Jump to content


Photo

UC steering rack too wide?


  • Please log in to reply
28 replies to this topic

#1 hawk

hawk

    Forum Fixture

  • Members
  • PipPipPipPipPip
  • 1,974 posts
  • Name:steve
  • Location:Berwick, Melbourne
  • Car:UC Torana
  • Joined: 16-July 09

Posted 21 April 2021 - 07:19 PM

Hi Guys,

Had my rack rebuilt this week with new rack ends

I used the only ones listed through resto country, the 287mm ones and their new tie rod ends.

When I bolted the rack up, even with the tie rod ends screwed all the way on, the wheels point outwards.

Where have I gone wrong?

The rest it fully rebuilt with all standard UC bits including steering arms.

Please help as this is quite frustrating.

#2 S pack

S pack

    Scrivet Counter

  • Members
  • PipPipPipPipPipPipPip
  • 13,713 posts
  • Name:Dave
  • Location:Luggage Point
  • Car:73 LJ
  • Joined: 25-January 10

Posted 21 April 2021 - 09:15 PM

Others have been there before you Steve. Something about UC have shorter tie rod ends than LH/LX.

http://www.gmh-toran...19-uc-tie-rods/

 

My guess is there are no suitable aftermarket chinese crap tie rod ends available to suit the UC.


Edited by S pack, 21 April 2021 - 09:18 PM.


#3 ls2lxhatch

ls2lxhatch

  • Members
  • PipPipPipPipPipPipPip
  • 5,289 posts
  • Location:Perth
  • Car:LX Hatch
  • Joined: 29-May 06

Posted 21 April 2021 - 09:22 PM

The ball on the factory rack arm sits in the socket on the rack. The aftermarket rack arms typically have the seat for the rack arm ball built in to the rack arm. This moves the pivot point of the rack arm out 10 - 20 mm on each side which will effect bump steer.

 

In my opinion the rack should be shortened so the factory rack arm pivot point is retained. The amount the rack needs to be shortened may fix your problem or you may have the wrong rack arms.

 

I am interested to hear what Axistr has to say on the subject. It would be worth sending him a PM.

 

Kingswood Country do a 275 mm and a 287 mm arm, both appear to have the built in ball seat.

 

https://www.kingswoo...m-long-l/RE7025

 

https://www.kingswoo...87mm-lon/RE7026


Edited by ls2lxhatch, 21 April 2021 - 09:24 PM.


#4 hawk

hawk

    Forum Fixture

  • Members
  • PipPipPipPipPip
  • 1,974 posts
  • Name:steve
  • Location:Berwick, Melbourne
  • Car:UC Torana
  • Joined: 16-July 09

Posted 21 April 2021 - 09:34 PM

Thanks for the info. The 275mm ends are listed as LH only.
As I'm on a budget and have just paid to rebuild the rack, I'm not too keen on having to pay to redo it all.
Will definitly be having a word with resto spares as it's pretty frustrating.

Apparently I can cut the thread further onto the rack ends and trim them by 15mm a side. Will this work?

#5 S pack

S pack

    Scrivet Counter

  • Members
  • PipPipPipPipPipPipPip
  • 13,713 posts
  • Name:Dave
  • Location:Luggage Point
  • Car:73 LJ
  • Joined: 25-January 10

Posted 21 April 2021 - 10:13 PM

Thanks for the info. The 275mm ends are listed as LH only.
As I'm on a budget and have just paid to rebuild the rack, I'm not too keen on having to pay to redo it all.
Will definitly be having a word with resto spares as it's pretty frustrating.

Apparently I can cut the thread further onto the rack ends and trim them by 15mm a side. Will this work?

Can't see why it wouldn't work as long as the section of the tie rod end to be threaded is the same OD as the threaded section.
 



#6 hawk

hawk

    Forum Fixture

  • Members
  • PipPipPipPipPip
  • 1,974 posts
  • Name:steve
  • Location:Berwick, Melbourne
  • Car:UC Torana
  • Joined: 16-July 09

Posted 22 April 2021 - 10:33 AM

Ok been doing a bit more reading and it seems like the 275mm rack ends could work but would need to delete the rack end lock nuts and tighten them fully onto rack.

Does that sounds right?

