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View Full Version : Opinion Needed on Thread Depth on Strut Rod


67TXStang
02-15-2015, 02:53 PM
I could use some help on the front suspension of my '67 Mustang.

I replaced the strut rod which connet the front frame to the lower control arm with an aftermarket piece using a heim joint at the front frame connection. There is an adjustment sleeve on the piece which is used for performing an alignment. The original setup came with a 10" sleeve.

I had the car aligned 4 years ago. The alignment shop adjusted them with vice grips which tore up the aluminum sleeves. I recently performed some work on the front end (Shelby drop) and need another alignment. So I decided I would replace the sleeves and then take it in (to a different place).

There was only about 3/16" of an inch of thread left at both ends of the strut rod assembly after the last alignment. This is not much adjustment. I decided to buy some 9" sleeves thinking losing a 1/2" of sleeve off each side would not be much and would give extra room for adjustment. Now I'm not sure. This is what is looks like with the 9" sleeve adjusted exactly to the same length as used by the last alignment.

http://2.bp.blogspot.com/-n_Td0TsAZ6o/VOEnGbMKsuI/AAAAAAAABGY/-Yx4zF1Gf5o/s1600/a20150215_162916.jpg

If the same amount of adjustment is needed as last time, the sleeve engages almost exactly 1/2" of the heim thread and opposite side thread. The heim and threaded rod at the other end is 5/8". This also leaves much more thread exposed. I'm not sure if I have enough thread engagement or not. Thoughts?

This is the old sleeve laying next to the new configuration.

http://4.bp.blogspot.com/-rcdajy1NLnk/VOEnIbUCiBI/AAAAAAAABGg/Z8hQ6m-zUSY/s1600/b20150215_163026.jpg

Chassisworks
02-16-2015, 10:12 AM
The general rule of thumb for minimum thread engagement is engagement is equal to the thickness of the shank. For example if it's a 3/4" shank rod-end then you need min. 3/4" of thread engagement. MINIMUM. That's in tension or compression only. Ideally, we would like to see an inch or more in my example. The simplest way to put it is you don't want more than a handful of threads exposed.

You don't need a very large adjustment range, you just need enough adjustment to fine tune the alignment. If the alignment is set correctly and there is a lot of thread showing, I would measure the exposed thread and then get a longer tube to make up most of the difference.

67TXStang
02-16-2015, 03:55 PM
Thank you for the response. I appreciate the help.