[TR] TR6 rear shock mount break

Sat Oct 11 11:05:20 MDT 2025

My tube set up mounts to the tail of the trailing arm and then to a L 
plate reinforcement to the body tub..Pretty solid.. 8 new bolts through 
3/8" plate. No chassis involvement. DaveP

Car came to me this way, so no clue about origins..

On 10/11/2025 9:17 AM, Tim Gaines wrote:
> I've been doing a lot of web surfing for videos and info on my problem 
> of the cracked rear cross member caused by replacing the original 
> lever shocks with a tube shock mount. I now see that the problem has 
> been widely discussed, probably here on Triumphs as well as on various 
> forums. I wish I had paid attention earlier. Inasmuch as both shock 
> setups bolt to the same mounting plate on the cross member, I had 
> difficulty understanding why the tube setup should do so much damage 
> compared to the stock lever shocks. Well, I just found an old thread 
> (Ken D, 2018) where one contributer (Walt P) explained a lot with 
> reference to Ken D's photo.
>
> "Ken was concerned about the angle of his lever shock link and 
> wondered if something was wrong. The consensus was that it was 
> probably normal unless the rear spring wasn't seated properly. Walt P 
> offered this great explanation.
>
> Notice the angles in the two lever-shock link-arm photos.
> Now, imagine that a standard Fixed Mounting of a shock absorber/damper 
> was used (between the frame & the TA) to replace the lever-shock & 
> link-arm.
> As the Trailing Arm pivoted through its full movement, would the Fixed 
> Mounted Shock Absorber be able to move- as the Link-Arm did?
> Or, would the Fixed Shock Absorber remain in place and rip apart the 
> relatively fragile frame that it was mounted on?
> Because that is exactly what happens when a Fixed Shock Absorber is 
> used to replace the Lever-Shock.
>
> Something to consider if the idea of a rear shock appeals to you.
>
> Some venders DO sell a replacement shock system that pivots with the 
> TA movement,
> but Others do not.
> Be aware of what you are seeing in the their ads."
>
> Well, I had already installed the tube shocks long before this 
> explanation came out, so I won't kick myself in the ass too hard. Some 
> of you may be interested in another aspect of the "fix" for the 
> cracking problem, namely putting lever shocks back on a new or 
> repaired cross member. I found a great "Elin Yakov's Rusty Beauties" 
> Youtube video that showed how to service the original lever shocks.
> https://www.youtube.com/watch?v=AxrBaaLEHpw
> I got out my own old pair, opened them up for the first time, and did 
> what the video showed. It turned out that Yakov's shocks were pretty 
> clean and in good shape. Mine looked bad inside, but I plowed ahead. 
> First, I noticed that each of mine had a grease zerk installed in the 
> cover, but Yakov's had a bolt (as do the new ones I have seen at 
> Moss). Even worse, mine had a load of grease in them and not much 
> else. Who knows who put those on! So maybe that is why my ride was so 
> bad, and that in turn was why I replaced them with the tubes. I wish I 
> had looked inside, but the idea of the tube conversion looked so 
> inviting back then. I soaked the units in degreaser overnight, after 
> drying filled the first one with motorcycle fork oil as per the video, 
> and it now offers great resistance to movement, just as Yakov's did. 
> In a few minutes I head to the garage to do the other one. I think I 
> am going to have two good lever shocks. Now I need to see if my cross 
> member can be removed without too much trouble (the left side is 
> actually unattached to the rail now) and repaired with some welded braces.
>
> Tim
>
> ------ Original Message ------
> From "Tim Gaines" <mtgaines at presby.edu>
> To "Triumphs" <triumphs at autox.team.net>
> Date 10/8/2025 4:37:00 PM
> Subject TR6 rear shock mount break
>
>> I have been hearing a slapping sound either under or behind me in the 
>> 1974 TR6 when I encounter even slightly rough pavement, so today I 
>> decided to sort it out. I thought I had found the problem quickly 
>> when I saw that the spare tire securing hook bolt had come loose, but 
>> no such luck. When I finally gave up on simple fixes and jacked up 
>> the left rear end and removed the tire, I saw that the cross member 
>> had cracked near where the after market shock mount adaptor bolts on. 
>> I did a quick check with the Moss parts catalog and that cross member 
>> is not available with them. So, I'm wondering if this shock mount 
>> replacement for the old lever shock (I installed a couple of decades 
>> ago) was a bad idea and put too much pressure on that frame member. 
>> It occurs to me that there may be some folks out there who have gone 
>> through this and can tell me just how a fix should be attempted.
>>
>> That crack shown in the photo seems to be only on the back side of 
>> the cross member. I have learned some welding skills in the last few 
>> years, and I have a mig welder, but I have never done anything under 
>> a car. I really don't like the proximity of the gas tank either. I am 
>> thinking that my local pro welder would be the guy to call on, but is 
>> this really something that can be fixed that way?
>>
>>
>>
>>
>>
>>
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