#7 ls2lxhatch

ls2lxhatch

  • Members
  • PipPipPipPipPipPipPip
  • 5,289 posts
  • Location:Perth
  • Car:LX Hatch
  • Joined: 29-May 06

Posted 22 April 2021 - 11:29 AM

No. Deleting the locks nuts is a bad idea.

 

It is unlikely it would cause any problems however I doubt it would pass rego inspection.



#8 hawk

hawk

    Forum Fixture

  • Members
  • PipPipPipPipPip
  • 1,974 posts
  • Name:steve
  • Location:Berwick, Melbourne
  • Car:UC Torana
  • Joined: 16-July 09

Posted 22 April 2021 - 12:09 PM

I am talking about the lock nuts menioned in the thread that Spack linked. Rodomo said he deleted them on an early model rack.

Lock nut is seen in the first pic below.

Attached File  rack.JPG.jpg   100.43K   3 downloads

Attached File  Screenshot_20210422-120713_Samsung Internet.jpg   75.56K   6 downloads

Edited by hawk, 22 April 2021 - 12:09 PM.


#9 ls2lxhatch

ls2lxhatch

  • Members
  • PipPipPipPipPipPipPip
  • 5,289 posts
  • Location:Perth
  • Car:LX Hatch
  • Joined: 29-May 06

Posted 22 April 2021 - 01:34 PM

My mistake, I thought you were talking about the tie rod lock nut.

 

You can remove the rack lock nut and use Loctite when attaching the arms to the rack.



#10 Bigfella237

Bigfella237

    Socially Distant

  • Members
  • PipPipPipPipPipPip
  • 3,705 posts
  • Name:Andrew
  • Location:Far South Coast of NSW
  • Car:(s) not as many as I'd like but more than I've got space for!
  • Joined: 31-October 14

Posted 22 April 2021 - 01:50 PM

If you remove the lock nut, how do you adjust the preload on the little socket cup in the end of the rack?



#11 hawk

hawk

    Forum Fixture

  • Members
  • PipPipPipPipPip
  • 1,974 posts
  • Name:steve
  • Location:Berwick, Melbourne
  • Car:UC Torana
  • Joined: 16-July 09

Posted 22 April 2021 - 02:40 PM

The aftermarket rack ends don't have adjustable preloaded. It's built in.

#12 76lxhatch

76lxhatch

    That was easy!

  • Members
  • PipPipPipPipPipPipPip
  • 6,860 posts
  • Location:Unzud
  • Car:SS
  • Joined: 04-August 08
Garage View Garage

Posted 22 April 2021 - 04:14 PM

Removing those inner lock nuts would actually be preferable, the replacement tie rods are altering your bump steer by increasing the rack width so removing them brings the inner joint back closer to where it belongs.



#13 hawk

hawk

    Forum Fixture

  • Members
  • PipPipPipPipPip
  • 1,974 posts
  • Name:steve
  • Location:Berwick, Melbourne
  • Car:UC Torana
  • Joined: 16-July 09

Posted 22 April 2021 - 04:17 PM

Doesn't matter now, rack is stuck it the car as the new cotter pin for the steering uni won't come out. so it can sit there and rot. Over it.

#14 76lxhatch

76lxhatch

    That was easy!

  • Members
  • PipPipPipPipPipPipPip
  • 6,860 posts
  • Location:Unzud
  • Car:SS
  • Joined: 04-August 08
Garage View Garage

Posted 22 April 2021 - 04:27 PM

Just remove the tie rods with it in the car...?



#15 hawk

hawk

    Forum Fixture

  • Members
  • PipPipPipPipPip
  • 1,974 posts
  • Name:steve
  • Location:Berwick, Melbourne
  • Car:UC Torana
  • Joined: 16-July 09

Posted 22 April 2021 - 05:21 PM

Motor and box are back out, big hammer and a well bent cotter pin later, the rack is back out.

Measured up against the standard rack and its at least 50mm too wide.

Calmed down a bit now. So by the looks of it I will have to get the centre of the rack threaded back to the step to still retain a locknut and move the rack end in 10mm each side or until it bottoms out on the thread.

I will also need the 275mm rack ends instead of the 287mm ones.

But even doing this I'm doubtful that the rack will be narrow enough to align properly.

Attached Files



#16 76lxhatch

76lxhatch

    That was easy!

