Project EF Civic Racecar: Refurbishing the Rear Suspension

It’s part 2 of our Civic’s suspension overhaul.  Today we are looking at the multilink rear suspension of our 1991 Civic racecar and giving it a thorough overhaul replacing all of the wear parts in our 30 year old Honda.

Old suspension in the Civic. Ground Control coilovers and an ST Suspension rear swaybar are the only upgrades in sight.
Just like with the front we started by removing everything. Unlike the front we are also removing the Ground Control coilovers. They work well enough but as you can see here they are in desperate need of a helper spring. Lots of penetrating oil and patience were required to get everything freed without breaking any bolts. We also removed the rear brakes as the brake lines and parking brake cables are integrated into the trailing arm and cannot be removed assembled.
Civic Rear Coilovers with and without the helper spring
Ground Control no longer services the Advanced Design coilover but the springs are standard Eibach parts so we were able to measure and spec exactly what we needed. The car needs to be corner weighted anyway: not only will all of our suspension work require a full realignment, but I weigh about 100 lbs less than the previous driver so the corner weights are off for me already. We popped off the top mount, gave everything a light cleaning, then reinstalled the dampers. Normally one would put the helper springs on the bottom, but the collars interfere with the damper body so we had to flip them.
EF Civic stock rear trailing arms
The rear suspension is a multilink arrangement with a big trailing arm, a lateral control arm, and two small links to control camber and toe. The trailing arm pivots on the giant rubber bushing in the middle. This bushing is a major source of free play. It is made of rubber and has NVH absorbing voids in it that contribute to unwanted suspension movement.
Pressing on the bushing shows the tearing in the rubber that will make for very unstable handling
On top of that, our 30+ year old bushings are tearing from age and in need of replacement. The bushings are so bad you could actually feel the rear end squirming when slaloming. This made for a very unstable feeling car.

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3 comments

  1. Place some plywood under those jackstands. I know the Civic is a featherweight, but that tarmac looks paper thin, and it doesn’t take much for the feet on those stands to sink right through. Hot day, or water saturation in the substrate combined with a tiny contact surface. It can topple, if you’re lucky it won’t be when you’re wrenching on it. Ask me how I know.

    Reply

    1. Pavement is 60 years old. It’s not thin, but it has sunk a bit. It’s getting repaved soon. Appreciate the concern though!

      Reply

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