Thank you, but to clarify I served with a closely Allied nation (hint my Avatar) but I was loaned to the USN for a year in the '80s on a tech exchange program. And happy to catch up for an ale
LX470 AHC Stiff Ride Correction
- Thread starter wkbogie
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
PabloCruise
SILVER Star
What springs will you go with?
I have heard folks talk about King springs, but have not heard if they are ideal...
PabloCruise
SILVER Star
With a '99 you've got to expect the 4x damper accumulators (aka spheres, globes, gas springs) to be nearing the end of their effective life if they're originals, but you can still optimize what you've got without any big outlay in $.
Fresh fluid with its associated bleed is a great start, particularly if you don't know when it was last changed. Search for my "1 can easy bleed procedure". Quick, easy, can't screw up and doesn't waste new fluid. If the fluid is really old and contaminated you can do a follow up bleed in a week or three.
Start with basics like tire pressures, inspect your shock actuator bushings and cushions etc. New front/rear sway bar link ends with their cushions returned a huge improvement for me, helps to stop telegraphing road noise chatter into the body as well as improves steering feel etc.
Ensure your FR and FL are even in heights, i.e. front is level. If one side has sagged (usually the DS) then the damping response balance between torsion bar spring and gas spring isn't optimum. The gas spring side of the damping has a faster, more sensitive response than the torsion bar mechanical spring and if the balance between these two factors is off then you get poor and uneven damping, harshness etc.
You'll be lucky to get 1MPa drop in rear pressure with just spacers, expect closer to 0.5MPa, but it's all good and going in the right direction.
Do the L to H graduation count test to gauge the general state of health for your globe accumulators. If you get 9 or 10 grads then your damping should be fine - 14 is new, 7 Toyota says to replace. If interested you can put the system in test mode and manually step through the damping from softest to hardest. This is good if you suspect one corners damping is worse than the others as you can walk around and check the compression/rebound effort at each corner in your driveway. You can also lock damping in the softest setting and go for a drive. This is actually helpful if you want to determine if a damping issue is predominantly a mechanical/hydraulic or a damping control issue.
Probably enough to chew on for the time being
More good stuff - Thank you @PADDO
PabloCruise
SILVER Star
Whoops, just found page 2. How long have you had your King springs? They brought your pressures into spec? How much $?
DirtDawg
"It'd be alot cooler if you did"
I haven't received mine yet, they're in the mail on the way from Australia as we speak. I will be using mine in a lifted application, 2" AHC lift, and I will post an extensive report on everything I do once all my parts get in because I'm venturing into unknown territory. My goal is to have stock ranges and pressures once lifted which I think I will be able to achieve. @Ramathorn15 currently has the king springs running them at stock height. He has a thread posting up his results and he seems pleased with the ride. Mine were about $200 including shipping off of eBay seller spares box.
PabloCruise
SILVER Star
- Thread starter
- #48
King Springs AHC KTRS-79
I think I read these will give you a stiffer ride if your truck is stock, as mine is.
I think I read these will give you a stiffer ride if your truck is stock, as mine is.
DirtDawg
"It'd be alot cooler if you did"
Did you read the thread? He is running his stock too.
- Thread starter
- #50
I like your avatar. Yes, I read the entire thread. "the rear rides nicely, but is definitely more firm. It not harsh though." This is compared to his ride with a rear pressure of 7.1mpa before the springs.
I am hoping for a more cushy ride and I do not plan to add any weight as he does. "Once it's loaded up with my bumper and other stuff, I presume it will come back."
Sorry is this has been covered, but is there instructions for turning the torsion bars. Im going to try it on level ground with the ahc on high.
From what i gather these are under alot of tension, and i dont want to cause an injury.
Maybe im over thinking it...
From what i gather these are under alot of tension, and i dont want to cause an injury.
Maybe im over thinking it...
PabloCruise
SILVER Star
You are welcome. I hate to see good systems screwed up by technicians who are flying blind and haven't bothered to fully learn their craft. I'm a retired Military Technician and Engineer and making $hit up on the go for critical systems wasn't an option. I was also in a position to be walked and talked through the AHC/AVS systems and their diagnostics on purchasing a new LX when the brand was introduced to challenge RR in Aus. Lexus Aus ran a "geek squad come Genius Bar thing" to blow the Range Rover/Land Rover Experience thing away which was great if you're into servo and control systems engineering. Most people were interested in the wicker hamper, Pavrotti CDs and nice bottles of wine that came with the purchase. I was more interested in this "hand held SST tester thing" ....and the wine.
