There's a minimum threshold that separates the functional from the unfit. When we first started on this XJ, it was clearly the latter. Sagging suspension and threadbare tires were only two of the issues that needed to be addressed. The stock bumpers were only slightly thicker than tin cans. They had to go. It seemed fitting that the hood badging was missing an "e" from "Jeep."
With a Skyjacker suspension, Mickey Thompson tires and wheels, a re-commissioned winch, and a pair of Proto Fab bumpers, the XJ was looking like something that could conquer commute and trail alike. The hood badging was replaced during the process, re-asserting its status as a real Jeep. Faults remained.
The biggest offender was the poorly-functioning ABS brake system. Known as the Bendix 9, this ABS system was overly complex and questionably reliable when it was brand new. Throw in nearly two decades of use and neglect, and the brakes were downright dangerous. Stepping on the pedal resulted in weak stopping power. Worse, the ABS system would randomly pulse the brakes, pulling the XJ in every direction but straight even on dry ground.
Next, the fenderwell under the battery tray was rusted through, and the battery hold-down was missing. Forty-some-odd pounds of lead and acid bouncing around under the hood is not a good thing. The battery mounting system needed to be completely replaced.
Stock headlights are decent for street use, but they're inadequate for trail use after dark. The Proto Fab front bumper has a pair of light tabs on its upper hoop, ready to be filled with something powerful. The steering box had a sloppy sector shaft, and puked power steering fluid all over the place. No good.
During our mechanical ventures, we also discovered the stock air cleaner housing was warped and no longer had an adequate seal around the filter. This, too, had to be remedied. These remedies had a deadline. Nope, not just an editorial deadline, but an educational deadline. My college-kid brother, Seth, owns this Jeep and the wrenching had to be done in time for him to drive it back up to school in Utah before the new semester started. Midnight oil had to be burned.
A double-diaphragm brake booster...
A double-diaphragm brake booster from Dave's Customs Unlimited is the solution to our ABS problem. While it would have been possible to repair the factory ABS system, that system worked poorly even in 1991 when it was brand new. Furthermore, ABS systems typically don't work well in the dirt, reducing stopping power and increasing stopping distance at exactly the wrong time. Dave Seger of Dave's Customs Unlimited chose our master cylinder based on the stock axles and brakes. If we'd had custom axles and monster-sized calipers he would've picked a master cylinder to match those, too.
The first step was to remove...
The first step was to remove all the ABS hardware and supporting electronics. There's a pressure vessel shown behind Seth's gloved hand that has to be safely de-pressurized before it can be removed. We'll not attempt to duplicate the owner's manual here. Instead, we'll say that you need to get one and study it before working on the brakes. Most of the wiring for the brake system wasn't re-used, but it was smarter to take the time to disconnect the wires at the connectors rather than to butcher the wiring with a pair of cutters. Unnecessary wiring can be eliminated later after the new system is up and running.
The ABS system has a control...
The ABS system has a control module under the left-side seat on the second row. This was removed and discarded.
The stock proportioning valve...
The stock proportioning valve was retained and re-used.
The stock ABS system is powered...
The stock ABS system is powered by a hydraulic pump instead of engine vacuum. This plugged port on the intake manifold was opened up and a new fitting was installed to supply vacuum to the Dave's Customs booster.
Dave uses all-new parts to...
Dave uses all-new parts to make his booster systems. The clean, shiny booster was set up against the firewall for a test fit.
Seth ended up missing a couple of days' worth of classes, but he lucked out and his instructors cut him some slack. He arrived back at school with a functional XJ: capable of commuting, fit for the trail. No Jeep is ever "finished," but this one is well over that aforementioned minimum threshold. It's gone from unfit to fully functional. Now the fun can finally begin.
The test fit revealed a flange...
The test fit revealed a flange in the way. A pair of sheet metal pliers made it easy to bend the flange upward, creating the needed clearance.
Some wiring was also re-located...
Some wiring was also re-located above the flange. This shows a firewall that's ready to have the booster installed for the final time.
Once the booster was bolted...
Once the booster was bolted up, the master cylinder was removed and set into a vise for bench bleeding. This was also the right time to adjust the length of the booster's pushrod.
There's no mounting bracket...
There's no mounting bracket for the proportioning valve. Instead, the valve is suspended in place by the brake lines.
Dave supplies this pedal-to-pushrod...
Dave supplies this pedal-to-pushrod adapter, making his booster system a true bolt-in experience. Gold zinc plating adds a professional touch.
Rather than use adapters,...
Rather than use adapters, we cut and double-flared the brake lines leading to and from the proportioning valve. Several fittings simply bolted in, so we only had to use the flaring tools on a couple of connections. We discovered that aftermarket mild steel brake lines are much easier to flare than the factory hard lines.
The booster tilts upwards...
