TR6 IRS Rebuild Sequence

By the King of Rebuilds Roger Bolick

New shock links and bushings will remove the "throttle" steer and slop from the rear. It raised the rear bumper 1" on mine. Half the droop in the OEM TR6 setup is the springs, half is the rotten rubber bushings. I have been replacing the bushings and using the spring spacers to correct the sag. Seems new bushings and the TRF spacers are about perfect to raise the rear of a sagging car. This corrects the camber, toe-in will need to be adjusted.

I had some new Nylon ones from TRF laying around (British NW is cheaper, these are poly, they are not self-lubing, but neither are the nylon ones I've found out as well, warning: some cheaper kits do not have the steel sleeve inside), pack synthetic grease around the steel pin with either type) TRF just added a nylatron kit with the critical front bushings and rear assembly, HP129, HP130 very expensive. These are made by Good Parts, really nice and provide shims for the rear (great idea).

For my quality judgement, I buy the TRF/Good Parts rear kit. I am not convinced the price of the front kit is justified, but the Nylon rear kit contains the shim pack not included in the BPNW poly setup. The Nylon is a little stiffer, but both kits fit like a dream... compared to the replacement rotten rubber plugs. This cures a host of rear-end related handling problems... provided that the rest of the rear, i.e. trailing arms are intact.

HINT: I screwed the shock pin off/on several times to support as necessary and used a small bottle jack to raise/lower the trailing arm against the spring. The rest of the rear is resting on 2 jack stands placed far enough forward to be out of the way.

NEGATIVES: None that I have found, though each time this is mentioned on the Internet, many folks that have never tried this voice their opinion. To my knowledge there are no negatives. If the diff or anything is making noise already, it will indeed be louder... otherwise I use this on the car I drive daily. I can detect NO change other than that the rear end follows the front through the S-curves, making the car MUCH safer. I have 35k miles on this setup.

Materials needed:

Procedure:

  1. Drop arm, remove spring
  2. count position and number of shims at brackets
  3. Release brake hose at mount to arm, disconnect line
  4. Remove outside pivot pin, loosen nut on inside
  5. Remove top inside pivot bracket bolt and remove nut from the lower one
  6. Drop outside edge down to ground and pull back, the inside pivot pin can be removed over the frame, rear of the body, twist whole unit around
  7. Using the C-clamp, PVC, wood with silicon lube or Armor-All press the old bushings out. Found a closed end offset wrench to work well wedged against the C-clamp shaft for leverage
  8. Scrape, sand, remove the old rubber in the hole
  9. Press in new Poly with C-clamp, make sure its centered
  10. Press in shaft against wood to allow some overshoot for centering (using the C-clamp allows perfect alignment of the bushings/pin
  11. Use the washers to give a tight, but non-touching fit to the arm (you want the combo that is one 0.010 less than the one that binds)
  12. Grease inside of sleeve and bolt, reverse w/spring, bleed brakes

Other suggested tasks while back there:

  1. Grease and re-boot the splines, need new boots and tie wires
  2. Rebuild brakes, need new shoes and rebuild kits (I use DOT 5)
  3. Replace shocks and use new shock links (I use Apple Heavy Duty levers) (BPNW makes poly shock link mounts)
  4. Replace the diff mounts with the BPNW poly ones and check the right front bracket for hairline cracks. Pinion seal is a good addition, but careful on the later cars, count turns so as to not disturb the compressed spacer internal to the diff.