I was getting a harsh stiff ride and with the fluid change it went back to the "new" LX ride. I think everyone needs to change the fluid on the recommended interval.
Harsh riding '05 LX this can't be normal
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- #42
Thanks for the reply. It's due to go in for an alignment and an oil change, I'll have them change out the fluid.
I don't have time to mess with it. It's my wife's rolling office, and I can't get it away from her for a significant amount of troubleshooting time.
If that doesn't fix it, it's getting traded. It's a nice looking rig, but frankly, if it doesn't ride well, it's of no use to us.
I don't have time to mess with it. It's my wife's rolling office, and I can't get it away from her for a significant amount of troubleshooting time.
If that doesn't fix it, it's getting traded. It's a nice looking rig, but frankly, if it doesn't ride well, it's of no use to us.
Jim_Chow
V8_Fan
Why don't you then replace the suspension w/ an OEM LC suspension. You can buy the parts for around $1200 (t-bars, rear coils, shocks, rear sway-bar & bushings) on discount and DIY or have Slee do it (only 1 state over from 'ya).
hoser
SILVER Star
I would go used T-bars and springs for $150 at most and then new bilstein shocks. The sway bars are or near identical. We measured them last time.
- Thread starter
- #45
Jim and Hoser, thanks, I have considered going to new springs and bils if the fluid change doesn't work.
I had assumed at the 60K mile service the lexus dealership would have done the fluid change, but looking at the bill, I don't see it. The trunk has 75k miles so it's more than due, and hopefully that takes care of it.
I'll change the AHC fluid and report back so others that are experiencing this will know if that fixed it.
I had assumed at the 60K mile service the lexus dealership would have done the fluid change, but looking at the bill, I don't see it. The trunk has 75k miles so it's more than due, and hopefully that takes care of it.
I'll change the AHC fluid and report back so others that are experiencing this will know if that fixed it.
harsh ride caused by?
When a LC-100 or LX-470 --with AHC rides harsh over small stuff, but speed bumps are OK, it may be caused by having tightened up the torsion bars too much and or installed stiffer rear springs.
The hydraulic side pressure at normal ride height needs to be somewhat less than the pre-charge gas pressure in the accumulators. Otherwise a harsh ride over small stuff results because the accumulator 'looks' hard to the suspension. Larger bumps will create high enough pressure to get into the accumulator and will be absorbed. The FSM explains how to adjust the torsion bars to bring the oil side pressure to the 'proper' amount for OEM accumulators.
Conversely, when an accumulator gas charge gets low, the ride is hard over LARGE bumps as there is little room left in the units to absorb more oil from a compressed strut (actuator).
The vehicle SHOULD ride very well. If it does not, something is wrong.
When a LC-100 or LX-470 --with AHC rides harsh over small stuff, but speed bumps are OK, it may be caused by having tightened up the torsion bars too much and or installed stiffer rear springs.
The hydraulic side pressure at normal ride height needs to be somewhat less than the pre-charge gas pressure in the accumulators. Otherwise a harsh ride over small stuff results because the accumulator 'looks' hard to the suspension. Larger bumps will create high enough pressure to get into the accumulator and will be absorbed. The FSM explains how to adjust the torsion bars to bring the oil side pressure to the 'proper' amount for OEM accumulators.
Conversely, when an accumulator gas charge gets low, the ride is hard over LARGE bumps as there is little room left in the units to absorb more oil from a compressed strut (actuator).
The vehicle SHOULD ride very well. If it does not, something is wrong.
do you have a copy of the FSM on how to adjust the TB's? how will i measure the proper pressure?
Hi all,
Having the same problem with my 99 lx, it absorbs the large bumps great and is fine at high speed , but at low speed you can feel all the cracks and joints in the road. but the strange thing it is intermittent, sometimes it is perfect at low speed and very pleasant and other times it is harsh and unpleasant at low speed, I can not pin point whether it depends on the outside temperature or not.
Does the system have a temperature sensor in it that is playing up, or am i looking in the wrong direction?
Having the same problem with my 99 lx, it absorbs the large bumps great and is fine at high speed , but at low speed you can feel all the cracks and joints in the road. but the strange thing it is intermittent, sometimes it is perfect at low speed and very pleasant and other times it is harsh and unpleasant at low speed, I can not pin point whether it depends on the outside temperature or not.
