Upper Control Arm Bushing Replacement

A bushing on a car is a lining that provides a cushion between two metal parts. As could be expected, bushings will wear down or out based on the number of miles driven and the varying road conditions that the steering mechanism has to accommodate.

In my case, a recent visit to my mechanic* revealed that the front left upper control arm bushings had worn down considerably. Among other issues, the worn bushings made it impossible for the front wheels and tires to stay in alignment. This led to improper wear on the front left tire, essentially destroying it in the process.

Removing the upper control arm A-frame revealed the extent to which the front and rear bushings had been damaged.

Removing and replacing the bushings** requires that the upper control arm be removed entirely from the car.

WARNING: Because the steering mechanism includes a heavy spring under tremendous pressure, the removal of the A-frame must be done with safety in mind. Extreme caution is advised and service manual procedures should be followed. The lower control arm and spring needs to be compressed and adequately supported during the whole disassembly and reassembly process otherwise bodily injury or death can occur!

Upon disassembly it's important to take note of the alignment shims (spacers) behind the A-frame shaft held in place by the two large bolts. These adjustment shims control the camber + caster angles for front end alignment. There are most likely a different number of shims of different thicknesses on each bolt so it's important to keep them separate and marked for reassembly.

The upper control arm A-frame is held in place by the ball joint stud, nut, cotter pin and two control arm bolts. Once these are removed and the A-frame pulled out, it is fairly easy to work on the bushings. In the following photo, you can see the A-frame mounted in a vice showing the two new bushings already installed.

Editors Note: As an alternative, you can choose to leave the ball joint attached to the steering knuckle and instead remove the ball joint from the A-frame by removing the three attaching bolts. It’s six of one, half dozen of the other, although lining up the three bolts can be a hassle.

Since the A-frame is already out, it is a good idea to check the condition of the ball joint and its dust boot. This boot seals moisture out and holds grease to lubricate the ball joint. If care is not taken with the dust boot while the A-frame is being removed, it is likely that it will be cut/destroyed in the process. If reinstalled in a damaged condition it will allow moisture and road debris to enter the ball joint and accelerate wear. If the boot is damaged, you will need to have a new boot available (or a new replacement ball joint which includes the boot) so as not to slow down the repair.

In the following photo, you will see that the boot was not damaged during the A-frame removal process.

In this case, the joint parts just need to be cleaned and the joint repacked (i.e. greased).

At this point, the A-frame just needs to be put back onto the steering assembly. The crucial step in this process is to make sure that the (male) ball joint stem is properly seated in the (female) steering knuckle. Both of these are tapered to allow for a very tight fit. The secret here is to use the proper number of spacers behind the two mounting bolts on the car (see above).

Editors Note: If the tapered ball joint bolt is partially seated, torquing it to proper specs should cause it to completely seat.

Since the steering knuckle pivots on the lower ball joint while the upper ball joint is disconnected, you'll need to align the steering knuckle into position to install the upper ball joint stud.

The last step is to tighten all the bolts (to manufacturer specifications) using a torque wrench and then put back the cotter pin to prevent the ball joint nut from coming loose.

Since all of these steps tend to alter the ride, it's a good idea to have the car realigned.

THE END

* - Tom Robinson - Sundown Transmissions and Auto Repair, La Anna PA - (570) 676-0313

www.sundowntransmissions.com

** - New bushings were obtained from Joe Pollard of Checker Auto Parts, Chatsworth CA - 818-999-1485 - www.checkerparts.com