Hydraulic Leak AHC (1 Viewer)

[LXinOBX]

Morning, hoping for some guidance. My '98 100 (LX variant) is leaking suspension fluid from what looks like the passenger side rear strut. AHC flashes "off". This started Friday when I "lifted" the AHC to the highest position as expecting flooding with Hermene on the way. Large pool of fluid underneath when driving out off car port a few hours later. Assume added pressure of the "hi" setting did it.

I cannot get under the vehicle (rear has lowered almost to the stop) to actually see where the leak is originating but I believe it is the supply line from to the strut. Reason I think it is the supply line is that torsion bar is covered in fluid and dripping from there. If it were the actual strut wouldn't the fluid drip be further to the rear of the truck at the tire?

Anyway, I have two cans of AHC fluid on order. My plan was to fill the reservoir and see if it will be enough to raise the vehicle to drive height.

Does this "sound" like a break in the supply line or a failure in the strut? Does anyone have a photo they can post that "shows" the orientation of the supply line to the strut assy? I've looked at the shop line drawings but can't determine the relative position.

Thanks so much

 

[LXinOBX]

Morning, hoping for some guidance. My '98 100 (LX variant) is leaking suspension fluid from what looks like the passenger side rear strut. AHC flashes "off". This started Friday when I "lifted" the AHC to the highest position as expecting flooding with Hermene on the way. Large pool of fluid underneath when driving out off car port a few hours later. Assume added pressure of the "hi" setting did it.



Thanks so much

Truck is getting picked up by roll on tomorrow on way to dealer. Can anyone tell me the recommended on rear springs? Is the general consensus that BOTH rear springs be replaced? If so, how about the struts? If only the one side is faulty should I also replace the other side?

Thanks so much!

 

[DirtDawg]

Both sides need to have the pressure raised, so you need to either replace both springs with OEM or aftermarket, or add spacers. Only replace the strut that is leaking, these usually don't go bad, they either work or don't. Is it leaking a substantial amount? Or just weeping? The fact that you say that the leak is all over the TBs makes me think it is in the engine bay or a supply line. Have you gotten under there to try to chase the leak? Just know that most mechanics have never seen/touched our AHC system and don't know how to fix or work on it properly.

 

[LXinOBX]

Thank you DD; got it, so long as equal spring force on both sides, I'm good.

It is a slow drip, maybe ( at rest and low setting) about a drip every 30 seconds - must be more at lifted level as only was parked about an hour (fully lifted, locked in 4WD) when noticed puddle of suspension fluid and low fluid. Can't get underneath to see as on rear bumpers two days later (couldn't get to it until then). Talked to Toyota service manager w advisor, am comfortable w him (he also has extensive experience w "salty" undercarriages as we have here).

Gets picked up tomorrow morning - 100 mile ride - I know the worst case, but hoping it's strut feeder line has rusted through/popped. So new feeder line, two springs, a shed-load of suspension fluid and it's good!

 

[DirtDawg]

Let us know the outcome or how we can help further. Fingers crossed it doesn't take much.

 

[LXinOBX]

Thanks, DD, will do. Wrecker just left - never in it's 18 years has it been in this "position" - kinda sad...

 

[PADDO]

How bad is your underbody corrosion?

 

[LXinOBX]

I've seen worse...but not many.... A sprinkler gets dragged underneath quite frequently. And when at a place where my tools/lift are I go through PB Blaster by the case...

May I ask why you ask? We are thinking it may be the hard feeder line from the accumulator/actuator to the shock?

 

[PADDO]

The rigid line from the damper assembly to the shock actuator (the larger diameter line) has some tight bends and is tucked up pretty tightly. It's difficult to get good access to wash salt off and apply corrosion inhibitor. It's possible the flex line has ruptured but from what you've described I'd expect that the line will be corroded through. If OFF is flashing you'll need to clear DTCs to get the pump to run after repair and topping up fluid as its gone into fail safe for self preservation (not run itself dry).

