KDSS Lean after install

[Jasalvas]

Hi everyone,

In recently reading through a build thread I noticed the owner mentioned after lifting/installing a new suspension they experienced some KDSS lean (KDSS had increased the overall lift at times by a couple of inches)...

About 3 weeks ago I installed 6112's in the front 2.5" and 5160's in the rear with Icon 2" rear coils and it looked great after the install. About a day or two later I noticed the truck was up about an additional 2" in the rear, so all together a 3-4" increase in ride hight in the rear of the vehicle.

As of now the truck looks to be sitting correctly but I wanted to hear from others on their experience on how KDSS has reacted to the lift that was installed.

Thanks all and I look forward to hearing from you.


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[Sleeter]

I haven't noticed any significant difference in lift that can't be attributed to cargo weight. Did you take before, after, and current measurements or is this eyeballed?

 

[4Rager]

My truck leaned to the right until the springs settled in, and it was fine. Now for some reason after 8000 miles it's an inch lower on the right side again. It's quite noticeable at times, but when I measure on flat ground it's only an inch. That being said, since it leans to the right it's probably pretty much level when my 200lb ass is in the driver's seat. But it did seam weird that only the back seemed to be affected. The front has been pretty much level from day 1.

 

[wfo9]

The typical KDSS lean after a lift is higher on the drivers side lower on the passenger.

There is a KDSS balancing procedure you should try, but we found it to only worked short term for the common KDSS lean.. The lean kept coming back. The only permanent fix was small spacers to raise up the passenger side.

If you do the balancing procedure read the instructions carefully. When they say back out 10mm or whatever... they are talking about measuring from the outer portion of the bolt head, so only back 4mm or so less than the instructions state.

I've never seen KDSS be the source of front/reverse rake.. That should just be springs...

 

[Thesoundofpanic9]

The typical KDSS lean after a lift is higher on the drivers side lower on the passenger.

There is a KDSS balancing procedure you should try, but we found it to only worked short term for the common KDSS lean.. The lean kept coming back. The only permanent fix was small spacers to raise up the passenger side.

If you do the balancing procedure read the instructions carefully. When they say back out 10mm or whatever... they are talking about measuring from the outer portion of the bolt head, so only back 4mm or so less than the instructions state.

I've never seen KDSS be the source of front/reverse rake.. That should just be springs...

I experienced this and performed the KDSS calibration. Before, my driver's side sat about 1.5" higher than the passenger's side. With the calibration I was able to bring it down to about .75" higher. Still not perfect but much less noticeable. It has remained at .75" for about 5K miles.

The calibration is simple, but as stated, if you back the bolts out too far, you are ****ed.

 

[carlomagne]

I've been at 3/4 of an inch difference for the last 16,000 miles after the install. Evens out when I have more than half a tank of gas. Doesn't bother me.

 

[OC4X4]

Can the "Lean" be resolved by adjusting the front coil-overs, by cranking up or down? Also is it something you have to constantly be adjusting?

 

[Jasalvas]

My truck sits level from driver to passenger so far... The lean consisted of the rear of the truck being about 2" higher than it should be or should have been. No measurements were taken before and after swap out of suspension (I know... I know) so all by the eye. The truck seems to sitting properly now though the KDSS may act up again.
I guess I need a better idea of how KDSS works. I believe it is the accumulators that monitor and control the amount of compensation applied by the hydraulic system. Would that be right?

Also would the amount of lift have an affect on the amount of "lean" some are experiencing?

Maybe this is why the KDSS feature was removed from the TRDPro test models as they are a higher riding vehicle. The videos of test drives I've seen seemed like the test vehicles sat higher than the standard TRDPro seem available today.

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[mybabydaddy]

OP seems to be referring to something different than what we (on the forum) refer to as the “KDSS Lean”..... He was referring to front-back “rake” (specifically, the rear height), and if it was somehow affected by KDSS.

OP - I have never heard/read anything on here about KDSS somehow affecting the (ride) HEIGHT of a lift, but I don’t claim to be the expert by any means.

I have (first hand) experience on the “KDSS Lean” that we are all referring to/familiar with... As I have a 2014 w/ KDSS and a small lift... and yes, mine varies from 1/2 inch to full inch passenger-side lean depending on load and how/where the truck is parked. But I stopped paying attention to it a loooong time ago. And I’m OCD as hell.... :crazy:

 

[T5RUNNER]

The whole "KDSS lean" theory doesn't make any sense if you look at how the system actually works. It is still a sway bar. If you lift a truck equally on both sides, the bar just rotates. It does not effect the KDSS piston position at all.

Now a lift kit can absolutely create lean, most OEMs use different springs on the front sides to avoid lean, but most lift kits don't. You can fix it by adjusting the spring height in various ways like shims. My understanding is the turd pro version of the 6112 kit has two collar positions, one for each side, to get around this.

It has nothing to do with KDSS.

 

[wfo9]

The whole "KDSS lean" theory doesn't make any sense if you look at how the system actually works. It is still a sway bar. If you lift a truck equally on both sides, the bar just rotates. It does not effect the KDSS piston position at all.

