The well-known black S197 Ford Mustang has returned to the shop to get another suspension upgrade. This time, the rear suspension is the area of focus. This J&M Upper Control Arm (UCA) will eliminate the unwanted control arm flex and also has the ability to change & correct the pinion angle on a lowered car. Our original StangNet.com write-up (with hi res images on demand) gives a real world overview and interpretation on how to perform the UCA installation on a 2005 Ford Mustang GT. StangNet Staff member bigcat shows us just how it’s done.

Tools needed: 18mm socket, 21mm socket, 1 ½” wrench, 18mm wrench, 21mm wrench extensions, ratchet, jack, jack stands, (optional: ramps), & magnetic angle finder.

NOTE: Any time a suspension fastener is loosened or removed, Ford specifies a new fastener should be used.

Step 1. Raise and properly support the vehicle at a comfortable working height.

Step 2. Using your 18mm socket, remove the nut from rear mounting bolt for the upper control arm. This is the bolt that holds the upper arm to the rear axle. It is a flag bolt and will hold itself while turning the nut. You may find it helpful to put slight upward pressure on the axle to remove the bolt.

Step 3. Using the 18 and the 21 mm wrenches, remove the nut from the front mounting location of the upper control arm. The nut is 21mm, and the bolt head is 18mm. A ratchet type wrench is useful for this step.

The Bolt will not be able to be removed from the control arm yet, only the nut. The bolt will hit the gas tank at this point when trying to remove it.

Step 4. Using an extension and the 18mm socket, remove the two bolts from the UCA mounting bracket. These bolts go straight up into the body of the car.

Step 5. Remove the rear seat cushion from the car. There are two mounting tabs at the front edge of the seat. Press them in and lift the seat cushion out.

Step 6. Locate the 21mm nut in the center of the car along the drive shaft tunnel. It is located just in front of the seat back along the flat portion of the tunnel.

Step 7. Loosen the bolt with your 21mm socket. It is not necessary to remove it, only loosen.

Step 8. Back under the car, you can now rotate the UCA bracket and remove the bolt from Step 3.

Step 9. Inspect your new parts and grease the bushings with the supplied lube. It is easiest to assemble the 3 piece bushing into the arm, and then install the metal sleeve into the bushing. This will prevent air pockets from forming inside the bushing. Air pockets in the bushing will push the outer bushings out of the arm and make it difficult to install into the car. With no air in the bushing, the bushing will fit tight to the arm.

Correct bushing assembly order shown below.

Step 10. The control arm is preset to the stock length. If you are installing this part as a replacement for stock, no adjustment is necessary. If the suspension is lowered from stock, adjustment IS required. Loosen the jamb nuts for the adjuster on the control arm with your 1 ½” wrench. A good starting point is 8 3/8” between the center of the mounting holes. Another way to measure is to install the bolts, and measure from the outside edge on one bolt to the inside edge of the other. This will be a good starting point when measuring pinion angle. Tighten the jamb nuts.

Step 11. Install the anti-clunk bushings into the UCA mounting bracket. Install them on the outside of the bracket.

Step 12. Install the UCA to the mounting bracket that you loosened in Steps 4 and 6. Use the large metal washers on each side between the bushing and the mounting bracket. Insert your bolt into the bracket and arm and attach the nut. Leave it loose so you can pivot the arm when installing the rear bolt in step 14.

Step 13. Loosely reinstall the two mounting bracket bolts that were removed in Step 4. Try to realign it to the marks on the body and tighten the bolts. There should not be much to adjust, but check it to be sure. Torque to 85 ft-lbs.

Step 14. Tighten the 21mm bolt inside the car to 129 ft-lbs (factory specification) and reinstall the seat cushion.

Step 15. Back under the car, install the control arm rear-mounting bolt and nut.

Step 16. To torque the bolts and to check pinion angle the car must be level and with a loaded suspension. Using a drive-on lift is easiest. If the lift is not available, use ramps or place the jack stands under the front lower control arms to load the front suspension. Place the jack stands under the axle tubes in the rear to load the rear suspension.

Step 17. With the suspension loaded, torque the control arm bolts to 129 ft-lbs, as per the factory specification.

Step 18. Now it is time to check the pinion angle. This step is different for one and two-piece drive shafts. Both methods are covered below. BEFORE STARTING, jounce the car to let the suspension settle. (Jounce: verb. move up and down repeatedly.)

FACTORY TWO-PIECE DRIVE SHAFT: Use your magnetic angle finder and attach it to the FRONT drive shaft. Record the front drive shaft angle. Next, attach the angle finder to the pinion flange. Record the angle. Subtract the pinion flange angle front the front drive shaft angle to get your net pinion angle.

AFTERMARKET ONE PIECE DRIVESHAFT: Use your magnetic angle finder and attach it to the transmission bell housing at the mounting surface to the engine. Record your angle. Then take your recording for the pinion flange. Subtract the pinion flange angle from the transmission reading to get your net pinion angle.

Step 19. If necessary, loosen the jamb nuts on the upper control arm and adjust the pinion angle. Once you are satisfied with the pinion angle, double-check all fasteners and jamb nuts. Measure pinion angle again, just to be sure.

Test drive the vehicle. If you notice vibration that was not present before you installed the adjustable upper control arm, recheck your pinion angle.