Height Differences Between Corners OK? Why? (1 Viewer)

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Dan Higgins

Dan Higgins

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Jul 24, 2016
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So when I measure the height from the middle of a hubcap to the fender I see up to an inch or even a bit more variation. I am usually doing the measurements for testing before/after for my trailer weight distribution hitch setting but sometimes it is just sitting in my garage which has a relatively level floor. These are not simply front to back differences. They are also side to side. Front left seems to usually be the lowest. And generally the left is lower than the right.

When I queried Slee about this (they did the 2" lift for me) they claimed this is "normal". They said the set the lift to be 2" above whatever they measured when I brought the truck in. Really? Why? And why would Slee do that? If the truck was "crooked" when I brought it in wouldn't they try to "fix" it? Of maybe it wasn't "broken"?
 
Unscrew your KDSS valves three turns and take a slow drive through the neighborhood. Close valve, measure and report back.
 
Dan Higgins said:
So when I measure the height from the middle of a hubcap to the fender I see up to an inch or even a bit more variation. I am usually doing the measurements for testing before/after for my trailer weight distribution hitch setting but sometimes it is just sitting in my garage which has a relatively level floor. These are not simply front to back differences. They are also side to side. Front left seems to usually be the lowest. And generally the left is lower than the right.

When I queried Slee about this (they did the 2" lift for me) they claimed this is "normal". They said the set the lift to be 2" above whatever they measured when I brought the truck in. Really? Why? And why would Slee do that? If the truck was "crooked" when I brought it in wouldn't they try to "fix" it? Of maybe it wasn't "broken"?
Click to expand...

Slee should indeed do exactly what they did...because it is most likely just a KDSS lean...which changes all the time based on how your truck sits on non-level surfaces. If they tried to straighten it with springs or preload...tgere’s A good chance it would stay screwy regardless of KDSS adjustments.

Btw... Never unscrew the KDSS valve more than 3 full turns.
 
Thanks. Never more than 3 full turns. Got it. I guess if I do it comes out and then I'm in big trouble. ;) I think I'll have the Toyota dealer service dept do this Monday AM when I take it in to get the brake rotors adjusted. I'll tell them no more than 3 full turns. But if something gets messed up then its on them. ;)
 
Asked the dealer to try out what you all suggested above (3 turns, slowly drive around, tighten). But all I had to do was mention "KDSS" and "lifted" and they sort of freaked. Didn't want to touch it. :rolleyes:

As it ends up, I checked the height when parked at a flat spot today and everything measured 21'5" within 1/4". So I assume it is just a matter of how I have it loaded, if the gas tank is near full and maybe the fact that the progressive 2721 springs I have sink a bit more than the front at first (when I drop the trailer on them) but then stiffen up more as they sink a bit.

In any case, disappointed in Groove Toyota service department but no longer concerned about "lean".
 
Very possible it's KDSS. But it's just as likely that there's always some form of a natural lean. Especially as the vehicle ages.

If you go to the 100-series forum, those vehicles don't have KDSS. And there are many threads and cases of cars leaning. Many 1", but some even more. It's just what happens to a slinky tall and heavy vehicle over time.

I'm not completely familiar with your suspension system but is there ability to adjust ride height via a spring perch? Or they are fixed position perches and lift?

Trim packers of various thicknesses are used to compensate for this side to side lean. The 100-series also had the advantage or torsion bars to easy adjustability. Looks like you're just fine though.
 
I had no success doing the KDSS adjustment that MSCruiser did. YMMV.

It is super easy if you have a set of metric allen wrenches. Yes you don't want to open it more than 3 turns, but all you need to do is line your allen wrench up parallel to the frame and then count the number of turns. You can probably stop at 2.5... I've done 3 turns but somewhere around turn 1.5-2 the KDSS opens up (you can't tell unless you have the vehicle on a lift, and then when you turn it the suspension will quickly and obviously droop). To make opening the KDSS easier I use a cheater - a 10-12" piece of 1/4" copper pipe I slide over the allen wrench handle, which gives extra leverage and makes it super easy to turn the valve.

