Ok gang - time to get these AHC rigs riding like new. I highly recommend this for anyone with a high mileage AHC vehicle. It has totally transformed how my LX rides and it's not a difficult job i've you've done basic suspension swaps in the past. I was apprehensive but nothing here is that complicated.
Backstory - My LX has ~245k miles. Always been a California vehicle. I've always kept my AHC system in pretty good spec. Cranked torsion bars to lower the front pressure after installing my ARB bumper. Installed rear King springs to lower rear pressure to account for my drawers and tent. Flushed the system with new fluid about a year ago.
In the past 4 months my car has still become borderline undriveable with how bouncy it is on the freeway, and how jarring it is over low speed / small bumps. Speed bumps almost put my head through the roof.
Yesterday I finally refreshed the whole system. Here's what I did:
- 4 new OEM globes/accumulators
- New AHC fluid
- New lower shock bushings for the front shocks (mine were completely toast)
- New front upper shock cushion bushings (mine were completely toast)
All in all I spent under $1,000 in parts - Amazing value for money in my mind given the results. This is cheaper than swapping to springs and coils and (in my opinion) a better and more comfortable solution for the way I use it.
If you're going to take the time to drain the whole system to do the globes, just remove the front shocks and change bushings while it's empty. It's not difficult and I guarantee all of your bushings are as bad as mine were at similar mileage. They were virtually nonexistent and it will make a huge difference.
On to the writeup! Apologies as I took absolutely no pictures. Use your imagination. I'll keep this fairly high level but happy to answer any questions.
DISCLAIMER- this process worked for me. I'm not a professional so do this at your own risk and use jack stands, eye protection etc. You're dealing with a big car, high pressure fluid. Lots of ways to hurt yourself. Don't be dumb.
Parts required (for a 2000 LX470)
- 2x new front globes (49141-60010)
- 2x new rear globes (49151-60010)
- 1x can of AHC fluid (08886-01805)
- 2x O rings for front shock hydraulic line (90301-11022) (this may be a different part number for different years. Double check for your year)
- 2x Backup plastic o ring for front shock hydraulic line (90562-12003) (this may be a different part number for different years. Double check for your year)
- 2x front lower shock bushings (90903-89016)
- 2x lower shock cushion (90948-01075)
- 2x upper shock cushion (90948-01076)
Tools required:
- The obvious full set of sockets / box wrenches / screw drivers / plyers etc that you would need for any suspension work
- A press to press in and out the lower shock bushings (or your own homemade threaded rod thing if you prefer)
- a 36mm fan clutch wrench to remove and install the globes. I've heard a strap wrench or a hammer and chisel works as well
- clear tubing like you would use for bleeding brakes
- Turkey baster or your preferred method of removing fluid from the reservoir
- small picks to remove and install the o rings in the hydraulic line
- a lot of shop towels. I managed to make quite a mess of AHC fluid.
The method:
1) Park the car on a flat surface, turn off the engine and I recommend disconnecting the battery so there is no way the pump can run and shoot fluid everywhere
2) IMPORTANT: Relieve all pressure in the AHC system and remove/drain as much fluid as you can. ALSO IMPORTANT: the ride height of the vehicle will drop significantly down to the bump stops when you release the pressure so make sure you are not under the car. I started by turkey basting all the fluid out of the reservoir. Then I went to each of the 5 bleed nipples and drained them into a drip pan until there was virtually nothing coming out. Maybe leave each one open for 2 minutes or so.
3) Remove whichever globe you want to start on (the order doesn't matter) with your preferred method. Being a West Coast truck, I had no rust to contend with and my 36mm fan clutch wrench spun them all off. This isn't as scary as it sounds. As long as there is no pressure in the system they will unthread and you'll lose a bit more fluid before they come off completely. Have a drain pan ready. They're also pretty heavy so don't let it squash your hand / foot / face.
4) Inspect your new globe and rub a bit of AHC fluid on the o ring. Thread on your new globe and tighten good and tight. I forget the exact torque spec but I went pretty tight.
5) Repeat steps 3 and 4 for all 4 globes. Congrats you're half way there. Even at this point it will ride much nicer, but we can do better. Time to replace the rubber in the front shocks.
6) Start with the passenger side as it's a bit easier. Jack up the front of the car and use jack stands to support it. I did one corner at a time. Remove the front wheel(s)
7) Remove the two 12mm bolts that attach the hydraulic line to the top of the shock. Once those are out you should be able to pop off the hydraulic fitting. You may need to gently pry it. Have a rag ready as more fluid may seep out.
NOTE - I've heard with rusty trucks, these bolts can break and be a pain. I can't help you much here but I guess if it looks crazy rusty maybe you're not destined for shock bushings and you should skip to step 18
8) Unbolt and remove the big lower shock bolt and nut. You may need a second jack to gently lift the hub if it doesn't come free
NOTE - This "shock" is still full of AHC fluid. If you compress the shock at all, expect it to shoot a high pressure stream of nasty AHC fluid out the top of the shock all over your engine bay / face / garage. Ask me how I know. I recommend putting a heavy rag over the top while you work here
9) Time to remove the top nut on the shock. The clearance here is tight and I couldn't get it from the wheel well side. What I did was bend the sheet metal slightly towards the outside of the car so I could get a long socket on it from the engine bay. A few extensions + an impact gun and it should come right off.
