Step By Step AHC Lift Help

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7schulz

7schulz

10 Year 15 Year
Joined
Dec 9, 2008
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Location
Zionsville, IN
I've searched AHC lift a dozen different ways and haven't found a step by step build thread of how to KEEP AHC and provide a small lift inch or 2 so when I go 285's it looks better.

1. I believe turn torsion bars. How many times?
2. Use 80 series stock rear springs(I have a set)? or just use a 30mm spacer
3. Adjust AHC brackets for proper ride height.
What else and how do I do all of this.

I want to make sure I don't hurt or overuse the AHC by tricking it to be in high mode all the time. I want it in neutral mode properly set up but lifted.

I'm looking for a step by step with detail so I can do this myself.

Thanks MUD you are the :censor:
 
7schulz said:
I've searched AHC lift a dozen different ways and haven't found a step by step build thread of how to KEEP AHC and provide a small lift inch or 2 so when I go 285's it looks better.

1. I believe turn torsion bars. How many times?
2. Use 80 series stock rear springs(I have a set)? or just use a 30mm spacer
3. Adjust AHC brackets for proper ride height.
What else and how do I do all of this.

I want to make sure I don't hurt or overuse the AHC by tricking it to be in high mode all the time. I want it in neutral mode properly set up but lifted.

I'm looking for a step by step with detail so I can do this myself.

Thanks MUD you are the :censor:
Click to expand...

Having done exactly what you are talking about doing, here's my 2 cents:

ANYTHING over 1" will result in a terrible ride, no matter how you 'tweak' it. At 1", mine rides like stock. At 1.5", it rode like my 40 does.

I changed out my AHC fluid, adjusted my AHC sensors up until I got the 1" height, then added a 30mm spring spacer in the rear, then put about two full turns on each torsion bar (in that order). And when you are done, get an alignment!
 
schulz, I think you just wrote the FAQ on this in that one post!

You'll want that $35 tech stream software to measure the AHC pressure.

Set-up the rear first. With 30mm spring spacer, you'll get 30mm of lift. If you choose to use the 80 series springs, you'll need a 10-15mm trim packer on one side since the spring height difference is more on an 80 than a 100.

Set the rear AHC pressure to whatever it says in the FSM or slightly lower (might preserve your AHC longer). The combination of springs and proper AHC pressure will determine the rear ride height.

If you are getting more than 2" of lift, then I'd consider different springs. You want a reasonable amount of down travel on those shocks.

Go to front AHC height sensors and adjust front ride height to approximately 1" lower than rear. You will turn off vehicle, adjust a little, then turn back on (maybe drive back on forth a few feet) and re-measure.

After height is correct, then adjust front AHC pressure by cranking T-bars. More cranking reduces AHC pressure.
 
The 80 springs have a higher spring rate than the AHC springs no matter how many miles on them. They'll provide more lift and allow higher weight capacity.

On the AHC equipped 100, springs suspend part of the weight and the AHC system suspends part of the weight. I suspect 80 springs would be too much spring for a stock weight 100.
 
For running 285/75/16 you don't need to lift the LX. They will fit without any problems.
 
hoser said:
schulz, I think you just wrote the FAQ on this in that one post!

You'll want that $35 tech stream software to measure the AHC pressure.

Set-up the rear first. With 30mm spring spacer, you'll get 30mm of lift. If you choose to use the 80 series springs, you'll need a 10-15mm trim packer on one side since the spring height difference is more on an 80 than a 100.

Set the rear AHC pressure to whatever it says in the FSM or slightly lower (might preserve your AHC longer). The combination of springs and proper AHC pressure will determine the rear ride height.

If you are getting more than 2" of lift, then I'd consider different springs. You want a reasonable amount of down travel on those shocks.

Go to front AHC height sensors and adjust front ride height to approximately 1" lower than rear. You will turn off vehicle, adjust a little, then turn back on (maybe drive back on forth a few feet) and re-measure.

After height is correct, then adjust front AHC pressure by cranking T-bars. More cranking reduces AHC pressure.
Click to expand...

Is it necessary to get a spacer for the shorter spring? Can't you just cut the longer spring by 10 or 15 mm?
 
It's generally not a good idea to cut springs. You can also get two left's or two right's and they are close enough in height. Or use the non-AHC 100 series springs.
 
I just got my 80 series springs in. They are from an LX 450, a 1996 With 166,000 miles. I bought them off of eBay. In good condition with no rest. The diameter of the 80 series springs versus the 100 series springs seems to be different. The 100 series springs being wider by about an inch. Do I need to worry about Them seating properly when I'm doing The install?

Also, is the install of the new 80 series springs just a traditional spring uninstall and then reinstall using spring compressors?

I also got a 30mm spacer from metal Tech, So I'll be playing with a combination of things within the next week.

On and off Road trip I took last weekend, I loaded up the rear of the car with about 200 pounds. A total of 800 pounds including the driver and passenger and separate items on the roof rack. I did over pressurize the system as it went into low during some trail riding and the car was not capable Of going Into high mode. Because of this, I decided to try the 80 series springs as well as/ or in place of the spacers, as I didn't think the spacers alone would make enough of a difference. My only concern is how the car will act differently with stock weight versus fully loaded for a trip. I'll try these and keep you posted.
 
