Neewby - AHC Leaking Shocks - Replace?

[MrGreenJeans]

First, as a neewby I want to say that I worked my way through @ 130 of the 550 pages of the forum topics - I am blown away by the amount of info on here and those that contribute.

Now my question as I have not seen this directly answered elsewhere - If I have a MY2k with 167K, the major components of the AHC have never been replaced, and I have 3 weeping shocks, is it in my best interest to replace:

A) Just the shocks? (Non dealer mechanic is saying $1,400 for all four / Park Place Lexus parts total is @ $730 for 4)

B) Just the accumulator globes (Park Place $487 / unit)

C) Shocks + globes + rear coil springs?

If I understand what I have read - since the shocks are really hydro rams served by remote reservoirs, they leak b/c much pressure is induced b/c of flat globes.

So the question becomes - does replacing the shock actually cure the reason the shock is leaking in the first place?


Yesterday I did the High - Low count the notches test (@ 10) and then drained / replaced the AHC fluid. Felt a little better, but nothing like my 740i (does a fully functioning AHC feel that good?)

I have basically zero mechanical experience and few tools, but after reading as much as I have (and maybe I am kidding myself) I think I can do this repair - if I know what I need to repair. However, I would like some input from you all - is this something I should have a pro do?

Please let me know your thoughts.

TIA

 

[super90]

Let's think about all this a little...

1) Define "weeping"? And where is it weeping from?
2) Have you cleaned it all up and watched to see how fast the fluid appears again at each corner?
3) Are you having to add fluid to the reservoir to keep it within spec?
4) Is the ride suffering?
5) Has a mechanic recommended this work be done?
6) Where are you located? (add to your profile)

This truck will never ride like a 740i, so that's not a yardstick.

If you do need parts for it, also consider buying from Toyota. IIRC the 2006+ LandCruiser were all AHC as well and the parts might be a little cheaper. I just ordered rear springs for my '03 LX from Toyota for about $73 ea. I'm proactively replacing them and adjusting torsion bars and doing another AHC fluid flush.

 

[CappyKD]

Subscribed. I want to see what everybody's opinions are on this topic.

Kirk

 

[TXLX100]

Once you start replacing those components you are basically in for at least $3k in parts plus labor. In my opinion, at some dollar amount, it's worth considering trading out of it and into LX/LC with lower miles, if you want to keep that feature.

I have an older LX, when that system starts to go, I will likely put it off as long as possible and then get a lift. Right now, parts for a lift start around $1k I believe. The gas mileage and the day the AHC starts to crater are the only bad things about owning a LX.

 

[MrGreenJeans]

OK so I got to the mechanic's while they still had it on the lift (doing the brake / front hub repack). The service writer initially said that the mechanic told him "DSF and PSR are leaking", but then seemed to expand that to both fronts - and then said you should just replace them all - with LX parts and labor $1,400 out the door.

So I met with the mechanic (nice guy) and he put it up in the air and walked me around, gave me his flashlight, and I took a good look at it.

With respect to Super90's questions:


1) Define "weeping"? And where is it weeping from?

On both the DSF and PSR the weep was minimal to say the least. Furthermore they appeared to be seasoned as the there was sediment trapped in the lube. The 'weep' emanates from the top half of the lower tube (internal to the larger exterior top half of the shock) and some lube / dirt is present on the small dimension (lower half) of the shock where it is covered by the large dimension (upper half). I stood under it looking straight up the shock body with a light and thought - really? This is a concern?

2) Have you cleaned it all up and watched to see how fast the fluid appears again at each corner?

No, but that is the next move; that and watch it over time.


3) Are you having to add fluid to the reservoir to keep it within spec?

I just got this 2 weeks or so ago and I have been reading and soaking things up like a sponge - that said I know just enough to be dangerous. However, from what I saw yesterday when I replaced the fluid the level is in the exact same spot as when I bought it.

4) Is the ride suffering?

I don't think so, but I don't know what to expect. It falls somewhere in between my 740i and Z71 Suburban. Although every once in a while seems to hit a bump and feel like it rocks once or twice not only fore and aft, but laterally at the same time. I can not explain it better than that, it has only happened a few times, and it isn't reproducible (I have turned around and driven the same line - but it seemed fine on the second pass)

5) Has a mechanic recommended this work be done?

