Definitive list of AHC maintenance items (5 Viewers)

[jtb517]

Avid reader of this thread that now needs some direction.

Last year, I adjusted TBs, cross leveled, exchanged fluid, etc and got the pressures back within spec. I was without Techstream for a few months and noticed the ride quality degrading especially in the rear. When I got Techstream working and was able to read pressures, the rear pressure had increased up to 7.8. I ordered new LC AHC springs and installed a couple of weeks ago. Pressure is still on the high side at 7.4. Ride is improved, but I’d still like to get the pressure lower to be in spec.

What should I try next to reduce rear pressure? Spacers? Any other ideas?

 

[brauski]

Avid reader of this thread that now needs some direction.

Last year, I adjusted TBs, cross leveled, exchanged fluid, etc and got the pressures back within spec. I was without Techstream for a few months and noticed the ride quality degrading especially in the rear. When I got Techstream working and was able to read pressures, the rear pressure had increased up to 7.8. I ordered new LC AHC springs and installed a couple of weeks ago. Pressure is still on the high side at 7.4. Ride is improved, but I’d still like to get the pressure lower to be in spec.

What should I try next to reduce rear pressure? Spacers? Any other ideas?

I was at 8.0 and switching out the tired old stock ahc springs for King KTRS-79s took me down to 5.1 (almost empty tank, no RTT at the time). Can't say enough about them if you have some extra weight on your rig. Noticable difference in ride quality as well.

 

[brauski]

Accidental double post.

 

[jtb517]

I was at 8.0 and switching out the tired old stock ahc springs for King KTRS-79s took me down to 5.1. Can't say enough about them. Noticable difference in ride quality as well.

How much additional weight do you normally carry?

 

[brauski]

How much additional weight do you normally carry?

Steel bumper F&R, 12k winch, sliders, roof rack, and roof top tent. I plan to add some drawers here soon.

But like I said, the 5.1 was with almost no gas and no RTT. So with a full tank I'd bet it's closer to spec. I have tomorrow off, I'll see if I can go fill up the tank and rerun techstream to see what it's looking like after 1500 miles, you've got me curious now.

 

[jtb517]

Steel bumper F&R, 12k winch, sliders, roof rack, and roof top tent. I plan to add some drawers here soon.

But like I said, the 5.1 was with almost no gas and no RTT. So with a full tank I'd bet it's closer to spec. I have tomorrow off, I'll see if I can go fill up the tank and rerun techstream to see what it's looking like after 1500 miles, you've got me curious now.

I’m only currently running sliders and a roof rack. That combined with a 33in spare might put me around 125-175lbs over stock weight. Rear seats are still in there for now and I maybe carry 25-50lbs of tools and gear daily.

I was initially going to order Kings, but thought it may be too much spring for me.

 

[tjb]

I replaced my 145k rear springs with new Lexus springs and saw no difference in pressures. (They’re high, don’t have numbers handy.) I’m spec all the way around - I’ve got a sleeping platform instead of the rear seats in the back - but no real extra weight.

I’m also interested in what mechanically or physics-wise causes brand new springs to fail to reduce the pressure.

 

[spaber05]

I just want to confirm here what I'm already pretty sure needs to happen. These are stock springs with 191k on them, just made a recent addition of a Trekboxx system in the back a month ago. I have yet to crank the TBs for the front but the rear will only climb.

What I'm assuming I need are fresh OEM springs and some 30mm spacers, sound about right? Nothing besides drawers on the truck, no plans for any additional weight other than weekend trips to Vermont so I don't think I need anything heavier duty.

Input appreciated!

 

[DickM]

I had similar pressures with 192K on a 2006 LX. With the addition of new OEM springs and 30mm spacers,( after new globes and fluid) I was able to get factory spec pressures. Only additional weight is a set of Metaltech sliders. No rear seats.
HTH

 

[spaber05]

Can you upload a photo of your setup with this kit? Thanks.

I had similar pressures with 192K on a 2006 LX. With the addition of new OEM springs and 30mm spacers,( after new globes and fluid) I was able to get factory spec pressures. Only additional weight is a set of Metaltech sliders. No rear seats.
HTH

@DickM :Thanks, definitely does help. I feel like weight wise, I'm just on the cusp of needing beefier springs (no rear seats but drawers probably have me at +100lbs), but I love the soft, cushy OEM ride so I think I'll stick with OEM and spacers. I did a flush recently so I'll probably do springs then crank the TBs a bit and see where that gets me.

Did your rear ride height change at all? Any more of a rake than the factory?

 

[jtb517]

Just an update on my experience with new OEM LC AHC springs.

It’s been three weeks since they were installed and my rear pressures have continued to fall. I’ve been adjusting and checking pressures in Techstream weekly and am down to 6.8 in the rear.

Not sure why the pressures have been dropping, but I went from L to N three times and received the same readings.

 

[DickM]

Did your rear ride height change at all? Any more of a rake than the factory?

The only change in height was very slight as I lowered the rear sensor less than 1/8" to get the neutral height more on to the springs. Not really sure if this was a big part of the puzzle, but it seemed to help the rear neutral pressure a bit. In truth, with some much fiddling and tweaking to fine tune the numbers, it is hard for me to say exactly what did what in the end. The system seems to greater than the individual sum of it's parts.

