KDSS and the LEAN. It's really very simple. (8 Viewers)

[Aussie Mick]

Gday all,
Having purchased a used 200 series, I wasn't aware of the lean that can occur with the KDSS. I have the petrol model and it came standard with KDSS.

First up, I am self employed in hydraulic repairs so I have some experience and I'm happy to share what I've found.

KDSS for the Land Cruiser was designed by a guy over in Western Australia. In a nut shell it's awesome and I'd highly recommend the system. It is a basic system, with NO electrical or computer assistance build into the system.

The way to check if there's an issue with the system which can cause the lean is to climb under the vehicle and have a look at the 2 hydraulic cylinders. In Australia, they're on the passenger side or in other words the same side as where the valve body is with the 2 bleed screws we all know about. The rear one is located in front of the rear axle housing and the front is located in front of the front axle housing. Both are connected to their appropriate sway bars. Once located, look at the end where the rod comes out, if you see any of the rod sticking out of the cylinder then the system has not return home correctly. You shouldn't see any rod at all and the clevis (which is attached to the end of the rod and in turn connected to the sway bar), should almost be touching the front of the cylinder. If both cylinders look like this with no rod sticking out, then the issue IS NOT with the KDSS as the system has allowed for both cylinders to return back to the retracted position.

I must admit, I bled the system (you know, release the screws a max of 3 turns etc) about 6 times, as I was reading all the success others had in leveling their Cruiser. I couldn't get the 50 mm / 2" lean to improve at all. My lean was to the right when looking from behind.
So, after talking with a few Toyota dealers and basically having them tell me that it must be a KDSS issue I decided to check the spring issue

Problem solved: Right rear spring had lost some life to it and there was the cause of the lean. I had a new set of rear springs installed and now there's a 10mm / 3'8" difference between the 2 sides. Perfection at last.
In conclusion, don't get stuck on the KDSS being the issue, remember, there's a large fuel tank on the right rear which in itself weights a bit, which all contributes to the life of the spring.
So, if all cylinders are fully closed in, then I'd be looking at replacing the rear springs.

Hope this helps and happy to answer any questions if the need arises.

Have a wonderful day and enjoy life

 

[NLScooby]

Thanks for sharing your insights. It's great to have a hydraulic expert on the forum. Perhaps I'm just speaking for myself, but I don't have a great deal of experience with these systems. Your spring "failure" is the first I've heard of.

 

[M1911]

Aussie Mick:

Could you post a picture of what that rod end should look like?

 

[SQRRRL]

My rig leaned to the left. It's a 2013 I purchased in July. The learn is gone after I did a road trip fully loaded with a rear cargo carrier. When I unloaded the LC, no more left lean. SWEET. Might be something to try?

 

[linuxgod]

If you have a small lean, it's apparently easily rectified by loosening the KDSS screws a bit, then driving the high side up on a block of wood

Fixing a KDSS lean - Balancing KDSS

Sounds like Aussie Mick's problem was much larger though. Glad to hear he resolved it.

 

[Bwriston]

Any pictures available for KDSS rods?

 

[stithis]

Bump, want to see the pics of the cylinder

 

[fasteddie2015]

I have a 1 inch difference from right to left in the rear, measuring to the top of the fender opening or rear bumper. Is 1 inch something worth trying to fix? I dont want to turn a minor issue into a major one.

 

[Alpinhi]

So I have had the lean upto 2 inches at a time to the driver's side. I tried the method described in the video by driving up on the boards with no luck. I did jack up the truck on the driver's side and then release the valves. I could hear the hydraulic fluid move through it and that did make a big difference to the point where I got it level. After a couple of days of driving the truck has settled back down leaning to the driver's side. I have a new suspension ready to install when I have time but I'm not sure a "soft" spring is the issue or not. I would love to see a photo of the pins you speak of so I can verify they are in the correct spot. If they aren't, what's the next step? Is this something that has to be done by the dealer?
We just arrived in Moab today driving in from the Kansas City area. While on the highway the truck loaded with luggage and food, the suspension felt very soft and spongy. We hit a couple of decent sized holes coming down the west side of Loveland Pass and I almost lost control. It feels like my old Jeeps with swaybar disconnected, that's kinda why I think it might be the KDSS and not a spring issue. I'm going to crawl under it tomorrow in the parking and see if can figure this pin situation or not.