Proper way to measure is fill the vehicle with half a tank of fuel, park it, turn the KDSS screws 2.5-3 turns, let the vehicle sit about 20 minutes, bounce it at all corners, tighten the KDSS screws back up, and then measure. Toyota says left-to-right should be within 15mm (5/8") for factory setup. If it's more you're supposed to take it to a Toyota dealer and have them bleed and repressurize the system using their special tool.

With my 2" lift I'm spot on in the rear left-to-right, and IIRC about 3/8" difference in the front (I have numbers in a thread somewhere around here). When the rear springs were swapped on the wrong sides originally I was 1-1.5" off left-to-right. I seriously doubt Slee put your springs on the wrong side though - that's the kind of amateur mistake only I make.

KDSS will apparently "re-level" your vehicle over time if your parking spot is not level. Basically the left-to-right and front-to-back chambers are isolated, but not really. So an extremely small amount of fluid will leak its way between chambers over time while the vehicle sits at night.

If the KDSS adjustment doesn't help and you're more than 1/2" off left-to-right (especially in the rear), I'd consider a 5mm or 10mm trim packer in the rear to get it closer to level. Then do the KDSS adjustment again. They're easy to install, and as you adjust the rear level you'll find the front also adjusts.
 
Thanks! I read through that thread, @Markuson. I don't think I'll mess with it unless it is really noticeable. (Unlike the rest of you, it is only with great fear and trepidation that I crawl under any vehicle - especially with some tool in my hand with the intent of turning something.) But I may take this information (or the OME procedure pdf) to my dealer should I need to and see if they will do it.
 
Thanks, Geoff. I wonder if some of this is due to my garage floor not being perfectly level. Also, since you tow as I do, could it be that the weight of the trailer, the leverage of the WD bars, etc. could leave the KDSS a bit lopsided and that maybe that would go away if I leveled the truck by putting it on risers like the ones we use to level a trailer?
 
No I don't think towing has an impact. I think it takes weeks or months of parking on a non-level surface overnight for the KDSS to self-adjust. Also WD shifts front-to-back, but left-to-right is really determined by the vehicle load since the trailer only has one weight-bearing contact point (the 2" receiver hitch) in the center.

If the lean is due to the garage floor, doing the leveling thing will fix it probably for a few months at least, maybe indefinitely. My driveway is brick paver and is most definitely not level (there are ruts where the vehicle is parked) and I don't think there's more than maybe 1/4" difference currently left-to-right because of it. A slightly non-level driveway shouldn't impact you much. If you do the KDSS leveling and it doesn't correct the lean, I'd look at trim packers in the rear as the next step since they're cheap and easy to try.
 
Dan here's the official Toyota FSM pages for your 2016 for KDSS leveling. Note that you don't need to remove the cover over the KDSS (step 2a).

upload_2018-6-13_10-41-26.png

upload_2018-6-13_10-41-42.png

upload_2018-6-13_10-41-55.png
 
linuxgod said:
Dan here's the official Toyota FSM pages for your 2016 for KDSS leveling. Note that you don't need to remove the cover over the KDSS (step 2a).
Click to expand...

@linuxgod Is that FSM available for purchase anywhere other than a techstream account?
 
A suggestion I might add is after you loosen, drive it around the block a bit. Then let it settle. This is more to relieve bushing friction than KDSS. When the KDSS valves are open, the hydraulic arm can easily be moved by hand and is no longer a component of the lean. I'm not convinced that a 200 lbs man pushing on a 6,000 lbs truck is going to get anything to settle. The rubber suspension bushings and tire position can cause the vehicle to not completely relax. Driving it around and cornering will exercise the arms and links and get it to its static state. This is particularly true if the vehicle has just come off jack stands and the tires are bound up. Go for a quick drive, come back, have a beer, then tighten them up.

Interesting that it also suggests to bleed air if there is a L/R lean.
 
Last edited:
Good point. ARB's instructions also include this warning. With the open KDSS valves you're driving with your anti-roll disabled so the vehicle will feel very soft in corners. Not something I'd recommend on the highway but around the block shouldn't be a problem unless you're first name is Mario.
 
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