Original U Shackles

[Spacecrab]

Hi guys,

My 3B has the original style U Shackles and two seem to slowly unscrew themselves as I drive.

Every few months I catch them and tighten.

Does anyone have any tips to stop this? Is it why they originally had left hand & right hand thread?

Do you think upgrading to the M38 A1 style with the reinforcement bar would cure this?

Any tips welcome, thank you.

[Rus Curtis]

When I reference the Service Manual (SM), to refresh my memory - paragraph S-6 describes where those left-hand threads are.  I'd suggest to first verify those are in the right position. 

To paraphrase, they go in the front left and back right and DOWN only in the spring eye.  It's been a long while since I've had mine apart.  Once eliminated, right-handed threads were used without any problems that I've read about.

The later style I'm not familiar with and may have its own rare issues.

[oldtime]

Beyond what Rus mentions I will say that good rubber seals and tension are important.
Beyond sealing in grease, the rubber seal helps retain the bushing from backing out.
Proper bushing tension against the rubber seal is key.
The rubber needs be compressed about 1/8” by the bushing.
To achieve this you need exert some sideways hand pressure agaist the “u” type shackle just as the bushing threads begins to engage with the shackle threads.
I have never had a “back out” problem with proper shackle rubber seal to bushing tension.

[tow hook]

thanks, that's good info

[Spacecrab]

Thanks Rus & Oldtime, I'll check the 3b over on all counts.

Merry Christmas and Happy New Year too!