Apex rear control arms (transverse link) - NOOB

[AydinZ71]

Hi all!

 

So I got this pair of apex rear control arms I picked up used from another dude locally almost a year ago. Finally putting the suspension onto the race car, and honest have no idea what I’m doing. 
 

I have disassembled the old control arms so I am familiar with the OEM geometry and parts. With the apex units, I’m clueless! 

A few questions:

 

1) so no bushings on the strut side of the arm? Seems like it’s just a 5/8” bolt and washers.

2) what are the washers for? Do they come this way from apex?

3) any adjustment I should make before I put them on? How exactly do you adjust the track width on these guys? 
4) the link on the left is on a heim join and pivots up and down (in and out of the photo). Is that normal? Does it need to be bolted down further so it does not pivot? 
 

any help you can provide would be most appreciative!! 
 

 

[Ben280]

14 hours ago, AydinZ71 said:

1) so no bushings on the strut side of the arm? Seems like it’s just a 5/8” bolt and washers.

2) what are the washers for? Do they come this way from apex?

3) any adjustment I should make before I put them on? How exactly do you adjust the track width on these guys? 
4) the link on the left is on a heim join and pivots up and down (in and out of the photo). Is that normal? Does it need to be bolted down further so it does not pivot? 

 

1) Nope, no bushings, just that bolt and the washers. 

 

2) The washers are there to help adjust the wheel fore/aft in the wheel well, so you can get your strut to be vertical.

 

3) Track width is adjusted with the "toe link" piece, and that second heim joint. If you want to maximize your track width, adjust the rearward heim with the arms off the car, so you can match the length left to right a bit easier. 

 

4) Totally normal! No need to eliminate the up/down pivoting, it helps in the event of binding from not getting the strut dead perpendicular to where the bolt wants to be. 

[AydinZ71]

@Ben280 very helpful as always Ben!

 

so if I understand correctly, if I want to maximize track width I would run out the bolt/nut just below both (fore and aft) heim joints to the max (leave at least 5 threads engaged). I would check that the spindle bolt is parallel with the ground, which would be a neutral toe.

 

any recommendations on how to adjust the camber plate? If I understand correctly, I should be aiming for about 2 degrees if negative camber. The further out the control arm is, the further out the camber plate needs to go to maintain camber. So for maximum negative camber (just for the sake of argument), the camber plate would be shifted towards the centerline of the car, while the control arm would be adjusted to its maximum length. 

Edited April 28, 2021 by AydinZ71

[Ben280]

For track width, that rear heim joint and nut are the ones that need to be adjusted off the car. That "toe link" piece is just like a tie rod, and is designed to be adjusted on the car. You'd want to make sure the spindle pins are parallel to each other, and the centerline of the car. That would be neutral toe. For a heim joint, I THINK rule of thumb is 1.5x diameter inserted. So for 1/2" heim, you'd want 3/4" of threads engaged. 

 

Your understanding on the camber plate is correct and 2* of camber is a good starting spot. Personally, I'd set track width first and see where that puts you. There is a chance that you'll run out of adjustment on the camber plate, and need to narrow the track width to get camber where you want, but I think you'll be ok!

[Ben280]

[tube80z]

12 minutes ago, Ben280 said:

 

One thing I add to these are safety washers on the outside of the rod ends on the strut.  In case you need a link here you go, https://www.amazon.com/Safety-Washer-Prevent-Twelve-Through/dp/B07RB7RWMB.  I think if you search around you can get a better price but it's been years since I've bought any.

 

Cary

[AydinZ71]

30 minutes ago, tube80z said:

 

One thing I add to these are safety washers on the outside of the rod ends on the strut.  In case you need a link here you go, https://www.amazon.com/Safety-Washer-Prevent-Twelve-Through/dp/B07RB7RWMB.  I think if you search around you can get a better price but it's been years since I've bought any.

 

Cary

ahh thank you! That’s a great point. I see that if the heim joint fails, the hex head could just pull through. Il grab four  

[AydinZ71]

47 minutes ago, Ben280 said:

this is awesome! Thank you! Totally clear now. I disassembled the joints so I see what you mean by doing the rear one off-car (the joint needs to spin w/o the 5/8 bolt, since it’s not a turnbuckle). Il adjust the toe turnbuckle on the car  

 

il do some searching on ways to set my own alignment. @jhm suggested I could do this, since I’m the past I thought a shop was the only solution. 

[Ben280]

5 hours ago, AydinZ71 said:

il do some searching on ways to set my own alignment. @jhm suggested I could do this, since I’m the past I thought a shop was the only solution. 

Check out Longacre or Joes Racing, they make a lot of good tools for us homegamers to keep tabs on alignment. You can also do string alignments and things with plumb bobs, but I like having the right tool for the job! I will say, having the tools to do alignments at home or at the track is great, and it's pretty helpful to check, but I would recommend taking the car to a shop once or twice a year, to get the thing fully lined up. Particularly when you've done a full suspension rebuild, it's very helpful. They can address things like Caster, CAI, KPI and wheelbase which is very hard to measure in a garage. My car for example has a nasty habit of getting longer on one side than the other! 

[JMortensen]

18 hours ago, Ben280 said:

2) The washers are there to help adjust the wheel fore/aft in the wheel well, so you can get your strut to be vertical.

 

3) Track width is adjusted with the "toe link" piece, and that second heim joint. If you want to maximize your track width, adjust the rearward heim with the arms off the car, so you can match the length left to right a bit easier. 

2) Strut doesn't need to be vertical with this design as you mention in point 4. It can tilt and the freed up toe link allows the strut to compress without side loading. You can move the wheel back for aesthetics if you want, just not so far that the toe link or the rear link bottoms out as the suspension goes through its travel (I think you'd have to go really far for this to happen, but never tried it).

3) I did the math 15 years or more ago, but if you use the 1.5x the thread diameter I think that means you can move the heims joint out 5/16" before you run into the limit. There are a lot of people who run them further out than that, including me - my front LCAs were out probably 1/2" for a long time, might still be - but anyone doing this is ignoring the rule of thumb in that case. How big a deal that is is up to you.

[AydinZ71]

2 hours ago, JMortensen said:

2) Strut doesn't need to be vertical with this design as you mention in point 4. It can tilt and the freed up toe link allows the strut to compress without side loading. You can move the wheel back for aesthetics if you want, just not so far that the toe link or the rear link bottoms out as the suspension goes through its travel (I think you'd have to go really far for this to happen, but never tried it).

3) I did the math 15 years or more ago, but if you use the 1.5x the thread diameter I think that means you can move the heims joint out 5/16" before you run into the limit. There are a lot of people who run them further out than that, including me - my front LCAs were out probably 1/2" for a long time, might still be - but anyone doing this is ignoring the rule of thumb in that case. How big a deal that is is up to you.

 

Thanks! 1.5X diameter seems pretty conservative for a link that in theory should not be experiencing cantilevered bending forces. Both ends of the link should be free to move, but I suppose we are planning for the “upset” conditions like running over a blown tire. I agree with you. I checked for seven threads of engagement, but since the threads are fine I’m going to pull them off and measure what that comes out to in length. I might go with 1X or 1.2X the diameter (especially given it is fine threaded). The retaining/locking nut further supports the bolt and limits bending forces from reaching the engaged threads (keeping them in uniform tension).