Project: Slippery Slope – a ’91 MJ runner

[Gjeep]

Tailgate lock in place and virtually unseen. It's always a good time getting the bracket and actuator through the opening, followed by the handle itself… But in and working, and tied in to the recently added power window, door lock, and mirror wiring. 

 

 

 

The original door stop checks were swapped out for the latest Mopar rev that includes the rubber bushing on the inside to ease the rebound of the door when opened.

 

 

I’m always on the lookout for areas of possible unwanted water entry when rebuilding an MJ/XJ. This Jeep wins out of all I’ve had… the firewall had the open 1.25” passage right of center, and then inside the cab on the upper transmission tunnel another uncapped 1.5” hole (used for the early CAD front axle vacuum lines). Both holes now successfully plugged with OEM Caplugs brand insert.

 

 

Lastly, I replaced the brittle and broken door lock cylinder gaskets.

 

 

Next up is installing the cab harness (hanging around the steering column in this pic). I made from the amplifier to the speakers, and various other add-in’s and changes (cargo light, XJ ebrake, and power tailgate).

 

[fiatslug87]

Did the 97+ door handles ever come in chrome?

[Gjeep]

Chrome is available aftermarket for the 97+ XJ door handles -- never from factory though.

 

[Gjeep]

Pulling parts out of storage – ’91 MJ will get the same Borla/Magnaflow (cat) set up as in my other MJ. I’ve had numerous header/muffler set ups over the years on MJ's and XJ's and Borla hands-down sounds the best on the 4.0L. (Banks a close second; they swapped the muffler they use recently on the XJ kits and it sounds better than their first gen.) The MJ will also get the newer intake manifold at install.

 

 

 

 

Speaker wires from the amp were tied in to the existing factory speakers into the doors for a clean install.

 

 

And the world of repop is finally making the ‘95/’96 F-series combo cargo and brake light. I had been looking for this year’s back, but nothing was available outside of old and used – selling for a ridiculous amount on eBay. But finally… it’s being reproduced withOUT the Ford logo on it. I’ve always though this light would look best on an MJ as the shape matches the cab corners. Will need to see what/ if it needs to be reshaped a bit to fit the Comanche.

 

[Salvagedcircuit]

On 12/24/2024 at 10:48 AM, Gjeep said:

I replaced the brittle and broken door lock cylinder gaskets.

Curious, where did you end up finding new lock cylinder gaskets? I made some out of old bike tire tube and they did not come out too great. Thanks.

[Gjeep]

Your MJ is Renix era and had different lock cylinders than mine -- the notches in the door sheet metal had large at the top and smaller notches to keep cylinder in place rest of the way around. Meaning, you can likely use GM era 2-key gaskets from whenever they started I'd guess 70s through early 90s. These would work -- https://www.usa1industries.com/1973-87-square-body-chevy-gmc-truck-door-lock-cylinder-gaskets-each/

 

 

[Gjeep]

Engine accessory replacement begins – with tear-down. Oil pan, rear main and valve cover gaskets will be done (and installing ‘96+ stamped steel valve cover); all cooling related items will be completely replaced; harmonic balancer; power steering pump & gear box; 200 amp alternator going in; upgrading the oil filter housing the later side mounted set-up; spark plugs, injectors, intake, sensors, etc… Also will be installing factory R134a AC with this ‘rebuild’.

 

 

Also pulled and  tossed the single diaphragm brake booster of pure terror. Stopping within a football field at anything over 30mph is an absolute miracle. Going with tried and true for me ’95 XJ dual diagram brake booster. Undecided at this point if keeping the load sensing valve on this MJ. I eliminated on my other and no lock-up out back; whereas when I had load valve on my ’92 MJ it did lock up when empty and that was with it having a camper shell. Maybe had an issue, don’t think so…

 

 

[fiatslug87]

I think you’re at lease 3/4 of the way down that slippery slope. 

[Red Mistress]

14 hours ago, fiatslug87 said:

I think you’re at lease 3/4 of the way down that slippery slope. 

 

He was more than 3/4 down on drive home with 8 ball MJ :)

 

Wouldn't expect anything less 

[Gjeep]

And it is out… non AC dash box is out and apart. I forgot what a pain these first gen boxes are as compared to the 97+ XJ HVAC box. Endless screws to remove and a glued in heater core seal and heater core melted to it. I’ll tackle its clean-up and reassembly soon…

 

 

With the dash removed (and VIN tag), I learned why no air was blowing out of the passenger side duct. Someone at the factory wasn’t paying attention on the assembly line and didn’t put the tubing in the retainer. It has been smushed back side of the glove box flat as a pancake since September 1990.

 

 

 

The shocks, exhaust, sway bar, and several other items on the underside are gone as of today too.

 

[Salvagedcircuit]

On 12/26/2024 at 8:48 PM, fiatslug87 said:

I think you’re at lease 3/4 of the way down that slippery slope. 

Hahaha. This is the only way to go

Excellent work @Gjeep

[Gjeep]

Notched the firewall pinch weld to fit the larger brake booster… though I won’t be installing it until I replace the steering column (converting to AW4 floor shift versus column) and get all the old transmission cables out and floor shift related ones in.

