LX470 - Replaced AHC w/ LC suspension - VSC Lights and Questions about alignment (1 Viewer)

Joined
Jan 3, 2007
Messages
37
Location
Lawrenceville, GA
 
I just completed the replacement of the AHC system in my LX470 with LC shocks and springs today and have some questions. I hope someone who had done this can help me :

1. I have removed the two AHC fuses in the engine
compartment and two in the DS kick panel (#42 and
#48). Now I have got the "VSC OFF" and "VSC Trac
" lights. Can someone tell me if I have missed any other
fuses and how to get these lights to go off?

2. Now that my LX470 has LC suspension parts, the
question is what specs do you follow when doing a front-
end alignment? The FSM specs for front-end alignment
have many differences in term of vehicle height, camber,
toe-in, ... between the 2 vehicles - or does it really
matter?

3. I have yet to crank the t-bars to bring the front end up to
match the height of the rear. Are the front and rear
supposed to be equal on stock LC? If not, does anyone
have the numbers as to what they should be?


 
Joined
Feb 19, 2008
Messages
7,730
Location
Charleston
 
 
I just completed the replacement of the AHC system in my LX470 with LC shocks and springs today and have some questions. I hope someone who had done this can help me :

1. I have removed the two AHC fuses in the engine
compartment and two in the DS kick panel (#42 and
#48). Now I have got the "VSC OFF" and "VSC Trac
" lights. Can someone tell me if I have missed any other
fuses and how to get these lights to go off?

2. Now that my LX470 has LC suspension parts, the
question is what specs do you follow when doing a front-
end alignment? The FSM specs for front-end alignment
have many differences in term of vehicle height, camber,
toe-in, ... between the 2 vehicles - or does it really
matter?

3. I have yet to crank the t-bars to bring the front end up to
match the height of the rear. Are the front and rear
supposed to be equal on stock LC? If not, does anyone
have the numbers as to what they should be?



Read my post I put up yesterday....

1. Replace the 20a fuse in kickpanel for AHC IG, 2nd row from bottom, 2nd fuse from left. It is also the power source for your Steering Angle Sensor....so removing that fuse causes it to not work and therefore no VSC capability I am guessing or limited capability.

2. I would go for standard alignment required by factory....the setup should be the same no matter what as the springs and shocks were replaced but no geometry was changed....go with stock settings.

3. I measured rear from bottom of allow wheel to fender....then set the front to be 1/2 inch lower. That will account for full fuel tanks and loaded with gear or people in rear. They will settle over time so may have to do again...just remember to flex front end a few times in between twisting TBs for a more accurate reading...and do it with vehicle front wheels off the ground....then set back on ground to flex a few times and measure. THen lift back up if needed to adjust more.
 
Joined
Jan 3, 2007
Messages
37
Location
Lawrenceville, GA
 
Thanks for the suggestions.

1. I put fuse #42 (20amp) back and the VSC lights are gone, except that the AHC "off" light is now
blinking. I guess I can live with that because that's exactly what I did, disconnect the AHC
system!

2. I will go with standard (Lexus) alignment as you have suggested.

3. I have tried to crank my torsion bars and the front shocks don't feel like they are bottoming out
any more as they did right after the replacement and the ride is better. However, I am still
getting the forward rake, that is, the front is much lower than the rear.

From the center of the hub to the fender lip, the front height is currently at ~16 3/4 inch, whereas
the rear is at ~21 3/8". I turned the torsion bar bolts 4 revolutions, test drove and measured and
then 8 revolutions, test drove and measured. The front height did not change very much at all,
although the ride is getting better.

I think I am running out of threads on the torsion bars to crank it up another 3-4". Do you think I
may have to re-index the torsion bars to get more room to crank it up?
 
Joined
Feb 19, 2008
Messages
7,730
Location
Charleston
 
 
1. or can remove light from back of cluster...no more blinking OFF

2. Got mine done today....$54 at local shop...standard numbers are what you want.

3. 6 half turns only moved mine about 1/8 inch after i got load on them....I bet I did 20+ cranks to each side to get them within 1/2-3/4 inch of rear....and level from left to right. That being said mine went from totally untwisted to where they are in that period. Are you sure you indexed them correctly?

Did you buy a matched kit for TB, rear springs, shocks or put one together yourself? I find it hard to believe that you are at limit for adjustment unless they are wrong TBs or your rear springs are way too stiff for weight carrying.

If you look at adjustment bolt you turn you should see a shiny spot on it where it used to be hidden inside the shiny brass looking object inside of mount. If that shiny spot is below the brass looking fixture then you got room to go. If not then I wonder if you indexed them incorrectly during install?

Raising the front corners will also affect height of rear corners...as lift on one end or corner will also effect opposites on rear. So while you may have 3-4 inches to raise front....once you get the TB tight and start really cranking you will notice rear lower too as it shifts weight balance.

Ensure rear springs are right and then start cranking both sides in 6-8 half turns each and then lower to floor and jump on front bumper and push down to flex suspension a few times and measure again and notice relational measurements on all four corners. Be sure to do TB adjustment off the ground with no load on tires as well. Otherwise I would take to shop and let them check it for you.....

Originally with no load on TBs and rear springs changed...the front went up and down very easy...and had a good 4-6 inch rake. After some up and downs on the rack and making adjustments I can barely push down front end and make it move with my 250lbs on 6'2" frame.....but the measurements are dead on. IF you went with offroad suspension then you should not be able to move front end very much as it is stiffer feeling. I have a 185-200lb bumper plus a 100lb winc on front of mine and it still was a job towards end to get it to flex with just me pushing down on it.
 