Now a lift kit can absolutely create lean, most OEMs use different springs on the front sides to avoid lean, but most lift kits don't. You can fix it by adjusting the spring height in various ways like shims. My understanding is the turd pro version of the 6112 kit has two collar positions, one for each side, to get around this.

It has nothing to do with KDSS.

At first glance... I thought the same thing. But two KDSS trucks I looked at were perfectly level for quite some time and then suddenly had a significant lean while parked... Hard to say what they were doing at speed. The balancing procedure resolved it both times, but it would come back. So we knew KDSS was at play.

We also eventually found a Toyota master tech who had worked on quite a few KDSS trucks with the same problem. He could not explain why it happens, but said it is common and a spacer in the rear + adjustments up front usually resolve it.

I think it has to do with the geometry of the KDSS system in the front. It is not like a typical swaybar and connects to the spindles much differently...(it actually ties into the lower control arms directly) there is some additional binding in the front at ride height once you lift one with KDSS. It still works fine.. Some people are just anal about the lean.. And it seems to be permanently resolvable by adjusting the coil overs in front and adding a small spacer in the rear. We will have to see what happens over time to be sure though. One thought on why they bind up and lean at times may a signal for new bushings.... IDK. But I do know the KDSS system/swaybar itself is at play.

 

[T5RUNNER]

At first glance... I thought the same thing. But two KDSS trucks I looked at were perfectly level for quite some time and then suddenly had a significant lean while parked... Hard to say what they were doing at speed. The balancing procedure resolved it both times, but it would come back. So we knew KDSS was at play.

We also eventually found a Toyota master tech who had worked on quite a few KDSS trucks with the same problem. He could not explain why it happens, but said it is common and a spacer in the rear + adjustments up front usually resolve it.

I think it has to do with the geometry of the KDSS system in the front. It is not like a typical swaybar and connects to the spindles much differently...(it actually ties into the lower control arms directly) there is some additional binding in the front at ride height once you lift one with KDSS. It still works fine.. Some people are just anal about the lean.. And it seems to be permanently resolvable by adjusting the coil overs in front and adding a small spacer in the rear. We will have to see what happens over time to be sure though. One thought on why they bind up and lean at times may a signal for new bushings.... IDK. But I do know the KDSS system/swaybar itself is at play.

But what read what you wrote, it wasn't always there and you didn't actually fix it. Lean varies based on weight, fill up your gas tank and your lean will change.

KDSS is linked backwards from typical sway bar but that doesn't change the way it works. Both sides will bind equally.

Again, it is very common for lift kits to cause lean. It has nothing to do with KDSS. If he completely removed his sway bars, the lean would not change.

 

[wfo9]

But what read what you wrote, it wasn't always there and you didn't actually fix it. Lean varies based on weight, fill up your gas tank and your lean will change.

KDSS is linked backwards from typical sway bar but that doesn't change the way it works. Both sides will bind equally.

Again, it is very common for lift kits to cause lean. It has nothing to do with KDSS. If he completely removed his sway bars, the lean would not change.

Yea, lifts kits and loads... can cause lean.. Duh. I'm talking about a complexly different thing.

Please don't take offense to this, but I constantly feel like I'm talking to a brick wall whenever KDSS comes up. People just can't seem to look at any issue unbiased and think they are all experts. The system can and does cause leans. It is well documented. It is nothing like a regular swaybar setup. The system has pros and cons.. Some people just can't step back...

If you don't believe me... Why does the repair manual state this in the troubleshooting guide for KDSS.

I'll attach a screen shot so you don't think I'm making this stuff up LOL

 

[T5RUNNER]

Yea, lifts kits can cause lean.. Duh.I'm talking about a different thing. Please don't take offense to this, but I constantly feel like I'm talking to a brick wall whenever KDSS comes up.

Haha I feel the same way right now! KDSS can lean, (accumulator pressures out of whack I guess?) but lift kits don't make it lean. Lifting does not change the piston position.

Or just use your general problem solving skills:
before lift=no lean
after lift=lean
lift=lean

The lean would be the same on a non KDSS truck. KDSS never moved unless you forgot to secure the piston. Another thing to check is what the lean was before the lift. Most vehicles lean to the passenger side to compensate for the driver and fuel.

Fix the lean by adjusting the spring height, just as you would on any other truck. Or just leave it, or change the weight of your girlfriend.

 

[wfo9]

Haha I feel the same way right now! KDSS can lean, (accumulator pressures out of whack I guess?) but lift kits don't make it lean. Lifting does not change the piston position.

Or just use your general problem solving skills:
before lift=no lean
after lift=lean
lift=lean

The lean would be the same on a non KDSS truck. KDSS never moved unless you forgot to secure the piston. Another thing to check is what the lean was before the lift. Most vehicles lean to the passenger side to compensate for the driver and fuel.

Fix the lean by adjusting the spring height, just as you would on any other truck. Or just leave it, or change the weight of your girlfriend.

We got our signals crossed at some point...