10) Now the shock should be free. You might have to compress it a bit to wiggle it out. I remind you to watch for the super soaker of fluid that will come out if you don't have a rag to stop it.
11) Once the shock is out, Use your desired method to press in and out the lower bushing. The top bushings should be fairly obvious to swap in and out. Check parts diagrams or look at the other side if you get lost.
12) While the shock is out, look up inside the hydraulic line that was attached to the top of the shock. You'll see a small o ring up in there. Below the o ring there is a plastic split washer. You will be replacing both of these with the parts listed above. This part is really finicky and honestly my least favorite part of the whole thing. I used a couple of small picks and a lot of swear words. It's not difficult, just finnicky. Double check parts diagrams, but the order (from below) goes plastic ring, rubber o ring. I'm not sure how necessary this part is. My original o ring was still in good shape and seemed pliable. Potentially not required but I'd hate to put it all back together and have it leak.
13) Reinstall the shock in the reverse order that you took it all out. Don't forget to reattach the hydraulic fitting up top. Torque to spec.
14) Repeat steps 6 - 13 on the driver side. Everything exactly the same, the only difference is I found the top shock nut to be more difficult to get to. I had to bend the sheet metal a little bit further, and also had to unbolt my fuel filter bracket to get access.
15) Put your wheels back on and put the car back on the ground.
15) Fill the AHC reservoir back up well above the max line. I filled it to the seam on the plastic reservoir to start. You're probably safe to put the whole 2.5L can in there.
16) Reconnect the battery and start the car. Let it think for a couple of minutes as the AHC pump refills the empty shocks and globes. Cycle to low, normal, high a few times. Have someone keep an eye on the reservoir so it doesn't go empty.
17) Put the car back to normal height and fill the reservoir to factory spec. Somewhere in between min and max
18) Do a quick bleed on the 5 AHC nipples to get any remaining air out. If you want to completely flush all the old fluid this would be a good time to do so but you may need more AHC fluid than just the one 2.5L can.
19) clean up all the AHC fluid you spilled and squirted everywhere.
20) Enjoy your new comfortable AHC vehicle
The result - the car has completely transformed. Night and day difference. Not only is it 100x more comfortable, but it feels more stable at speed. I hardly feel speed bumps or cracks in the road anymore even with my E load tires. I can't wait to get it off road as I expect it to soak up washboards pretty nicely.
I hope this is helpful for others who are wary of doing this. Happy to answer any questions.
Backstory - My LX has ~245k miles. Always been a California vehicle. I've always kept my AHC system in pretty good spec. Cranked torsion bars to lower the front pressure after installing my ARB bumper. Installed rear King springs to lower rear pressure to account for my drawers and tent. Flushed the system with new fluid about a year ago.
In the past 4 months my car has still become borderline undriveable with how bouncy it is on the freeway, and how jarring it is over low speed / small bumps. Speed bumps almost put my head through the roof.
Yesterday I finally refreshed the whole system. Here's what I did:
- 4 new OEM globes/accumulators
- New AHC fluid
- New lower shock bushings for the front shocks (mine were completely toast)
- New front upper shock cushion bushings (mine were completely toast)
All in all I spent under $1,000 in parts - Amazing value for money in my mind given the results. This is cheaper than swapping to springs and coils and (in my opinion) a better and more comfortable solution for the way I use it.
If you're going to take the time to drain the whole system to do the globes, just remove the front shocks and change bushings while it's empty. It's not difficult and I guarantee all of your bushings are as bad as mine were at similar mileage. They were virtually nonexistent and it will make a huge difference.
On to the writeup! Apologies as I took absolutely no pictures. Use your imagination. I'll keep this fairly high level but happy to answer any questions.
DISCLAIMER- this process worked for me. I'm not a professional so do this at your own risk and use jack stands, eye protection etc. You're dealing with a big car, high pressure fluid. Lots of ways to hurt yourself. Don't be dumb.
Parts required (for a 2000 LX470)
- 2x new front globes (49141-60010)
- 2x new rear globes (49151-60010)
- 1x can of AHC fluid (08886-01805)
- 2x O rings for front shock hydraulic line (90301-11022) (this may be a different part number for different years. Double check for your year)
- 2x Backup plastic o ring for front shock hydraulic line (90562-12003) (this may be a different part number for different years. Double check for your year)
- 2x front lower shock bushings (90903-89016)
- 2x lower shock cushion (90948-01075)
- 2x upper shock cushion (90948-01076)
Tools required:
- The obvious full set of sockets / box wrenches / screw drivers / plyers etc that you would need for any suspension work
- A press to press in and out the lower shock bushings (or your own homemade threaded rod thing if you prefer)
- a 36mm fan clutch wrench to remove and install the globes. I've heard a strap wrench or a hammer and chisel works as well
- clear tubing like you would use for bleeding brakes
- Turkey baster or your preferred method of removing fluid from the reservoir
- small picks to remove and install the o rings in the hydraulic line
- a lot of shop towels. I managed to make quite a mess of AHC fluid.