Those height sensor assemblies are expensive, if there is a next time and all you need is the actual sensor potentiometer then grab a Dorman 924-755 height leveling sensor for $55. Work great.
I'll take a 200
This is gold! Is that Dorman sensor a direct plug-in?
I think you also had some ideas about re-charged globes that cost a little less than the $1600 for new?
PabloCruise
SILVER Star
This is the first reference I have seen with spring rates listed for the various springs - thank you!
Are the 80 springs a direct bolt-in?
The various spring rates have been mentioned a few times as this topic comes up in some permutation pretty regularly.
80/450 series rear coils - there are three or four OE variants between MY and with/without 3rd row seats - will drop right in BUT you need to be running significantly more weight (+500 lbs) and be prepared to understand and work with the system to achieve satisfactory results. Have a look at @frogers935 thread and his sand hauling!
80/450 series rear coils - there are three or four OE variants between MY and with/without 3rd row seats - will drop right in BUT you need to be running significantly more weight (+500 lbs) and be prepared to understand and work with the system to achieve satisfactory results. Have a look at @frogers935 thread and his sand hauling!
I found that if you jack the front end up enough to get the tires off the ground (like the LC procedure) they are easy enough to turn using nothing more than an 18" breaker bar. Each 360 degree rotation results in about 0.2 change in the TechStream reading. Don't see a need to do this with AHC on high. Is there something else you were asking and I missed the boat? My best guess for a more thorough procedure would be to search torsion and the user name PADDO - almost certainly will find a knowledgeable explanation.
FSM (search the term "FSM AHC" for previously posted PDFs) stipulates adjusting torsion bars on flat level ground and that is what I advocate fwiw. Raising to high relieves some tension and makes an easy job easier if it helps. You should only see 60-70 ft lbs torque so that should be achievable for most with simple hand tools. I try and disassociate people from thinking "conventional LC suspension" because some get easily and very confused between the two systems. Also I'm a KISS advocate, if some people feel they have to get jacks stands and a decent jack they may be less likely to grab a 30mm socket and bar, Techstream and go out and adjust.
Last edited:
I will be awaiting your report on your results, I'm currently sensor lifted 2" and this is very relevant to my interests.
Are you staying stock weight or adding bumper, drawers, sliders, rack or any combination of the above?
- Thread starter
- #58
Thanks for all the advice and knowledge guys!
Alrighty...
30mm spacer came in and I installed them in about 1.5 hours. It was a bit tricky to get them in there since I did not remove the entire springs, just dropped it a bunch.
1. Jacked up one side of the axle
2. Put a tall jack stand under the frame near the rear axle front suspension link mounting point
3. Removed the wheel
4. removed the sway bar bolt
5. Put on spring compressors (didn't tighten them much due to the limited space and the bolts were too long) but they helped keep the spring from extending fully when the axle was lowered
6. Lowered the axle
7. Removed the bottom shock bolt
8. Lowered the axle about 2" from the ground
9. Squeezed the 30mm spacer around the bump stop and up against the body.
10. Jacked the axle back up to seat it on the spacer
11. Removed the spring compressors
12. Lowered the axle
13. Installed the shock lower bolt (took some wiggling and a rubber mallet)
14. Raised the axle in order to insert the sway bar bolt
15. Put the tire back on
Opposite side was the same, just quicker.
I drove it around for a few minutes and I do not think it is much better, but I will find out tomorrow when I have some more seat time.
Just for more data, I plugged my $25 Amazon Techstream into my 13 year old XP laptop to get some pressures.