 

[SQRRRL]

So I have had the lean upto 2 inches at a time to the driver's side. I tried the method described in the video by driving up on the boards with no luck. I did jack up the truck on the driver's side and then release the valves. I could hear the hydraulic fluid move through it and that did make a big difference to the point where I got it level. After a couple of days of driving the truck has settled back down leaning to the driver's side. I have a new suspension ready to install when I have time but I'm not sure a "soft" spring is the issue or not. I would love to see a photo of the pins you speak of so I can verify they are in the correct spot. If they aren't, what's the next step? Is this something that has to be done by the dealer?
We just arrived in Moab today driving in from the Kansas City area. While on the highway the truck loaded with luggage and food, the suspension felt very soft and spongy. We hit a couple of decent sized holes coming down the west side of Loveland Pass and I almost lost control. It feels like my old Jeeps with swaybar disconnected, that's kinda why I think it might be the KDSS and not a spring issue. I'm going to crawl under it tomorrow in the parking and see if can figure this pin situation or not.

Rears spring swap? Tall spring goes on drivers side.

 

[linuxgod]

Rears spring swap? Tall spring goes on drivers side.

Nope. Tall spring goes on the side with the gas tank. That’s the drivers side in Australia but the passenger side in the US. I did it wrong the first time and it resulted in about 2” of lean with the drivers side being way higher

 

[SQRRRL]

Nope. Tall spring goes on the side with the gas tank. That’s the drivers side in Australia but the passenger side in the US. I did it wrong the first time and it resulted in about 2” of lean with the drivers side being way higher

My bad intel. Sorry brah. What he said . passenger side. I’m getting forgetful these days. : /

 

[BAY2MTN]

Nope. Tall spring goes on the side with the gas tank. That’s the drivers side in Australia but the passenger side in the US. I did it wrong the first time and it resulted in about 2” of lean with the drivers side being way higher

Me too. 1.5" high on driver's side. Waiting to swap springs before doing the KDSS mambo.

Strangely, there doesn't seem to be consensus on this. Gary at Mudrak, on of the more respected LC customizers, told me, "Taller spring on driver's side". It's also written that way on a couple others' websites. But from what I can find: "A" spring, taller, passenger....I hope.

 

[Alpinhi]

So I haven't swapped out a y of the suspension yet, it's still in stock form with approximately 140K on the odometer. I have a set of Icon remote res with the CDCV valves for the front and OME 2721 rear springs. Like I said none of this is installed yet but maybe it is just a bad spring. I'm hoping that's the issue because my local dealer is clueless when I asked about the KDSS system. The only other valves I have seen in the hydraulic system are just in front of the proportining valves used to adjust the system. I'm attacking a photo but I dont see any "pins" sticking out.

 

[Alpinhi]

Well I guess when I install the springs I'll try taller on the passenger side first then swap if I need to, not that big of deal. My lean on the stock suspension is low on the driver side and if I dont adjust it every few weeks it gets real low, to the point it looks broken. I dont know, I just wanna figure it out. This is my first KDSS vehicle, my 4th gen 4r had the XREAS that I deleted when I installed Icobs on it. I REALLY like the way it rides and handles now.

 

[TeCKis300]

KDSS lean is a red herring. It likely has nothing to do with KDSS, unless someone lifted their vehicle without following reset procedures.

Since the beginning of time with SUVs and trucks, or vehicles with tall soft springs, there's been a tendency to lean over time. Once a lean starts, more weight is carried by the lower side, further exacerbating the lean.

What to do? It's why trim packers exist. 5 or 10mm springs spacers to be fitted to the sagging side to re-level the vehicle.

KDSS's function is strictly as a on demand sway bar. Sway bars generally do not impart any twist or lean on the vehicle and will tend to keep it flat/neutral. Messing with the KDSS system to fix a lean is misdirected and a fix that won't last.

 

[linuxgod]

Me too. 1.5" high on driver's side. Waiting to swap springs before doing the KDSS mambo.

