Figuring out my AHC

[cek347]

*Sorry if this exact situation has been covered. I have been searching and looking for similar problems/posts. If you remember a similar situation, let me know what to search for*

Picked up my '99 LX470 over a week ago. I knew it had some AHC problems. The owner let me know the suspension feels bouncy and he has not serviced the fluid in 6 years he has had it (he only put a few thousand miles a year). After reading and searching and more reading initial thought is spheres. I factored that into the price when I made my offer. I did drive it and yes, feels a bit bouncy but not out of control or anything. It did get more bouncy when I moved the switch to comfort. When I got back to the driveway I put it in H (all doors and hoods closed as I learned from searching here) The pump operated and it started to lift, after about 20 seconds it was definitely higher all around and then it just falls and goes back to N. The Off light just blinks. I let it be and came back out to mess with it a bit later after I got it home.

I somehow didn't notice but the driver side front is down (measured 1.25" lower then the passenger side front). The PO had a driveway with a wicked slope and I didn't even notice....my fault. I hopped in and tried H again. Same thing, gets up there, holds for a little, then falls back to N. I shut it off, restarted it was at N, i put it in L and it went right down. Went back to N no problem. I checked the fluid at N and its low (below min).

So I guess I need suggestions on the low driver side front.
-1.25" seems like more then a TB adjustment?
-Could that be a internally blown front hydraulic shock?
-Blown front sphere?

As far as the H drop:
-I thought maybe if the system was trying to fill to reach H and the reservoir runs out of fluid and that makes the pump shut down and it falls back to N?

I don't see any outward leaks in the system. I thought maybe I'd flush and fill the system and see if that had an effect on anything.

I also thought I'd just go ahead and order up an OME 1.5" lift from Slee and move on. I'm not opposed to that.

 

[Ramathorn15]

Your first step should be to order a techstream cable/software and figure out the neutral pressures. This will tell you a lot about the system.

 

[cek347]

Your first step should be to order a techstream cable/software and figure out the neutral pressures. This will tell you a lot about the system.

Ok, I ordered a cable and software off of amazon. I'll get it loaded up.

 

[PADDO]

Its pretty much assured the reason it's stalling going into high is your neutral pressures are excessively high - basically the system thinks it's overloaded.
With 6 + years on the fluid (could be original, who knows?) I'd start with a one can drain and bleed (maybe repeat in a few weeks) to purge the system of the old contaminated fluid and gases and put 5 or 6 CW turns on the low side tb adjuster bolt while you're waiting for Techstream. Once you can read your pressures you'll need to do the standard package: adjust for cross level; check & set front and rear heights; adjust TBs for front optimum pressure and in all likelihood fit new rear coils with spacers to optimize your rear pressure. You probably should ensure the height sensor lever mechanisms arent frozen up with corrosion and are free to move too. All very standard catch up maintenance for these systems. The spheres have no affect on the vehicles ability to raise to H.

 

[randomquickness]

Please keep is updated. My driver side front corner seems to sit lower sometimes but not all the time so it has me confused.

 

[cek347]

Its pretty much assured the reason it's stalling going into high is your neutral pressures are excessively high - basically the system thinks it's overloaded.
With 6 years + years on the fluid (could be original, who knows?) I'd start with a one can drain and bleed (maybe repeat in a few weeks) to purge the system of the old contaminated fluid and gases and put 5 or 6 CW turns on the low side tb adjuster bolt while you're waiting for Techstream. Once you can read your pressures you'll need to do the standard package: adjust for cross level; check & set front and rear heights; adjust TBs for front optimum pressure and in all likelihood fit new rear coils with spacers to optimize your rear pressure. You probably should ensure the height sensor lever mechanisms arent frozen up with corrosion and are free to move too. All very standard catch up maintenance for these systems. The spheres have no affect on the vehicles ability to raise to H.

Great advice, I've been reading your AHC post as recommended by another member. Hopefully I'll be able to connect with my Techstream I ordered. Still waiting to get my truck back from PA inspection. My usual dealer for toyota parts doesn't sell AHC fluid... I'll see if the other local dealer has it.

Please keep is updated. My driver side front corner seems to sit lower sometimes but not all the time so it has me confused.

Will do. I hate dead end threads.

 

[cek347]

Update, picked up the truck from the inspection shop. I had them install the OEM front sway bar links I picked up. Looked at the truck and now it is sitting level at least... Maybe since the had it on the lift and the suspension drooped? Who knows. I'm picking up some OEM AHC fluid from Lexus tomorrow. About $32 for a can. They wanted $44 but matched my other Toyota dealers price. Going to follow the drain and bleed instructions to baseline the fluid.

Also need to figure this out:

Found some instructions online. My wife's laptop is win7 64bit. See if I can figure it out during the rain and watching football tomorrow. Garage too small to get in there.

Updates to follow.

 

[Ninja Cruiser100]

Is that Techstream? I am curious what you learn, please share your observations.

 

[cek347]

Ok, followed instructions for drain and bleed. I got a lot out but still didn't see the fresh pink stuff. Im about two thirds through the second can. I went around the truck to each bleeder twice.

That brake bleeder bottle was very helpful. Has a magnet on it to hold onto the frame. The milk jug was near the end. A little lighter but the new stuff is very clear with a bit of pink. So didn't see any of that.

Tested height functions....they all work. H, N, L. No problems there.

Techstream will not connect. Went through the 64bit instructions that someone posted on the ft86 site but will not connect to the vehicle. Next option is running XP on the laptop virtual machine. Just need to find my old xp disk. Will update when I figure that out.

Soaked the TB adjustment bolt with PB blaster. Got out the breaker bar and gave it 6 clockwise turns. Marked with chalk. As of now I have 19.25 on driver side from center of wheel hub to fender lip when sitting at N. Passenger side is 19.75. Should I crank anymore or could this mean the TB is tired?

Anyway. It is definitely riding better. Less bouncy. Its livable for the time being. AHC tank graduations test only shows a 5 mark change. Not good but it's riding ok. Hope to get this techstream going to really dig in and find out what to do.

 

[PADDO]

Are you using the "one can bleed method" I've posted? the other method in the stickies is time consuming and exceedingly wasteful of new fluid. Usually the best approach to correct a significant front cross level problem is to split the difference i.e. to fix a 1 inch error you'd raise the low side 1/2 in and lower the high side 1/2 in, check/adjust height via sensors then adjust both sides TBs equally to set the pressure. Get your pressures optimized then do your grad check for accuracy.

 

[cek347]

As far as pressure and sensors go, I need to get my Techstream working. Hopefully this weekend.

As far as flushing I filled the empty reservoir with a new can. Then bled the accumulator. Started the truck and got back to N. Shut off truck. Did driver front sphere bleed. Start, then shut off. Driver rear sphere bleed. Repeated for the other two. Checked level between each bleed. Had to go with Can 2 to finish. Since I still did not see fresh fluid, I did a second round of bleeding. Still no fresh fluid but close.

I'll report back after I can get a computer to verify pressures.

 

[PADDO]

Search for the "one can fluid exchange method" I've posted - it avoids the starting/stopping and fluid waste you're experiencing. You can tweak your front and rear heights without Techstream, but it's necessary for pressures (unless you have a suitable gauge and adaptors) and helpful in ensuring your front sensors dont have a delta that's excessive.