I lowered my '99 FS several months ago and now have a vibration over 65 mph. I've decided it is time to install the shims I received with my lowering kit to see if it helps. Wheels and tires are new so it shouldn't be them plus I had the vibration with the old tires.

Anyone have some useful hints to installing the shims, jack location, sequence, etc. thanks.

 

guys i posted this a week ago, surely someone has installed these shims before and can give me some advise. i'd really appreciate it.

 

Hey buddy I haven't installed these shims on your particular vehicle but I've put them on many others, usually lift kits to correct pinion angle. Its all the same; however, I don't know how you lowered your vehicle. Is it a flip kit (axle above the springs) or is it standard where you have the axle hanging below the springs?
The only thing thats different is that, you start the same way:
-jack the truck up and support with jack stands on the frame rails.
-You want to relieve pressure on the springs, this is the part that depends on whether you have an over or under axle, so that you can get your shims in place.
-If your diff/axle hangs below the springs, then do 1 side at a time so that you don't lose your pin location. The other side will help maintain your forward to aft movement. If this is your style of orientation, (axle hangs below springs) you can also do this while the truck sits on the ground also.
-Center your floor jack underneath the pumpkin/diff with a 2X4 across it or something similar to spread the load. You aren't going to pick-up the truck by the diff you are just going to unload the springs a little bit.
-Jack the axle up about 2 inches.
- Start loosening the u-bolts, not all the way. You can loosen and remove the outer ubolt completely. You want to keep the inside one connected for guides. (Do One side of the truck at a time only). Just loosen them up enough to about double the thickness of the shim your adding. You can see that by how much thread is showing or how far the ubolt is hanging down by.
-Now slowly lower your jack, so that the axle drops away from the spring and begins to hang into the loose ubolt.
-Hopefully you've got enough room to wedge in the shim. Direction is important. If your axle is below the springs then you install the thick part towards the front of the truck. If its above the springs (flip kit) then you install them to the rear.
-If you notice your shim has a thin side and a thick side. On the thick side you will see that it intersects one of the flats with a right angle. You want that flat side towards your axle perch and the other angled side towards your spring.
-Once you get it in and centered with the pin, you can use the jack to push the axle back up, clamping it against the spring. Now tighten down the ubolt enough to get it snug. Install the other you bolt you removed at this time and tighten also.
- Make sure your pins are all centered and located properly, otherwise you'll feel like you've got one of those new 4 wheel steering trucks!
-Now repeat to the other side.
-Once both sides are done, set the truck down on the ground and torque all the ubolts to the proper spec.

If your axle is above the springs the difference is you will use the jack to lift the axle as you loosen the ubolts. And don't forget the orientation of the shims.

Good Luck,I hope this helped and didn't confuse you. If not let me know, I'll try again.

 

I used two cheap jackstands and the little bottle jack that came with the truck.
I did one side at a time, jacking up the truck under the axle. I put the jackstands under the leafspring, one to the left of the axle, the other to the right.
Took off the wheel, removed the Ubolts, put 2 C Clamps on the leafsprings to hold them together and removed the bolt that holds the springs together. I dropped the jack down to get some space between the springs and axle, put in the shim (thick end facing front), jacked up the axle again, put in the bolt, put the Ubolts back on, put on the tire and then did the other side.

If you can't do it an hour, have your grandma do it for you.
It took me an hour and a half, because I had to figure out how, now that you know, it will be cake.

Steve

 

It's as easy as 1-2,no three .....make sure you do one side at a time though..and you need longer centering bolt's for the leafs

 

New center bolts for the leaf springs??? What kind of shims are you installing? These should be 1 or 2 degrees; you shouldn't have to use longer bolts, just ones with longer heads.

 

My DJM kit came with longer bolts and spacers to increase perceived head length