Strangely, there doesn't seem to be consensus on this. Gary at Mudrak, on of the more respected LC customizers, told me, "Taller spring on driver's side". It's also written that way on a couple others' websites. But from what I can find: "A" spring, taller, passenger....I hope.

When you remove the old rear springs you’ll notice the taller factory spring is on the passenger side in the US.

I cannot speak for every kit. Different coil rates, heights, etc might make a different manufacturer need to reverse them. But I can say for certain that with Tough Dog the taller spring goes on the side with the gas tank. I’ve also read that OME says to swap driver and passenger side in the US, presumably because the drivers position is not on the gas tank side here.

YMMV but if you start with the taller spring on the drivers side in the US and have a lean, you already have the right answer and it’s not KDSS

 

[bloc]

So I haven't swapped out a y of the suspension yet, it's still in stock form with approximately 140K on the odometer. I have a set of Icon remote res with the CDCV valves for the front and OME 2721 rear springs. Like I said none of this is installed yet but maybe it is just a bad spring. I'm hoping that's the issue because my local dealer is clueless when I asked about the KDSS system. The only other valves I have seen in the hydraulic system are just in front of the proportining valves used to adjust the system. I'm attacking a photo but I dont see any "pins" sticking out.

View attachment 2234430

That is where the system is filled and drained. If you remove the caps pointing forward in this photo (not pointing down) you’ll see a clean quick disconnect fitting with a schraeder valve in the middle. Don’t go messing with those valves.

OP was talking about the KDSS cylinders themselves, which on mine have pleated plastic covers protecting the polished shaft, and the balance valves located in the block on the inside of the frame rail.

Well I guess when I install the springs I'll try taller on the passenger side first then swap if I need to, not that big of deal. My lean on the stock suspension is low on the driver side and if I dont adjust it every few weeks it gets real low, to the point it looks broken. I dont know, I just wanna figure it out. This is my first KDSS vehicle, my 4th gen 4r had the XREAS that I deleted when I installed Icobs on it. I REALLY like the way it rides and handles now.

The odd thing here is if you balance things it’ll level then find a lean again. To me it seems like a spring issue would present itself when the balance valves are open too, and be “captured” or locked in once the balance valves are closed.

Hypothetical: I wonder whether this might be caused by say the front axle having level springs and the rear having uneven ones, which does something odd with the KDSS hydraulics over time. Or maybe like I suspect is wrong with mine.. where the suspension bushings weren’t in a truly neutral ride height position when tightened so the bushing is acting as another spring lifting one side, even if the coil springs themselves are level enough.

 

[bloc]

Another confounding factor to this thread.. respectfully, I think OP had it wrong.

At normal ride height I’m pretty sure the KDSS cylinders should be in the middle of their travel, not retracted. They need to be able to move both directions from ride height to allow each sway bar to “disconnect”

I took pictures of this at some point.. will try to dig them up.

 

[linuxgod]

The odd thing here is if you balance things it’ll level then find a lean again. To me it seems like a spring issue would present itself when the balance valves are open too, and be “captured” or locked in once the balance valves are closed.

Hypothetical: I wonder whether this might be caused by say the front axle having level springs and the rear having uneven ones, which does something odd with the KDSS hydraulics over time. Or maybe like I suspect is wrong with mine.. where the suspension bushings weren’t in a truly neutral ride height position when tightened so the bushing is acting as another spring lifting one side, even if the coil springs themselves are level enough.

I've read somewhere on this forum in an official-ish PDF that KDSS allows for fluid to "leak" left-to-right and front-to-back over time. It might be in MSCruiser's old thread. So any KDSS adjustment you do will eventually "reset" itself (and conversely any KDSS imbalance should eventually rectify itself). I've also read that if you leave you vehicle parked on a hill or slant that can affect the KDSS lean. All that said KDSS lean is irrelevant if your springs (or spring rates) are off - get them correct first and then use KDSS to fine-tune the balance if it's still off.

As a side note, the FSM says if you're within 15mm IIRC left-to-right it's considered within spec, so anything within 5/8" is totally normal. Also keep in mind when you put 200# in the driver's seat your driver's side ride height will change slightly