No slam on the mechanic - I am very sure he is highly qualified, however this particular vehicle isn't that common around here and most folks that have them would more than likely take them to either the LX dealer (230 miles away) or to the Toyota dealer here locally. So in the end I asked a lot of questions and just sort of listened to what he had to say and mentally compared it to what I have read here and at Club Lexus / Expedition Portal, and came away with the realization that I am going to have to up my mechanical skills and learn to fend for myself more instead of having someone else just start throwing parts at the problem when they may not be 100% on the system. Again - not to take anything away from the mechanic or the shop. In general the mechanic saw no reason to suspect the globes were the issue and made a logical case for this. We went through my bleed procedure (thank you NTSAINT https://forum.ih8mud.com/100-series-cruisers/438560-ahc-fluid-change-how-need-input.html#post6127557) against LX recommendations, and he gave me his thoughts what to do next (he favored replacing the shocks. I asked him about the rear springs, adjusting the T bars and scanning for pressure equalization on the globes. He said, 'yeah' in that luke warm tone that says so much. I asked if they had the ability to scan the corners and he said he wasn't sure. (And we know how much the scanner has been discussed around here)

6) Where are you located? (add to your profile)

SW OR - and I will add that (I was a lurker for @ a year and just read so the profile is pretty light)


For now I would say the system works fine. I intend to put some sliders and some good meats on it by fall but that is about it. I doubt I'll ever put a lot of weight in / on the rig so the biggest reason for a lift then would be cost to repair the AHC. For now anyway it looks like I can kick that can down the road a bit.


However for those that understand the system, I'd still like to know the answer to my question - if the shocks are leaking, is it really a symptom of flat globes that send pressure spikes to the shock? ie do leaking shocks necessitate the replacement of shocks (hydraulic rams), or globes, or both?

Also I have come across the thought in other threads on AHC, but never seen a definitive answer - can the rams (shocks) be rebuilt?


TIA

Good luck

 

[TXLX100]

To address your question, it's possible if the globes have failed that additional stress could cause the shocks to weep, but in my opinion that is unlikely. The shocks are designed to take a lot of pressure and weight with perfect globes. If the globes on your vehicle have truly failed it will feel like you are riding in a wagon. Leaking shocks may not indicate the globes need to be replaced. I have never heard of rebuilding the shocks. If it were my vehicle I would put new fluid in the system and clean up the leaking shocks and keep an eye on them.

 

[PADDO]

With 10 grads on the reservoir from low to high and the ride is ok/good that suggests the accumulators are still ok, toyota's test requires more than 7 grads. I wouldn't get too excited ATT about the trace of fluid evidencing on the shocks. Sure, they aren't suppose to leak at all, but if there is no obvious drip and the reservoir level holds constant them you don't need to take any urgent action IMO. I'd focus on clean AHC fluid, read your neutral pressures and adjust TBs accordingly and contemplate replacing the rear coils or at least inserting 10mm packers. There is a better than average chance the TBs have never been adjusted to compensate for their age, and the coils will be tired too. Speculating, your neutral pressures are likely high which equates directly with the AHC pump's output pressure necessary to lift the vehicle from low to normal height, hence ensure the neutral pressures are in spec and this will lower the system's quiescent pressure and provide a better ride, might even reduce any leakage through worn/failing shock seals.

Sent from my iPhone using IH8MUD

 

[tabraha]

I think PADDO gives a good summation. Tackle springs and t-bars to get back within spec first, take it from there. Another potential sign is if the ahc is having to "pick itself up" on the front end every once in awhile. If so your t-bars are probably tired and need a little crank.

Now lets get that profile and signature up to date.

 

[super90]

I think PADDO gives a good summation. Tackle springs and t-bars to get back within spec first, take it from there. Another potential sign is if the ahc is having to "pick itself up" on the front end every once in awhile. If so your t-bars are probably tired and need a little crank.

Now lets get that profile and signature up to date.

Agreed on all fronts. This is easy, and relatively inexpensive (fluid and springs) to do and will let you "baseline" your AHC, in a manner of speaking.

I personally think the AHC gets a bad rap for failures and there is a bit of a scare out there. Don't panic yet. It's a system that needs maintenance to stay in spec. Most owners didn't provide any, it gets old and way out of spec, and then it fails. This might be at 15 years old, and the better part of 200k miles. It then costs $1-$3k to fix, on a vehicle that cost roughly $50k-$60k new (depending on YOP). No big surprise.

 

[uHu]

Lotsa good comments here. Will add just a bit:

Before doing the grad's test (where u got 10) you have to get the pressures right. If coils are never changed and TBs not cranked, the press. is for sure high, probably so high that 5 passengers would be a problem. After changing the rear springs (which I presume is required) and adjusting front springs (TBs), you will see that you get more graduations on the test. Also check the heights at the same time.

If you have 10 grad's with the pressures and heights within specs, you would probably still see a slightly improved comfort if you changed the globes.

Re "rocking laterally": If the steering wheel is straight within 30 degrees, the valves are open between left and right, and it might rock slightly. In curves, the valves are closed and the damping is increased, so it will rock less. - And lean less than conventional suspension with a soft set-up.

I suggest getting the pressures right first, then check the weeping again. I've had a weep on one shock for 3 years now, without it getting any worse, and without loosing any amount of fluid that can be detected.

Get techstream. Check pressures and steering angle - critical factors for a smooth ride.