Front AHC shock replacement procedure?

[LXneewb]

I have searched and can only find folks upgrading their shocks to delete the AHC system. My AHC system works great. Neutral pressures are in spec, globes in good shape etc. I would like to replace the front shocks as I have 165K on them. Does anyone have the correct procedure to replace the front shocks with the AHC ? Thanks in advance!

 

[jsloden]

You never really need to replace the ahc shocks unless they're leaking. They aren't really shocks. They work more like hydraulic pistons. As long as you have the globes replaced you should be good. They are what really cause the poor ride quality.

 

[IndroCruise]

I have searched and can only find folks upgrading their shocks to delete the AHC system. My AHC system works great. Neutral pressures are in spec, globes in good shape etc. I would like to replace the front shocks as I have 165K on them. Does anyone have the correct procedure to replace the front shocks with the AHC ? Thanks in advance!

Unless the shocks are leaking badly (usually only happens as result of long term excessive AHC pressures), or unless the shocks are rusted out, suggest save your money and your effort!

On an AHC-equipped vehicle, the so-called 'shock absorbers' are merely very long life hydraulic struts used to hold the vehicle at the chosen height and respond to suspension movements on the road along with the 'globes'. AHC 'shock absorbers' do not act (and do not 'wear out') in the same way as conventional shock absorbers -- 165 k miles by itself is not a reason to replace them.

On these vehicles, the actual shock absorbing (damping) is done within the Damping Force Control Actuators (to which the 'globes' are attached).

Good damping requires the 'globes' to be in good condition.

AHC pressures (correct or otherwise) tell NOTHING about the condition of 'globes'.

The test of overall 'globe' condition requires observation of the level of fluid at the AHC Tank at "LO" height compared to the level at "HI" height, vehicle on level floor, no persons or loads on board, AHC pressures within FSM-specified range, etc. Then a difference of 14 graduations means 'globes' are as new; when this declines to 7 graduations, it means replace all four 'globes'.

If 'globes', heights, AHC pressures and AHC function are all good -- celebrate!!

 

[IndroCruise]

Unless the shocks are leaking badly (usually only happens as result of long term excessive AHC pressures), or unless the shocks are rusted out, suggest save your money and your effort!

On an AHC-equipped vehicle, the so-called 'shock absorbers' are merely very long life hydraulic struts used to hold the vehicle at the chosen height and respond to suspension movements on the road along with the 'globes'. AHC 'shock absorbers' do not act (and do not 'wear out') in the same way as conventional shock absorbers -- 165 k miles by itself is not a reason to replace them.

On these vehicles, the actual shock absorbing (damping) is done within the Damping Force Control Actuators (to which the 'globes' are attached).

Good damping requires the 'globes' to be in good condition.

AHC pressures (correct or otherwise) tell NOTHING about the condition of 'globes'.

The test of overall 'globe' condition requires observation of the level of fluid at the AHC Tank at "LO" height compared to the level at "HI" height, vehicle on level floor, no persons or loads on board, AHC pressures within FSM-specified range, etc. Then a difference of 14 graduations means 'globes' are as new; when this declines to 7 graduations, it means replace all four 'globes'.

If 'globes', heights, AHC pressures and AHC function are all good -- celebrate!!

Below are the Factory Service Manual (FSM) on-line references for the Front suspension with AHC on LC100. The LX470 has the same suspension and the same description applies for removal and re-installation of LX470 Front ‘shock absorbers’ – if that is necessary.

For the reasons given in the earlier posts in this thread, this would be an unusual job unless there is permanent damage from rust, or, excessive long term AHC pressures damaging the internal seals within the ‘shock absorbers’, causing major AHC fluid leaks. Minor leaks -- ‘sweating’ – of the ‘shock absorbers’ often can be fixed by correcting AHC pressures.

One cause for removal can be the need to replace the ‘shock absorber’ bushings. Unlike a vehicle with conventional suspension, in an AHC-equipped vehicle the so-called ‘shock absorbers’ are really hydraulic struts. Unlike conventional shock absorbers, these struts carry a share of the vehicle weight at all times (some say about 40% overall), with additional force added when the suspension is responding to vehicle and suspension movements when travelling.

