Shock Absorbers (Suspension Dampers)

This describes how I installed new Monroe 65406 shocks on my Mog.

I suspected that the shocks on my Mog needed replacing. The OEM Boge shocks were very expensive ($250 each) but a guy on the Mog mailing list (Von) said he had found some Monroe shocks that were very close to the OEM spec, and much cheaper: Monroe Gas magnum 65 series, model 65406. I bought a set of four from my "local" (90 miles away in Billings, MT) truck supply - they cost me $47.88 each.

The mounts on the Monroe shocks were different, but I decided that adding an M20 x 5mm thich flat washer on each side of the Monroe mount would work. I got these from McMaster-Carr, part number 98040A110.

The first problem was removing the wheels. The lug nuts were tight and I couldn't move them even with a big wrench and extension. I ended up buying a 1" drive industrial impact wrench from Harbor Freight Tools - up to 1400 ft-lbs, which made short work of the problem.

impact wrench

I removed the rear wheels, the top bolt from the shock, removed the lever from the torsion bar, but then ran into a problem - the threaded pin that goes through the bottom of the shock was stuck (in the shock) and there was no room to fit a puller (or even a hammer) in the space between the end of the pin and the hub. After various failed attempts, I found a solution: I used the nut and washer from the upper bolt, oiled the threads, put the nut on first as far as it would go, then the washer. Next I cut a length of SCH40 1" pipe and slid it over the end of the bolt; I made it as long as possible that would fit in the clearance available. I then slid a small piece of scrap 1/4" plate in between the end of the pipe and the hub (it sat on a couple of bolt heads). I backed the nut down the pin and it slowly pushed the pin out of the shock. I had to cut three different lengths of pipe because I kept running out of thread, but I finally got the thing out.

All the parts were in reasonable condition except the "rubber" seals on the arm bearings. It took a long time for the seals to show up from Germany (via Jim Ince - thanks, Jim), but once they arrived I was able to replace the shocks without any difficulty.

rear shock

While I was testing out the new rear shocks, I got a flat. My Mog came from the desert and much of the rubber is in bad shape - including the tires. I'd been planning to replace them, but I kept putting it off because of the cost. This latest flat convinced me that the time had come. I did some research and found that I could get new Conti MPT 81 335/80R20 tires mounted on used Suedrad rims shipped to me from Sean Philyaw at Eurotruck Importers for only a little bit more than just new tires from the supplier in Billings, MT. Plus I wouldn't have to make two trips to Billings with the trailer. Plus I'd have a spare. I bought from Sean.

Once the new wheels and tires showed up, I installed the front shocks - it was fairly straightforward.

front shock



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