Hardest Fix On Your XJ?

[bluejeepkid]

stock balljoints with 170,000 miles and no air tools sucked pretty bad lol

 

[Ecomike]

Cool thread idea!!!

My worst one was a Renix sensor that gave me random high idles, and non starts on cold mornings (I had fuel and spark).

Took me months to figure that one out. That was before I had an FSM and my early days on .

Once I figured out it was the Intake manifold temp sensor that was bad it took all of 5 minutes to fix it.

Runner up was a brand new CPS that worked one minute and not the next on starting. Once it started it was fine. It preferred to not start, on cold rainy nights when my daughter 40 plus miles away.

In my driveway, and under tests it always worked, and was new.

The random, gremlins that strike at the most in-opportune times and then run and hide are the worst nightmares, and they are usually electrical in nature.

 

[rocknxj]

I've got to vote for the RMS. I've replaced in on my '99 and the kid's '01 and both jobs took about 10 hours each. Also fought the APN header on the '99 but I learned a few tricks along the way so the third time I had it off was very quick and easy. Next PITA job will be the clockspring.

 

[Matthew Currie]

In terms of diagnostic difficulty, the hardest fix I've had was on my stepson's 93. It developed a miss when it got hot, and threw a code that indicated a bad injector circuit, and occasionally a couple of others that seemed random. I checked the injectors, and the harness using an injector testing rig, went through all the sensors, and even got a junkyard PCU. Nothing changed, and the problem persisted. It would start up fine, then start missing either after a half hour or more, or on a hot restart. I finally isolated it to the injector harness, where with an ohmmeter I found resistance from a bad splice. It delivered nearly full voltage cold, but as it heated up it dropped down to about 8 volts, enough to kill the injector. The injector tester hadn't caught it. Hours and hours of diagnostic work, and a bunch of replacement parts, and the fix was about 15 minutes and a foot and a half of wire.

Competing with this is one I never did quite solve. The signals on my 95 stopped working, first intermittently, sometimes buzzing, then gone completely. Not the flasher, not the switch. I traced as much as I could using the FSM wiring diagram, and the wires shown seem not to exist at all. I never found the wire that I'm pretty sure was the bad one. It vanished into the harness never to come out the other side. Nothing corresponding to it appeared at the PDC where it was supposed to end. After hours of dicking around, I gave up and hot wired it to the fuse panel.

Jeep wiring never fails to entertain.

 

[cheapcherokee93]

yet another vote for the RMS :gee:

i spent 3 days under the jeep to get it done

day one: get off oil pan. like some of you have said, mine was cemented onto the block as well. eventually just wedged a pry bar in and bent up the pan to get it off. pounded it back pretty straight and reused it.

day two: spent scraping the rock solid gasket off the block and pan.

day three: replacing the RMS and putting the pan together.

funny because before i did it everyone told me it was gonna be a cake walk! HA

 

[crimsondragon]

Changing the rear axle seal. The seal itself wasn't the issue. It was putting the spider gears back in that killed me. Two whole hours of rotating the wheel back and forth trying to get both gears to go in correctly

 

[scoobyxj]

I don't get the deal with the crank position sensors? Pop the trans linkage off, pull the front drive shaft off the front diff, and a socket- swivel- and a long extension will pull it right off. I pulled one off my parts Jeep and replaced the bad one on my project is about an hour.

So far the hardest fix on any of my Jeeps has been a broken tap on a rear shock bar pin. Ended up cutting a hole in the floor, and using a bolt through a hole drilled off to the side. However I have suspicions that anything to do with the suspension on my project Jeep is going to be major PIA

 

[Ecomike]

In terms of diagnostic difficulty, the hardest fix I've had was on my stepson's 93. It developed a miss when it got hot, and threw a code that indicated a bad injector circuit, and occasionally a couple of others that seemed random. I checked the injectors, and the harness using an injector testing rig, went through all the sensors, and even got a junkyard PCU. Nothing changed, and the problem persisted. It would start up fine, then start missing either after a half hour or more, or on a hot restart. I finally isolated it to the injector harness, where with an ohmmeter I found resistance from a bad splice. It delivered nearly full voltage cold, but as it heated up it dropped down to about 8 volts, enough to kill the injector. The injector tester hadn't caught it. Hours and hours of diagnostic work, and a bunch of replacement parts, and the fix was about 15 minutes and a foot and a half of wire.

Competing with this is one I never did quite solve. The signals on my 95 stopped working, first intermittently, sometimes buzzing, then gone completely. Not the flasher, not the switch. I traced as much as I could using the FSM wiring diagram, and the wires shown seem not to exist at all. I never found the wire that I'm pretty sure was the bad one. It vanished into the harness never to come out the other side. Nothing corresponding to it appeared at the PDC where it was supposed to end. After hours of dicking around, I gave up and hot wired it to the fuse panel.

Jeep wiring never fails to entertain.

My solution to that is to carry the ohm/volt meter with me, and pull over and test the sensors live, hot while it is messing up. Got to try and catch those E-gremlins red handed, LOL!!!

 

[Ecomike]

I have gotten the CPS swap down to 5-10 minutes on the 89, 2wd, just using woblers and 3ft of extensions with a ratchet from the rear side of the Transmission cross plate support. Maybe the 4x4 is harder?

