AMC Eagle Den Forum

The Shop => Suspension, Steering, Brakes, Wheels & Tires => Topic started by: Illeagle1984 on March 09, 2021, 07:55:50 PM

Title: New Strut Rods
Post by: Illeagle1984 on March 09, 2021, 07:55:50 PM
Do you need new strut rod bushings, but the nuts won't move?  Need to adjust the alignment, but the nuts won't move?  Or does your strut rod look more like a toothpick, like the bottom piece in the first image?  My bushings split in half after 180,000 miles and one side would not budge, even with heat.  No parts store lists a new strut rod for our Eagles.  Luckily for us, the popular first-gen Mustang has some very similar front end parts.  Yes that's right, with a little work the Mustang strut rod fits into an Eagle suspension.  Not the first time I put parts from other cars onto the Eagle, and won't be the last.  The complete parts list for this job:

Strut rod: SPC # 94220 x 2 ($70 each)
Strut rod bushings: Moog # K8157 (optional, $50)
Extra nuts (optional)

I took some measurements beforehand to measure similarities to the Eagle and my 73 Mustang, and determined I could make it work.  The whole job may be done with the wheels resting on the ground so you end up close to where you started.  It turned out very well, but took four modifications:

1. You need a few inches of extra threads on top of what it came with.  A proper machine shop is what you need for this, unless you have access to such equipment.  I went with three inches of extra threads; you can see where the stock threads are black and the new ones are shiny in the middle rod.  Have them chamfer the transition from threads to bare rod as shown.  Right angle transitions are what's known as a stress riser, and can lead to structural failure.  Cost me $40 for the pair, but I knew the guy.

2. One new hole must be made, the other one enlarged.  Compare to your stock strut rod and get holes drilled.  Chamfer your edges here as well.  Once your stock bolt fits through, get a bit a couple sizes bigger and take the 90 degree edges off the holes.  I did this with a hand drill and progressively larger bits.  The machine shop can probably do this too if you don't have a drill or bits that go above 1/2 inch.

3. Next, it must be bent like the original strut rod.  A propylene or acetylene torch may be used.  See the top strut rod, right after the last bolt hole is a shiny spot.  Heat it in the middle of that zone where it goes from flat to round.  Once it becomes bright orange you can shape it without fear of weakening the metal.  Once it becomes hot yellow, it may lose its heat treat and might not resist bending or bowing.  Dull red, it will bend but may develop cracks due to not being hot and malleable enough.  Simply put the entirety of the flat end in a vise, heat it all the way around, and push on the top of the strut rod until the desired angle is reached.  It takes surprisingly little force to bend it when properly heated.  Heat, bend, check.  Repeat as needed.

4. The last step is easy.  Install it with whatever bushings you want.  In the end I used the Moog bushing kit, yes also for a Mustang.  I thought they fit better, but I think the bushings it came with would have worked out fine if you need to keep the cost down.  Remember you should still 'pony' up for an alignment when you're done.  The SPC rods come with two nuts apiece, but I put them both on the front as jam nuts and used mechanical self-locking nuts on the rear.  Probably optional.  The SPC strut rod is also just a tad smaller than the AMC rod, so your old nuts won't work even if you get them off.  Once you get them close, there will be too much strut rod sticking out the back and it may contact the frame or exhaust.  Just lop an inch or so off the end with a cutoff wheel.  May want to wait until after the alignment so you don't end up too short or too long.

Now just take it to your favorite mechanic for an alignment.  I know, that's like saying your favorite dentist, right? ;)  I've put about 5000 miles on these modified Mustang strut rods with new tires and everything is going great.  No evidence of metal fatigue, no noises, tires wearing good.  They do look pretty rusty after just a few years, maybe I should have painted them or something.  Oh well.  Keep those AMCs rolling!
Title: Re: New Strut Rods
Post by: Taylor on March 11, 2021, 05:29:49 PM
Excellent, I need to do the same repairs. Thanks for the detail.