AHC "Topping Out" or something in High (1 Viewer)

[xplorre]

I googled, I promise!

2003 LX, 250k

My AHC is completely overhauled (10k miles ago), new globes and fluid, TBs, spring spacers, neutral pressures, the works, rides great. Until I shift into high... No matter the surface, I get sudden jarring noises from the rear over the smallest of bumps. I thought this was only offroad and was the result of limited downtravel but it does it over expansion joints in the parking lot too.

I changed out all my rear rubber besides shock bushings, no change. Have all the rubber for the fronts, waiting to find time for the job. I was thinking shock bushings but I don't get the sound/vibration in N, only in H.

Thoughts?

 

[Coin]

Less weight on the springs in high, more weight on the shocks. Could be bushing related… maybe.

I feel you on not swapping the rear shock bushing though. I still have them on my shelf. It’s the last of my bushings to be replaced.

 

[suprarx7nut]

Interested to hear what you find. My bet would be on shock bushing (lower) or the upper cushions.

 

[2001LC]

To be clear: "Until I "shift" into high" Switch/raise AHC to H (high)?

Are height sensors at factory position, or has there been a sensor lift?

Did you replace the rubber insulators at tops of coils?

Have you inspected bushing?

What's condition of stabilizer system?

Here's some from shocks bushing, that are shot.

 

[xplorre]

"Until I "shift" into high" Switch/raise AHC to H (high)?

Are height sensors at factory position, or has there been a sensor lift?

Poor choice of words, you're correct. "Switch from Neutral to High"

Height sensors are factory height, I followed the PDF and ABCs approx 10k miles ago.

 

[2001LC]

Poor choice of words, you're correct. "Switch from Neutral to High"

Height sensors are factory height, I followed the PDF and ABCs approx 10k miles ago.

Sorry, I kept adding to my above post. Be sure to look back over it.

In the ABCs of AHC, has fender to axle heights, different (higher) than I get measuring factory unchanged set-up. Some, adjust sensors to get the higher heights. Which then results in a higher H. Which takes more weight of coils. At greater height. Especially when the top of coil rubber insulator removed. We then sometimes, get coils (springs) banging.

I've also found a few times. Where shocks bolts not properly torque. When the top nut of shock, not tight. We get a rattle on bumps.

Also worth note: Bushings of shocks LWR and control arms bolts. Need torque down, while weight of vehicle on tire in neutral stance. Not doing so, reduce bushing life. As does hot dry deserts, which SoCA not, but than where is you vehicle from. At 250K miles, may need some refresh.

Other than some incorrect assembly or set-up issue. Most likely your issues, be bushing related. Camera is be diagnostic tool here, to start with.

 

[xplorre]

Sorry, I kept adding to my above post. Be sure to look back over it.

In the ABCs of AHC, has fender to axle heights, different (higher) than I get measuring factory unchanged set-up. Some, adjust sensors to get the higher heights. Which then results in a higher H. Which takes more weight of coils. At greater height. Especially when the top of coil rubber insulator removed. We then sometimes, get coils (springs) banging.

I've also found a few times. Where shocks bolts not properly torque. When the top nut of shock, not tight. We get a rattle on bumps.

Also worth note: Bushings of shocks LWR and control arms bolts. Need torque down, while weight of vehicle on tire in neutral stance. Not doing so, reduce bushing life. As does hot dry deserts, which SoCA not, but than where is you vehicle from. At 250K miles, may need some refresh.

Other than some incorrect assembly or set-up issue. Most likely your issues, be bushing related. Camera is be diagnostic tool here, to start with.

Thanks so much for the input. Once the rain lets up here I'll get under there and inspect the shock bushings. I have spring spacers installed to get AHC pressures in spec, and I remember seeing the upper rubber insulator in place. Will report back!

 

[2001LC]

Thanks so much for the input. Once the rain lets up here I'll get under there and inspect the shock bushings. I have spring spacers installed to get AHC pressures in spec, and I remember seeing the upper rubber insulator in place. Will report back!

I usually take out, the factory insulator, when installing spacers. Only because, they don't fit well together. Shouldn't be a issue either way.

With new coils and spacers. Coils bang around is unlikely.

 

[xplorre]

I usually take out, the factory insulator, when installing spacers. Only because, they don't fit well together. Shouldn't be a issue either way.

With new coils and spacers. Coils bang around is unlikely.

Backed the LX into the driveway, put ahc in high. Lower shock bushings look pretty good, centered on bolt side to side and only slightly off center in relation to the bolt when looking down the eye. Rear coils are interesting though. I'm able to move one of them (DS) around a bit. I have to give it a decent jerk but it's not immovable...

 

[2001LC]

Backed the LX into the driveway, put ahc in high. Lower shock bushings look pretty good, centered on bolt side to side and only slightly off center in relation to the bolt when looking down the eye. Rear coils are interesting though. I'm able to move one of them (DS) around a bit. I have to give it a decent jerk but it's not immovable...

DS uses taller coil.. Even with spacer, if coils PS on DS. The coil may be loose in H.

I may be wrong on colors. So check part number and google pictures, for your VIN# at www.partsouq.com

They have a identifying color paint on them. It's been reported, Toyota/ Lexus have different coils and we've 4 different P/N. I use Toyota AHC coils.

This are in my note for replacements coils. Factory's may be colored differently.
Toyota AHC: DS-Brown, PS- Purple
Lexus AHC: DS-Green, PS-yellow

 

[2001LC]

Also make sure your tool kit secure and spare tire full and secure. Or they'll bang, clunk, clank, thud, rattle..