AHC Bouncy & Stiff Front End

[NorCalFJ100]

@LndXrsr so my DS is lower, can I just turn that TB? Do I turn it counterclockwise or clockwise to raise it? I think honestly, my PS could be right at 19.75 - I could've been ever so slightly off in my measurements.

Do I check the side to side leveling by measuring again?

 

[97 AZ LC]

@LndXrsr so my DS is lower, can I just turn that TB? Do I turn it counterclockwise or clockwise to raise it?

Clockwise to raise, probably about 5-6 full turns to the inch.

 

[NorCalFJ100]

Clockwise to raise, probably about 5-6 full turns to the inch.

I just did 5 full turns and got probably 1/2" increase in height. However, my pressures dropped to 5.4 from the 6.1-6.2 they were previously.

 

[97 AZ LC]

You can go counter clockwise on the other side. Drive it around a bit to let it settle in.

 

[NorCalFJ100]

You can go counter clockwise on the other side. Drive it around a bit to let it settle in.

Okay. Just to be clear, I only raised/turned the DS TB. Should I have been turning the PS the same amount, just counterclockwise? Thank you for your help!!

 

[97 AZ LC]

Okay. Just to be clear, I only raised/turned the DS TB. Should I have been turning the PS the same amount, just counterclockwise? Thank you for your help!!

With an LX with AHC you adjust the TBs only to cross level from side to side. You can adjust either side. Clockwise will raise that side and lower the front pressure reading. Counter clockwise will lower that side and increase the front pressure reading. Your front pressure is now low so I would go counter clockwise on the passenger side to lower that side - assuming you are still too high on that side (relative to the driver's side). I have to admit I don't get too scientific with this stuff - if I'm level side to side and have a little rake front to back and it drives OK, I call it good. But if you want scientific there are some smart people and great threads available in the search function.

 

[NorCalFJ100]

@LndXrsr @97 AZ LC Thank you for your help! I went ahead and adjusted both sides equally. I did 8 clockwise turns on the PS and counterclockwise on the DS. The front end evened out completely. Right now I am at just shy of 19.5" on both sides. So probably need to adjust the height sensors now. Pressure is back at the 6.0 mark upfront, which is still a bit low. I ran out of daylight and called it good. Drives much better already!

 

[RPLX470]

Does the vehicle need to be running to do the T-bar adjustments... or off?

 

[trdcorolla]

Does the vehicle need to be running to do the T-bar adjustments... or off?

Off if your 100 has AHC.

 

[uHu]

Does the vehicle need to be running to do the T-bar adjustments... or off?

What do you mean?
For turning the adjuster bolts, it doesn't matter if its off or on or upside down.
For measuring the left/right lean it doesn't matter if it's running or not.
For measuring the AHC neutral pressure, it has to be running.

 

[LndXrsr]

Does the vehicle need to be running to do the T-bar adjustments... or off?

Anytime you're physically adjusting something, the car should be off for safety. As uHu mentions above, measuring pressures or checking the results of adjustments to the AHC sensors (changing ride height) needs to be done with the car running.

 

[RPLX470]

Thanks for all the replies.

It is a bit confusing because you do two things at once when you tighten/loosen the T-bars with the vehicle not running/off:
1 - Adjust side to side level.
2 - Adjust AHC pressures

To check AHC pressures, on Techstream, you must then turn the vehicle on/start engine.

Right?

 

[NorCalFJ100]

Thanks for all the replies.

It is a bit confusing because you do two things at once when you tighten/loosen the T-bars with the vehicle not running/off:
1 - Adjust side to side level.
2 - Adjust AHC pressures

To check AHC pressures, on Techstream, you must then turn the vehicle on/start engine.

Right?

I am by no means an expert here. The mudders here on this thread helped me out a great deal!

My approach here is to level side to side with the vehicle turned off. The AHC system can suddenly self level and could put you in danger. Once you have the cross leveling dialed in, you can check pressures with the truck on. Keep in mind you must check them after going from N-->L-->N

 

[suprarx7nut]

Thanks for all the replies.

It is a bit confusing because you do two things at once when you tighten/loosen the T-bars with the vehicle not running/off:
1 - Adjust side to side level.
2 - Adjust AHC pressures

To check AHC pressures, on Techstream, you must then turn the vehicle on/start engine.

Right?

I am by no means an expert here. The mudders here on this thread helped me out a great deal!

My approach here is to level side to side with the vehicle turned off. The AHC system can suddenly self level and could put you in danger. Once you have the cross leveling dialed in, you can check pressures with the truck on. Keep in mind you must check them after going from N-->L-->N

The exact order isn't critical, but here's my approach:

1. Measure neutral pressure.
2. Measure side to side lean.
3. If you're high on pressure (almost everyone is), use the torsion bar on the low side to crank it up to level the car.
4. Recheck pressure after moving the car a little (allowing suspension to move and settle).
5. Adjust torsion bars equally until pressure is correct.

 

[RPLX470]

Here is where I’m sitting at:

 

[NorCalFJ100]

Here is where I’m sitting at:

View attachment 2437994

Was that measured after going from N-->L-->N ?

 

[RPLX470]

Was that measured after going from N-->L-->N ?

Yes, a few times.

 

[NorCalFJ100]

Yes, a few times.

Mine was also low pressure. But after I cross leveled it got a little better for some reason. Still a bit low. I probably need to go tweak it a bit. The procedure was given to me earlier in this thread.

 

[fotomon]

I thought I'd update everyone. I would definitely do this differently given the opportunity. And I'm not going to know all the proper words so if you're an A type find some forgiveness. My typical shop didn't want to touch the AHC system, Toyota told me it was a goner. I went with converting the AHC system to a BASE system. That all went fairly well until I picked up the cruiser. The front was noticeably lower. I attempted a TB adjustment. They were fully extended. SO, I searched out a LC garage and was lucky enough to find a mechanic in Charlotte, NC. He had a used pair of BASE TBs and installed them, adjusted them, and leveled the cruiser. The ride is great and the truck is level. All is well that ends well.

If I had it to do over I would have searched out the garage earlier and given them the opportunity to fix the AHC. 278,000 miles and a year from going to my daughter. I think I'm good to go.