awhile back i was trying to get a how to on the 99 and 01's...here was w write up on the swap..hope it helps
The Swap
IRS Cobra (’99 or ’01) – Solid Axle GT (99-up) Swap Notes
Exhaustively Detailed – by Hamilton (a.k.a. quick01snake, SNKPWR)
1. First off, it’s most important to get parts you’ll need beforehand, depending on what you’re swapping with (i.e. Auto vs. Manual GT).
a. If the GT is a manual, the driveshaft can be swapped straight up, but check to make sure the yokes fit the other transmission if you swap the driveshaft (if the driveshaft length difference is <1”, you can probably keep the driveshaft on the original cars).
b. If you’re swapping with an Auto GT, you’ll need to get two U Joints (I got mine from NAPA for 12.xx each); because you’ll have to swap the front yokes on the driveshaft and swap driveshaft between the two cars (i.e. each car will need the other driveshaft, but will need to retain its original yoke). It is not necessary to swap the rear flange that bolts to the rear end.
c. Ford also suggests replacing the bolts and nuts that hold the control arms to the body and to the axle, as well as the upper shock nuts and cushions, lower shock bolt and nut, pretty much any bolts and nuts that are removed, they recommend replacing. I didn’t, but you can if you want.
d. When you remove anything that is going to be re-used, be sure to set it in a place where they won’t be lost, and it helps to write on the bolts (w/ a sharpie) where they came out of (i.e. lower control arm-to-body) and indicate with an arrow on the bolt which end goes toward the center of the car.
e. Digital pictures are great for documenting how brackets were attached and how hoses were routed, etc. before you took them apart, and I highly suggest using them for reference. Take as many pictures as possible, I wish I had!
f. Both vehicles should have all the same holes and structures to swap things over to. If they don’t, something is wrong.
g. Read through these instructions completely before proceeding, so that you don’t miss something important.
h. Torque specs:
Torque Specifications
Description Nm Lb-Ft
Rear shock absorber (upper attachment) 40 30
Rear shock absorber (lower attachment) 80 59
Shock absorber clevis bracket-to-axle nut 108 80
Upper arm-to-frame bolt 97 72
Upper arm-to-axle bolt 111 82
Lower arm-to-body attachment bolt 150 111
Lower arm-to-axle bolt 150 111
Stabilizer bar-to-lower arm bolt 55 41
Parking brake cable bracket 55 41
Axle damper front bolt 90 66
Axle damper rear nut 90 66
Axle damper bracket-to-frame bolt 80 59
Pinion bumper mount-to-body bolts 14 10
Bracket assembly-to-differential housing bolt 48 35
Wheel nuts 129 95
The following instructions apply to both cars:
2. First, you’ll want to get some stuff out of the way before you get your hands dirty, such as removing the liner from the trunk. There are four push pins that hold the trunk floor carpet in place, located just behind the rear seat backs, once you pull those out, the floor carpet will come right out. Next, there are four push pins holding the trunk latch cover in place. Then there are two “screw” on pieces that hold the rear trunk liner in place, you’ll have to have a flathead screwdriver to remove them if the car didn’t come with a cargo net, you can do it by hand if they have the cargo net hooks on them. Now the tricky part, there is a pin on each of the side trim panels, underneath the quarter panels, oriented vertically, that just pull out. Then the fronts of the side trim panels are attached to the sides of the opening of the trunk area-to-passenger compartment by clips. If you can grab the clips and pull toward the center of the car, they should come right off, but should stay attached to the trim piece. Now you should be able to remove the side liners. You also need to disconnect the Speed Sensor/ABS wires, located under the rear lower seat cushion. To remove, there is a small opening under the seat cushion (lift up on the cushion to see, about 6-8” in from the side of the cushion on both passenger and driver’s sides) that a flathead screwdriver will slip into. Gently do this as to not break the clip. Release the pin on each side and the cushion will lift right out. With the cushion out of the way, you’ll see a wire harness connection just behind the carpet on both sides of the vehicle. Unplug this connection and feed the plug out through the bottom of the car through the grommet hole.
See picture below for details (picture courtesy of Joe Lynch).
3. Now you can get your hands dirty. Jack the car up; at the axle you’ll need at least 1.5-2 feet of vertical working room to get the rear ends in/out. We jacked the cars up and put tall jack stands on the “framerails” just forward of the axle area, making sure to not block access to the forward lower control arm or forward IRS mounting bolts. Also be sure to place chocks in front of front wheels, and leave parking brake lever disengaged.
