Polyurethane Suspension Bushings

Polyurethane Suspension Bushings:

The stock A1 suspension components are mounted to the body with rubber bushings. Over time, the rubber hardens, cracks and vulcanizes itself to the moving components. This can result in a vague feeling to steering input and a reduction in suspension compliance. When I replaced the ball joints a few years ago, I noticed the lower suspension arm felt like it was spring-loaded when disconnected from the strut due to the rubber bonding to the metal.

To remove the rear bushing, I clamped the arm in a vise and used a pipe wrench to twist the rubber off the rear pivot. Liberal amounts of WD-40 helped to loosen the rubber's grip. The front bushing, however, appears to be one piece, probably molded in place inside the front pivot. I used the following steps to remove it:

• Trim off the lip on the front side of the bushing.
  • This end will be pushed through the hole.
• Clamp the arm in a vise, forward edge up.
• Drill 6-8 small holes (1/8" - 1/4" in diameter) through the rubber, parallel to the metal bushing.
  • This relieves the pressure holding the bushing in place.
• Insert a bolt and tighten a nut on it.
• Hammer the bolt head to push the bushing out a half inch or so.
• Twist the bolt head (the nut needs to be really tight) and the bushing will eventually pop out.
  • Once again liberal shots of WD-40 will help this process.

The new urethane bushings are a joy to install. Just grease them up with that sticky clear bushing lube and pop them into place. The front bushings are split, so installation is easy. Its a rather tight fit getting the new bushings into the front recess, I pressed them in place with the vise jaws. Once in there the motion is much smoother than before. Be sure to grease the front bolt (18mm) and torque it to specifications (53 ft.lb.).

Here's the new bushings installed on the lower arm (lower left and right corners). Also note the replacement ball-joint and sway-bar attachments both bolted on. Now is a good time to clean and paint the metal. The leading edge gets pitted from road debris and can develop rust.

I also took this opportunity to upgrade the steering rack bushings to urethane as well.

• This involves removing the two U-brackets that hold the rack to the firewall, slipping off the old mounts and installing the new ones.
• If your steering has some play in it, this is a good time to tighten the pinion pre-load that is conveniently located on the back side of the rack.
  • I had previously adjusted mine; had to go back a few times to get it just right.
  • Mine was a little tight on the ends of travel, but over a month or two, that eased up and now the pinion is tight in the rack from lock to lock.

I'm impressed with the ride after this upgrade. My cornering speed is improved a great deal and the road feel is much better. The ride is more solid than before, but it is not harsh. However, I think I have found a few new rattles, than need to get tracked down. Except for that, it now feels like a new car (except for some new rattles).

Cost:

  1   Suspension bushings     $50
  1   Steering rack bushings  $20
  -------------------------------
                              $70
  

Rating:

Sway Bar End Link Bushings:

By all means, this is an ideal application for polyurethane bushings.