The method:
1) Park the car on a flat surface, turn off the engine and I recommend disconnecting the battery so there is no way the pump can run and shoot fluid everywhere
2) IMPORTANT: Relieve all pressure in the AHC system and remove/drain as much fluid as you can. ALSO IMPORTANT: the ride height of the vehicle will drop significantly down to the bump stops when you release the pressure so make sure you are not under the car. I started by turkey basting all the fluid out of the reservoir. Then I went to each of the 5 bleed nipples and drained them into a drip pan until there was virtually nothing coming out. Maybe leave each one open for 2 minutes or so.
3) Remove whichever globe you want to start on (the order doesn't matter) with your preferred method. Being a West Coast truck, I had no rust to contend with and my 36mm fan clutch wrench spun them all off. This isn't as scary as it sounds. As long as there is no pressure in the system they will unthread and you'll lose a bit more fluid before they come off completely. Have a drain pan ready. They're also pretty heavy so don't let it squash your hand / foot / face.
4) Inspect your new globe and rub a bit of AHC fluid on the o ring. Thread on your new globe and tighten good and tight. I forget the exact torque spec but I went pretty tight.
5) Repeat steps 3 and 4 for all 4 globes. Congrats you're half way there. Even at this point it will ride much nicer, but we can do better. Time to replace the rubber in the front shocks.
6) Start with the passenger side as it's a bit easier. Jack up the front of the car and use jack stands to support it. I did one corner at a time. Remove the front wheel(s)
7) Remove the two 12mm bolts that attach the hydraulic line to the top of the shock. Once those are out you should be able to pop off the hydraulic fitting. You may need to gently pry it. Have a rag ready as more fluid may seep out.
NOTE - I've heard with rusty trucks, these bolts can break and be a pain. I can't help you much here but I guess if it looks crazy rusty maybe you're not destined for shock bushings and you should skip to step 18
8) Unbolt and remove the big lower shock bolt and nut. You may need a second jack to gently lift the hub if it doesn't come free
NOTE - This "shock" is still full of AHC fluid. If you compress the shock at all, expect it to shoot a high pressure stream of nasty AHC fluid out the top of the shock all over your engine bay / face / garage. Ask me how I know. I recommend putting a heavy rag over the top while you work here
9) Time to remove the top nut on the shock. The clearance here is tight and I couldn't get it from the wheel well side. What I did was bend the sheet metal slightly towards the outside of the car so I could get a long socket on it from the engine bay. A few extensions + an impact gun and it should come right off.
10) Now the shock should be free. You might have to compress it a bit to wiggle it out. I remind you to watch for the super soaker of fluid that will come out if you don't have a rag to stop it.
11) Once the shock is out, Use your desired method to press in and out the lower bushing. The top bushings should be fairly obvious to swap in and out. Check parts diagrams or look at the other side if you get lost.
12) While the shock is out, look up inside the hydraulic line that was attached to the top of the shock. You'll see a small o ring up in there. Below the o ring there is a plastic split washer. You will be replacing both of these with the parts listed above. This part is really finicky and honestly my least favorite part of the whole thing. I used a couple of small picks and a lot of swear words. It's not difficult, just finnicky. Double check parts diagrams, but the order (from below) goes plastic ring, rubber o ring. I'm not sure how necessary this part is. My original o ring was still in good shape and seemed pliable. Potentially not required but I'd hate to put it all back together and have it leak.
13) Reinstall the shock in the reverse order that you took it all out. Don't forget to reattach the hydraulic fitting up top. Torque to spec.
14) Repeat steps 6 - 13 on the driver side. Everything exactly the same, the only difference is I found the top shock nut to be more difficult to get to. I had to bend the sheet metal a little bit further, and also had to unbolt my fuel filter bracket to get access.
15) Put your wheels back on and put the car back on the ground.
15) Fill the AHC reservoir back up well above the max line. I filled it to the seam on the plastic reservoir to start. You're probably safe to put the whole 2.5L can in there.
16) Reconnect the battery and start the car. Let it think for a couple of minutes as the AHC pump refills the empty shocks and globes. Cycle to low, normal, high a few times. Have someone keep an eye on the reservoir so it doesn't go empty.
17) Put the car back to normal height and fill the reservoir to factory spec. Somewhere in between min and max
18) Do a quick bleed on the 5 AHC nipples to get any remaining air out. If you want to completely flush all the old fluid this would be a good time to do so but you may need more AHC fluid than just the one 2.5L can.
19) clean up all the AHC fluid you spilled and squirted everywhere.
20) Enjoy your new comfortable AHC vehicle
The result - the car has completely transformed. Night and day difference. Not only is it 100x more comfortable, but it feels more stable at speed. I hardly feel speed bumps or cracks in the road anymore even with my E load tires. I can't wait to get it off road as I expect it to soak up washboards pretty nicely.
I hope this is helpful for others who are wary of doing this. Happy to answer any questions.
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