4. Remove wheels.
5. Now you get to take stuff apart. To make things easier (MUCH easier, trust me) on yourself, put a clamp (one used to pinch rubber brake lines, auto parts store should have these) on the rubber flex part of the brake lines, as close to the caliper as possible. This will eliminate the need to do a lengthy brake bleeding; all you’ll have to do in the end is get those few inches of air out of the lines.
6. Remove the brake line fitting from the caliper (I believe it was 12mm) and place up and out of the way. Have something to catch the dripping brake fluid, or let it drip and clean up before working further, its very messy and slippery I found out.
7. Finish pulling the speed sensor/ABS wire out through the bottom of the car, noting how it is routed, since you’ll have to reinstall it the same way. Remove retaining bracket on IRS (12mm). Attach to axle/IRS out of the way.
8. Remove Parking brake cable end from rear brakes. I used a set of channel-locks to compress the spring, and then used pliers to grab the end and work it free. This is where it is important to have the parking brake disengaged to have as much slack in the parking brake as possible. Using pliers, remove E-Clip that holds the parking brake in the mounting hole. Snake parking brake cable out of hole and out of the way.
Here where the two split off – IRS Removal
1. Remove the four fasteners holding the cat-back to the H-pipe (14mm or 9/16, whichever you have. Remove cat-back.
2. Remove four bolts that hold drive shaft to rear end (12 point 12mm). Use a pry bar or long screwdrivers to keep driveshaft from rotating while you’re loosening the bolts. You should then be able to slide the front yoke out of the transmission, pulling gently rearward, and set driveshaft aside. This is a good time to swap yokes if you need to, I won’t go into detail about how to change a U Joint, and it’s pretty simple.
3. In the trunk, remove the two upper shock nuts and rubber isolators and set aside.
4. Using a trans jack or whatever you have available to lower the IRS, support the IRS ON THE IRS FRAME, NOT THE DIFFERENTIAL HOUSING. Once you’re satisfied with the support, remove two front IRS mounting bolts (18mm). Lower front slightly too clear mounts, and re-support as necessary so that IRS is fully supported when you remove the rear bolts.
5. Remove two rear IRS mounting bolts (18mm) where the rear of the IRS frame mounts to the brackets. CAUTION! Do not use an impact gun to loosen these. There is a lock tab that can, and likely will, break off if you use an impact gun. Also, you may be thinking that you can just undo the brackets and remove everything together. Trust me it’s much easier to remove the brackets afterward and the same goes for reinstallation, put the brackets in first, then attach the IRS frame.
6. Lower IRS out of car slowly and steadily, leaving shocks attached; be careful this thing weighs 300+ lbs. Springs can now be just pulled out.
7. Remove 4 bolts (15mm) each side and remove rear IRS mounting brackets.
8. Now that the IRS is out of the way, disconnect the parking brake cable from the puller in the driveshaft tunnel, and use a 13mm deep well socket to remove the cables from the bracket, as shown in the picture below (courtesy of Joe Lynch).
9. Snake parking brake cable out toward rear of car, noting how they’re routed, since you’ll have to route them back when you reinstall. Keep mounting grommet/clip that is toward the rear of the cable on cable, remove pin/bolt from body.
10. You should now be complete in removing everything you need from the Cobra.
Solid Axle Removal
1. Remove driveshaft (See IRS removal, #2).
2. Firmly support the solid axle w/ jacks and/or jack stands under the axle tubes and differential housing.
3. Remove swaybar, two bolts each side on lower control arm, note how ABS wire bracket attaches to the sway bar bolt on each side, you’ll have to reattach it this way later.
4. Remove quad shocks on each side, two bolts (15mm I think) hold the bracket to the body, one bolt to the axle.
5. In the trunk, remove the two upper shock nuts and rubber isolators and set aside.
6. Remove one bolt each side (18mm) where the upper control arm mounts to the axle housing.
7. Slowly lower axle enough so that springs can be removed. Be careful, the only things holding the axle in at this point are the lower control arms, and the axle could rotate backwards on you if you don’t steady it.
8. It’s easiest to remove the shocks from the axle now so that they’re not in the way, 1 bolt each side.
9. With the axle steadied, remove 1 bolt each side (18mm) where the lower control arm mounts to the axle.
10. Now you should be able to slowly lower the axle out of the car.
11. Remove pinion snubber, 3 bolts (10mm); remove clip nuts to transfer to Cobra.
12. Remove the four fasteners holding the cat-back to the H-pipe (14mm or 9/16, whichever you have. Remove cat-back.
13. Remove rear exhaust hanger brackets two bolts each; remove clip nuts to transfer to Cobra.
14. Remove parking brake cables (IRS removal, #8).
15. Remove upper and lower control arms from body 1 bolt each (18mm).
Upper:
Lower:
16. You should now be complete in removing everything you need from the GT.
Note: Now is a good time to fix anything you need to on the rear ends, i.e. if you’re going to change gears, or if you have a leaking diff and need to reseal the cover, it doesn’t get any easier than when the rear is out of the car.
