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Old 12-03-2012, 07:16 AM
Thomas792's Avatar
Thomas792 Thomas792 is offline
327 Rambler
 
Join Date: Sep 16, 2007
Location: Woodbridge, VA
Posts: 622
Axle Swap and What I Learned (Part 1 of 2)

Long post so make a bathroom break and grab a cup of refreshment before begenning.

There will be no pictures as there is nothing revolutionary about the swap, just some precautions for those who are going to do the job.

I conducted an axle swap on the rear of my 88 Grand Wagoneer over the Veteran’s Day Weekend. I swapped the axle for several reasons: new bearings, new brake components, and change in ring and pinion gears.

As well as swapping one axle for another, I decided to go to a wide track in the front and rear. I eventually want to go to 33 x 12.5 tires and I currently have 32 x 11.5 tires as that is about as much as I can “fit” (street driven only right now) without an additional lift. In theory the wide track axle should allow full lock to lock steering without the tires rubbing on the spring or frame like I am experiencing now. I had the axles completely refreshed with new bearings and gears I got from BJ’s (best prices around) and new spring pads and shock mounts welded on to replicate the axle I then had under the Grand Wagoneer. After everything was totaled up I had the sudden realization that my wife would kill me if she found out how much I really spent. Some quick withdraws from the ATM and crafty funds transfer had it looking like the swap was fairly reasonable and MUCH cheaper than the work that was being done on our “new” Chrysler Pacifica. For a five year old car, it certainly spends its share of time at the dealership and it may be headed there soon as the drive train is “clunking” again. But back to the Jeep.

Here are some of the things that I have learned.

#1. PB Blaster is your friend, but not your savior. I liberally sprayed PB Blasters on all u-bolt nuts, track bar nuts, shock mount nuts, and anything else I thought I needed to take off starting on Friday the week before. I started wrenching on Friday afternoon and I ran about a 50% success rate getting those nuts off. I had to resort to cutting off the brackets on the frame for the track bar, cutting the bolt for the shock mount on the axle, and cutting through 75% of the u-bolts. The u-bolt nuts were so stuck that the bolts themselves ended up bending as the nuts were loosened. A few minutes with the sawzall and the 75% cut through bolts snapped with mild persuasion.

#2. The simple tools are sometimes the best. When I replaced my frozen brake cables six months ago I had a terrible time removing the brake cable from the backing plate. There are three or four “fingers” that hold the cable into the plate. I’d get one or two pressed in and try to rotate the cable so that I could get to the last one or two and the others would pop back out. I finally resorted to my metal chisel to cut the fingers off. I certainly didn’t want a repeat when swapping my axle so I devised a plan to use some safety wire and my safety wire pliers to compress all of the fingers at once. As I was looking for the safety wire and pliers I saw my combination wrench set and noted how the 1/2" box wrench looked very close to the size of the hole in the backing plate. After I took the brakes apart, I slipped the box end of the wrench onto the brake cable and gave a very gentle push and that brake cable came right out. That one’s going in the memory bank as a technique to remember.
#3. Those who cannot remember the past are doomed to repeat it. After I got the axle unbolted I dropped it to the driveway and rested the backing plates on two pieces of plywood. I pulled the axle out and slid it into my garage on the plywood. I had to lift the axle one side at a time and get my son to reposition the wood so that I could keep pushing it to its final destination. I must have lifted each side about 10 times and I was getting tired. When I finally got the axle in the garage I was looking at it and noticed the two HF furniture dollies with my front axle on it. The concept of the wheel then hit me and how much easier it would have been to use those dollies than slide that axle around which is why I bought the dollies to begin with.

So ended Saturday, without a bang (thankfully).

#4. Remember the 7 P’s - Prior Proper Planning Prevents P--- Poor Performance. Parts were taking longer than I had accounted for so Sunday morning I purchased some temp u-bolts at the parts store. The u-bolts were 1/2" diameter vice 9/16” but were otherwise useful and would serve the purpose of keeping everything together until the correct u-bolts arrived Monday morning. I should have ordered the u-bolts sooner and properly accounted for shipping times.

I put the new axle in place and bolted it to the springs. I turned my attention to the rear brakes, specifically the hydraulic brake line.

#5. If your brake lines are suspect, replace them. I ran all new brake lines on the axle and bent them up with a borrowed tool from the parts store. Bends were not as tight as I would have liked but I made it work. I used a brand new hose from the axle to the frame. I was able to separate the hard line from the combination valve to the flexible hose bolted to the axle. I used my line wrenches and didn’t destroy the nut too badly. When I tried to attach my flexible hose to the hard line, the flexible hose would not attach in the stock location on the frame as the mounting point was roughly three inches farther away because it was a wide track axle. I should have gotten a different flexible hose at that time but I decided to bend the hard line on the frame to a location that would work. I put the rest of the brake system together but could not figure out why the parking brake cable was too short. I connected the cables but was not able to seat them in the backing plate as they about 1/2" too short. I decided to worry about that later and got everything attached, refilled the system with brake fluid, and used my new vacuum bleeder. Everything bled out fine so I had my wife jump in the driver’s seat a pump it a few times. That hard line that I bent now had a steady stream shooting out every time she pumped. On top of that, I left the master cylinder cover off so I could top off the fluid easily. Brake fluid was now all over my engine and other components. I headed to the parts store for the second time on Sunday and came home with two of every length of 1/4" brake hard line they had. Routing the brake lines past the gas tank was a lot of trial and with surprisingly not much error. I should have suspected that something was wrong however when the length came out exactly correct and the line nut slipped nicely INTO the combination valve. It was starting to rain so I packed it up for the night.

So ended Sunday, again without a bang or an operational Jeep.

#6. Expect what you inspect. On Monday morning I started the day with bolting on my new shocks since I had to wait for the u-bolts to arrive. The new shocks were el cheapos since I wanted to do some real measuring after everything was all bolted up. The new shocks were gas charged so I pulled the wire holding them closed off and noticed that the shocks were about 4” different from one another. The boxes were the same but the tubes had slightly different numbers stamped into them. Closed they were the same length so I thought they matched. I quickly got skeptical on whether they were even valved the same and decided to reuse my old shocks. I actually had about 2” of compression before they bottomed out so I’m running them temporarily (I actually measured wrong on the shock bracket so it is not quite the same as the original axle.) If I had inspected the shocks prior to the actual install I would have been able to get the correct ones. This mess up actually saves me about $40 since I’m going to return the shocks.

(See next post for remainder)
__________________
1974 J10 (401, Th400, Q-Trac, D44s, 28" tires)
Mrs Tickity - 1988 GW (360, 727, 229, D44s, 32" tires)
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Old 12-03-2012, 07:18 AM
Thomas792's Avatar
Thomas792 Thomas792 is offline
327 Rambler
 
Join Date: Sep 16, 2007
Location: Woodbridge, VA
Posts: 622
Axle Swap and What I learned (Part 2 of 2)

(Continued from previous post)

#7. If everything seems to be going well, you have obviously overlooked something. I decided to button up the brake lines while I was still waiting for the u-bolts. Several frustrating moments later when the brake line nut would not tighten, I realized that the nut threads were a bit smaller than threads on the combination valve. Several frantic calls to my Dad and I was no closer to connecting things up. As a last resort, I called to the parts store and the attendant told me “Yeah, you need an adapter for that.” I voiced my frustration to him because I told him specifically that I was replacing the line from the combination valve to the rear brakes. I tried to send my wife to the store to get it but she refused. This had me on my third trip back to the parts store that weekend to purchase the adapter to the combination valve. Since the line with the adapter was now six inches longer than required, I put a nice loop in the brake line with the loop pointing down so as not to trap any air bubbles and hooked everything up. It worked out really well and I was able to get a fairly firm brake pedal.

#8. If it ain’t broke, don’t fix it. I tried to be slick and bleed the front brakes but the bleeder screws were rusted in place. I had previously twisted off the bleeder screws in the back before the axle swap so I decided to stop while I was ahead.

The UPS man arrived at around 11 a.m. and I had the correct u-bolts in hand. I ordered both the front and rear u-bolts so I actually got nine in the box. I looked through the paperwork two or three times and decided that Jeep made a change somewhere in the life of the FSJ so there were five u-bolts to cover the change to the front axle to make the kit non year specific. I replaced all of my 1/2" u-bolts with the proper 9/16” u-bolts and torqued them to 15 ft-lbs, then 35 ft-lbs, then 50 ft-lbs, then 75 ft-lbs, and then finally 100 ft-lbs.

#9. a squared + b squared = c squared. With the correct u-bolts I felt confident that I could put the wheels on, take out the floor jack and jack stands, and place the vehicle on all four tires. As I was putting the wheels on I noticed how far they now were from the springs and it dawned on me why the parking brake cables were too short. The original dimensions were roughly 20 inches from the frame hole where the parking brake exited and roughly six inches from the frame to the backing plate. This gave a required brake cable length of (20 x 20) + (6 x 6) = 436 => 20.88 inches. The new dimensions were the same 20 inches but the backing plate was now nine inches from the frame. This gave a new required brake cable length of (20 x 20) to (9 x 9) = 481 => 21.93 inches. This additional three inches resulted in an overall change of roughly one inch. The cables were fairly taught to begin with since I had a 2-3” lift but this additional width pushed me past the point of using the cable in its original configuration. Since I want to move the rear axle back about one inch in the future and cut two inches from the back of the rear wheel well, I’m going to need to swap in another cable but I haven’t found it yet. I know some threads suggest the J10 rear cable but that seems to be about eight inches longer than what I’ll truly need for my situation. I’ve searched through Raybestos catalog and came up with BC93888 which appears to have the same fittings as the Wagoneer cables I currently have. The Raybestos cable is about five inches longer and has similar cable and housing length differences that leads me to think that it will work.

#10. If you don’t get the answer you want, ask a different question. About the only thing that went without too much incident was bolting the driveshaft back in place. My original axles had the straps that held the universal joint in the yoke on the differential and the new axle had the u-bolts, or at least it had one u-bolt with one nut. I was one u-bolt, three nuts, and four washers short of a working package. I knew I’d need these parts so I got them during one of my runs to the parts store. I had a heck of a time finding them because they were not original to my vehicle. The parts store attendant told me repeatedly that the part I was looking for would not work on my vehicle. I had to trick the system into thinking that I had a ’74 J10 in order to get the correct part. Sometimes those parts personnel cannot think past the screen that they look at and become helpful.

#11. If some is good, more is better. My driveway has a two degree slope and when I parked my Jeep it was nose up. One of the last things I had to do was fill the differential. During the rebuild I read all the threads talking about not installing the axle seals inboard of the rear wheel bearings because the differential oil keeps the wheel bearings lubricated. Not wanting to run dry bearings from the get go I decided to grease them up really good so they don’t self destruct until the differential oil has a chance to get to them. I found a trick in an old Dana 44 manual that says to pull the outer seal down to the flange then fill the void between it and the bearing with grease. Then run some masking tape around the gap and pull the seal towards the bearing. The masking tape will form a dam and require the grease to go through the bearing to escape the pressure. I did this two times per axle shaft and everything is nicely greased up, at least until that differential oil can get to it.

#12. If at first you don’t succeed, try, try again. I unscrewed the fill plug off the differential cover and used my HF fluid transfer pump to fill the differential. Of course during the filling the hose popped off the pump and about 1/2 pint of gear oil shot across my driveway and left a terrible stain on the asphalt (my wife continues to remind me about this.) When I got the oil to the bottom of the fill hole I noticed that the oil level is below the bottom of the axle tubes. My question now is how do you fill the oil to a level that allows it to properly lubricate the wheel bearings? My solution was to turn the Jeep around so that it was nose down and pump in more oil. I may have gotten in another pint but I still don’t think it is enough to lubricate the bearings properly. At the 500 mile point I may pull the axle shafts and put a bit more grease into the bearings. I’ve had a failure before and it was not fun (less than 20 mph but it scared me really good.)

Two and a half weeks later and the Jeep is still running well. I think I need to address the brake cable fairly quickly to keep water out of the drums and to help them self adjust the shoes to the drums. Another thing I may have overlooked was that I think the drums had an anti-rust coating on them. The brakes are not as powerful as they were two weeks ago so I think the anti-rust coating is caked on the shoes. I’ll pull the drums and run some sandpaper on them to take off any glaze on there.
__________________
1974 J10 (401, Th400, Q-Trac, D44s, 28" tires)
Mrs Tickity - 1988 GW (360, 727, 229, D44s, 32" tires)

Last edited by Thomas792 : 12-03-2012 at 07:30 AM.
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