Consequently, the ‘shock absorber’ bushings work much harder on an AHC-equipped vehicle than on bushings on non-weight bearing conventional shock absorbers. Degradation of bushings can be expected sooner with the AHC bushings.

It is extremely difficult to remove the lower bushing and press into place a new bushing without removing the ‘shock absorber’ from the vehicle. It is impossible to replace the upper cushion with the ‘shock absorber’ in place.

Removing a ‘shock absorber’ from an AHC-equipped vehicle means first de-pressurising the system by releasing AHC Fluid through the bleeder valves into containers, before detaching the AHC tubes at the top of the ‘shock absorber’. Front ‘shock absorber’ removal is not a particularly difficult task but be warned – even with great care, this can be a messy process, prepare groundsheets before starting, find something to block the tubes to avoid continually dripping fluid, keep rags handy, etc.

As a tip before re-installing, turn the ‘shock absorber’ upside down and use the stem to suck up AHC Fluid, like a syringe, to fill the ‘shock absorber’ as best possible. The idea is to have the least possible amount of air in the system to make bleeding of air from the system as easy as possible.

When starting the bleeding process after this amount of disruption of the AHC system, even after filling the AHC Tank it is possible that the AHC Pump may refuse to start because the Pressure Sensor senses low pressure (due to air in the system). In this case, the “Active Test” can be used to get the Pump started. Bleeding in this situation is not difficult but can require a lot of persistence to chase air out of the system – best to have plenty of AHC Fluid on hand!

Anyway, this is what the FSM has to say ….

LC100 Workshop Manual - https://lc100e.github.io/ (then follow tabs at the index panel on the LHS of the opening page)
+ Repair Manual
+ SUSPENSION AND AXLE
+ Front Shock Absorber (Independent Front Suspension)

Then see the following pages:
SA-112 – COMPONENTS
SA-113 – REMOVAL
SA-115 – INSPECTION
SA-116 – DISPOSAL
SA-117 – REPLACEMENT (including replacement of bushing)
SA-118 – INSTALLATION

 

[LXneewb]

Below are the Factory Service Manual (FSM) on-line references for the Front suspension with AHC on LC100. The LX470 has the same suspension and the same description applies for removal and re-installation of LX470 Front ‘shock absorbers’ – if that is necessary.

For the reasons given in the earlier posts in this thread, this would be an unusual job unless there is permanent damage from rust, or, excessive long term AHC pressures damaging the internal seals within the ‘shock absorbers’, causing major AHC fluid leaks. Minor leaks -- ‘sweating’ – of the ‘shock absorbers’ often can be fixed by correcting AHC pressures.

One cause for removal can be the need to replace the ‘shock absorber’ bushings. Unlike a vehicle with conventional suspension, in an AHC-equipped vehicle the so-called ‘shock absorbers’ are really hydraulic struts. Unlike conventional shock absorbers, these struts carry a share of the vehicle weight at all times (some say about 40% overall), with additional force added when the suspension is responding to vehicle and suspension movements when travelling.

Consequently, the ‘shock absorber’ bushings work much harder on an AHC-equipped vehicle than on bushings on non-weight bearing conventional shock absorbers. Degradation of bushings can be expected sooner with the AHC bushings.

It is extremely difficult to remove the lower bushing and press into place a new bushing without removing the ‘shock absorber’ from the vehicle. It is impossible to replace the upper cushion with the ‘shock absorber’ in place.

Removing a ‘shock absorber’ from an AHC-equipped vehicle means first de-pressurising the system by releasing AHC Fluid through the bleeder valves into containers, before detaching the AHC tubes at the top of the ‘shock absorber’. Front ‘shock absorber’ removal is not a particularly difficult task but be warned – even with great care, this can be a messy process, prepare groundsheets before starting, find something to block the tubes to avoid continually dripping fluid, keep rags handy, etc.

As a tip before re-installing, turn the ‘shock absorber’ upside down and use the stem to suck up AHC Fluid, like a syringe, to fill the ‘shock absorber’ as best possible. The idea is to have the least possible amount of air in the system to make bleeding of air from the system as easy as possible.