Joined
Jan 3, 2007
Messages
37
Location
Lawrenceville, GA
 
I just replaced only the shocks and rear springs with LC stock parts, not the torsion bars. The torsion bars I am cranking are still the original on the LX470. So I have not indexed any thing yet. I was just wondering if that's what I will have to do when I run out of thread on the bolts and still need to raise the front end.

I raised the car and cranked the bolts. I have turned a total of 8 revolutions on the botls and for the first 4-5 full revolutions, the crank was easy and did not have much resistance, so I guess I have not gotten to the "real cranking" part for the control arms to raise the frame yet. I am still able to push down and move the front end now. I will try to crank up the remaining of the bolt this evening to see if it's going to raise the front any further.

It's good to know that the rear may go down as you raise the front because I don't need the rear to be that high anyway, just need to balance out both ends.
 
Joined
Feb 19, 2008
Messages
7,730
Location
Charleston
 
 
yeah if you only did 8 turns and it still moves easily when you push down...and not yet getting stiff when you try to crank the bolt...you got room to go. :) Remember to crank with the front wheels off the ground on jack stands or fully size shop lift.... Then lower to flex and measure....then repeat as necessary.

It will get difficult to crank unless you have a long cheater bar or something if doing by hand...some use impact wrench but we did them manually for more control.
 
Joined
Feb 10, 2005
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Location
in the nappy dugout
Brock has this pretty well covered. I've replaced and reindexed my TB in two of my LC's. It's a lot of 1/4 turns, lowering the front end then measuring. Make sure you are on a level surface as well and when you got them level then drive it around the block and remeasure. After you get the height where you want it then be sure and do a 4 wheel alignment.
 

uHu

Bridgeburner
Joined
Nov 27, 2005
Messages
2,032
Location
Oslo, Norway
 
 
Problem x2
The Torsion bars on the LX, or on the LC w AHC, are not strong enough to support the whole weight of the front end. Maybe you will be able to lift it, but the bars are just too thin for the job. The steel springs (coils & TBs) are just helper springs on an AHC equipped vehicle.
 
Joined
Jan 3, 2007
Messages
37
Location
Lawrenceville, GA
 
Problem x2
The Torsion bars on the LX, or on the LC w AHC, are not strong enough to support the whole weight of the front end. Maybe you will be able to lift it, but the bars are just too thin for the job. The steel springs (coils & TBs) are just helper springs on an AHC equipped vehicle.
Thanks for the info, guys. Do you happen to know how much thicker the LC's TBs compared to the LX's? I know there is a big difference between the AHC springs and stock LC springs.

Anyone with a good set of stock LC torsion bars gathering dusts in your garage?
 
Joined
Jan 3, 2007
Messages
37
Location
Lawrenceville, GA
 
Well I have cranked and maxed out the threads on the bolt and was able to raise only another 2". The front is still about 2.5" lower than the rear.

I will have to do some searches here to find out to re-index the torsion bars to see if I can raise the front higher.
 
Joined
Jan 3, 2011
Messages
314
Location
Dallas
 
Like these guys are saying, theres a lot of threads around here on the LX tbars....they're not strong enough to give you the lift you want to match the rear. Think about how much weight the AHC held. It was holding a good portion of the front end weight when it was in hi mode. And when in low mode the car was able to completely "compress" the TB's...new bars aren't that expensive.

Basically I don't think reindexing is going to do you a whole lot of good but then again I only know what I've read here when it comes to this.
 
Joined
Jan 9, 2006
Messages
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Location
North Alabama
I just replaced only the shocks and rear springs with LC stock parts, not the torsion bars. The torsion bars I am cranking are still the original on the LX470. <snip>
May be at risk of torsion bar failure under load, if you are using thinner AHC type torsion bars without AHC.

Those thinner torsion bars are twisted way beyond design intent, without the AHC supporting part of the load. Stress and strain will be way too high in bars in that condition. You are in uncharted territory.

PS - I wouldn't get underneath the vehicle with those overloaded t-bars, without additional support by jackstands. Sudden t-bar failure will not provide any warning.
 

2000UZJ

Where's My Hammer?
Joined
Oct 7, 2008
Messages
8,885
Location
Earth
 
 
Well I have cranked and maxed out the threads on the bolt and was able to raise only another 2". The front is still about 2.5" lower than the rear.

I will have to do some searches here to find out to re-index the torsion bars to see if I can raise the front higher.
you just need to get the proper torsion bars for the weight of your vehicle. AHC torsion bars are way to small. You can re-index all you want, the reality is that you are "twisting" something beyond it's specs...
 
Joined
Jan 3, 2007
Messages
37
Location
Lawrenceville, GA
 
Thanks for all the warnings. I might as well replace the torsion bars. Again, does anyone here have a good set of stock LC torsion bars ? If not, I will get new ones soon.

thanks everyone for your input on this.
 
Joined
Feb 19, 2008
Messages
7,730
Location
Charleston
 
 
order a set from OME or IronMan and save yourself more trouble....those are just too flexible. I know they are quite a bit smaller diameter than the aftermarket...a lot actually.
 
Joined
Jan 3, 2007
Messages
37
Location
Lawrenceville, GA
 
order a set from OME or IronMan and save yourself more trouble....those are just too flexible. I know they are quite a bit smaller diameter than the aftermarket...a lot actually.
Since I have already put in stock LC springs and shocks, I may not reap all the benefits of aftermarket torsion bars and stock LC bars may be good enough for me because I don't have any additional weights on the front end.

But can you tell me where I can go to find the costs of those aftermarket products? The prices may change my mind.
 
Joined
Jan 3, 2007
Messages
37
Location
Lawrenceville, GA
 
One other thing, do I need to get any thing else besides the torsion bars? New bolts, anchor arms, ....? or would I be able to re-use those from the LX470?
 

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