 

[ramangain]

I'm curious about the effect of rising rear pressure when raising TBs to lower front pressures which is commonly reported here. Mine was the opposite (completely stock suspension). After leveling and reading pressures, everything was high. I raised the truck about half an inch and all pressures fell into spec. I carry no extra weight, recent AHC fluid flush, no 3rd row seats. I'd be surprised if the rear springs are newer. 01 LX

 

[looking4lc]

Hi All,

I have few concerns about my 2007 lx with 260K Miles ride quality and would like your opinion.

when I read how other's compare their LX ride comfortless, I don't think I have that in mine. I can feel every bump on the road, specially when driving slow, and its worse if I drive over (-Botts' dots, road studs- )since we have so many in my country, I feel the whole car is shaking. I am trying to figure out what is causing that.

Background:
- AHC test: I have over 11marks ( up and down test)
- I flush it every 30K miles (done it less than 10K miles ago)
- Front pressure is 6.9------Rear is 6.4( replaced springs 3 years ago with 30mm spacer).
- shocks weep little bit
- one year old tires
- Code C1776 - Speed sensor ( I cleared it in techstream and came back again)

Things I have replaced over time( Rubber wise).
- Steering rack bushings ( Poly -local made)
-Front diff mount
- right side upper arm due to rusted bolt
- stabilizer bar link bushing
- what else should be replaced based on the truck age and mileage? pinion? sway bar bushing? front and rear control arms?

Every 6 months or so I do underneath check up for any rubber damage/movements/ tears and wears by specialized mechanics and everything else seem okay unless there are things can not be seen.
=============================================

my other concern is that I have one of the T-bar cranked more than the other, I could see the difference on thread lefts are not equal, however, last time I checked the front height is on specs ( haven't checked lately). is this something I should be worried about? if so, how do I fix it? if I try to crank it counter-clock wise to make it even , the front pressure will be high....then how?

your feedback is appreciated

 

[Moridinbg]

I need some help identifying the part numbers for the O-ring and washer that go between the shock absorber (ok hydraulic strut/ram) and the hose.

I am looking at the diesel equivalent of this diagram:

(Diesel one is here: 480651N.png, same part numbers for the o-rings and washers)

The o-ring and washer (red rectangle) have two variants, depending on the numbers in the orange rectangle. What are those numbers? How do I pick the right one?
The two different sets of o-rings and washers have completely different part numbers, different prices, so they must be different...

 

[uHu]

That's the build year and month. March 1999 is the cutoff. (I hope that's not your build month)

 

[Moridinbg]

Year/Month, of course... Thankfully, I am far from the cutoff.

Turns out the PO changed the AHC fluid with some other oil at some point relatively recently. It's light green, instead of pink. Slight burnt smell, somewhat similar to differential oil. Hopefully, it's Citroen LHM at least and not some random oil. It has been a good flush, as the hydraulic struts are full of it as well. My understanding is that oil usually pools there and does not mix too much through the system.

Is my best course of action to disconnect all struts and empty them, when changing the fluid? I might just as well change the bushings.
The system works incredibly well otherwise. No dives or harsh ride, High works consistently, 10-11 graduations.

 

[2000LX4me]

Year/Month, of course... Thankfully, I am far from the cutoff.

Turns out the PO changed the AHC fluid with some other oil at some point relatively recently. It's light green, instead of pink. Slight burnt smell, somewhat similar to differential oil. Hopefully, it's Citroen LHM at least and not some random oil. It has been a good flush, as the hydraulic struts are full of it as well. My understanding is that oil usually pools there and does not mix too much through the system.

Is my best course of action to disconnect all struts and empty them, when changing the fluid? I might just as well change the bushings.
The system works incredibly well otherwise. No dives or harsh ride, High works consistently, 10-11 graduations.

oh my, have not heard of LHM fluid since my days of working around the Merak, 90's. The Green stuff! The DeTomaso influence on Maserati

 

[shiretowndown]

Job done! By a 1st timer! I think she does ride a little smoother!
Wow, I really appreciate @PADDO and all the other input!

 

[riffman12]

so my OBD cable is on the way and I plan to be getting my pressures in spec soon, ideally with a small (1") sensor lift. I've looked through a few threads and I haven't quite found a step by step guide on what to do. Here's what I have so far, would the knowledgeable folks in here let me know if this is correct? I've put some questions in line as well.

1) Park vehicle on a flat surface. Measure from fender to center cap and make sure the left and right side are the same (or close to). If not, crank the torsion bars in opposite directions until the car is even.
Q: Is this done with the vehicle off? Do I have to do this in the rear? If so, what do I adjust? Do the AHC height sensors come into play here at all?

2) Plug in OBD cable and fire up techstream. Have the vehicle in Normal height and check the pressures. Adjust both torsion bars equal amounts until pressure is in spec.
Q: do you do this right after raising it up from Low mode? Vehicle on or off?

3) after front is in spec, if rear pressure is out of spec, either replace springs with OEM, or add spacers, or add King 79 springs for added weight

Am I missing any important details?

Also, where does getting a slight lift fit into all of this?