrier.

I then rolled the axle over and drained all the oil out. I then removed the pinion nut and the yoke. I used a soft hammer to tap the pinion out. I then pried out the front seal.

I made a drift out of a piece of soft steel pipe and drove out the pinion bearing races. I set the races and crush sleeve aside to be replaced.

The gear set came from Ebay. It was slightly used but in perfect condition. The first odd thing I noticed about he 8.25 is that the bolts that hold the gear to the carrier are reversed threads. I was sure glad I read that before I tried to get one loose. They are marked with a big “L” on the heads as a reminder. I had to clamp the carrier in my vise to get them loose as they were very tight.

With all the bolts out, I used my heat gun to warm the ring and gently tapped it off with a soft hammer. I set the old ring gear aside to be sold.

Removing the carrier bearings was a bit of a challenge. I used a bearing separator and a two jaw puller to get them loose. I also warmed the bearing with the heat gun to help reduce the force needed. Due to the shape, I could not fit it in my press. I made a plug out of an old ball joint for the puller to press on while pulling the bearing off.

I installed the new bearings by warming them with the heat gun and chilling the carrier in ice water. I tapped them with my soft hammer to make sure they seated.

I chilled the carrier and warmed the new ring to slip it in place. I then snugged the bolts down to make sure it was seated properly.

Next, I removed the lower pinion bearing from the old gear set to retrieve the shim under it. I used the bearing separator in my press this time. I also had to heat the bearing with a torch to get it to release. With the shim retrieved, I set the old pinion aside and put the shim on the replacement pinion.

I then used my die grinder to open up the inner race of the pinion bearing until it slipped easily on the pinion shaft. This became my “set up bearing.”

I used my bearing driver set to press new races into the housing. I did chill the races in ice water before installing them. However, I did not attempt to heat the housing. There was a noticeable difference in the sound of the hammer on the driver when the races seated.

I assembled the new pinion with the old bearings and yoke but no crush sleeve or seal in to the housing and snugged the pinion nut just enough to take out any end play. I then set the carrier into place with the new bearings and races installed.

I fabricated a tool to turn the back lash adjusters using a nut from a Ford fan clutch, a length of ¾” pipe and an old ½ inch drive socket. I welded the nut to one end and the socket to the other end. The back lash adjusters are 36mm hex. A Dana 30 axle nut will work as well as any other 36mm nut. You can also use the miller tool C-4164.

I set the adjusters in place beside the bearings and set the caps on. I tightened them finger tight at first. I then used the tool to turn the adjusters to take out all the back lash but not put any extra pressure on the gear.

I made sure that all the end play was eliminated from the carrier bearings. I had to rotate the assembly a few times to get the bearings seated in the cones. I then set the back lash to about .003 inches using about 10 ft lbs of torque on the adjusters.

I then tightened the cap bolts to 70 ft lbs. I then tightened the right side adjuster to 75 ft lbs. or until I got a back lash of between .006 and .008 inches. I then checked the left side and found it to be close to 75 ft lbs as well.

I then coated the ring gear teeth with yellow marking compound. I rotated the assembly to get a gear wipe pattern. I was very happy when the pattern showed the pinion depth to be correct since the shim I had from the old gear was the only one I had. The Timken rebuild kit we got did not come with pinion shims.

Since I was happy with the pattern, I removed the carrier and pinion. If I had needed to change shims, I would have slipped off the set up bearing and tried a new shim using the same procedure.

Next, I installed the new pinion bearing by heating it and pressing it on the pinion shaft. I then installed the new crush sleeve, outer bearing, seal and yoke using the new nut from the kit.

I repeated the back lash adjustment procedure to get a back lash of .006 inches with the adjusters at 75 ft lbs. I rechecked the torque on the ring gear to carrier bolts. I then compressed the crush sleeve to get a pre load of 20 inch pounds. I noticed that then nut turned a long way with no change in preload and then suddenly the preload went up as I made the last 1/8 of a turn on the nut.

The torque needed to compress the crush sleeve was significant. I had to use a long breaker bar to turn the nut and a large pipe wrench to hold the yoke. With the preload and back lash set, I installed the keepers on the adjuster plates.

Since the adjuster tool had made numerous trips across the axle seals, I replaced them before installing the axle shafts. I reinstalled the Lock Right locker and secured the axles with the c clips.

I then put a bead of RTV on the gasket surface and installed the new Differential cover. I tightened the bolts finger tight and then let the RTV set up. I then tightened them the rest of the way down.

I waited until the axle was back in the Jeep to add the gear oil. The new cover held almost a quart more than the stock cover did.

The result was a smooth running rear end with no noise. I expect it to last a long time.

