Completed Project - Brian1's Twin Trail Build (Lift, Gears, TTB Mods, Bumpers, Sliders, Cage & More!) | Ford Explorer Forums - Serious Explorations

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Completed Project Brian1's Twin Trail Build (Lift, Gears, TTB Mods, Bumpers, Sliders, Cage & More!)

Use this prefix for completed projects that are not "How to" articles or threads asking for help.
Brian1's Twin Trail Build

1991 Ford Explorer 4-Door XL 5-Speed Manual 4x4

Project Background and Goals:

I bought this Explorer at a Police auction in August of 2015. I really didn't know what I was going to do with it when I bought it but I couldn't pass up the great deal I got. I stored it away for a bit while deciding to part it out, build it up or just flip it. In the end I decided to build it into a cheap trail truck and use it to R&D some new ideas I had on how to build an Explorer and develop some new parts.

The goal of the build was to do it cheaply while keeping it low, lightweight, and simple. Another goal was to completely transform the Explorer into a trail machine and debut it at the 20th anniversary forum run in Moab (May 2016) while keeping the entire build a secret.

The build has already been completed and made its successful debut in Moab. I will be adding to this thread as time permits of what I did.

Table of Contents - Modifications

to be filled in as the thread progresses for quick access

1" Body Lift
Rear 8.8 Swap and Build
Rear F150 Hybrid Leaf Springs
Front Daystar 2" Coil Spacer & F250 Shock Tower Conversion
Corbeau Seats Pt1
Corbeau Seats Pt2
Rear Shock Bar Pin Eliminators
Dana 35 TTB Beam Boxing
Hybrid Dana 35 Beams with Dana 44 Outer Conversion
Extended Radius Arms
Dana 35 Diff Build with LockRight Locker
Power Steering Cooler
Cutting the Rocker Panels Off
Rear Bumper Build
Front Fender Cutting
Rock Sliders Pt1
Rock sliders Pt2
Front Winch Bumper Build
Extended Breathers and Fuel Pump Access Panel
Rear Fender Cutting
Cage Building
Fabricated Door Panels/Skins
Doubler Install


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The Starting Point

The Explorer was 60 miles away and I bought it sight unseen. I only had a few pictures to go on of its condition. As it turns out it was in good mechanical shape but the interior and body were in not so great condition with dirty carpet, poor seats, dents and some major rust in the rockers. When I arrived at the impound yard to pick it up I had to change the front passenger tire out with the spare tire. I don't know the history of it or why it was in Police custody but I'm guessing it was in some kind of police chase. The front steel wheel was flattened out and the tire had blown out ripping the plastic inner fender and removing/bending the back corner of the front fender that was already weakened by rust.

I hadn't planned on getting a twin to mine but I guess I lucked out on finding a very similar one. They are both 91s with the 5-speed manual and 4-doors. The differences are my other one is an XLT and has the 2-tone brown paint vs the solid brown and XL trim level of my new one.


Checking the mechanical condition was the deciding factor on keeping it and building it up. The engine ran strong and the drivetrain seemed to be good. The engine had a lifter rattle which isn't out of the norm for these engines. Many of the parts like the starter solenoid, alternator, fan, fan clutch and thermostat all looked like new.

I browsed Rockauto and loaded up my cart with tune-up parts. I opted for many of the close-out parts to keep my order as cheap as possible. A cleanable Fram AirHog filter for $1 - sure! Add to cart! A 50-cent private label wix oil filter? Add to cart! I also bought a few more parts I knew I would need later like pivot bushings and door hinge pin kits.

I did the tune-up in mid-December. I checked the compression on all but the hardest to reach plug. All new plugs, wires, fuel filter, oil and filter, radiator cap and shifter bushing kit were added along with checking off some typical maintenance issues on Explorers like cleaning the heater resistors - yeah it was packed full of fire hazard like most are!

Parts Collecting and Building

I spent most of December and January buying new and used parts as well as fabricating my own parts I knew I would need. I cut out a set of my extended radius arm kit with new cross member and made a set of my HD motor mounts and redesigned my HD transmission mount. I made a set of my u-bolt skid plates and front diff guard (on a spare beam) as well as made some LED light brackets. Some of the parts are exactly like the ones I use on my other Explorer and a few were designed just for the new project.

Crossmember Dimple (1).jpg

1" Body Lift

The first mod I made to the Explorer was a custom 1" body lift. Again, very similar to my other Explorer. Years ago I made my own 1" body lift for my Explorer out of some aluminum but this time I opted for steel since I already had a piece I could make them out of. After spending lots of time on the band saw, lathe and milling machine I had a complete set of steel pucks. The lift went on in mid-January.

