[AMC-List] Strut rods '70 and up, probably more than you wanted to know.

["John Elle" <johnelle@xxxxxxxxx>]

I have worked quite a bit with the '70 and up suspension, as far as
anything earlier I have pressed bushings etc. on parts brought over to
me. I have not actually repaired or restored a whole trunion suspension.
But, 
The '70 suspension which uses the same brakes etc. as the '69 is unique.
The steering stop is part of the steering knuckle and bracket assy. The
strut rod just positions the lower control arm. As such the end that
bolts on to the control arm is different than anything newer. The newer
front ends, the steering stop is part of the strut rod. I have had to
replace a '70 strut rod as rust damage to the threads of the adjustments
were so sever that the part was destroyed. I was able to take a '71 or
newer, most probably from a Hornet, Spirit or Concord and my handy  6"
bench grinder and grind down the end  that bolted onto the lower control
arm so that it looked like a '70 strut rod and it fit perfectly and got
the job done. Of course this means if you replace the drums or the
problem prone 4 piston Dunlop brakes with something newer you will loose
the steering stop. But if you also use the newer strut rod you should
get it back. The shape of the bend and the length appears to be the
same. This may differ if you are looking at a senior car as a donor. I
don't know that for sure as all of my Donor cars have been Hornets,
Concords and Spirits. I am still running the problem prone 4 piston
Dunlop brakes on my 1970 Javelin 'cause at the time they acted up I did
not know that I could install newer brakes on the car and spend a ton of
money buying replacement parts. I do however, have a set of 1980 Concord
brakes on the shelf that I will install if I have to. 
I have also installed the lower ball joint from a '70+ AMC car such as a
Javelin or small cars on 68/69 trunion Javelin/AMX lower control arms by
re-drilling the holes in the mounting plate. This was done on a drill
press and I did not have a real problem in drilling through the mounting
plate. The cost difference between the 68/69 lower ball joint and the
'70+ is significant. The early lower control arm was used as a pattern
to locate the holes in the ball joint mounting plate. 
There is a one piece strut bushing available for the 70+ strut rod. It
is shown in the '70 and '80 TSM that I have in the front suspension
section. I will be installing a set on at least one of my Hornets. I
personally prefer the 2 piece bushing as do most of the people that I
know.  However they came with the package of parts that I ordered from
Kanter, they are paid for and I will use them. 
Kanter delivered within 5 days from the order. They also included a new
catalog. I do not have any complaints about their service or the
products nor have I heard any from people that I know that have used
them. 
I have taken a serious look at the 70+ lower control arm. It is a really
cheesy looking design. In stripping parts cars out for donor pieces the
lower control arms will have some creative and serious damage to them. A
lot of the damage comes from advanced neglect. However the upper control
arms seem to get by that o.k. 
I suspect that most of the damage which is located at the bushing
mounting area is because the bushing only is fixed to one side of the
control arm. The other side has a small clearance. The adjustments of
the strut rod cause the lower control arm to pivot front to rear at the
bushing. If the bushing was to be fixed to both sides such as in welding
the bushing in there would be no give at that point and the control arm
would be forced to bend. This probably also adds excessive stress to the
strut rod bushing and mount causing problems there. There is also a
certain amount of give in the lower control arm rubber bushing. If you
replace it with a polyurethane piece which has no give, now you are once
again forcing all of the give to be at the control arm causing it to
bend. This excessive bending can cause the bushing mounting area to
crack in two and woggle out the clearance hole on the opposite side.
This now allows the bushing to fall out causing further damage. Neglect
with rubber going bad only aggravates the situation.  Of course all of
this time the strut rod bushing and mount is not overly happy as the
excessive bending at the lower control arm impacts the operation of the
strut rod. 
My gut feeling is that a significant portion of strut rod bushing
problems is caused by excessive wear and tear of the lower control arm
and or well intentioned  efforts to re-enforce the pivot point of the
lower control arm causing the arm it self to bend and probably
aggravated by the installation of polyurethane bushings.
If the lower control arm can not pivot as designed, all attempts to
adjust alignment using the adjustable strut rod could get a bit iffy too
leading to the alignment adjustments not being stable or being able to
get good adjustments. 
Now for the guy who wanted short sentences!
Use OEM replacement parts. 
Install them correctly 
Problems will be minimal 
'gnite!
John
 
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