Does the system have a temperature sensor in it that is playing up, or am i looking in the wrong direction?
Hard ridiung AHC
B and B suspension developed a real simply and easy way to test the condition of each of the 4 suspension accumulators (actuators in Toyota/Lexus speak) on the LX-470 and LC-100
We call it the Curb Drop Test
Accumulator test on Vehicle
(Curb Drop test)
All testing is performed at Normal ride height, no cargo or passengers, only driver and fuel. This test fundamentally creates a ‘test bump’ for a single wheel at a time to allow the vehicle owner to easily monitor or determine the condition of the suspension accumulator(s)
Carefully drive one wheel up on a 8” high curb or parking lot divider. Use a nearly ‘straight on’ angle, like turning into a driveway to provide an abrupt fall off the curb. When the single wheel is up on the curb, quickly back off, dropping that wheel onto the pavement. Observes how well (or poorly) the suspension accumulator (which Lexus/Toyota call an actuator which it isn’t) for that wheel allows the bump to be absorbed. A good accumulator will allow a smooth, well-damped drop with no harsh jars or jolts. The vehicle body corner will drop to below Normal, rebound to a little above Normal , and then settle back to Normal height.
A bad accumulator will NOT allow any suspension travel and the result is a hard hit with a series of rapid sharp bounces as only the tire is absorbing any energy.
Repeat the test for each wheel, noting the performance of each wheels accumulator in absorbing the bump.
B and B suspension developed a real simply and easy way to test the condition of each of the 4 suspension accumulators (actuators in Toyota/Lexus speak) on the LX-470 and LC-100
We call it the Curb Drop Test
Accumulator test on Vehicle
(Curb Drop test)
All testing is performed at Normal ride height, no cargo or passengers, only driver and fuel. This test fundamentally creates a ‘test bump’ for a single wheel at a time to allow the vehicle owner to easily monitor or determine the condition of the suspension accumulator(s)
Carefully drive one wheel up on a 8” high curb or parking lot divider. Use a nearly ‘straight on’ angle, like turning into a driveway to provide an abrupt fall off the curb. When the single wheel is up on the curb, quickly back off, dropping that wheel onto the pavement. Observes how well (or poorly) the suspension accumulator (which Lexus/Toyota call an actuator which it isn’t) for that wheel allows the bump to be absorbed. A good accumulator will allow a smooth, well-damped drop with no harsh jars or jolts. The vehicle body corner will drop to below Normal, rebound to a little above Normal , and then settle back to Normal height.
A bad accumulator will NOT allow any suspension travel and the result is a hard hit with a series of rapid sharp bounces as only the tire is absorbing any energy.
Repeat the test for each wheel, noting the performance of each wheels accumulator in absorbing the bump.
I did the curb test and it was all good, the problem is the really small stuff like cracks and joints in the road at city speed and it is intermittent (sometimes the ride is great even on the small stuff.
Does anyone have a wiring / schematic diagram for the AHC system?
Does anyone have a wiring / schematic diagram for the AHC system?
You are carrying a bit of extra weight on your 1999 Lexus. No doubt you have compensated with higher tyre pressures? If so, that could be a contributor to feeling all the little road imperfections at low speed.
I know that with mine, which weighs in at about 3200 Kg with all the gear and on which I run 40psi pressures all around, I feel more of the small stuff than I did when I bought it at two years old. My AHC is working fine though, it is just the extra weigh and tyre pressure.
I know that with mine, which weighs in at about 3200 Kg with all the gear and on which I run 40psi pressures all around, I feel more of the small stuff than I did when I bought it at two years old. My AHC is working fine though, it is just the extra weigh and tyre pressure.
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Thanks for the tips guys. I wondered why I kept feeling all the small cracks and stuff, even after changing all 4 accumulators and my steering rack. Seems like my TBs were cranked too much.
I loosened them, and now the ride is so much better and I can hardly feel it when it goes over potholes and stuff.
Question is :-
1. Without the LSPV gauge or the handheld tester, is there any other way to measure and get the correct balance between the TBs and the accumulators? Can i just use a simple pressure gauge complete with hose?
2. After loosening my TBs my car is much lower
it doesnt look that cool anymore....if I adjust the 'height sensors' to make it higher will it affect the pressure and subsequently will the 'harsh' ride over small cracks come back?
