AHC Rear Shock Shield Replacement (1 Viewer)

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In the process of fixing a 2007 LX which is mostly rust free except in a few spots. One of the spots is on the shield that covers the driver side rear shock. I'm a little nervous about replacing the entire shock due to fighting with the upper nut and AHC line. From what I hear it can be a series of unfortunate events when things break removing the AHC shock and I don't want to go there if I don't have to. I plan on riding the AHC until it fails and parts costs get too expensive. I don't want to summon it's demise just to fix this problem. Is there any way to replace just that sleeve without unbolting the top of the shock. Any other suggestions? Someone somewhere said they cut out the rust and used some pvc pipe in it's place but I can't for the life of me find that post again. If anyone has done this photos and details would be awesome!

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suprarx7nut

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In the process of fixing a 2007 LX which is mostly rust free except in a few spots. One of the spots is on the shield that covers the driver side rear shock. I'm a little nervous about replacing the entire shock due to fighting with the upper nut and AHC line. From what I hear it can be a series of unfortunate events when things break removing the AHC shock and I don't want to go there if I don't have to. I plan on riding the AHC until it fails and parts costs get too expensive. I don't want to summon it's demise just to fix this problem. Is there any way to replace just that sleeve without unbolting the top of the shock. Any other suggestions? Someone somewhere said they cut out the rust and used some pvc pipe in it's place but I can't for the life of me find that post again. If anyone has done this photos and details would be awesome!

View attachment 2545944
If that were me I would absolutely replace that entire shock. The shock is not that expensive. A complete AHC failure is.

That's got significant corrosion on the shock body beneath the shroud.

I have removed two sets of rear shocks on a non-AHC. I know AHC is harder, but I don't think it's *so* much harder that I would shy away from replacing that shock. Cutting a hole in the floor, while crazy to me, would be better than leaving that thing until it fails and leaves you stuck on the rear bumpstops cursing the AHC gods. :)
 
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likely in the salvage yard
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If that were me I would absolutely replace that entire shock. The shock is not that expensive. A complete AHC failure is.

That's got significant corrosion on the shock body beneath the shroud.

I have removed two sets of rear shocks on a non-AHC. I know AHC is harder, but I don't think it's *so* much harder that I would shy away from replacing that shock. Cutting a hole in the floor, while crazy to me, would be better than leaving that thing until it fails and leaves you stuck on the rear bumpstops cursing the AHC gods. :)
I picked off some more of the loose bits and was able to took up into the shock. The black you see behind the shroud is not a moving part from what I understand. The moving part up up inside slides into that component. The moving part is shiny and rust free. I'm not so concerned about the cost of a shock. My concern is getting the AHC line off:

Stolen from another post:
"The tricky part is removing the two 12mm head bolts on the top of the shocks that hold the AHC line on, especially on the left side. If those are rusted and you round them off, then it’s a real PITA because you have to cut and replace the line, for which you have to pull the tank IMO. One of the bolts is very hard to get to with the shock in place, but if you cut out the shock it is even harder to hold it in place. That’s when the AHC begins to start being expensive, because chances are that it’s also rusted and won’t come lose from the actuator, so you might have to replace that as well & the globe. Then that actuators feed might be rusted onto the 4 way valve as well, etc. etc.
The safest and easiest way IMO, if you really want to hang onto the AHC is to cut the floor panel & try a proper socket on the top bolts, but even then it’s not 100%.
So if those 2x12mm bolts won’t come off, then the reasonable thing to do is go with a conventional suspenion conversion IMO"

I don't mind paying for a shock but I do mind if it ends up being more than that...
 
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If your goal is to slow the rust and keep debris out:
1) wire brush the loose rust
2) treat the rust with chemprime
CHEMPRIME® Rust Converter and Inhibitor - https://dab-a-do.com/products/chemprime-rust-converter-and-inhibitor
3) apply rust inhibiting primer
4) wrap the with the shield with Fiber Fix Heat Wrap - Google Search - https://www.google.com/search?q=Fiber+Fix+Heat+Wrap&oq=Fiber+Fix+Heat+Wrap&aqs=chrome..69i57j69i60&sourceid=chrome&ie=UTF-8

5) paint the wrap black
I'm liking this at least as a temporary measure!
 

suprarx7nut

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I picked off some more of the loose bits and was able to took up into the shock. The black you see behind the shroud is not a moving part from what I understand. The moving part up up inside slides into that component. The moving part is shiny and rust free. I'm not so concerned about the cost of a shock. My concern is getting the AHC line off:

Stolen from another post:
"The tricky part is removing the two 12mm head bolts on the top of the shocks that hold the AHC line on, especially on the left side. If those are rusted and you round them off, then it’s a real PITA because you have to cut and replace the line, for which you have to pull the tank IMO. One of the bolts is very hard to get to with the shock in place, but if you cut out the shock it is even harder to hold it in place. That’s when the AHC begins to start being expensive, because chances are that it’s also rusted and won’t come lose from the actuator, so you might have to replace that as well & the globe. Then that actuators feed might be rusted onto the 4 way valve as well, etc. etc.
The safest and easiest way IMO, if you really want to hang onto the AHC is to cut the floor panel & try a proper socket on the top bolts, but even then it’s not 100%.
So if those 2x12mm bolts won’t come off, then the reasonable thing to do is go with a conventional suspenion conversion IMO"

I don't mind paying for a shock but I do mind if it ends up being more than that...
Perhaps a good approach is to delicately attempt to crack loose those 12mm fasteners. If you're able to crack them loose, go for the shock replacement. If you round off a bolt, keep the current shock.