  • Members
  • PipPipPipPipPipPipPip
  • 6,860 posts
  • Location:Unzud
  • Car:SS
  • Joined: 04-August 08
Garage View Garage

Posted 22 April 2021 - 05:35 PM

I'd be digging out the originals, with the adjustable ball setup unless they're really buggered they're usually perfectly good to re-use. You really want to ensure that the inner joint position has not been altered, not sure how the captive ball design can achieve this without trimming a few mm off the rack?



#17 hawk

hawk

    Forum Fixture

  • Members
  • PipPipPipPipPip
  • 1,974 posts
  • Name:steve
  • Location:Berwick, Melbourne
  • Car:UC Torana
  • Joined: 16-July 09

Posted 22 April 2021 - 05:44 PM

The guy who rebuilt the rack has likely already binned them and the ones on my parts rack are rusted and siezed.

I'd rather not buy a third rack then have to rebuild it as well.

The most frustrating part is that this is the only thing I have paid someone else to do and its the only thing that has had major issues.

#18 axistr

axistr

    Forum Fixture

  • Members
  • PipPipPipPipPip
  • 1,009 posts
  • Location:North west sydney
  • Joined: 19-November 05
Garage View Garage

Posted 22 April 2021 - 05:53 PM

Do a quick check to see how the rack ends sit in relation to the best bump steer curve. First centre the steering rack in the straight ahead position. Then pull back the dust boots and get a straight edge holding it up in line with the centre of the top control arm pivot mount bar and the centre of the lower control arm inner mount bolt. (see photo) If the centre of the inner rack end ball align centred both sides its good.

 

Attached File  DSC_0121_21270.JPG   78.58K   3 downloads

 

The new tie rod ends should be around the 180-190mm total in length with out the outer tie rod ends fitted. I got 320mm from the centre of the inner rack end joint to the centre of the outer tie rod end stud.

 

If the rack end inner joints are close as explained check above, I would run a dye nut down the outer tie rod bar threads adding a further 15-20mm and cut the same amount off the end with a cutting disc. You can do this in the car with no need to remove the rack. Are the threaded ends metric or imperial ?  

 

Attached File  DSC_0123_11271.JPG   140.01K   2 downloads

 

If you really want to check for bump steer even further, measure from the centre of the inner rack ball joint to the centre of the lower control arm inner mount bolt (looking from the front) record measurement. Then measure from the centre of the lower control arm outer ball joint and centre of the outer tie rod end ball. The difference in height is how far out holden designed the front steering geometry. Unfortunately you can't move the manual rack around to reduce the difference in height, but this is where most of the bump steer is generated. The UC steering arms improved the curve due to an increased step down towards the outer tie rod end reducing the difference in the inner and outer rack ends heights. Adding lots of positive caster pulls the steering arms up making this difference in angles worse. 

 

Just for the sake of perfection, if the steering rack inner rack end ball centres were at the same height and centred with the lower inner control arm mount bolts, and the lower ball joints were inline with the outer tie rod end ball centres there would be next to no change in the bump steer curve. Maybe it was down to packaging or plain ignorance, but I would have thought the Holden engineers could have designed a better steering geometry, this is the very basics in steering design. 

 

 

 

      



#19 hawk

hawk

    Forum Fixture

  • Members
  • PipPipPipPipPip
  • 1,974 posts
  • Name:steve
  • Location:Berwick, Melbourne
  • Car:UC Torana
  • Joined: 16-July 09

Posted 22 April 2021 - 06:10 PM

Thanks Axistr, it will be Saturday before I can get some measurements as tomorrow is going to be a long day. with the motor and box removed again it will be a bit easier.

The photo below shows the rack end where it can be threaded a bit further although this section is a slightly smaller O.D than the thread. therefore thread depth may be an issue.

Or is the difference negligible?

Attached File  20210422_054422.jpg   103.84K   3 downloads

#20 76lxhatch

76lxhatch

    That was easy!

  • Members
  • PipPipPipPipPipPipPip
  • 6,860 posts
  • Location:Unzud
  • Car:SS
  • Joined: 04-August 08
Garage View Garage

Posted 22 April 2021 - 06:12 PM

That first check is an OK approximation, I wouldn't get too bogged down with the second as its hard to get sensible numbers with the varying positions of all the joints both inner and outer.

