Adjustable Control Arms: Upper or Lower and Why?

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Dissent

Dissent

Questioning my life choices...
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10 Year
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Sep 27, 2012
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Location
Sweetwater, TN (East of Knoxville)
I may have to buy some adjustable control arms to fix a pinion angle issue after a 4" lift. I just installed new OEM bushings on all the control arms and the upper arms are a PITA to remove and install. Would adjustable lower arms correct the pinion angle? I'd rather take the opportunity to beef up the lowers than remove the uppers again.
 
Adjustable lowers would change pinion angle, but in the wrong direction. You need adjustable uppers because they actually have to get shorter to correct pinion angle. If you can weld you can make adjustable uppers for about $75



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I was just going to ask, if you shorten the uppers to rotate the pinion up, wouldn't lengthening the lowers rotate the pinion up and be the same net effect? I can't weld but I may have access to a fabricator but that introduces a whole new set of logistical issues. The Metal Tech adjustable lowers seem like a good upgrade and they seem to adjust to lengthen which would pitch the pinion up. I'll get my pinion/driveshaft angles measure tomorrow to confirm but I can already see my rear DC shaft isn't 90 degrees to the flange on the pinon end which is causing my vibration.
 
It looks like adjustable lowers require different modification than the uppers to protect the adjustment mechanism from damage. Is there an aftermarket weld in kit for the lowers, I didn't notice the price of the adjustable lowers at first. :eek:
 
Dissent said:
It looks like adjustable lowers require different modification than the uppers to protect the adjustment mechanism from damage. Is there an aftermarket weld in kit for the lowers, I didn't notice the price of the adjustable lowers at first. :eek:
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Rear LCA? Sure cut and sleeve.

Kit? Not sure, but seen many examples here.
 
I need to either shorten the upper or lengthen the lower about .375 to .500 inches according to what I've found through searching on this issue. I need to raise the pinion.
 
I bought slee's adjustable upper control arms. I replaced them one at a time.

I blocked all wheels and did it with the truck on the ground.

Once installed I adjusted the arms by counting the number of turns with the wrench.

I did this making small amount of turns and going back and forth between each arm.

I got the angle right the first go.

It took me about 45 minutes total.
 
nukegoat said:
Not sure what @jcardona1 is saying. Adjustable lowers are fine too. You can adjust adjustable links to be longer OR shorter than stock.
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In my mind it just seemed like mechanical forces wouldn't allow the pinion to rotate down with lower links and it would be easier with upper links. With that said, I think the easiest/cheapest route for an adjustable link is the uppers. But if you don't need them adjustable, just sleeving the lower and making them whatever length you need would be even easier.
 
maxamillion2345 said:
Maybe I'm tarded but aren't we all backwards here with the shortening and lengthening and rotating the pinion up?

You want to lengthen the uppers or shorten the lowers to raise your pinion. From the picture in the other thread you do want to raise your pinion don't you?
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You're right. I just saw this other thread. Didn't realize he had a rear DC shaft. I was thinking stock shaft, which requires you lower the pinion after a lift (shorter upper links). Opposed to a DC shaft, which requires the pinion be pointed at the TC (longer upper links).

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Dissent said:
I need to either shorten the upper or lengthen the lower about .375 to .500 inches according to what I've found through searching on this issue. I need to raise the pinion.
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You need to bring your pinion up ever so slightly, from the photos you posted. Adjustable uppers are you best bet and they need to be longer but not that much. I have the MetalTech adjustable uppers and lowers. These are HD but I don't think you will like the price. Iirc the uppers were $300.
 
Very nice! I was going to take this approach but the drivers side bolt on the UCA hit the LPSV valve and didn't want to come out, then the right side bolt hit the spring and I had to jockey the hell out of the axle with the floor jack to get the bolt removed/inserted. I think the UCA's were the worst thing I've had to deal with outside of the birf overhaul which is why I was leaning towards the LCA. The beefier LCA looks desirable too.
 
Do you mean longer uppers or lowers? I know it's confusing after I go back and forth on it. :)

I wonder if it would be easier/cheaper to go leave the pinion and UCA/LCA alone and go with a new OEM shaft? My splines were worn and seemed to be causing the GRRR sound in the rear with the front shaft removed. I picked up the DC for the rear because it was relatively cheap but now the pinion angle is an issue.....very frustrating.
 
Dissent said:
Do you mean longer uppers or lowers? I know it's confusing after I go back and forth on it. :)

I wonder if it would be easier/cheaper to go leave the pinion and UCA/LCA alone and go with a new OEM shaft? My splines were worn and seemed to be causing the GRRR sound in the rear with the front shaft removed. I picked up the DC for the rear because it was relatively cheap but now the pinion angle is an issue.....very frustrating.
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Longer uppers = pinion rotates up
Shorter uppers = pinion rotates down

If you put the stock shaft back in and still have vibes, you'll still need adjustable links to rotate the pinion down as shown in the above diagrams. Getting the bolt out from the uppers was a pain. I used the hi-lift on my rear bumper to decompress the springs a bit and let the bolt slide out.
 
Dissent said:
Very nice! I was going to take this approach but the drivers side bolt on the UCA hit the LPSV valve and didn't want to come out, then the right side bolt hit the spring and I had to jockey the hell out of the axle with the floor jack to get the bolt removed/inserted. I think the UCA's were the worst thing I've had to deal with outside of the birf overhaul which is why I was leaning towards the LCA. The beefier LCA looks desirable too.[/QUOTE

There are some sneaky ways to get the upper frame end bolts out pretty quickly. Rotate the spring, obviously, and grind the corner off of the LSVP bracket. Does not affect the action or structural integrity of the valve.
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If I go back into the UCA arena, I will gladly chop up that LSVP bracket. :mad: I didn't have it jacked enough to rotate the spring but that's a great idea! I may just pull the UCA and have them chopped and sleeved but I haven't seen a kit yet that's below Slee's at $275 which seems a smidge high. o_O
 
You can now install that bolt by the lspv from the other way and the same goes for the rear bolts. Been there won that game. Your into a Landcruiser, it's a real truck with heavy parts. One modification will only lead to another. It is inevitable. There is no way that a new standard drive shaft will work because your pinion angle is almost zero.
 
So the pinion needs to be adjusted either way then. I'm totally aware of the mods and what it leads to which is why I didn't go with the Slee 4" kit but ended up there anyway. :/

I saw your posts about the bolts, wasn't sure if there were frame index marks for those like the lateral rod which I learned about AFTER removing the nut. Doh!
 
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