Adjustment of torsion bars and reindexing are different things, yeah? I’m pretty sure yes but just wanted to double check
To answer your question, I have started by attaching a twelve year old article about Torsion Bars written by IH8MUD Member
@Gunney way back in 2011. It contains some good pictures and diagrams about how torsion bars work.
It maybe helpful and includes a description of torsion bar indexing. However, while the pictures are good, the article is about
Non-AHC Landcruisers.
Be very careful not to become confused. Ignore all the dimensions and measurements -- just follow the pictures -- these illustrate how the torsion bars work and illustrate in principle how torsion bars are indexed on any 100 series vehicle.
AHC Torsion Bars and how they work with the AHC system on LX470 and LC100 are different to the torsion bars on a conventional suspension, as is well-explained elsewhere by others.
In the case of your Torsion Bars and how they work on your vehicle fitted with AHC, consider the following:
If the vehicle is very heavy, then there may not be enough spring effect, not enough weight carried by torsion bars, too much weight carried by AHC system, Front AHC pressure will be too high, giving poor damping and a harsh, bumpy ride quality.
If the weight exceeds the capacity of the AHC system, then the vehicle may drop to LO height and stay there.
Torsion bar adjustment is the first step.
In the extreme, it can be that there is not enough adjustment thread at the torsion bar adjusters to transfer enough weight to the torsion bars to allow correct AHC pressures to be achieved.
This what happens when there is too much non-stock weight on the Front suspension and all the thread has been used on the torsion bar adjusters and no more adjustment is possible.
It is in this extreme case that "re-indexing" of the torsion bars is necessary on an AHC-equipped vehicle. Unlike a conventional suspension, adjusting torsion bars and indexing torsion bars
has nothing to do with regulating the 'ride height' of the vehicle.
"Re-indexing" means removing the torsion bars and re-assembling them in the vehicle after rotating one end by a few splines. This increases the 'pre-load' on the torsion bars and allows them to carry more load before running out of adjustment.
Torsion bar adjusment is an easy task which takes minutes.
Re-indexing torsion bars is a do-able DIY task but it is not trivial job.
This previous post may help:
It's not necessary to loosen control arms to adjust torsion bars. You do not need to remove the torsion bars either unless you need to re-index them if you have run out of thread on the adjusting bolt.
forum.ih8mud.com