When starting the bleeding process after this amount of disruption of the AHC system, even after filling the AHC Tank it is possible that the AHC Pump may refuse to start because the Pressure Sensor senses low pressure (due to air in the system). In this case, the “Active Test” can be used to get the Pump started. Bleeding in this situation is not difficult but can require a lot of persistence to chase air out of the system – best to have plenty of AHC Fluid on hand!

Anyway, this is what the FSM has to say ….

LC100 Workshop Manual - https://lc100e.github.io/ (then follow tabs at the index panel on the LHS of the opening page)
+ Repair Manual
+ SUSPENSION AND AXLE
+ Front Shock Absorber (Independent Front Suspension)

Then see the following pages:
SA-112 – COMPONENTS
SA-113 – REMOVAL
SA-115 – INSPECTION
SA-116 – DISPOSAL
SA-117 – REPLACEMENT (including replacement of bushing)
SA-118 – INSTALLATION

Thank you so much! my LX rides really smooth. But....When going over cracks in the road or slight bumps, I hear a thud which should be more muffled given how smooth the ride is. There is no "bouncing" when going over bumps. I already replaced the links. I figured maybe the bushings in the front shocks could be the culprit. Thanks for the FSM link!!

 

[IndroCruise]

Thank you so much! my LX rides really smooth. But....When going over cracks in the road or slight bumps, I hear a thud which should be more muffled given how smooth the ride is. There is no "bouncing" when going over bumps. I already replaced the links. I figured maybe the bushings in the front shocks could be the culprit. Thanks for the FSM link!!

If you have not seen this thread initiated by @Travis Bickle then it is definitely worth a read:

Front AHC shock bushing and cushion replacement

I tackled this job yesterday, figured the shocks/rams were not leaking so why not refresh them? Maybe they'll last another 300k :p Rears are not as bad and I'll wait a little bit, lower ball joints are next. New VS Old Painted up

forum.ih8mud.com

 

[Red Beard]

Thank you so much! my LX rides really smooth. But....When going over cracks in the road or slight bumps, I hear a thud which should be more muffled given how smooth the ride is. There is no "bouncing" when going over bumps. I already replaced the links. I figured maybe the bushings in the front shocks could be the culprit. Thanks for the FSM link!!

I'm with ya on the shock bushings, mine need it on all 4 ahc shocks. I'm also planning on replacing the hoses and hard lines associated as PM.

 

[harshjay]

this is mint, but unfortunately I have left this bit of research until the day of, and do not have the o-rings detailed, that are listed as single use items......fack. So, do I order said o-rings, or just hope for the best?

 

[suprarx7nut]

I have searched and can only find folks upgrading their shocks to delete the AHC system. My AHC system works great. Neutral pressures are in spec, globes in good shape etc. I would like to replace the front shocks as I have 165K on them. Does anyone have the correct procedure to replace the front shocks with the AHC ? Thanks in advance!

As you've already heard, the shocks are essentially lifetime units. The wear component of the shock assembly is the globe at each corner.

If you've got thuds and harshness it's almost certainly slop in the control arm bushings, ball joints, or both. Replacing all the rubber is tedious and time consuming, but probably something almost all 100 series need at this point if still original.

 

[IndroCruise]

this is mint, but unfortunately I have left this bit of research until the day of, and do not have the o-rings detailed, that are listed as single use items......fack. So, do I order said o-rings, or just hope for the best?

Suggest "hope for the best" -- unless someone reports that 'globes' actually were received without the O-ring and the Backup Ring. My experience was that OEM 'globes arrived and the rings already were fitted. See also Post #145 and #147 at:

Impex is LEGIT 4 new AHC globes. Door To Door from Japan, less than 2 weeks

ordered globes and about 500$ in other LX parts from Impex. Took a good 2 weeks, no issues really, other than their system is a little strange. Quirks of Japan I'd say. BUT, I did get issues with US Customs, they wanted to know detail about the parts in the shipment and their respective...

forum.ih8mud.com

For additional comfort, suggest check availability at a large Toyota or Lexus Dealer, using the Part Numbers given in the above link.

