TR4/4A TR4A IRS Trailing Arms and Bushings

[KVH]

A few quick questions:

a) are the trailing arms adjustable with eccentric bolts like in the modern German cars?

b) are the trailing arms a hassle with all the bushings?

c) is there a wheel alignment issue or regular maintenance program with trailing arms?

 

[tdskip]

Hi Kent - hope you had a good weekend.

a) Not that I am way of, arms are shimmed but otherwise not much adjustment potential as stock. Richard Good makes an adjustable trailing arm kit for the TR6, which should work just fine on an TR4A IRS. I've installed the kit on my TR6 and it is a <span style="font-weight: bold">very</span> nice piece of kit. I'm planning on going this way o on the '68 IRS when that time comes.

b) Not really, you need to get the old ones out which is a pain but Bob's site covers this really well. (thanks Bob!)

https://tr6.danielsonfamily.org/TrailingArmBushings.htm

c) I wouldn't say "issue", but an alignment should be done. Make sure to count the shims and their orientation upon removal to get close, but a 4 wheel alignment is a good idea.

Does that help?

 

[M_Pied_Lourd]

Hi Kent,

One other thing that you need to look out for and one of the week points are the mounting studs in the aluminum trailing arm. They are easily stripped if you are not careful torquing them. There are some fixes however if you find any issue and these are covered on Bobby's website as well. Once done, you won't have to do them again for another 35 years.

The only thing I would suggest along with what Skip says is to invest in a set of Goodparts adjustable brackets. A good investment over the stock components.

Cheers,
M. Pied Lourd

 

[Randy Forbes]

A few quick questions:

<span style="font-weight: bold">a) are the trailing arms adjustable with eccentric bolts like in the modern German cars?</span>

b) are the trailing arms a hassle with all the bushings?

c) is there a wheel alignment issue or regular maintenance program with trailing arms?

That's a good one! Okay, I'm ready for the punchline... :wink:

Seriously though, there are kits for the BMW Z3 Series that adapts the modern BMW (5 Series) hdwr to allow adjusting the trailing arm suspension. The kits have to be welded in, and then you would have to have the car aligned properly.

This is the kit, as fitted to an M Coupe:

The Z3/M Coupe suspension, for comparison:

Laying out the kit(s) to weld the locating pads:

Original hole must be elongated to allow for eccentric adjustment bolt movement:

If you need details about these kits (available from Ireland Engineering) you can contact me via PM or E-mail.

 

[RJS]

On my list of TO DOs for the TR4A is to replace the trailing arm bushes. I don't know but, I suspect they are original rubber on there now. I plan to use the poly urethane replacements with the metal sleeves. I hear this can make a world of difference.

Even better if I can do this in-place - without removing the hubs, etc.

Bob