They were heavy so I spent time adding speed holes to lighten them up. Also my rockers were toast so I didn't really care if I smashed them when I jacked the body up so I only used 1 jack to lift 1 side up at a time. I only had to buy 2 new bolts for the front core support, the rest were adequate, some just barely.


Rear 8.8 Axle Build

I picked up a second gen rear 8.8 from the u-pull on half price day. I found a barely used set of Yukon 5.13 gears and got a Powertrax Lock Right locker along with a Lube Locker gasket and Solid diff cover. I degreased it, power washed it and then wire-wheeled the axle before working on it. I welded the tubes using pre and post-heat and then tore out the gears to put the new ones in along with a solid pinion spacer - much better than a crush sleeve and under $20. Bearings were fine so I only used a minor install kit that came with new bolts. I did have to grind a tooth down to fit the center pin in since the 5.13s are thick. New axle seals were also put in. I gave it a coat of paint and cut the factory brake line over the top of the diff and flared it to work with the 1st gen brake lines - a personal preference to do this as either can be made to work with each other.

Rear Springs (3).jpg
Rear Springs and Axle Swap + First Cuts into the Body

Mid-February is when the project started to get serious and things started happening.

First major mod was swapping in the newly-built rear axle with a custom leaf spring pack into the rear. When I bought the axle I also pulled the rear springs off a F150 right next to the donor Explorer. Following a well-documented mod on this site I combined my Explorer main leaf with the rest of the leaves from the rear of a F150. I left out the overload spring since I wouldn't be towing, I wouldn't carry much cargo and they just hang down and out and would catch on stuff. I also added a pair of 1.5" lift shackles I made and my u-bolt skid plates.

I wanted to stay spring-under and only have a 2"-ish lift which was accomplished. I wanted the Explorer to be low and since it was a twin to my other one, it has a very similar lift.

While the axle was out I also took the opportunity to cut the rear chrome panel off for more tire room and better departure angle and clearance.

Front Suspension 2" Lift and F250 Shock Tower Conversion

I decided to go with my stock coils and just add a F150 spacer to match the 2" lift like my other Explorer has however I had an opportunity come up to use a Daystar polyurethane 2" coil spacer and some of their shocks. I did an article for P4WOR magazine on the lift install which you can check out here: daystar-leveling-kit-install-1991-ford-explorer

Keeping the twin theme going I modified my coil towers with the F250 shock towers to fit a longer shock which my other Explorer also has. I ground off the coil buckets from the frame, cut them down the middle and welded on the new towers after slotting one of the holes slightly so the tower would use a factory frame bolt hole. It goes a lot faster the 2nd time I did this mod. With a 2" lift I am able to use a 10" stroke shock. the F250 towers also have a better top mount to eliminate the weaker stud mount.


Corbeau Seats - Part 1

For the same magazine issue as the coil spacers I also had the opportunity to try out a pair of Corbeau Baja XP seats along with their seat sliders and 5-pt. harnesses. At this point I had stripped out the carpet and some of the interior panels as well. The seats arrived the end of February just days before my deadline so I rushed to get them in. Initial impressions were good but there were a few issues and I couldn't mount the harnesses until I made my cage. The seats were installed temporarily for the article then taken back out to continue the modifications. More in part 2 later but long story short - the seats fit in the Explorer good and are very comfortable for trail use. I loved having them in Moab.

You can see the article here:


Rear Shock Bar Pin Eliminators

In order to fit custom or better shocks that don't come with a upper bar pin (which is most of them!!) I made a new version of my upper bar pin eliminators. The other Explorer has a machined pair I made several years ago that were very time-intensive to make.

They bolt in the factory location and only decrease the mounting length by about 1". I installed the same set of 10" Daystar Scorpion shocks as I did in the front.

Note the broken stud on the factory shocks - weak!


"TTB" gets some TTB Upgrades!

In early to mid March I ripped all the front suspension back out to continue with my planned upgrades. Out came the axle beams, radius arms and cross members. In went a new cross member, longer radius arms and some hybrid beams with plating for strength.

To start I modified the passenger side beam with a plating kit I made and I also opened up the axle shaft window for more room to flex. The plate kit is 2 pieces and boxes in where the factory left off - an area highly prone to cracking with hard use. I rounded the corners of the axle window during and after cutting since 90 degree corners promote cracking as well.

I also ground out the center yoke for a little more angularity. With a bit of grinding you can get a noticeable amount of additional travel in the axle without weakening it too much.

Boxed Pass Beam.jpg

I didn't even see the beam work last weekend. So glad you documented everything as you went, and did this thread to share all the awesome with us. :thumbsup:

Your fab skills are simply incredible!