 

[harshjay]

Suggest "hope for the best" -- unless someone reports that 'globes' actually were received without the O-ring and the Backup Ring. My experience was that OEM 'globes arrived and the rings already were fitted. See also Post #145 and #147 at:

Impex is LEGIT 4 new AHC globes. Door To Door from Japan, less than 2 weeks

ordered globes and about 500$ in other LX parts from Impex. Took a good 2 weeks, no issues really, other than their system is a little strange. Quirks of Japan I'd say. BUT, I did get issues with US Customs, they wanted to know detail about the parts in the shipment and their respective...

forum.ih8mud.com

For additional comfort, suggest check availability at a large Toyota or Lexus Dealer, using the Part Numbers given in the above link.

Yah, not globe related, but at the connection to ram. If you look at the first page of the service manual under the shock replace / removal, it shows the parts, and indicates to be replaced.

All my ‘ram’ bushings are cracked + flattened down UFO’s!

I have the same ‘clunk’ as OP, and only under a more severe suspension impact. The lower control arms are still intact, and not moving around.

If I still have any noise after bushing refresh, the upper + lower, and diff bushings get refreshed next.

Truck is 02’, no corrosion, 70k miles, full AHC reservoir gradient volume change.

 

[IndroCruise]

Suggest "hope for the best" -- unless someone reports that 'globes' actually were received without the O-ring and the Backup Ring. My experience was that OEM 'globes arrived and the rings already were fitted. See also Post #145 and #147 at:

Impex is LEGIT 4 new AHC globes. Door To Door from Japan, less than 2 weeks

ordered globes and about 500$ in other LX parts from Impex. Took a good 2 weeks, no issues really, other than their system is a little strange. Quirks of Japan I'd say. BUT, I did get issues with US Customs, they wanted to know detail about the parts in the shipment and their respective...

forum.ih8mud.com

For additional comfort, suggest check availability at a large Toyota or Lexus Dealer, using the Part Numbers given in the above link.

Apologies. Dumb post by me. Did not “read the question” and “failed the exam”!!

 

[harshjay]

Apologies. Dumb post by me. Did not “read the question” and “failed the exam”!!

None required. Your advise, and quick responses are a resource I am thankful for. I wouldn't be three weekends in, to a one day job, if I knew what I was doing! I have just forged ahead before, but that always costs me more time eventually...so, this time, I will gather all the correct parts (needed or otherwise) then tackle the job.

I will likely refresh all the bushings, diff and otherwise, but bring it to a shop to do. I don't love crawling around on the ground, and it will need an alignment after anyhow. I am at least saving the "T-tax" by buying my OEM parts through Partsouq, or having a Japanese contact source locally (like a steering rack)

Thanks again.

I will put up my work pictures (and my collection of assorted rubber bushings for the rams, as my model has options, and I didn't know what I had until I could get the old ones out).

this is my first order, but I re-ordered the other options to make sure I had on hand.

 

[harshjay]

so, this went great! Easy, no difficult processes or hard to reach parts. Making a video up of the process, and the real part numbers. There is another thread in here, where the parts they used are the wrong bushings.

 

[Coin]

I am looking at starting this project in the next week. Looking forward to your video.

 

[Red Beard]

so, this went great! Easy, no difficult processes or hard to reach parts. Making a video up of the process, and the real part numbers. There is another thread in here, where the parts they used are the wrong bushings.

Definitely interested in that video as well.

 

[Wilsil]

so, this went great! Easy, no difficult processes or hard to reach parts. Making a video up of the process, and the real part numbers. There is another thread in here, where the parts they used are the wrong bushings.

Did you do it or a shop as you mentioned in September?

 

[harshjay]

Did you do it or a shop as you mentioned in September?

Myself, garage.

Here’s vid

 

[harshjay]

I have searched and can only find folks upgrading their shocks to delete the AHC system. My AHC system works great. Neutral pressures are in spec, globes in good shape etc. I would like to replace the front shocks as I have 165K on them. Does anyone have the correct procedure to replace the front shocks with the AHC ? Thanks in advance!

Just did it all, super easy, check it out

 

[harshjay]

Definitely interested in that video as well.

Done, links in this thread.