Lots of folks freak out about the rear shocks - AHC or not. I was waiting for the difficulty to come and it never did. 🤷 Don't let the horror stories stop you from trying. It might be plenty doable and may save you from a very inconvenient failure.

My concern on a corrosion-laden shock like that for AHC would be that the top seal areas where the line connects to the shock may have damage near the seal. Once you get corrosion at the mating surface, that seal is toast and you're sitting on the bumpstops.

The shiny metal you see on the shaft is often chromed. That shaft is not something that fails by corrosion from anything I've seen. The shock will fail from sealing failures long before a spec of rust shows up on the shaft.
 
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Perhaps a good approach is to delicately attempt to crack loose those 12mm fasteners. If you're able to crack them loose, go for the shock replacement. If you round off a bolt, keep the current shock.

Lots of folks freak out about the rear shocks - AHC or not. I was waiting for the difficulty to come and it never did. 🤷 Don't let the horror stories stop you from trying. It might be plenty doable and may save you from a very inconvenient failure.

My concern on a corrosion-laden shock like that for AHC would be that the top seal areas where the line connects to the shock may have damage near the seal. Once you get corrosion at the mating surface, that seal is toast and you're sitting on the bumpstops.

The shiny metal you see on the shaft is often chromed. That shaft is not something that fails by corrosion from anything I've seen. The shock will fail from sealing failures long before a spec of rust shows up on the shaft.
I agree if I go at this I will try to crack it loose first. If it does not come I'll just let it be.

Thanks for the explanation for concern about failure. Under this thought process do you think I need to replace all my shocks? This is really the only one that has rust on the shroud. The other side has just a small area of surface rust. The isolated rust in certain spots is kinda strange on this truck seems weird that this one is toast but the rest look fine.
 

suprarx7nut

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I agree if I go at this I will try to crack it loose first. If it does not come I'll just let it be.

Thanks for the explanation for concern about failure. Under this thought process do you think I need to replace all my shocks? This is really the only one that has rust on the shroud. The other side has just a small area of surface rust. The isolated rust in certain spots is kinda strange on this truck seems weird that this one is toast but the rest look fine.
I wouldn't replace the others if they look fine. Many people have original AHC shocks last the life of the car. If they don't look damaged or leak, leave them be. Globes on the other hand, haha...
 
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I believe it was me who wrote that what freaked you out. I can tell you that looking at your picture my truck was more rusted than yours is, so I think you won't have issues with the 12mm bolts.
 
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Ok so looks like replacement is going on my to do list. How does one get the air out of the line downstream from the globe and in the shock itself on assembly? Those familiar with my last AHC adventure know this presented a big problem for me when I got air in my system in the past.
 
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In the FSM it just says bleed the system. Can someone who understands how this system works confirm that this will do it? Probably only need to bleed the driver rear where the work is being done?
 
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In the FSM it just says bleed the system. Can someone who understands how this system works confirm that this will do it? Probably only need to bleed the driver rear where the work is being done?
Pasted below is a link to an old post from @PADDO which may help. It relates to front shocks, not rear shocks, but the relevant hint is about flushing the actuator and filling the replacement shock as far as possible with AHC fluid prior to installation, so as to reduce air content. I have contemplated rear shock replacement for a long time, in my case mainly because the bushes are breaking up, not leaks, and I figure that if the rear shocks have to come out for any reason, then new shocks can go back in -- after a deep swallow about the cost! As you will have seen, there are many posts about rear shock replacement and there are a range of good ideas about how how to overcome the difficulties -- and I have seen enough to make me avoid this job as long as possible! Hope it goes well for you.

By the way, suggest bleed all round any time the AHC system is open, noting especially that when the AHC system is "OFF", the Gate Valves in the Control Valve Assembly are open and the Right and Left sides are connected.

See Post #11 at:

 

uHu

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Link to 2 threads :

Post in thread 'Bilstein Shock Compatability with AHC' Bilstein Shock Compatability with AHC - https://forum.ih8mud.com/threads/bilstein-shock-compatability-with-ahc.1229819/post-13444311


That fix has kept up for 6-7 years now.
 
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I like this as a temporary measure. The next time I can snag some lower milage ahc shocks for cheap I will do so. Untill then this will work. I skipped the steps for rust treatment because what is under there is really shot. Once I started grinding at it it started to crumble. Seems to be rusting from the inside. Seems strange that for the most part this truck has a little surface rust but these shock shrouds are garbage. Same with the other side thought I'd just do a little wire brush on the grinder and the thing started falling apart. Also in the meantime I'll periodicly hit the top side nuts with PB Blaster so that when the time comes I won't be totally miserable getting the top undone, maybe? That line looks a bit corroded but the nuts are not terribly rusty maybe I should just wait till the system fails and jump ship. I'm on original globes getting 9 grads.

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