 

[souske]

Body swap 96-87

 

[kastein]

crank position sender. even after you drop the transmission cross member and use 4-5 feet of extension. its only 2 bolts. ive been told by mechanics its all but impossible. only took me like 4-5 hours.

troubleshooting the renix 87-90 4.0 you have to back probe every sensor there is no check engine light no obd its all charts and diagrams

cracked manifold... they all do it just a matter of when. good solid weekend project to replace it.

the biggest problem of all is money. never enough. followed only by time.

Cps - 10 minutes max, with a hot motor, on the side of the road. Easy. Lie under the jeep with your head just inboard of the left front tire. 3ft of extensions and a wobble joint in right hand, reach up around the outside of the front ds with left hand and guide socket onto bolt heads. Done.

Manifold - annoying, but only a 4 or 5 hour job max unless you break off a stud at one end of the head. I keep a spare on hand, when one cracks I weld up the spare, throw some new studs in the downpipe end, stick it in the jeep, and refurb the one coming out the same way. Only had to do this twice now between 4 jeeps.

I would say that the first time I had to take my front hub bearing units off it was probably the most difficult thing I've had to do. those things were stuck fast. took much pb blaster, a 3 lb sledge, and a couple of chisels to get the thing off.

while I had it off, I sanded out the rust from the seat. now they come off easy.

stick a 1/2 drive extension crosswise through the ujoint yoke and turn the wheel a little, it will pop the hub loose easily.

stock balljoints with 170,000 miles and no air tools sucked pretty bad lol

put pressure with the press, then whack the inner c with a bfh. Turns an annoying job into a one hand job, with no straining or cursing involved.

I have gotten the CPS swap down to 5-10 minutes on the 89, 2wd, just using woblers and 3ft of extensions with a ratchet from the rear side of the Transmission cross plate support. Maybe the 4x4 is harder?

Not any harder, the shaft helps keep your arm off the exhaust, even! :laugh2:

I would have to say rms or leaf eye bolts are my least favorite fix on the XJ. So glad that leaf eye bolts are a non issue on MJs, and so are rear shock weld nuts for that matter.

 

[GrimmJeeper]

Body swap 96-87

been there done that TWICE with my 95, I don't reccomend it haha.

 

[souske]

If anyone ends up doing it, i would highly reccommend that unibody stiffeners be installed while the jeep is stripped.
Wish i would have undercoated it while empty as well

 

[Matthew Currie]

I have gotten the CPS swap down to 5-10 minutes on the 89, 2wd, just using woblers and 3ft of extensions with a ratchet from the rear side of the Transmission cross plate support. Maybe the 4x4 is harder?

No, it's the same. Once you know where to reach and what to reach it with, it's really not so bad. Reinstallation is much easier if you have the plastic dust cover, too.

 

[wacho4]

Leaf bolts- always a pain, once you figure it out not too bad.
CPS- Same way, figure out the right angle and collection of extensions and not too big a deal.
Ball joints - This would have to be my biggest PITA

Quote:
Originally Posted by bluejeepkid
stock balljoints with 170,000 miles and no air tools sucked pretty bad lol

put pressure with the press, then whack the inner c with a bfh. Turns an annoying job into a one hand job, with no straining or cursing involved.


QUOTE]

If all rusted, busted, and a bent up inner C it will still suck big smelly monkey but.

 

[kastein]

If all rusted, busted, and a bent up inner C it will still suck big smelly monkey but.

I've never had to use more than one arm even on original balljoints in a super crusty 200 thousand mile axle from massachusetts. If one arm won't do it, apply some heat.

 

[1985xjlaredo]

Hardest = Getting the 30mm axle nut off. I had broken 1 Craftsman and 1 Wright 1/2" breaker bars. Then I got a 3/4" Wright, still would not break loose. I had to get a 6' iron pipe, I then took and positioned it so it was pointing straight up. I had the pipe pushed all the way down to the door handle and cracked the mirror before it broke loose. I bet I had well over 1000lbs of force on it before it went.
Time = Replacing floor in my first XJ, probably would have went faster if I would have bought replacement floor panels but I decided to form my own stainless floor. OMG that was the worst idea I have ever had.

 

[kastein]

good point. Those nuts really do suck. I had one on my 98 XJ break a Husky 1/2" extension, it just sheared right off. First one I'd ever broken. I was hauling on a 3 foot cheater bar on the breaker bar though, so can't really blame it.

I made good use of a propane torch for a few minutes, then applied aerokroil to quench it, then torched it again, and it popped off with just the breaker bar.

edit: the impact also wouldn't even budge it before I used heat.

 

[Super mud]

Overheating or Renix high idle. One of those things that you can't put your finger on and comes and goes as it pleases. All mechanical stuff just takes some tricks. Popping the unit bearings out and heating the leaf spring nuts works like magic once u know what your doing.

 

[rydizzy]

The hardest thing I've done was only difficult once. Swapping the front axle the upper control arm bolts(torx head) were so tight it broke the torx bit. The only thing we had to get the bolts off with was a dull hack saw. It took a very long time to cut through the bolts this way. I've done a few axle swaps and this was the only time this happened.