 

[LXinOBX]

Copy that, thank you, PADDO, very much appreciated. I suspect you are correct. The rear AC line suffered an identical fate last year, but I was at a place where I have tools and a lift.

It will be tended to by the Toyota of Chesapeake VA Service Manager (30 years of experience) with TechStream so should be in good hands

while I have you, when you mention corrosion inhibitor, do you have a recommendation? I'm always looking for good advice on how to keep beach trucks moving - no longer can we find what we used back on the 60's and 70's which was tar undercoating (it never really dried but did an incredible job of protecting the underside).

 

[PADDO]

I like Fluid Film applied with a compressed air applicator, got mine from the Rust Store.

 

[LXinOBX]

Thank you, never heard of it, but will check it out. Do you recommend first treating with a neutralizer (like POR 15) or is it an "all in one"?

 

[DirtDawg]

Fluid film just coats the existing corrosion and doesn't allow air or water into the rust areas meaning they can't expand. I've used it before and it can be a godsend with a rusty frame, but for my small amount of rust it just became a big mess. Though I highly recommend you treat the rust or use an inhibitor. Also I like to use anti-seize on all the frame/suspension bolts. It ensures that they will never rust, and I know they will be easy to take apart in the future.

 

[PADDO]

Thank you, never heard of it, but will check it out. Do you recommend first treating with a neutralizer (like POR 15) or is it an "all in one"?

I suspect fluid film, which is applied directly to the metal surfaces to be protected, and POR 15 which is advertised as a rock hard, non porous coating aren't really compatible. I've never used POR 15 as I purchased my '03 as a rust free 18 month old and, even though I live in an area that very rarely salts, it gets fluid filmed twice a year. Have a look at theruststore.com as they have a great info resource center or eastwood.com. I think that as long as you follow your chosen thin film surface protection scheme's cleaning and application regime you'll go a long way towards mitigating your corrosion problems.
Having retired after nearly 30 years of Naval Surface Ship engineering there were very few approved corrosion preventatives and Fluid Film was one of them.

 

[LXinOBX]

First, Paddo, thank you for your service. You were spot on - corroded line (highlighted) and this part is on order. Now the challenge is that it is not readily available and service department didn't get back with me in time to fly it in.

The reservoir is empty, as it drained while sitting these last few days. Is your experience if the vehicle (AHC pump) was not operated "dry" then refilling the system, properly bleeding and resetting if needed - all "should" be OK?

 

[DirtDawg]

Correct. Even if the pump was run dry I believe there is a bleeding procedure to get it going again, but I doubt it ran dry. Glad to hear that it is just a line compared to a more expensive system-critical part.

 

[LXinOBX]

Of course, now I'm wondering just how many other lines are "rotting". This environment is just about as unforgiving as can be on vehicles - I think I'm definitely going to try Paddo's recommendation of Fluid Film to at least stabilize the oxidization.

 

[LXinOBX]

Quick update and one, I hope, last question.

High pressure hose replaced and service adviser, following my email (they don't pick up the phone at this dealership...) on techstream data on globes/accumulators (basically trying to find out how many "gradients" between lo and hi on the suspension fluid tank, writes: "TANK IS FULL,AND NO FAULT CODES"

Does this tell me that the system is operating properly? Would a blown/faulty globe throw a bad code?

I pick up the truck in the morning, then have a 300 mile drive - kinda prefer to find out if any issues before getting on the road....

 

[Ramathorn15]

I don't believe you will get any fault codes from bad globes. I believe you can either do a gradient test or tell if it rides like crap.

 

[PADDO]

There aren't any fault codes associated with the damper accumulators unfortunately. The factory way of determining their health is to count the graduations between low and high - this is somewhat obtuse but better than guessing. You can put the AHC/AVS into test mode and starting at position 1 (softest) step up to the stiffest setting incrementally and feel the compression/rebound at each corner. If you've got a blown accumulator or one that's worse than the others you'll detect it with this test.