Gasdruck stossdampfer

kyb_1211a.jpgThe 17-year-old shocks in the FJ80 were long overdue for replacement, but something got it in my head to replace them this past Saturday – maybe it was the swervy, edge-of-the-envelope, Caddy-like ride.   Went by Car Quest and got the appropriate KYB (Kayaba) units on Friday.  At one time I was considering upgrading to something like Edelbrock IAS’s, but since the FJ80 may be retired soon, I just went with the direct OEM replacement.

Install procedure seemed pretty straightforward in the FSM – jack up axle, support frame on jackstands, remove wheels, unbolt shocks, lower axle and remove shocks.  The reality was a little more involved.  The FSM describes holding the flats on the end of the shock shaft with a wrench while loosening the nut that holds the shock in place.  The flats are 6mm, but an adjustable wrench works best for leverage.  An 8″ would be good since it is about the same length as the 17mm open-end for the nut.  The nuts are tight from the factory, so penetrating oil is helpful.  The left shock tower is right below the LHD master cylinder, so you can’t cheat and use a pneumatic impact wrench.  Between the brake lines, the emissions vacuum lines and the manifolds, there is about 45-degrees of turning space for the wrench, so patience is required.  The right side is more open, but the ignition coil, igniter, and A/C hoses limit the wrench swing.

kyb_1212a.jpgAfter removing the upper and lower nuts, use some twine and tie the shock compressed.  I looped twine over the shock ends inboard of the cushions and tied them together in the middle.  This way, when the axle is lowered, the shocks will not extend with the gas pressure and you can get them out easily.  Similarly, tie the new shocks compressed before removing the shipping straps.

kyb_1210a.jpg

The rear shocks came out a little easier.  The bottoms of the shocks are eyeletted, being retained onto hollow studs on the axle by bolts.  The upper shaft ends are mounted through a plate held onto the underside of the frame by bolts.  Use a 17mm socket to remove the bottom bolts, after which the eyelets can be yanked off the studs. Use a 14mm socket on a long-ass extension to remove the bolts that retain the upper plates – there is little working space up near the bolts because of the frame, the suspension links, and anti-roll bar, so you’ll need a 18″ extension.  Penetrating oil won’t help much on the stud bolts, since the oil probably won’t make it past the shock eyelet bushing to reach the bolt threads.  The top bolts can be oiled through the slit between the top of the frame and the bottom edge of the body fender bucket – use a straw on the oil nozzle.  The top bolts were super-tight from the factory, and the extension bar was wrapping up like a quarter turn before the bolts popped free!  The left rear shock had no pressure left – I didn’t check if it was stuck-down, but it didn’t extend when the eyelet was freed from the stud.  Probably explains the massive clockwise body-roll during left turns (no left rebound damping).

After removing old shocks, remove plates and reinstall onto the new shocks – be aware that there is a left and right plate, and there is a top and bottom to the plates.  After installing the shock eyelet to the axle studs, undo the twine and allow the shock to extend teh plate into place.  With a little twisting, the bolt holes will line up and the plate bolts can be reinstalled.  I probably should have used some anti-seize during reassembly, but didn’t want to go digging around trying to find it.

Rides like new!

Around $300, 2-3 hours, medium difficulty (little more difficult than rotating tires).

Tools required:

  • 8″ adjustable wrench
  • 17mm open-end wrench
  • 17mm socket
  • 14mm socket
  • socket wrench or flex handle
  • 18″ extension bar
  • jack
  • jackstands
  • twine
  • scissors or EMT shears
  • penetrating oil
  • anti-seize compound

kyb.jpgThe instruction sheet hasn’t been changed for decades – it’s full of Engrish and some odd translations.

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