I didn't notice a major difference in diameter when I installed them. But it's been 4-5 years so far on the 80 springs and it's been fine. I can't remember if I used a spring compressor or not but I want to say not.
 
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hoser said:
I didn't notice a major difference in diameter when I installed them. But it's been 4-5 years so far on the 80 springs and it's been fine. I can't remember if I used a spring compressor or not but I want to say not.
Click to expand...

Got it. I measured at 80 series springs versus some spacers I had laying around and I noticed about an inch difference in diameter and I thought sizing might be an issue.

I lifted the LC up until the wheel was up in here and the springs and they're pretty tight. I think I will have to use spring compressors.
 
hoser said:
The 80 springs have a higher spring rate than the AHC springs no matter how many miles on them. They'll provide more lift and allow higher weight capacity.

On the AHC equipped 100, springs suspend part of the weight and the AHC system suspends part of the weight. I suspect 80 springs would be too much spring for a stock weight 100.
Click to expand...

I know this is really just semantics, but I've seen a couple times in this thread how the 80 springs or spacers are providing lift and as I understand it, that's not what is actually happening and I'm just afraid expressing such will confuse the AHC uninitiated...

Doing nothing but replacing springs will net no lift whatsoever. Unless the springs are too stiff and actually supporting the entire weight of the vehicle by themselves. Otherwise, the 100 is going to settle back down to whatever height the rear sensor is set for. The springs or spacers just allow you to then adjust your height via the sensor while still staying within AHC pressure specs. For example, I added 10mm spacers, then actually lowered the rear by about 1/4" to further help my pressure reading on my tired stock springs.

Anyway, perhaps everyone on this thread already understands this, but it just stuck out as possibly confusing to me. I'm sure the end result of 80 series springs and adjusting pressures back to speck by adjusting the height sensor is indeed a lift for the rear, but it's actually the height sensor doing the lift and not the springs...

Maybe, I just tend to overthink things...sorry for the interruption, carry on...
 
codertimt said:
I know this is really just semantics, but I've seen a couple times in this thread how the 80 springs or spacers are providing lift and as I understand it, that's not what is actually happening and I'm just afraid expressing such will confuse the AHC uninitiated...

Doing nothing but replacing springs will net no lift whatsoever. Unless the springs are too stiff and actually supporting the entire weight of the vehicle by themselves. Otherwise, the 100 is going to settle back down to whatever height the rear sensor is set for. The springs or spacers just allow you to then adjust your height via the sensor while still staying within AHC pressure specs. For example, I added 10mm spacers, then actually lowered the rear by about 1/4" to further help my pressure reading on my tired stock springs.

Anyway, perhaps everyone on this thread already understands this, but it just stuck out as possibly confusing to me. I'm sure the end result of 80 series springs and adjusting pressures back to speck by adjusting the height sensor is indeed a lift for the rear, but it's actually the height sensor doing the lift and not the springs...

Maybe, I just tend to overthink things...sorry for the interruption, carry on...
Click to expand...

Thanks for the post and a great point. I'm glad you clarified as I thought I needed to adjust the height sensors in order to get it back to normal height. The reason I'm installing The 80 series springs is to give the rear more weight capability. On the trips I've been on, and on off road trails, with up to 200 pounds in the rear, the LC is not capable of staying getting into high mode and on the past couple of trips, it's gone into low mode because of over pressurization.

I'm hoping the springs and 30 mm spacers, or one or the other, will solve this problem.
 
BTW...here is a picture of the difference in diameter between the 80 series springs and the 30 mm spacers made for the 100 series springs. I hope it's not an issue when I try to install the springs on the LC.

image-133024192.webp
 
1meancruiser said:
I'm hoping the springs and 30 mm spacers, or one or the other, will solve this problem.
Click to expand...

ntsaint said:
I changed out my AHC fluid, adjusted my AHC sensors up until I got the 1" height, then added a 30mm spring spacer in the rear, then put about two full turns on each torsion bar (in that order). And when you are done, get an alignment!
Click to expand...

1meancruiser, JMHO I think the 80 spring with the 30mm spacer looks pretty unstable. I would do the 80 spring, or the stock spring with the spacer, not both.
 
Dinosaur said:
1meancruiser, JMHO I think the 80 spring with the 30mm spacer looks pretty unstable. I would do the 80 spring, or the stock spring with the spacer, not both.
Click to expand...

Point taken. I will probably do one or the other. However, I am concerned that the diameter of the 80 series spring is so much smaller than the hundred series spring. No one else seems to have had an issue so I think I should be okay but I'll probably figure it out once I get under there and pull The existing springs.
 
7schulz said:
Are you sure that's a rear spring? I dont remember the rear springs tapering like that.
Click to expand...

I assume it is because the seller sold it to me as right rear and left rear springs from an LX. And I have seen other 80s series springs with the taper.
 
Hoser, I have to say that those look a lot more like the 100 series AHC springs I have on my Land Cruiser currently, then 80 series springs?

If you are sure those are from an 80, then I've got to talk to the retailer. It may just be that the retailer on eBay sold me front springs from an 80 and marked them as rear???

image-3927015074.webp


image-2039694625.webp


image-3922811321.webp
 
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