Re: [Amc-list] New toy ...I need a TSM

[Frank Swygert <farna@xxxxxxx>]

Unusual, though I have seen it happen once. If the lower shock mount bolt gets loose the arms will move more than intended, and can cause cracking when coupled with age. There is a large spacer in the lower shock eye that tightens between the arms and holds them steady. Of course badly worn rubber bushings will also cause more movement than desired and add to the possibility of such a failure. 

The lower arms can be changed without removing the spring, the upper arms will limit downward travel. You can use any 58-61 AMC lower arms with American bushings and of course the cross bar. 

The lower trunnion is pretty easy to check. If the trunnion rotates freely in the cap screws (ends that screw into the arms) then it's fine, just keep it greased. The upper one is a bit harder. The pin should remain stationary in the arms. Turn the steering wheel all the way to one side and look at the horizontal pin head/nut as someone bounces on the front bumper. Check the front on one side, back on the other. As a double check turn the wheels the opposite way and check again. If the pin rotates in the arms it's frozen inside the trunnion and must be removed ASAP. The arms won't take much turning before the hole is worn out. They can be fixed by  drilling and threading a piece of 1/4" plate, then welding over the original holes, or welding a "jam nut" (about half the thickness of a normal 5/8" nut) over the hole. I've saved a few this way, and there won't be a turning problem again! 

My best advice is to pull the entire front suspension out and apart even if it appears to be working as designed. Clean all the joints, put some anti-seize on them, reassemble, grease, then reinstall. Should be good for another 100K miles or so if greased regularly. It won't hurt to modify the horizontal pin for better greasing as Tom suggests, and I always put a tack weld on the lower trunnion cap screws and the upper pin head. This keeps them from turning a bit, but most importantly is a ready indicator of trouble. If the caps or pin starts to stick much the small tack weld will easily crack, indicating that the joints need to come apart, be cleaned, greased, and reassembled (or replaced). Just a small tack weld placed so that it can easily be struck off with a small chisel is all that's needed. 

With modern grease you can safely triple the recommended interval (every 1000 miles!), or grease yearly regardless of mileage. When I was driving a 63 American on a daily basis I only greased it yearly even when putting an average of 4-5K miles on it. Never had any problems at all. 

----------------------
Date: Mon, 2 Jun 2008 15:43:25 -0700 (PDT)
From: WILLIAM SERCKIE <realtorbill@xxxxxxxxxxxxx>

 I just got out from the 1963 and found thet the trunions and tie tors/ends appear to have been greased at regular intervals as the previous owner confirmed with me today...What the problem appears to be is that the lower control arm  sheared at the outer bolts.  It looks like a clean break, my assumption is that it was due to age, rust and simple metal fatigue.
   
  Does anybody out there have a set of lower control arms that the are willing to part with ?
I'll even take all four (both uppers and lowers) if they are available.
   

-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)

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