[TR] TR4 Investigating replacing the Armstrong lever shocks with telescopic rear shock conversions
Brian Kemp
bk13 at earthlink.net
Sun Dec 6 11:50:17 MST 2020
Will - I'm not as familiar with the solid axle of the TR4, so this may
or may not be relevant to your situation.
There are at least three styles of tube shock conversions for the TR6
and I assume the 4A. The one with three triangular brackets that go
through the body (likely the one you looked at from Moss), A bracket
that bolts to the body with no frame attachment, and a single plate
bracket that bolts to the lever shock mount.
Also watch for feedback on people that just get the lever shocks rebuilt
with a heavy duty rebuild. If I was starting over, that is probably
what I would do.
A sample of the three plate design at Moss is 670-128 - see
https://mossmotors.com/rear-tube-shock-conversion-kits - the Monroe
shock version for the 4A is available. They have an article at
http://www.mossmotoring.com/tr6-tube-shock-conversion/ It looks like a
sturdy design, but takes significant effort to install. Read the
instructions from their website.
I do not recommend the bracket that just bolts to the body without a
frame attachments.
I used the single plate version because it was much easier, but this
design leads to flexing of the frame cross member and cracking of the
frame, including mine. See the 0091, 2217, and 2218 images attached of
other people's cars discovered at a local club tech clinic. If you have
this design, I recommend you check the frame cross member regularly. If
you have the rear spring out for any reason, run the trailing arm
through its full range of motion and you will probably see the top of
the shock mount move front to rear.
After having my frame cracks welded, I built a new version of the single
plate design available from some vendors. I extended the top mount for
the shock back about two inches and added two braces. One is a length
of 1" angle iron that goes between the two shock mounts near the top of
the bracket, just below the body to side to side stability. The other
is the more important addition and goes from the top of the shock
bracket rearward to the frame at about a 45 deg angle. This one stops
any front to rear motion of the shock bracket. Unfortunately the car
isn't easily accessible right now and I can't find my pictures.
Below is an item I wrote 20 years ago or so. The 5-6025 kit is the
single plate design that in my opinion needs at least the added bracket
from the top of the shock mount to the frame.
Tube Shock Conversion Notes
Notes on my TR6 tube shock conversion:
> Would like to know if anybody on the list has any knowledge or
experience with
> the shock conversion kit that v.b. sells as part # 5-6025. It is
listed on
> page 11 in the summer catalog.......
I put similar brackets on my car. They are the easiest design to fit,
taking about 30 minutes to install. I purchased my brackets from
someone who made them for his car for $40. I bought the shocks from Pep
Boys for $12.95 each. The VB shocks must be pretty good to command the
$189 price tag. My driving can often be aggressive, especially at
autocross events (2nd place in class at the Moss festival and first
overall at Triumphest in 1998). The cheap shock seem to work fine for
me in the rear, though I may just not know any better. The PO put
Koni's on the front.
Installation made a tremendous improvement in my car, but that's because
my lever shocks were dead. I've heard lots of good things about the
heavy duty rebuilds to the lever shocks. Doing it again, I'd give this
serious thought.
Disadvantages of this design:
- When the car is in the air, the limit stop for the trailing arm travel
is the tube shock. I had a shock fail after only a year (exchanged for
free replacement). I think the other one may also need replacement, as
there's oil on the tube. This tension is transferred through the shock
to the bracket, at a slight angle, torquing the frame cross member that
holds the shocks and rear differential mounts. I mention this because I
just discovered several broken welds including both rear differential
mounts and the crossemember to frame connection near the right shock
mount. The car had the differential reinforcing brackets installed for
the DPO. I don't know if the shock conversion caused this, but I think
it aggravated the problem. (Any comments on this from others?)
- You are limited in tire width to 205 series tires, which may rub the
bracket if you have lots of camber or weak springs.
Safety considerations:
- The Gabrial shocks I purchased only have a single nut on each end of
the shock. The guy I got the brackets through had a shock come undone.
Your shocks should be double nutted. I used a nylocs because I had a
box of them, but any nut should work.
- Check the tires and brackets for rubbing. I have a little bit on the
right side recently, but nothing I'm concerned about. I can't see any
indication on the tire, just some rubber dust on the bracket. I run
205/65 tires and will adjust the camber on the right tire.
If your into welding, you can make your own brackets looking at the
picture. Drop me an e-mail and I'll look up the shock number again.
It's off 50's Studebakers and Cadillacs if I remember correctly.
The Moss kit is an effort to install. It has three triangular brackets
per side. One to the standard shock mount, the second inside the body by
the fuel tank, and the third in the wheel well area. The first step in
the instructions was to remove the fuel tank.
I'd always avoid a shock that only bolts to the body. The dampening
forces need to go to the frame.
Brian
On 12/6/2020 8:34 AM, Will Daehler wrote:
>
> When going over bumps in my TR4 I have quite a rattle from the right
> rear area of my car. I have poked around by the axle, and thought I
> have fixed the problem a couple of times. I have replaced the springs
> and refilled the Armstrong shocks. I have poked around. While looking
> through my Moss catalog I noticed the kits for replacing the Armstrong
> shocks with these brackets that you could mount shock absorbers to.
> But the kits are NLS. No Longer Supplied. I was wondering why the
> kits were discontinued. It could have been that they caused damage to
> the frame, or just didn’t work. I was hoping somebody had any
> first-hand knowledge or experience on this topic that they could
> discuss. I wonder if the racing group all have custom and proprietary
> set ups.
>
> Will Daehler
>
> 63 TR4
>
>
> ** triumphs at autox.team.net **
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