[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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