AHC TB Reindexing in Case of Failure... But What About Droop? (1 Viewer)

[GTV]

@GTV why not just learn/document the reindexing process and keep the tools/process printout in your car? I wouldn't do it ahead of time, but I do think knowing how to do so in the field is smart. Prepare for failure, but don't plan your life assuming it's all going to go wrong, haha.

I will learn the process by doing it, likely within the next day or two hence why I posed the question. I've got a par of OME reinforcement brackets to install (probably not needed for my use but they're cheap insurance) and my adjusters aren't equal from side to side so I figured I might as well balance them out and give them a couple clicks at the same time. I keep a 30mm socket on board and an assortment of metric tools, of course.

If the AHC gives up you are on bump stops and that's it. The stock torsion bars would have to be reindexed to unsafe levels to be able to even slightly lift the vehicle above the bump stops, if possible at all.

Maybe so, do you have a better idea?

The Strutmasters (AHC elimination) kit uses the stock AHC t-bars but specifies to re-clock them by 2 splines. I'm not recommending this kit, I'm just saying it can kinda support a stock weighted 100.

If somebody wanted to be ultra prepared, I'd say a 30mm socket and pre-installed Timbren or Wheeler Bumpstops front and rear would be part of the plan.

I think most common AHC failure is the AHC sensors. Three connectors with the "right" resistor that tricks the system into thinking all is fine and dandy would be cheap and helpful. I have not tested this theory though.

In my 20 yrs of ownership, I've had one AHC failure, 600 miles from home but I was able tinker with it and made it home without issue. It was an AHC sensor failure. When I got home, I disconnected the "bad" sensor and drove around town. Except for the blinking light, it was fine. The rear only has one sensor. So, if anything, a spare rear sensor would be most helpful.

I should perhaps test these theories further.... but maybe somebody else can!

The Strutmasters kit is a good point. "Kinda" supporting the weight is better than nothing at all.
Good idea on the aftermarket bump stops. I haven't researched them much but I imagine with the very slight sensor lift that I'm running (3/4") I'd be on the bumps all the time(?)
I keep 3 extra height sensors on board. I learned that lesson on day #1 of ownership. Mine was sky high with them connected and on the floor disconnected. Miserable ride quality either way and it wasted the front tires in 600 miles. Tricking the system with resistors is a clever idea...

 

[FxFormat]

I've decided to keep my AHC going, the new OEM shock should be here today and i'll get the other 3 as well and 4 new globes. As far as i know, the AHC on this truck is 100% original, and it lasted up to 230K miles before first hiccup so it's stout. I've taken it offroad several times, it's really not as weak as people make it out to be.

 

[Moridinbg]

Maybe so, do you have a better idea?

Not really... It's something that I have been considering often, as I have had both rear & front sensor failures and a pump failure.
The rear sensor was definitely the worst and it felt the most. If a single front sensor fails the system goes for something of a middle ground between it and the other front one. Pump failure means the car stays at whatever height it was last working and with the safe mode damping.
With rear sensor failure it either tries to drop as low as possible, which was not that terrible actually or it tries to lift it as much as possible which was increadibly and horribly stiff and bumpy.

I have since replaced the sensors and pump with a new rear and much less used front ones & pump - 100k miles instead of 280k on mine and hope for the best

 

[OEMGUY0720]

I found out that the shock itself has sprung a leak, looks to be from the valving/piston. I suspect the broken sway bar link might've attributed to the excess wheel travel and when i hit a bump it ruptured the shock. I don't have evidence but the same corner that the link broke, was the same corner the shock leaked, just days after the broken link. It's a good idea to have room in your TB to hoist the truck in case of a fail like mine, you'll still bounce around like a pogo stick but your wheel isn't gonna hit the fender like mine did.

If anyone has connections to some AHC shocks please let me know, i need one before saturday, i bought some aftermarket ones on amazon but will return that if i can't find an OEM ahc shock.

This is what I was thinking of as well, either the hydraulic line fitting at the top of the shock or the seal at the shaft/piston was the point of failure.

My next question is, do you have any pictures of your lower arm where the bumpstop makes contact? Any difference between the driver side and the passenger side bump stop marks on the lower arm? Reason for me asking is “if” there is a significant mark on the lower arm than the opposite side, that will tell me that the AHC shock may have been either under-pressured or over-pressured (that may have caused failure). That’ll be my telltale.

 

[suprarx7nut]

I've decided to keep my AHC going, the new OEM shock should be here today and i'll get the other 3 as well and 4 new globes. As far as i know, the AHC on this truck is 100% original, and it lasted up to 230K miles before first hiccup so it's stout. I've taken it offroad several times, it's really not as weak as people make it out to be.

243,000 miles on mine and only a globe replacement at ~160k. I added new rear springs with all my armor at ~220k. Aside form that, it's all original and no failures have occurred. Plenty of rough driving and trail obstacles since I bought it with ~215k.

 

[FxFormat]

This is what I was thinking of as well, either the hydraulic line fitting at the top of the shock or the seal at the shaft/piston was the point of failure.

My next question is, do you have any pictures of your lower arm where the bumpstop makes contact? Any difference between the driver side and the passenger side bump stop marks on the lower arm? Reason for me asking is “if” there is a significant mark on the lower arm than the opposite side, that will tell me that the AHC shock may have been either under-pressured or over-pressured (that may have caused failure). That’ll be my telltale.

I didn’t notice any difference between the two sides, the front shocks are hydraulically linked so if one side leak the other will slump down too and both are on bump stops. I got the truck almost 2 years ago and I had the AHC dialed in with correct neutral pressure and fluid flush and inspection. I thought if there was a leak it’ll be the rear passenger line first since the rear condensate and drip on that line, even southern trucks have that same rot. When the shock leaked first it shocked me hehe

Upon closer inspection, the sway bar link didn’t break off, some jerk off didn’t tighten the top nut enough and it popped off, I thought it was odd since my truck isn’t that rusty, but checked the passenger side and that nut was barely on. So a couple rubber cushions and a new nut and the sway bar is connected again

 

[OEMGUY0720]

I’m glad you’re refreshing and keeping your AHC system, still is the best setup than any aftermarket static suspension.

 

[FxFormat]

243,000 miles on mine and only a globe replacement at ~160k. I added new rear springs with all my armor at ~220k. Aside form that, it's all original and no failures have occurred. Plenty of rough driving and trail obstacles since I bought it with ~215k.

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Gorgeous exterior, but take a dust sweeper to that gauge cluster tho bro

 

[suprarx7nut]

Gorgeous exterior, but take a dust sweeper to that gauge cluster tho bro

It desperately needs a detail inside and out. Too busy building drawers and sleepers to get to it myself lately!

 

[GTV]

Ok, so I've got the torsion bars reindexed and the OME FK27 torsion bar reinforcement brackets in place. Very cheap insurance for only $22. My original plan was to give the drivers side 2-3 clicks and the passenger side 1-2 clicks to even them out but without the TB's completely removed it's difficult to count splines. So I wound both adjusters completely out and then back in a couple turns so they would just dangle there. I then pushed the back of the TB up with my knee, held the torsion bar up turned in the correct direction with one hand and lined up the TB control arm bracket with the holes and slid it home. So both sides are maxed out. I've got loads of threads to play with now and my front pressure is at 6.8.
Drivers side before:

After: