Another Shocking Story

by Dave Johnson

Finding shocks to fit the Tiger or Alpine is getting more difficult.

The original Armstrong Heavy Duty Shock had the following dimensions:

  • Extended Length 12″
  • Collapsed Length 8″
  • Top fitting stud
  • Bottom fitting 1 1/2″ ring with 3/8″ bushing sleeve
  • No Dust Cover

There have been several shocks listed by other tech tips that can be modified to fit. I found that the Monroe GasMatic shock 5824 fits the specs with the exception that the sleeve is 2 1/4″ long with a 7/16″ bolthole.

I tried cutting the sleeve but found that it was made of hardened steel. Even if I could cut it, I would still have to enlarge the hole in the mounting bracket from 7/16″ to 3/8″.

Using appropriate size sockets, and a vise, press the old sleeve out of the old shock. A 1/2” inch pipe ‘T’ fitting was just the right thing to press the old sleeve into. It held the bushing in place but allowed the sleeve to be pressed out.

Using the same sockets, vise, and pipe fitting, slowly press the new sleeve out of the new shock. I used silicone spray to lube the sleeve as I pressed. I would press forward about 1/2″ and then release the pressure on the bushing. By looking into the pipe’s hole you can watch your progress. Stop when the new sleeve is just starting in the new bushing (about 1/16″). Switch from the socket to the old sleeve and continue pressing the new sleeve out. It won’t take long until you will have replaced the wrong size sleeve with the correct size old sleeve. Your shock is now ready to mount using the original bolts and bracket.

The trick is to use the old sleeve to push the new sleeve out. If you push the new sleeve out first, the hole in the bushing will collapse to about 1/4″. You’ll never get the old sleeve in the new bushing without tearing it.

FURTHER NOTE: If you have an emotional attachment to the original Armstrongs and don’t want to remove the sleeve, most auto parts will carry a 7/16″ by 1 1/2″ sleeve. But you’ll have to enlarge the mounting hole and use a 7/16″ bolt.

Editors note: The latest Monroe Gas-charged shock absorber that I have found that matches these dimensions is Part # 20814 and are called “GasMatic GT”. These shocks were originally designed for the Ford Pinto and Mustang II and may be sold under many other names.

Leave a Reply