AHC Pressure from the FSM-
Spec calls for
Front 6.9+/-0.5 MPa (6.4-7.4)
Rear 5.6-6.7 MPa
Before:
Front 8.1mpa-g
Rear 6.8mpa-g
Accumulator 10.2mpa-g
TB bolt turn Only (6 complete turns)- This did help some, but not enough
Front 6.7 mpa-g (pressure lowered 1.4) = 0.23mpa-g/1 full turn of TB bolt
Rear 7.1 mpa-g (pressure raised 0.3)
Accumulator 10.2 mpa-g
Rear Spacers AND previous TB twist
Front 6.9mpa
Rear 6.3mpa (30mm spacers = only 0.5mpa drop)
Accumulator 9.7mpa
I am in spec! But it still rides pretty firm. So, I will drive it tomorrow and see how it rides. If it is still rough, I will turn the TB bolt tighter (without jacking up the car- Thanks Praddo) then drive it around for a couple days. If it is still rough, I may back the TB bolt out and see how that rides, who knows maybe it just needed the rear spacers and not as much TB twist from the beginning. Anyway, I think Prado is correct and this is going to be some trial and error.
I was surprised the spacers did not lower the Rear pressure more. The 0.5mpa for 30mm spacers was not what I was imagining. I thought it would be closer to 1.0mpa, oh well, maybe I need new springs after all.
Alrighty...
30mm spacer came in and I installed them in about 1.5 hours. It was a bit tricky to get them in there since I did not remove the entire springs, just dropped it a bunch.
1. Jacked up one side of the axle
2. Put a tall jack stand under the frame near the rear axle front suspension link mounting point
3. Removed the wheel
4. removed the sway bar bolt
5. Put on spring compressors (didn't tighten them much due to the limited space and the bolts were too long) but they helped keep the spring from extending fully when the axle was lowered
6. Lowered the axle
7. Removed the bottom shock bolt
8. Lowered the axle about 2" from the ground
9. Squeezed the 30mm spacer around the bump stop and up against the body.
10. Jacked the axle back up to seat it on the spacer
11. Removed the spring compressors
12. Lowered the axle
13. Installed the shock lower bolt (took some wiggling and a rubber mallet)
14. Raised the axle in order to insert the sway bar bolt
15. Put the tire back on
Opposite side was the same, just quicker.
I drove it around for a few minutes and I do not think it is much better, but I will find out tomorrow when I have some more seat time.
Just for more data, I plugged my $25 Amazon Techstream into my 13 year old XP laptop to get some pressures.
AHC Pressure from the FSM-
Spec calls for
Front 6.9+/-0.5 MPa (6.4-7.4)
Rear 5.6-6.7 MPa
Before:
Front 8.1mpa-g
Rear 6.8mpa-g
Accumulator 10.2mpa-g
TB bolt turn Only (6 complete turns)- This did help some, but not enough
Front 6.7 mpa-g (pressure lowered 1.4) = 0.23mpa-g/1 full turn of TB bolt
Rear 7.1 mpa-g (pressure raised 0.3)
Accumulator 10.2 mpa-g
Rear Spacers AND previous TB twist
Front 6.9mpa
Rear 6.3mpa (30mm spacers = only 0.5mpa drop)
Accumulator 9.7mpa
I am in spec! But it still rides pretty firm. So, I will drive it tomorrow and see how it rides. If it is still rough, I will turn the TB bolt tighter (without jacking up the car- Thanks Praddo) then drive it around for a couple days. If it is still rough, I may back the TB bolt out and see how that rides, who knows maybe it just needed the rear spacers and not as much TB twist from the beginning. Anyway, I think Prado is correct and this is going to be some trial and error.
I was surprised the spacers did not lower the Rear pressure more. The 0.5mpa for 30mm spacers was not what I was imagining. I thought it would be closer to 1.0mpa, oh well, maybe I need new springs after all.
Last edited:
Nice post and good documentation 'WKBOGIE'.
Please keep us updated. Several of us are following this thread and wanting to see the results.
Please keep us updated. Several of us are following this thread and wanting to see the results.
I'm about to start this whole thing again myself. I have an 05 with 127k on it, fully stock. I changed out the globes last year because of a horrific ride with 113k on it. Ride was back to stock, lovely. I never checked the pressures, everything worked fine. All of a sudden over the last few months the ride has been getting progressively worse. No changes at all, so I'm not sure the issue. I just borrowed the tech stream software and a cable (thanks @bozncsurf). I'm going to check my graduations, and the pressures and see whats' up. I will report back. Great info in this thread, thanks everyone.