Thanks in advance.
I loosened them, and now the ride is so much better and I can hardly feel it when it goes over potholes and stuff.
Question is :-
1. Without the LSPV gauge or the handheld tester, is there any other way to measure and get the correct balance between the TBs and the accumulators? Can i just use a simple pressure gauge complete with hose?
2. After loosening my TBs my car is much lower
it doesnt look that cool anymore....if I adjust the 'height sensors' to make it higher will it affect the pressure and subsequently will the 'harsh' ride over small cracks come back?Thanks in advance.
uHu
Bridgeburner
You can use any gauge with a suitable range and adapter, which doesn't mind a bit of hydraulic oil.
If the car is lower after loosening the TBs, it means that the AHC wasn't carrying any weight before. No wonder it didn't feel right.
Correct procedure is to adjust the correct (or wanted/suitable) height with the sensors, and then measure the AHC pressure and adjust the TBs until the AHC is carrying it's portion of the load, i.e. that the Neutral Pressure is correct.
If the car is lower after loosening the TBs, it means that the AHC wasn't carrying any weight before. No wonder it didn't feel right.
Correct procedure is to adjust the correct (or wanted/suitable) height with the sensors, and then measure the AHC pressure and adjust the TBs until the AHC is carrying it's portion of the load, i.e. that the Neutral Pressure is correct.
Question is :-
1. Without the LSPV gauge or the handheld tester, is there any other way to measure and get the correct balance between the TBs and the accumulators? Can i just use a simple pressure gauge complete with hose?
2. After loosening my TBs my car is much lower
Thanks in advance.
uHu
Bridgeburner
All that extra weight has also added to the AHC pressure. The TBs and coils are not carrying any of the extra weight as long as the AHC can keep the height. That means that the gas spheres will be very compressed, and not give their best. If you increase the normal weight of the car permanently, you have to adjust the TBs and change the coils to compensate and keep the neutral pressure of the ahc.
Wow, you all have scared the crap out of me.
I had been looking at 99-02 LXs but have yet to drive one. I have driven a 100-series LC and loved the ride.
Currently have an 80 LC, but need something a little more comfortable for 2nd row passengers due to a changing family situation.
I don't care for the front styling of the LC on the 100 series at all, the LX looks great front to back. Also prefer the interiors on the LX.
And I am floored by scrappy's post that his GX rides better than his LX. The LX is wider and has a longer wheelbase...but apparently if the AHC is slightly faulty non of that matters.
I had been looking at 99-02 LXs but have yet to drive one. I have driven a 100-series LC and loved the ride.
Currently have an 80 LC, but need something a little more comfortable for 2nd row passengers due to a changing family situation.
I don't care for the front styling of the LC on the 100 series at all, the LX looks great front to back. Also prefer the interiors on the LX.
And I am floored by scrappy's post that his GX rides better than his LX. The LX is wider and has a longer wheelbase...but apparently if the AHC is slightly faulty non of that matters.
uHu
Bridgeburner
As long as you don't need a lift or steel bars front and rear or sliders or drawers the AHC is fantastic, at least until the springs (gas and steel) need changing after 200 k miles.
You can use a brake pressure test kit that handles up to 3000 psi. I bought one of these brake pressure testing guage sets to test and adjust the front TBs. Waekon BEQ0397 ABS and Brake Pressure Testing Master Kit for about US$300. It worked well.
I have stiffer rear coil springs fitted, which carry more of the load than the originals, which means that the AHC fluid pressure required to lift the rear is a little lower than the standard spec. To balance it out, I have cranked up the TBs to achieve the same fluid pressure at the front. I also have B&B Spheres with custom lower than standard gas charge pressure to match the lower fluid pressure and still give proper damping and wheel travel. The fluid pressure at Normal height is 50 psi over the Sphere gas charge pressure, which means the Spheres are just compressed by the unloaded vehicle weight at Normal height, and I get full travel of the suspension. When I load the vehicle up, the AHC does a little more work to support the load, as was intended in the original design. Starting at a lower fluid pressure means that I have a greater load carrying capacity before exceeding the AHC pump pressure limit.
All is good.
uHu
Bridgeburner
Sounds like a perfect set up. What coils do you use? Any specs re load carrying, thickness, length, etc, compared to the original coils?
