PROJECT 99 SUPER DUTY
Affordable Bed Replacement & Spring Suspension Swap
This 20-year-old truck looked cool, has been worked hard over the years, and now it was time to correct several serious deficiencies.
The Superduty nameplate was attached to Ford F series HD pickups starting in 1999. The decision to keep solid axles front and rear was an instant hit with truck owners wanting the easy ability to lift and use the vehicles in demanding applications.
Of course, it wasn’t all good. The ride quality on early designs was awful, and some models came with a Dana 50 front axle (less desirable than a Dana 60). The
engine choices were decent with either a 5.4 L or 6.8 L gas, (later models were much better than early designs), and also a variety of diesel engines over the years. Early transmissions and transfer cases were carryovers from previous years and also greatly improved in later years.
In our case we had leaf springs front and rear, which meant a punishing ride. A day on the trail felt like we had just been put through a match with a Sumo wrestler (perhaps a slight exaggeration).
The 4” lift plus fender trimming allowed the use of 40” tires and consisted of an
aftermarket 4” lift in the front springs, and a 1” lift block plus an added leaf for the rear. This stacked block arrangement (with factory block) plus the short length of the rear springs had given us axle hop. To counteract this problem traction bars had been installed. The result was not much articulation in the rear as well a rock-hard bouncing ride that even good shocks didn’t help. Since not much could be done about the front suspension with out a major overhaul (later designs went to a coil spring) we decided to concentrate our efforts on the rear.
2 A common solution to poor riding leaf springs is to swap in a longer length spring from a similar application. Starting with the 2008 model year, Super Duty pickups went to a longer (and generally considered) smoother riding rear leaf spring. We looked up online to see what the options were and ended up getting a pair of 5” rear lift springs for a 2008 Ford Super Duty from our local parts retailer for $248.99 CAD each. In order to do the job properly we wanted to remove the bed. Time to get into the shop!
3 This truck had been used hard including having a salt spreader in the bed. Here you can see the rust, and that the bed supports underneath were completely gone. This is a common problem in the Southern Ontario area and other parts of the east where road salt is frequently used throughout the winter. Repairing the bed would have been a time-consuming thankless job so we searched for alternatives and found a used truck box.
4 We found a dealer that specializes in bringing up truck boxes from the Southern USA. They also offer new boxes (from aftermarket body dealers). In our case we didn’t need a mint condition box, and found this one with some damage, at a reasonable $1800 CAD. The rust and damage free underside of the truck box can be seen in this photo. Our plan is to use the truck for work and off-road adventures, so appearance wasn’t our top concern. We decided to do a bit of bodywork and painting to have the truck box match the cab colour.
5 After a trip to our automotive paint supplier we came back with two quarts of base coat and a clear coat kit. Good bodywork and painting can take years of experience to be done well.
6 Since we wanted to run 40’s without a huge lift we trimmed the front and rear edges of the lower fenders using a Sawzall. Preparation, temperature, ventilation and lighting are all critical to having a successful paint job. We did our best and are satisfied with the result, and know what to do better next time.
7 With the old truck box off and the new one ready to go we got back to work on the suspension. The new leaf springs measured roughly 8.5” longer than the old ones. Using a tape measure, we came up with 7” longer from the centre pin to the front eye and 1.5” longer from centre pin to the rear eye. To simplify the job, we moved the front spring hangar forward 8.5”. This conveniently re-used two holes from the front edge of the spring hangar, which are now two rear holes. We ground the heads off the rivets and removed the spring hangars. We left the rivets that hold the frame to the cross member and welded them to the frame.
8 Using two bolts to secure one side of the hanger and a C-clamp, we used the hangar as a template to drill the other holes. We welded the centre holes in the hangers to the frame and added a couple welds at the edges of the hangars to make sure they stay put. On the driver’s side, the P-brake connecting bracket had to be removed from the frame, and we lowered the gas tank to give access to the inside of the frame rail.
9 After the leaf spring hangars were moved, the P-brake bracket was re-attached to the frame (in the middle of the hanger) by using two pcs of 2x2 square tube steel, which were welded to the frame. The P-brake bracket was then welded to the spacer blocks, and the cables reattached. The front boltholes on the new spring were a larger size than the old ones so a trip was required to our local HD Supply outlet. We purchased (2) M20 x 120 Hex Cap 10.9 bolts $14.26 CAD each and M20 nuts $2.08 each. A stepped drill bit was used to drill the hangar holes larger. Since we were eliminating the rear factory lift blocks, we needed new axle U-bolts. Not many places carry different size U-bolts however most spring shops will custom make them. Our local spring shop bent a set of 4 for us while we waited for $50 CAD including nuts and washers. When we removed the aftermarket traction bars, we noticed that the axle had to move forward in order to fit the new leaf spring centre pins. So far, 8 hours of time had gone into the work on the bed for bodywork and painting. The bed removal and leaf spring work had been another 20 hours. Six (or more…) hours were spent sourcing materials. Including the time waiting between paint drying, sourcing materials and other matters, several weeks had passed by and now the farm operation shop (that by brother in law loaned us) was needed for other urgent matters. We quickly bolted everything together to get the truck out (plus we needed it for snow plowing). After reattaching the fuel tank, and checking everything over including bolt torques, we were ready to install the bed.
10 We positioned the new-to-us box in place using a forklift. At the front of the bed near the cab 9/16” x 5” gr 8 hex head bolts and large fender washers were used to attach it to the frame. Over the gas tank we used one of the factory nut-retaining clips (and put our nut in) with a tack weld to hold it. 1/2” x 4” gr 8 bolts, nuts and fender washers were used at the middle and rear. Red thread locker was used on all six bolts. Next, we hooked up the fuel tank filler hoses and taillights.
11 Using a forklift, we raised a tire and were pleased to see a good amount of flex, suspension droop and articulation.
12 Time to take it out of the shop for a test drive! Our first stop was a snow drift (couldn’t resist), which was covering a layer of ice, and we promptly got stuck!
After pulling the truck out and going for a test drive, the first thing we noticed (aside from the smoother ride) was a driveline vibration.
After getting under the truck to take a closer look we noticed the driveshaft slip yoke was almost completely compressed and the pinion angle and driveshaft were not in alignment. The factory blocks (we had removed) were a tapered design, which rotated the pinion up.
To alleviate this condition, we did two things. First, we brought the vehicle in to my shop, which is much smaller (wasn’t room in the farm shop at present), put the rear axle on jack stands, and pulled the rear wheels off, then undid the U -bolts.
Another order was made from our local parts retailer, for a set of Pro Comp 2.5” wide 4 degree spring pad shims. The shims were placed on the spring pads with the wide part to the rear. This would bring the axle pinion up at the front to be in-line with the driveshaft.
Next we took the 1” aftermarket aluminum blocks (previously removed) and drilled a 5/8” hole 1.25” ahead of the existing hole. The blocks were placed on the axle perch’s, and the axle pulled back so that the spring centre pin would fit into the newly drilled hole.
After putting the U -bolts back on and checking the torque we put the wheels back on and took it out for some testing. Due to the time of year (February) we couldn’t do any trail riding. However, we have driven it and can say it is a significant improvement over the old ride. The driveline vibration is gone, and the stance looks good. With the lift and the wheel wells trimmed the 35” tires look small. We plan to put on our bigger tires in summer.