Parts used:

Timken 8.25 rebuild kit
Carrier bearings and races
Pinion bearing and races
Pinion seal
Pinion nut
Gear marking compound
RTV for the cover seal

Axle seals
Gear oil
Pinion Yoke
4.10 ring and pinion set
Blue Torch Fabworks cover

Technical info came from this source

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Trail Maintenance

Trail Maintenance

I did a little trail maintenance this weekend. The big storms in the early summer put a tree down right across the intersection for three trail and right at the creek crossing. I cut the tree off the trails but at the time I was not able to move the stump out of the creek.

I had really hoped that the flooding would wash the stump down the creek. However, after several floods, the stump stayed put.

The trouble was that in order to cross the creek with a vehicle with limited articulation, you had to enter the creek where the bank was not so steep, drive along the creek and then exit at another place where the bank was not too steep. With the stump in the middle of the creek, this path was not possible.

There was enough water in the creek most of the summer to make access to the stump difficult, so I just left it alone. Now that the creek has dried up some, I decided to get in there with the chain saw and see if I could clear the path.

I began by clearing the mud off some of the larger roots. I did not want to damage my chain saw chain by trying to saw dirt. It seems nothing dulls a chainsaw blade faster than dirt.

I used an adz to chop away the small roots and free up the entrapped dirt. I was able to cut off several large section of the roots and clear a path past most of the stump.

I tried it with my off road Jeep. I could get by easily but I noticed that my rock rail was still hitting the stump as I went past. That would not bode well for street Jeeps trying to use the path to the campground.

I cut off part of the tree stump that was still sticking up and I noticed that I could now move the mass of roots around some. I decided to try winching it.

I could not get in a position to remove it from the creek bed. However, I was able to roll the stump up on its side and up against one of the stream banks. This provided plenty of room to drive past the mass of roots. I trimmed a few more of the ones that stuck out just to be sure.

Driving by in the off road Jeep with 33” Maxxis Buckshots was no trouble at all. So after some rest and a drink, I decided to try my Daily Driver XJ.

I had not trouble at all on the first pass. I went down to the campground and turned around. Getting back into the creek took some maneuvering to get the right angle to go past the stump. I went slowly and I sunk in the mud. I had to rock back and forth a few times before my 30” BFG ATs found enough bite to pull me through the mud.

I think as soon as the creek flows some it will wash some of the loose mud away and make it more passable. Or if it stays dry, it will simply dry up enough to get through.

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Fabricating a Rear Bumper for a Jeep Cherokee

Fabricating a Rear Bumper for the Jeep Cherokee

Old and new bumpers

My old rear bumper had gotten pretty mangled. In fact, it was so bent that it was difficult to open the hatch. Every time I dropped into a ditch or V notch, the bumper was always dragging. I wanted something slimmer and stronger. But I did not want to spend any money.

The whole concept of Scuffy II has been to build a reliable and capable off road vehicle with minimum investment. Sometimes I have had to sacrifice appearance for functionality. I decided I could do the same with the rear bumper and build one out of whatever scrap I had lying around.

I started with a piece of two inch conduit. It seemed strong enough and light enough. But since the back of the Jeep is curved slightly a straight pipe did not look right or provide protection. I wanted to be able to back into a tree and not break the hatch or a tail light housing.

I solved that problem by using my pipe bender and putting a slight curve in the pipe. I then decided to fabricate brackets to mount the pipe so that it stuck out about half the pipe past the hatch and tail lights. That should keep it from dragging when coming up out of holes.

I wanted to use the stock mounting points so I looked around and found a piece of I beam that had holes that looked like they were the right spacing already. I simply cut the beam in half and had my two brackets. I just had to ream the holes a bit to make them match the holes it the Jeep. I made a few notches to get them to clear the hatch and other flanges at the rear of the Cherokee.

I then made half moon cuts to hold the pipe. I used vise grips to line up the pipe in the brackets and then tack welded it into place. I then pulled the assembly off and moved it to the welding table to finish welding it up.

I had purposely cut the pipe long because I was not sure what I wanted to do with the ends. I had thought about making bends to match the front bumper but I could not make a tight enough radius with my bender to do hat I wanted and still protect the bottom of the tail lights.

I eventually decided to make angled cut on the ends to somewhat match the lines of the Cherokee. I set up my band saw at the angle I wanted to cut both ends the same. I liked the look but not the sharp edge it left. Also, there was a gap between the body and the pipe where I could easily hang a small tree.

I decided to make end caps that covered the end of the pipe and extended forward to fill the gap. I searched the scrap pile again and came up with a piece of 3x3x1/4 angle that I cut into two plates. I welded them to the ends of the pipe and smoothed the corners.

I painted the whole thing flat black and bolted it to the back of the Jeep. The rear tow hook is much more accessible now. I can open the hatch easily now. I will have to give it a test drive to see how it handles dragging the mud.