[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]

Originally Posted by 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...

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....

[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]

Originally Posted by 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.

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]

Originally Posted by wfo9

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]

Originally Posted by T5RUNNER

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]

Originally Posted by wfo9

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]

Originally Posted by T5RUNNER

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.