Dana 44 Outer Conversion

So what does a Dana 44 outer conversion get you and why did I want to do it?

  • Wider wheel bearing spacing
  • Bigger wheel bearing
  • Stronger locking hubs
  • Bigger brakes
  • Stronger outer stub shaft

The build plan was for big tires and I wanted the stronger wheel bearings to handle the load. As far as I know there are only 2 ways to accomplish the conversion - machining the D35 knuckles to accept the D44 spindle or modifying the upper camber sleeve to either accept the tapered upper ball joint or making the 44 sleeve fit in the 35. Neither way appealed to me so I did it a 3rd way and custom machined my own camber shims.

First step was to remove the knuckles, the passenger side came off with a big hammer but the driver side was very stuck. After some sketchy work on the press it came apart. Next was reaming the lower ball joint taper bigger to match the taper in the 44 beams. A little piece needs to be ground off inside the 35 beam for the nut to seat properly. After taking many measurements and doing lots of math I had a drawing I took to my milling machine to get to work. Once the camber sleeve was finished I installed it along with the knuckle, ground a bit of the 35 beam where the knuckle hit and then welded on some steel for the steering stops. The inner 35 axles were mated to the outer 44 stub with new Spicer U-joints and everything was reassembled. This was one of the hardest parts of the entire build but in the end it turned out great and is worth it for anyone keeping their TTB.

Top is the D35 sleeve next to the D44 sleeve. My custom one is on the bottom.

continued in the next post...

View attachment 90605

One problem with the 44 knuckles is the tie rod is mounted below the steering arm where the 35 mounts it above. I needed to flip the tie rods to maintain the steering angles for proper geometry. Bronco Graveyard sells a sleeve kit that is a great deal and saved me time of making my own. I hand reamed the knuckle to fit the inserts and then used the green Loctite (meant for securing gears to a shaft) to secure it in place.

Once the sleeves were made I made a custom thin wrench on my cnc plasma to hold them while tightening the upper ball joint nut. They have enough offset built in to accommodate the 2" lift using the factory drop brackets.

Everything bolted up nicely and made the TTB look so much beefier.




I skipped over some work slightly in the above posts. Before I pulled the beams for the conversion I measured for my radius arms. I had mounted the frame brackets previously so it was just a matter of removing the stock arms and crossmember and then measuring. I used 2" x .25" wall DOM and a 1.25" heim joint from Ruffstuff.

These arms are basically the exact same as the ones I built for my other Explorer but I moved some dimensions around on the TTB end plate mounts to eliminate tire rubbing on the arms. These are version 2.0 and work much better - I didn't notice any tire rub with an even bigger tire mounted up.


Front Diff Gears and Locker

I ordered 5.13 Nitro gears and a minor install kit for the front diff and set them up with a LockRight. Unfortunately I got a bit delayed because the pin that came with the locker was wrong and made for a bolt and not the roll pin. I had to order a new one and wait for it to come in before I could put my beams all back together with the diff installed. In the photos below is the comparison of the holes in the cross pin and the new part # you will need. The bigger hole is the one that fits the roll pin.


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Tire Fit and First Flex

Before completely wrapping up the front suspension I made my own J-hooks to hold the coils in the buckets. I first made a press brake out of some scrap steel and found some plasma drops that were the perfect size to bend up. I also made some 2" extended bump stops for the rear. I set the camber with a calibrated eye ball and the toe in to 1/8" with a tape measure.

Now that the suspension and TTB hybrid conversion was completed with working brakes again it was time to fit the tires. I had a set of 5, 36" super Swamper SX tires mounted on some aluminum 5 on 5.5 wheels laying around from a vehicle I parted out earlier. I knew I kept the tires for a reason and they would work great for this Explorer project.

I used 1.25" wheel spacers and adapters on the rear and the new 44 outers were the correct 5 on 5.5. I had to rough cut the rear of my front fenders to fit them.

I used my trailer to check for where I needed to trim the fenders and any other issues it would have. Remember - I am fitting 36" tires with only 3" of total lift

The flex test was March 31st - a month and a half to Moab and still lots of fab work yet to do!

J-hook press brake.jpg
extended rear bumpstops (1).jpg
extended rear bumpstops (2).jpg
Alignment toe in.jpg

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Such a great build, Brian! Killer custom touches and I love that it's the twin to your other rig, too.

I didn't even see the beam work last weekend. So glad you documented everything as you went, and did this thread to share all the awesome with us. :thumbsup:

Your fab skills are simply incredible!

Thanks guys!