Project EF Civic Racecar: Refurbishing the Rear Suspension

Stock vs Kingpin Machine modified rear control arms. Kingpin parts are clean and zinc plated with brand new spherical bearings and inserts. Stock arms are rusty and have worn out bushings
For the lower control arms we once again turned to Kingpin Machine for their Outlaw Rear Lower Arms. Like the front arms, Kingpin bead blasts, shot peens, and zinc plates the OEM Honda arms before blueprinting and sleeving the bores for aircraft grade spherical bearings. Most EF builders would jump to a billet aluminum aftermarket arm but they are not allowed in the Improved Touring class the Civic is currently built for so we have to stick with the heavy steel lower arm.
Detail view of the Si and non-Si rear control arms
The rear suspension in the EF Civic was used from 1988-2000 with only a few changes. The biggest change was in 1990 when Honda moved from a stamped steel arm with an eyelet mount for the damper to this cast design that uses a forked mount. The other change came in 1992 when all Civics got a rear swaybar and Honda added an end link mount to the control arm. In the ED/EF era, only the Si got a rear bar so our STD control arms are blank. Some SIs had special arms that had the mount, others used an eyelet that attach to the shock bolt. DA Integras came with rear swaybars so swapping to DA arms will also give EF owners sway bar options.

ST Suspension rear sway bar kit

A lot of EF rear swaybars are designed for either later model or aftermarket arms that have these mounting points on the control arms. ST Suspension’s rear bar mimics Honda’s design but adds spherical bearing end links, polyurethane bushings, a larger OD for more rotation, and adjustable mounting points. This is great for base model Civics that cannot use control arm mounted swabars like ours.

Blox rear swaybar end link and old ST Suspension end link
That is obviously a stock photo. The ST bar on our car has been in service for 20 years. It needs a little TLC. The end links are rusting and no longer compliant. Blox sells equivalent end links complete with spacers that will replace our seized end links.
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5 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

  3. Loving the EF content!
    I have the same chassis with a D15b, and we just replaced the rear drums with disk brakes
    Struggling a bit with the pedal feel though

    Should we upgrade to a 15/16″ master cylinder? (Current is a 13/16″)
    Booster is the factory 8.5 inch

    Reply

    1. You’ll be seeing our brake work in the next few weeks. Not sure when Mike is planning to run it, but it’s been written and submitted.

      I would not go to the larger MC. Both disc and drum Civics used the 13/16″ cylinder. The 15/16″ was for the Integra with bigger calipers. It will make the pedal firmer but the brakes will be a lot harder to modulate. I actually tried the Integra MC on this Civic and did not like it at all. The brakes, especially the rear, were very easy to lock. Not a fun way to drive.

      There are two things you should try first: 1) make sure the master cylinder isn’t leaking. If it’s new then move on to: 2) make sure it’s been properly bled. Master cylinders either need to be bench bled or vacuum bled. Using the brake pedal usually doesn’t get the full stroke of the piston and will leave an air bubble at the very end. If you have a new, properly bled master cylinder then try 3): make sure the pedal travel is correct. When I went back to the stock MC on my car the pedal travel was a lot longer than the Integra MC, but the brakes would still lock. I lengthened the pushrod on the back of the pedal by 3 turns and it made a world of difference.

      If none of this works, you’re better off just removing the booster. A number of companies offer kits that make it a (relatively) easy process. The booster location in the Civic is awful and doing the actual swap requires a lot of contortion. Some of the kits use the 13/16″ MC, others use an aftermarket MC that’s usually 7/8″. I’d try the free home fixes first though.

      Reply

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