Installing Polyurethane Bushings on a Lotus Elise
When bushings wear they can cause looseness in the steering and eventually some odd noises like knocking or squeaks.
You can replace the bushes with several different bushing types:
- OEM Rubber: Stiff for an OEM bushing, however they wear faster then poly and are a little difficult to press in.
- Polyurethane: Slightly stiffer then rubber. Generally longer lasting but known to squeak if they lose lubrication. Easy to install.
- Delrin, Nylon, and Nylatron: Hard plastics that deflect very little. Feedback seems to be mixed, many don't appear last long.
- Mono Balls: Zero deflection with a harsher ride. They are known for their direct feel on the track, and some say they are usable for street use.
I chose polyurethane because it seemed like a good upgrade for a street car, and I've had great results with the material in the past. One nice thing about polyurethane, is that they are super easy to install. They can be pressed in by hand (NICE!), while the others have to be pressed back in with a tool.
Note that I took the a-arms off of the car because I was replacing the ball joints at the same time, however the bushings can be replaced on the car with the right bushing press listed in the tools below.
Lift the Car and Remove the Wheels
Remove the Wheels
Remove the Belly Pan and Diffuser
Remove the 20 8mm bolts and 4 13mm bolts holding the belly pan and diffuser on the car.
Remove Control Arm Bolts
One control arm at a time, remove the 2 bolts that connect to the car's frame. Remove the bolts, replace the bushings and bolt it back to the car.
All A-Arm bolts use a 17mm bolts, you'll need a ratchet and an opened-end wrench to access them all.
You need to make sure you don't over-stretch the wheel sensor wires and brake cables, as such you should free them from the a-arm as you work. 4 use a small 10mm stud, with the others use a combination of zip ties and plastic clips.
On all 4 corners the upper a-arm limits the droop of the suspension. When you loosen the upper be sure to support the lower a-arm. We used this fancy tall jack.
Most bolts on the rear use these retaining tabs you'll have to bend out of the way.
All bolts use washers. In the case that the bolt uses a loose nut, it also uses a washer. The upper front a-arms are the only ones that use shims to adjust alignment. Keep track of the position of the front upper a-arm alignment shims when you remove them.
The front lower a-arm has one bolt that goes into the cabin. A friend will make this one easier to remove, but you can just lock a wrench against the a-arm and remove the nut inside the car.
Pressing Out A Bushing
You'll need a tool to press out the old bushings. Get the one that Lotus suppliers provide to make this job easier. We used a vice and a couple of sockets, but you'll need a large variety of sockets to be sure you'll have the sizes you need.
Press the bushing out in the direction of the hat.
Installing A New Bushing
Remove debrit and clean the bushing and the inside of the a-arm.
Fully Lube up the bushing, inside and out with the supplied grease. They typically supply barely enough - so you may want to buy more.
Lube up the inside of the a-arm and the metal insert.
Press the bushing into the a-arm. This can be done by hand. Install them so that the hats face out on the uppers, and in on the lowers.
Installing the A-Arm
With the new bushings, the a-arm may be a little tight to squeeze back in. Add lubrication to the frame surfaces and outsides of the bushings.
Wiggle, squirm, and squeeze the a-arms back in. When you get the holes near lining up, use a round shaft screwdriver to line up the arm and install the bolts.
The front upper's shims are a giant pain. Buying a set of the larger diameter shims will make it easier. Make sure you use the larger shims directly against the hats if possible.
There are 2 approaches to installing the shims:
- Glue the shims together and sort of place them in the frame opening to act as ramps for the a-arm. As you push it into place, the shims will squeeze and slide into place, sorta.
- Get the a-arm into place, and tap a shim into place by force with a screwdriver and a small hammer.
Once you get them near, poke a small tool in from the bolt hole to line up the shims and a-arm enough so the bolt will go in. I ended up persuading the bolts with a few light taps from a hammer.
Tighten all a-arm bolts to 33 ft-lbs.
Bend all the retainer clips back into place
Install all Cable Ties and Retainer
Make sure you secure any of the brake lines, wires, and cables you loosened before.
Install the Belly Pan and Diffuser
Your alignment (mostly camber & castor) may have changed as a result of the new arrangement of shims on the front wheels. It would be advisable to get an alignment done after this job, however you shouldn't have too much issue driving to the shop to do so.
I actually drove my car for about 600 miles before getting it aligned with no noticeable tire wear.