All the situations I have seen have been.

before lift = no lean for years
after lift = no lean for 6 months to a year, then intermittent to severe lean

after tilt calibration procedure = no lean for a few weeks, then it came back

did air bleed procedure = no lean for a few weeks, then it came back

final solution (as of right now), wait for the lean and adjust out with spacers and coil overs.

There is clearly a link between lifting it and the tilt in my mind. They don't have the problem stock and it changes over time with a lift. Trucks with a standard swaybar system may have a lean when first lifted... But it does not keep getting unbalanced like the KDSS systems seem to do. There is something about the system itself that causes leans. I can't explain exactly what it is. They don't all have the problem either.

 

[T5RUNNER]

We got our signals crossed at some point...

All the situations I have seen have been.

before lift = no lean for years
after lift = no lean for 6 months to a year, then intermittent to severe lean

after tilt calibration procedure = no lean for a few weeks, then it came back

did air bleed procedure = no lean for a few weeks, then it came back

final solution (as of right now), wait for the lean and adjust out with spacers and coil overs.

There is clearly a link between lifting it and the tilt in my mind. They don't have the problem stock and it changes over time with a lift. Trucks with a standard swaybar system may have a lean when first lifted... But it does not keep getting unbalanced like the KDSS systems seem to do. There is something about the system itself that causes leans. I can't explain exactly what it is. They don't all have the problem either.

haha ok last post from me. Even in your example the KDSS did not cause, and could not cure the lean. KDSS can effect the tilt of the truck, but don't start using it to try and cure lean caused by a lift kit. It can't. It would be like trying to fix it with fuel level, it would only work right now, its a bandaid.

The lift kit caused the lean. We are at least in agreement that adjusting the ride height is the way to fix it. That is because the ride height is the cause of it. I'm trying to crush this myth, and save people a lot of time and money.

YOU CAN ONLY FIX YOUR RIDE HEIGHT BY FIXING YOUR RIDE HEIGHT.
No one would suggest fixing lean by changing your sway bar link length. That is what messing with your KDSS does. My only guess is that the accumulators are not always at the same pressure when you shut the truck off, and that it does actually vary on a stock truck as well.

Don't worry though, my lift is still sitting in my garage. When I finally get time to install it, I may come crawling back to this thread.

 

[wfo9]

haha ok last post from me. Even in your example the KDSS did not cause, and could not cure the lean. KDSS can effect the tilt of the truck, but don't start using it to try and cure lean caused by a lift kit. It can't. It would be like trying to fix it with fuel level, it would only work right now, its a bandaid.

The lift kit caused the lean. We are at least in agreement that adjusting the ride height is the way to fix it. That is because the ride height is the cause of it. I'm trying to crush this myth, and save people a lot of time and money.

YOU CAN ONLY FIX YOUR RIDE HEIGHT BY FIXING YOUR RIDE HEIGHT.
No one would suggest fixing lean by changing your sway bar link length. That is what messing with your KDSS does. My only guess is that the accumulators are not always at the same pressure when you shut the truck off, and that it does actually vary on a stock truck as well.

Don't worry though, my lift is still sitting in my garage. When I finally get time to install it, I may come crawling back to this thread.

Ha ha, yep you might be. KDSS can and does affect the balance of the vehicle. It is difficult to know what is causing the issue once you modify the truck. There are solutions, it just takes some trial and error over time. I recommend trying the tilt calibration procedure before adjusting springs...

 

[Jetboy]

FWIW - KDSS, if set to zero properly, seems to have no effect whatsoever on lean in my 4runner.

I have air suspension and adjust my ride height all the time. I never notice any lean whether I'm at oem hight or +5 inches. (I can lift the rear until I max the shocks out). I don't totally understand why some people are having issues with KDSS and lean. It's something I'm struggling to understand the physics of as to why it happens. I can understand that if it's setup wrong initially it would lean, but if it's set level once, it should always be level regardless of lift. There must be something I'm missing. Like the leverage on the front piston is different than the rear due to geometry changes in the front control arm and over time it pulls the left side down or something? Or the rear without an adjusted trac bar is off center and causes some imbalance?

 

[CROWN14]

KDSS Lean

I took several measurements before and after my lift install.
I too had about a 3/4 inch lean on the rear passenger side and 1/2 in the front.
(full tank)

I remeasured six months later and it had reduced to about a 1/4 inch even on the passenger side.
I've checked it a couple more times and have noticed slight variations but never more than 1/2 inch which i can live with. Not really noticable to the naked eye.

I've never attributed this to the KDSS all be it possible.
Installing any suspention kit will alter the geometry. This is why it is important IMO to have someone you know has off road suspention experience do your install and alignments.

They're easy to do if your mechanicaly inclined ( I am) but just as easy to screw up. I gladly paid an old freind in the business and another friend for the alignment. I haven't had any issues and it rides like a dream.

 

[HKSJoo]

if most ppl w kdss have a lower, passenger side lean, why do my cornfed rear spacers have less lift on the passenger side and more on the driver side? should i reverse the orientation for the rears?