 

 

 

Unearthed an AC box I pulled back during “Cash for Clunkers’ days in California, circa 2009. The AC box is slightly different than the non-AC HVAC box that my MJ came with. Basically, there’s not enough room to fit the evaporator core in the non-AC unit. As always, I took the extra time to clean everything out and replace all of the necessary seals. 3 filthy rags were the result of the cleaning inside/ out. It’s worth it. NOS evaporator is in place and ready to cool. Important note -- For those of you restoring your Jeep or have upcoming MJ and XJ first gen restorations, @H3ADBANG4L1F3 is finalizing production of these HVAC box seals for Renix and HO era. He'll also be producing brake booster, steering column, and several other very very very well done reproductions seals. These are top notch and meticulously done. Can't stress that enough. Glad I'm able to build with them and help with fitment.

 

 

 

 

 

The foam on the lower HVAC door facing the passenger’s feet is always in rough shape as it dries out over the years and falls apart. I used very thin, adhesive backed closed foam to replace this mess. Now the HVAC door will close quietly as it was meant to.

 

Before:

 

 

Old foam removed:

 

 

After:

 

 

 

AC side finished...

 

 

The heater core side of the vertically split first gen HVAC box also received a thorough scrubbing and refresh.

 

 

[Salvagedcircuit]

11 minutes ago, Gjeep said:

Notched the firewall pinch weld to fit the larger brake booster… though I won’t be installing it until I replace the steering column (converting to AW4 floor shift versus column) and get all the old transmission cables out and floor shift related ones in.

 

 

 

Unearthed an AC box I pulled back during “Cash for Clunkers’ days in California, circa 2009. The AC box is slightly different than the non-AC HVAC box that my MJ came with. Basically, there’s not enough room to fit the evaporator core in the non-AC unit. As always, I too the time to clean it out and replaced all the necessary seals. 3 filthy rags were the result of the cleaning inside/ out. It’s worth the time. NOS evaporator in place and ready to cool.

 

 

 

 

 

The foam on the lower HVAC door facing the passenger’s feet is always in rough shape as it dries out over the years and falls apart. I used very thin, adhesive backed closed foam to replace this mess. Now the HVAC door will close quietly as it was meant to.

 

Before:

 

 

Old foam removed:

 

 

After:

 

 

 

AC side finished...

 

 

The heater core side of the vertically split first gen HVAC box also received a thorough scrubbing and refresh.

 

 

 

Those seals look mighty good! Nice job.

I did the brake booster upgrade, and if I did it again, I'd just add a 1/4in aluminum spacer behind the booster and not notch the firewall. The brake pedal would sit further back into the footwell which would be an added bonus. I find the height difference between the accelerator and brake pedal is substantial.

[Gjeep]

You’re saying you’d add a second aluminum spacer? As the donor booster should have already had one. I know the factory had the notch for the booster. 

[Salvagedcircuit]

5 hours ago, Gjeep said:

You’re saying you’d add a second aluminum spacer? As the donor booster should have already had one. I know the factory had the notch for the booster. 

I know the 96 booster+master combo has a 1/4in aluminum spacer on the back side from factory. Was there a notch in the firewall for the 96+ XJ? I've never seen one myself lol It sure is possible! I ended up doing the WJ booster+master and notched my firewall seam. I wish I used a 1/4in spacer and not bothered.

[Gjeep]

95/ 96 XJs were notched and had the spacer. I owned a 95, am sure of it. 

[Salvagedcircuit]

44 minutes ago, Gjeep said:

95/ 96 XJs were notched and had the spacer. I owned a 95, am sure of it. 

Good to know! Thanks.

[Gjeep]

Ringing in the new year with tinker time – Build up engine side begins. As with my other MJ, I relocated the ignition coil off the block and onto the passenger inner fender just behind the PDC. Much easier access should I need to replace it and no chance of temperature replated issues. Easy enough to extend the wires and use an aftermarket coil bracket that works perfectly on the Jeep. 4.0L ZJ’s had this TSB/ relocation as several were experiencing coil damage from temperature. I never had this issue with any of the 4.0L XJs I’ve had, but easy enough to move.

 

 

 

Dressed the front of the block with a new harmonic balancer, water pump, thermostat/ housing/ temp sensor, 200 amp alternator with notched mount and front bracket to accommodate the alternators size, and have the AC compressor bracket in place. I went with the newer style bracket without the additional pulley. By doing this and swapping the power steering bracket with later style, I can run the same serpentine belt as all the other XJs in the family. Besides that, first gen belt tensioning set up is just plain crazy.

 

 

Also, saying goodbye the original downward facing oil filter adapter in favor of the later horizontal mount.

 

[Gjeep]

Chipping away at it… Got the new motor mounts installed, Borla header, intake manifold, fuel rail with Bosch 4-hole injectors, IAT sensor with extension, and various vacuum lines cobbled together from the Renix era parts bin all in place. A good day.

 

 

 

 

 

[Skorpyo]

You are doing this so right. Makes me feel like I did a half-a** job on mine! Great work! Love the color!

[Gjeep]

Many thanks!

 

New fan clutch, emissions charcoal canister, R134a compressor, and power steering pump…

 

 

 

 

The power steering pump and factory fuel lines weren’t playing well together. There was a little over ¼” I needed to get ‘adjust’ so the pump could attach where it belonged. The solution was bending the supply and return lines for clearance. I wanted to make sure there was gap enough so nothing was rubbing together. Finally, as I did with the other Comanche, I used a 65/66 Mustang fuel line bracket to attach the fuel lines to the side of the manifold. Just need to bend that little bracket straight and works perfectly.