The booster tilts upwards in the engine bay. You don't have to get the master cylinder perfectly level in order to bleed the brake system, but it helps to lift the back end several inches. We were about eight degrees from perfectly level in this photo, and were able to successfully bleed the brakes and top off the master cylinder.
We used a 90-degree elbow...
We used a 90-degree elbow to connect the intake manifold to the vacuum booster. Teflon pipe tape made the installation go smoother and created a better seal.
Ready for the trash heap....
Ready for the trash heap. Our installation was tougher because we were converting from an ABS system to a non-ABS system. If you're replacing your factory single-diaphragm booster with Dave's dual-diaphragm booster it will be a simpler process. Another thing hindering braking performace: the rear drums were far out of adjustment. Between the Dave's Customs Unlimited brake booster and the adjusted rear drums this XJ now stops with authority, the way it should have a long time ago.
How's this for some rust?...
How's this for some rust? The factory battery tray rests on and connects to the fenderwell. Obviously, there's nothing to connect to here. One option was to cut out and replace the rusted sheet metal. We decided to make an overlay plate instead.
Here's the start of the new...
Here's the start of the new battery tray. That's 12-gauge cold-rolled sheet steel in the center, and one-inch angle iron around the edges. If you're TIG welding you'll need to grind the mill scale off of hot-rolled steel, such as found on angle iron, before attempting to weld.
Will Blumer (dad) and Seth...
Will Blumer (dad) and Seth made a pattern for the overlay plate out of cardboard and then transferred it to the 12-gauge sheet. Dad is shown setting up a guide fence for cutting.
Seth handled the Sawzall ...
Seth handled the Sawzall duties.
We've skipped several steps...
We've skipped several steps ahead here. This shows the finished overlay plate. The bend matches the contour of the fender well. The two angled brackets tie into the side of the fender well and to the radiator core support. Three standoffs lift the battery tray into the correct position. The welded-on nut adds an anchor point into a non-rusted part of the fender well.
Here's a close-up of the standoffs....
Here's a close-up of the standoffs. The lower half was welded onto the overlay plate, and the upper half was welded to the bottom of the battery tray.
The upper standoffs mount...
The upper standoffs mount below the battery tray. This means the bolt heads are sunken below the battery-holding surface and won't cause interference.
The hold-down bracket was...
The hold-down bracket was made from angle iron, flat bar, and pre-stamped tabs. It was designed so that the battery caps can be removed without pulling the hold-down first.
There was no question the...
There was no question the new battery mounting system would be subjected to nasty weather, so it was coated with textured Durabak. The upper hold-down was rattle-canned with gray Hammerite paint.
A bit of Durabak on the fender...
A bit of Durabak on the fender well should slow the progression of rust. This XJ probably won't be a long-term keeper. At some point, Seth hopes to purchase another XJ in better shape and transfer the good parts onto it.
The sharp outer edges of the...
The sharp outer edges of the hold-down were smoothed over before the paint was applied. There is a little clearance between the radiator hose and the battery hold-down, but this sleeve gives added assurance against destructive abrasion. The XJ has a very crowded engine bay, and making the battery clear the radiator hose was tougher than it should have been.
These 8-inch Daystar halogen...
These 8-inch Daystar halogen lights are a perfect match for a buildup like this one: they're high in value and low in price. This set is equipped with 55-Watt bulbs.
Daystar offers a wiring harness...
Daystar offers a wiring harness with an integrated switch. The harness has an inline fuse to protect the circuit. The switch can be mounted in many locations, but the spot above the cigarette lighter was the most convenient. If you're a smoker and use the lighter to fire up your cancer sticks, you might want to choose a different place to mount the switch so you don't melt it.
The Daystar lights look right...
The Daystar lights look right at home on the Proto Fab bumper. In this high position they don't block airflow to the radiator.
The central mounting location...
The central mounting location means the lights don't block much forward visibility. They're more like a big hood ornament that can light up the night. The sun was fading fast as this photo was taken, and we fired up the lights to compare them to the stock headlights. There's no comparison.
The original steering box...
The original steering box leaked like a sieve. There was also a lot of play in the sector shaft which contributed to sloppy steering. The only upside to all this was that the power steering fluid coated the front end and prevented the axle, tie rods, and oil pan from getting rusty. Painted surfaces and a non-leaking power steering box are a better idea. This one was plucked from a local wrecking yard, where several "Cash for Clunkers" donors were found.
The stock air intake box had...
The stock air intake box had distorted over time, preventing a good seal around the air filter element. This leaked dirt into the engine. It, too, was replaced with a better part from a "Cash for Clunkers" donor.
The stock front fenders hang...
The stock front fenders hang down at the front edge and look really goofy if you change out the stock front bumper for something more aggressive. The offending portion was cut out of the way with aviation snips. Trimming was also done at the rear lower corner of the factory fender flares to add needed tire clearance.