Note: Taking the rear cover off of the IRS rear for resealing/gear installation requires removing the halfshafts from the pumpkin, and removing the pumpkin from the IRS assembly. I won’t go into detail here, but if you need to know the procedure (so that you don’t mess up your alignment in the process) PM me (quick01snake on
www.svtperformance.com, or snkpwr on
www.stlmustangs.com and
www.502streetscene.net) and I’ll walk you through it.
Note: If you want to keep your same brakes, you’ll have to swap brackets, rotors, calipers, and pads.
Installing Solid Axle into Cobra
1. Install clip nuts and pinion snubber from GT, 3 bolts.
2. Install parking brake cables, reverse of removal from GT, except you won’t need the 13mm socket for the clips, they’ll pop right in. Reattach clip/grommet to body as it was on the GT.
3. Install clip nuts and exhaust hangers from GT, 2 bolts each.
4. Install cat-back into hangers and attach four fasteners to h-pipe.
5. Install upper and lower control arms with same bolts, but do not tighten nuts down for now.
6. Roll axle under car and lift until you can slide the lower control arms into the brackets on the axle and install bolt, 1 each side, but do not tighten nuts down for now.
7. Install springs, smaller side down, with the pigtail at the back of the perch, pointing toward the driver’s side of the car.
8. Reinstall shocks onto axle 1 bolt each, be sure that rubber isolator is still on the top of the shock where it mounts onto the lower side of the body.
9. Slowly raise the axle, guiding the springs and shocks into place, until you can work the upper control arms onto the flanges on the diff housing. Install 1 bolt each side, but do not tighten nuts down for now.
10. Inside trunk, install rubber isolators and upper shock nuts, leaving nuts loose for now.
11. After verifying that the springs are seated correctly, raise the axle until the car lifts off of the jack stands slightly.
12. Now go through and tighten all control arms nuts and upper shock nuts to Ford Spec (see table).
13. Route ABS wires through body and up into passenger compartment, seating grommets securely, reconnect plugs, reattach bracket.
14. Attach brake fittings to calipers, but leave clamps on flex hoses until you bleed brakes.
15. Install sway bar, reattaching ABS wire brackets where they were on GT.
16. Using similar method as removal, reattach parking brake puller at front of parking brake cable, and rear onto rear brakes.
17. Insert driveshaft yoke into back of transmission, then install rear flange onto rear end with 4 bolts.
18. Start car and run for a few minutes to heat up exhaust, and then retighten fasteners.
19. Bleed brakes.
20. Install wheels.
21. Lower car.
22. You should now be done.
Installing IRS into GT
1. Install parking brake cables, reverse of removal from Cobra, except you won’t need the 13mm socket for the clips, they’ll pop right in. Reattach clip/grommet to body as it was on the Cobra.
2. Install rear IRS brackets onto body, in the same place as they were on the Cobra, 4 bolts each side, but do now tighten down yet.
3. Place spring loosely in the lower perches on the IRS assembly in the manner they were on the Cobra.
4. Roll IRS under rear and slowly raise until the front mounting flanges can be inserted into the body brackets. Insert 1 bolt each side, but do not tighten nuts down completely yet.
5. Raise the rear of the IRS up, lining up springs and guiding shocks in, until the rear attachment point line up with the brackets. Install 1 bolt each side.
6. With all attaching bolts now in place, tighten down all nuts/bolts, remembering not to use an impact gun to tighten down the bolt that attaches the rear of the IRS frame to the bracket (Sorry I don’t have the IRS torque specs, but they shouldn’t be too hard to find).
7. Inside trunk, install rubber isolators and upper shock nuts, and tighten down.
8. Route ABS wires through body and up into passenger compartment, seating grommets securely, reconnect plugs. Reattach bracket.
9. Attach brake fittings to calipers, but leave clamps on flex hoses until you bleed brakes.
10. Using similar method as removal, reattach parking brake puller at front of parking brake cable, and rear onto rear brakes.
11. Insert driveshaft yoke into back of transmission, then install rear flange onto rear end with 4 bolts.
12. Reinstall cat-back and four fasteners to h-pipe.
13. Start car and run for a few minutes to heat up exhaust, and then retighten fasteners.
14. Bleed brakes
15. Install wheels
16. Lower car
17. You should now be done.
Thanks to Joe Lynch and Bob Cosby for info and input!!!
Useful Sketch (to be able to picture where things go, solid axle only, sorry):
