To prevent a failure of the outboard stub shaft which will result in expensive damage to the knuckle and brakes and which may result in a car wreck if the failure occus at speed. Here is a picture of the failure I had in March, 2001.
Here is what you want to find, which are cracks in the outboard stub shaft BEFORE a failure occurs.
Anyone who has a 99 up Cobra with stock Ford or aftermarket halfshafts from Raxle or GKN with several dozen 1.80 sec or faster 60' times or with 50 or more 1.90 or faster 60' times. Regardless of the tires used or the gears used. Cars suning 4.56 gears and 10" ET Streets are more likely to have damage than those with 4.10 gears and drag radials, however.
Before you start the 2002 drag racing season. Check them again every 20-30 runs afterwards.
Check both halfshafts, one side at a time. The check can be made without removing the halfshaft from the car. All that is needed is to raise the car, remove the wheel, remove the lower knuckle bolt, remove the axle nut, install a hub puller, push the axle part way out of the hub toward the pumpkin, clean the shoulder area, and examine it for cracks. If none is found, install the nut, run it down and tighten, install the lower knuckle bolt, install the wheels, and let the car back down. If cracks are found, order parts and replace when received.
5. What Tools Are Needed?.
13/16" lug wrench
36mm socket and large breakover bar
18mm socket, 18mm box wrench
hub puller Autozone # ______
socket for hub puller, usually 3/4"
6. What is the Procedure?
a. Raise car at frame so both rear wheels are off the ground.
b. Set jack stand under frame and let car down on jack stands.
c. Remove wheel.
d. Set parking brake and put transmission in 4th gear.
e. Make a note of how many threads are exposed on the end of the axle. Use a 36mm socket to remove the large axle nut. It will be very tight if it was installed correctly after the knuckle recall on the 99s.
f. Place a jack under the lower control arm and raise it slightly. Using the 18 mm wrenches, remove the lower knuckle bolt. If this is not done, the axle can't be pushed out of the hub far enough to see the splines and shoulder.
g.. Install hub puller using three lug nuts. Make sure there is some anti-seize on the bolt threads and on the contact surface between the puller bolt and the stub shaft.
h. Tighten the puller and continue tightening and observe the stub shaft moving out of the hub toward the pumpkin. The lower knuckle joint will slide out of the lower control arm.
i.. STOP tightening the bolt when some resistance is felt. The CV joints will have compressed all they can at this point and you must NOT continue pushing the shaft toward the pumpkin. You will see something like this, except yours probably won't have any duct tape on the CV joint.
j. Place the transmission in neutral and release the parking brake.
k. Clean the shoulder area with a cloth and see if you can see any cracks that look like the picture above. If you can't quite see the splines from the back side of the knuckle, take the parking brake cable loose at the clamp next to the spring using an 8mm socket. Now rotate the shaft using the other wheel and inspect for cracks for the full 360 degrees of the shoulder. This one is OK. The shadow from the flash obscures some of the shaft shoulder that you can see yourself. Sorry about that.
l. If no cracks are found, remove the puller and install the axle nut.
m. Line up the lower knuckle joint hole with the control arm and install the lower control arm bolt, start the nut. (You may have to raise or lower the jack slightly to get the knuckle and arm aligned for the bolt.) Raise the jack under the lower control arm enough so that the car comes off the jack stand slightly. Tighten the lower control arm nut to 66 ft-lbs . Let the car back down on the jack stand.
m. Set the parking brake and put the transmission in gear. Tighten the axle nut to 240 ft-lbs. If you don't have a torque wrench, that means get it as tight as you can. You should feel the shaft bottom out against the wheel bearing and hub and get very snug very quickly after all the parts are pulled together. Check the number of splines visible on the shaft. It should be the same as when you started. If it isn't, or the axle nut didn't pull up and abruptly tighten, FIND OUT WHY. Otherwise the bearing could be left loose. Make sure the axle nut and bearing assembly pulls together correctly in the hub.
m. Install the wheel and tighten the lug nuts to 95 ft-lbs.
n. Repeat on other side of car.
o. Set parking brake and put transmission in gear.
p. Lower car.
E-mail me with the results of your inspection and I will build a data base from which to make recommendations in the future. I need to know inspection date, approximate number and 60' times for your launches, your tire size/type, and gear ratio.