9 replies to this topic

[Antelope Hatch]

Hi all,
I’m rebuilding a UC front end for my LX Hatch and have found cracks in both lower control arms. One has them around the ball joint and the other around the bushes. Judging by the Repco ball joint I’d say cracks could have been caused by a ham fisted home mechanic on these two, however I purchased another set of UC arms and had the ball joints pushed out by a suspension specialist and one of these cracked.

My question is one set better than the other in regards to LH-LX-UC? LH are apparently thicker but are they softer steel? Are the UC arms made of a stronger but also more brittle steel?

Cheers

[koalasprint]

Hi Ben, have you seen this page? It is very, very handy for checking and comparing Torana LH/LX/UC suspension parts,

http://ls2lxhatch.com/suspension.htm

Some people will prefer the thicker LH LCA 5/32 for strength. Others will prefer UC LCA 1/8 for the larger shocker hole and lighter suspended weight. Others will just run with what they have because the perceived advantages of changing are not cost effective.

 

Regards, Steve

[Shiney005]

Now that is a handy reference.

[Bigfella237]

Also all the lower control arms are interchangeable but you have to use the UC LCA bushes in a UC K-member, and the older style bushes in all the other LH & LX K-members.

 

From memory the outer bush diameter is the same but the size of the bolts changed with the UC (I think it was a change from imperial to metric or something stupid like that).

 

There was a thread around here somewhere with the different part numbers but I can't find it right now.

[jaselx]

There is no need to use UC bushes (Mackay A1202 Front & A1203 Rear) in a UC crossmember they are interchangable between all models. Infact the Mackay A1203 has been discontinued and superseded by A1121 - the standard non RTS bush. The arm attaching bolts interchange between all models LH,LX and UC. The only bolts that are different are the steering rack attachment bolts - UC are metric 12mm and LH/LX are 1/2".

[Bigfella237]

I'll have to try and find the thread, I'm pretty sure it was Datto that supplied the info... I recall there were photos of the difference but I must not have saved them.

[Bigfella237]

Apologies, it was @fuzzypumper who posted the details in this thread: http://www.gmh-toran...fferent-bushes/

 

The steering rack in the UC doesnt use rubber bushes, it was replaced with steel sleeves.

The differences in the other bushes are only in the lower arm bushes as far as I know.

LH & LX(early non RTS) Torana used standard bushes in the lower arms, forward and rear
Front and rear Lower arm: GM #2807098 (9942588) OEM McKay A1121 bubber bush


UC all (RTS Version II) used tuffer lower bushes front and rear. Also used on LX Sunbird 77 onwards only(RTS version I)
Front lower arm: GM #9946831 (92005741) OEM McKay A1202 bubber bush
Rear lower arm: GM #9946832 (92005742) OEM McKay A1203 bubber bush

 

 

Note the diameter of the bolt holes through the centre sleeve.

[Antelope Hatch]

Thank you all for replying, it's much appreciated.

 

koalasprint: Thank you for referencing that link, it is extremely helpful.  And thanks heaps to ls2lxhatch for creating that page.  The extra weight of LH arms was a concern of mine, but I'm going to give them a go, just to try something different.

 

Bigfella237:  Thanks for highlighting a concern in regards to bolts, however, I'm currently replating my bolts and they are the same for LX and UC, at least in the front suspension (I've stolen some bolts out of my LX donor car).  The bushes are different in respect to the centre tube, having a thicker wall, which will compress the rubber to make the bush stiffer, the internal diameter is the same.  I have spoken to Mackay Rubber directly, I must say they were very helpful replying to my emails in a matter of hours.

 

Once again, thanks to all!

 

Cheers,

Ben

[Bigfella237]

Thanks Ben, must be an optical illusion with that photo, I'll make a note!

[jaselx]

Just note that the Mackay (and GMH original) RTS Style bushes are installed flush with the arms. The non RTS bushes (Mackay A1121 & GMH 2807098(9942588)) sit proud of the surface roughly 5mm. - I am currently working on a 1976 LX Hatch with original front arms with original GMH bushes (LH style heavy arms). I also have the arms from my 1979 UC Torana with the original bushes still in place.