 

My biggest concern would be if the tie rods have added 10mm per side to the inner joint position then your rack is 20mm wider - the LX to UC change was only 10mm overall and had a significant effect on bump steer. Hopefully that's not the case and they screw on further than the image above appears to show (or can be made to without too much hassle).

 

You can trim the outer ends as much as you like provided there is ample thread engagement in the tie rod end. I'd aim for at least twice the diameter so around 1 1/8"/28mm (the tie rods are 9/16" UNF from memory), plus room for the lock nut of course.

 

Sounds like you need to have a go at the guy who "rebuilt" the rack for you as he obviously didn't really know what he's doing? Ditching serviceable parts for disposable and not paying attention to even the most basic measurements...

 

edit: those tie rods can't really be threaded further - the threads have been rolled which raises them from the machine surface, cutting them with a die will make them too shallow. But you may still have room to shorten a bit before you run out of thread.


Edited by 76lxhatch, 22 April 2021 - 06:13 PM.


#21 hawk

hawk

    Forum Fixture

  • Members
  • PipPipPipPipPip
  • 1,974 posts
  • Name:steve
  • Location:Berwick, Melbourne
  • Car:UC Torana
  • Joined: 16-July 09

Posted 22 April 2021 - 06:35 PM

I had removed the old rack ends myself and supplied the new ones.Not really his fault as he used what I asked although he is also a torana owner so expected a bit better.

The photo here shows full engagement of the tie rod end on the rack end. Only a thread or two left at most to shorten it.



Will deffinitly have to get the 275mn rack ends and cut the thread further into the rack. hopefully it then screws on far enough with a lock nut still being usable.Attached File  FB_IMG_1618998033029.jpg   53.52K   8 downloads

#22 ls2lxhatch

ls2lxhatch

  • Members
  • PipPipPipPipPipPipPip
  • 5,289 posts
  • Location:Perth
  • Car:LX Hatch
  • Joined: 29-May 06

Posted 22 April 2021 - 07:16 PM

You should be able to trim 5-10 mm from the tie rod end so it will screw further onto the rack arm/tie rod.


Edited by ls2lxhatch, 22 April 2021 - 07:19 PM.


#23 hawk

hawk

    Forum Fixture

  • Members
  • PipPipPipPipPip
  • 1,974 posts
  • Name:steve
  • Location:Berwick, Melbourne
  • Car:UC Torana
  • Joined: 16-July 09

Posted 22 April 2021 - 07:53 PM

Took some measurements against my parts rack and its quite evident its all in the pivot point being out further the arms are within a couple of mm of each other.

The pictures speak for themselves. I'll drill out the dowels and remove the ends and lock nuts and see how much more they screw on. Might get away with only lock nut removal. Although will Loctite be enough to hold it on?

Attached File  FB_IMG_1619084900500.jpg   71K   1 downloads

Attached File  FB_IMG_1619084897527.jpg   61.46K   1 downloads

Attached File  FB_IMG_1619084903805.jpg   57.03K   2 downloads

Attached File  FB_IMG_1619084906624.jpg   44.47K   2 downloads

#24 76lxhatch

76lxhatch

    That was easy!

  • Members
  • PipPipPipPipPipPipPip
  • 6,860 posts
  • Location:Unzud
  • Car:SS
  • Joined: 04-August 08
Garage View Garage

Posted 22 April 2021 - 08:15 PM

The originals don't crank up tight so need the lock nut to ensure correct preload on the ball joint, but the captive one can just bottom out so yeah the Loctite should be fine. Hopefully you don't have to butcher the rack itself to get it to screw on far enough.

 

In the photos above you're measuring from the lock nut which could be in a different spot on the thread, the measurement you want to compare is centre to centre between the two inner joints.



#25 S pack

S pack

    Scrivet Counter

  • Members
  • PipPipPipPipPipPipPip
  • 13,713 posts
  • Name:Dave
  • Location:Luggage Point
  • Car:73 LJ
  • Joined: 25-January 10

Posted 23 April 2021 - 07:48 AM

The guy who rebuilt the rack has likely already binned them.


Call him and ask. If your original tie rods ends were serviceable he may have kept them as spares.






0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users