AHC and alignment

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KYLandy

KYLandy

Joined
Oct 17, 2016
Threads
11
Messages
188
Location
Louisville, KY
I recently replaced a height sensor on the DS front of my AHC but I did not make any adjustments. The height on both sides is equal and is 19.75" on the nose. I have noticed a slight pull in the steering wheel that seems to be related to the crown of the road. On the interstate, as well as around town, if I am in the right hand lane it pulls to the right and if I am in the left hand lane it pulls to the left. I am wondering if this exaggerated pull is normal or possibly an alignment issue.

I did check the front and rear pressures in the AHC and the front is out of spec at 8.4, IIRC. Should I adjust the pressure before I take it in for an alignment or is it safe to do it afterwards? I will be getting new tires and it makes sense to do the alignment there. I have never asked them if they can do an alignment on an LC with AHC but I will call and ask today. I will make sure they turn off the AHC when they have it on the rack. Anything else I should take note of when it comes to an alignment?
 
I would get the pressure in check before the alignment. I would go about 3 full turns on the torsion bars. Check steering rack bushings, tie rod ends and tire pressure.
 
Why the delay in lowering front pressure? At 8.4 you'll need about 7 turns both sides to get it to a point where it can be further optimized for ride quality. But high front pressure (within reason) doesn't change ride height which is the important factor here. I guess you can have them turn off AHC but I've never bothered, just need to ensure the alignment is done at your normal driving height. Don't over think it, just ensure that on the off chance they want to adjust torsion bars to adjust ride height they are correctly clued in that this is not done for AHC vehicles. There's a few recent posts on AHC and alignment that cover the topic.
 
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The only delay is in understanding where the TB are and which thing to turn. I need to study this so I understand what I am doing. I have the procedures from the FSM for adjustment but they don't show the TB.

And time...
 
I read the Slee procedure for adjusting the TB. Do the wheels need to be off the ground?
 
Wheels on the ground, you can raise to H if you like to take a little pre load off but you're only looking at 60-70 ft lbs torque at N height. Locate the 30mm bolt heads facing downward out of the TB lever arm brackets. They are on either side and about mid body on the inside of the frame rails. Adjusting AHC torsion bars for pressure/cross level isn't the same as adjusting conventional LC bars for height/cross level. Follow the "adjusting torsion bars for pressure procedure" I believe I've sent you earlier.
 
PADDO said:
Wheels on the ground, you can raise to H if you like to take a little pre load off but you're only looking at 60-70 ft lbs torque at N height. Locate the 30mm bolt heads facing downward out of the TB lever arm brackets. They are on either side and about mid body on the inside of the frame rails. Adjusting AHC torsion bars for pressure/cross level isn't the same as adjusting conventional LC bars for height/cross level. Follow the "adjusting torsion bars for pressure procedure" I believe I've sent you earlier.
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Got it. Now I have to buy a 30 mm socket.

Does the pull sound like alignment or is this just the way the LC drives. It seems like wants pull to downside of the crown on the road. There's no irregular tire wear that I can see, but I've only had it for 2 months and the tires aren't new.
 
With a good alignment, .75 to 1in rake and decent tires correctly inflated these vehicles should track perfectly straight. If not then start looking at and eliminating the usual suspects.
 
I've been working on the TBs all day and I cannot get either one to break loose. Broke an 18" breaker bar in the process. It was a Great Neck so it was cheap. Using a 1/2" Duralast ratchet now with a 3 ft pipe on the end and I still can't budge either side on the front. Been soaking the adjuster with Kroil and letting them sit for an hour or two and still no luck. I even jacked up the passenger side to get the wheel off the ground and take some tension off the TB but nothing is moving. I guess I'll soak them one more time and try again next weekend. Mean old rust!!!
 
KYLandy said:
I've been working on the TBs all day and I cannot get either one to break loose. Broke an 18" breaker bar in the process. It was a Great Neck so it was cheap. Using a 1/2" Duralast ratchet now with a 3 ft pipe on the end and I still can't budge either side on the front. Been soaking the adjuster with Kroil and letting them sit for an hour or two and still no luck. I even jacked up the passenger side to get the wheel off the ground and take some tension off the TB but nothing is moving. I guess I'll soak them one more time and try again next weekend. Mean old rust!!!
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Buy yourself a nice impact gun and it will make quick work of that TB bolt.
 
DirtDawg said:
Buy yourself a nice impact gun and it will make quick work of that TB bolt.
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I would need a much bigger compressor and the impact would have to be rated at 500 ft/lbs of torque to do any good. My compressor is only rated for about 4.2 scfm and that's not near enough for a good impact gun. Might take it to my tire dealer and tell them to give me 7 turns CW. Probably cheaper than a new compressor and impact gun. One thing is for sure, I'm gonna be sore for the next few days. Ouch!
 
Julian Stead said:
I would buy a new bolt and swivel seat, you might strip the threads.
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Strip the threads on a 30mm bolt? I doubt that.

Mine was impossible to move at the beginning. After some penetrating oil, breaking it with an impact gun, followed by some anti seize, my adjuster bolt moves a lot easier now.
 
DirtDawg said:
Strip the threads on a 30mm bolt? I doubt that.

Mine was impossible to move at the beginning. After some penetrating oil, breaking it with an impact gun, followed by some anti seize, my adjuster bolt moves a lot easier now.
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I would normally agree, but the rust(corrosion) might of already done the damage.
 
Here's a photo of the PS adjuster. The rust is mostly on the threads but I have seen worse. It's clear that the TBs have never been adjusted.

IMG_5873.webp


I am not sure if it moved that much or I painted the marks in different spots.

Here's the casualty from the event:

IMG_5872.webp


I am beginning to look at impact guns now since I'm sure that every bolt on this rig is going to put up a fight so it might be worthwhile to get a decent one. I am also looking at an impact head adapter that turns an electric drill into an impact wrench. I have a really good Dewalt corded drill that's over 10 amps that might work.
 
HF has 3/4" breaker bars for ~$30, it's my go to tool. Just be carefully to let bolts cool after each hard turn, reduces risk of snapping off. The 3/4" is a brute and will easily break loose nuts & bolts. You'll need 3/4" to 1/2" reducer to use 1/2" socket's, impact are the stronger reducers & sockets.

Notes: Don't use ratchets to break loose, it runes them. Use 6 point sockets, to get good bit on head.
 
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As mentioned in my above post go ahead and get you a bottle of anti-seize. I've used it on every bolt I've pulled out of my cruiser, including my TB adjusters.

Plus you know if you ever have to dig back into something, the bolt won't put up a fight.
 
KYLandy said:
This is the socket I am using and it seems to be really tough:

Amazon.com: Lisle 39510 30mm Axle Nut Socket: Automotive
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That's an impact socket which is very strong, but it's a 12pt. You can used it, but be aware it may (not will) damage head of nut. 6pt are preferred as they contact all six sides flush, so are not likely round off heads. A TB bolt should not be all that bad, unless frozen from rust.
 
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