KDSS knocking noise during lateral movement

[dhatcher]

I will try not to make this long winded as I know KDSS topics have nearly been beaten to death here but, I wanted to see specifically what advice folks here have regarding my situation.

2016 Trail Premium 4Runner. I had a Sonoran Steel lift kit installed by a professional mechanic (a bunch of other work has been done by the same person but, probably not as pertinent to this issue as the lift kit).

At some point (random) after the kit install, the 4Runner developed a significant knocking noise when the body moves laterally. Lots of troubleshooting later, between myself and the mechanic and unbolting the sway bar caused the noise to stop happening. So we narrowed it down to the likeliness of it being the front KDSS piston or KDSS system in general. He theorized there was probably air in the system and it needed to be bled out.

We both have researched enough to know not to attempt the process ourselves and that it should be done by a dealer. Headed over to my local dealer, they looked at the problem and agreed with our assessment but, then told me they don't have the equipment and their techs don't have the training to perform that procedure. They suggest I call around to other Toyota dealers who sell a lot more lifted Tacomas/4Runners and see if one of them can do it.

Supposedly, the tech who worked on my 4Runner has his own lifted 4Runner and has the same sound as mine and I was told via the service manager (never got to speak to the tech directly) that he's seen people have their KDSS system bled to get rid of that noise only for it to return later. Also, seemed to imply the noise is harmless (my biggest concern is making sure nothing about the system is beating itself to death) and that I could leave it alone and be fine.

What do you guys think? Leave it alone and turn the radio up or try to find a dealer (possibly Lexus dealer?) to bleed the system?

 

[Jivewalker]

I will try not to make this long winded as I know KDSS topics have nearly been beaten to death here but, I wanted to see specifically what advice folks here have regarding my situation.

2016 Trail Premium 4Runner. I had a Sonoran Steel lift kit installed by a professional mechanic (a bunch of other work has been done by the same person but, probably not as pertinent to this issue as the lift kit).

At some point (random) after the kit install, the 4Runner developed a significant knocking noise when the body moves laterally. Lots of troubleshooting later, between myself and the mechanic and unbolting the sway bar caused the noise to stop happening. So we narrowed it down to the likeliness of it being the front KDSS piston or KDSS system in general. He theorized there was probably air in the system and it needed to be bled out.

We both have researched enough to know not to attempt the process ourselves and that it should be done by a dealer. Headed over to my local dealer, they looked at the problem and agreed with our assessment but, then told me they don't have the equipment and their techs don't have the training to perform that procedure. They suggest I call around to other Toyota dealers who sell a lot more lifted Tacomas/4Runners and see if one of them can do it.

Supposedly, the tech who worked on my 4Runner has his own lifted 4Runner and has the same sound as mine and I was told via the service manager (never got to speak to the tech directly) that he's seen people have their KDSS system bled to get rid of that noise only for it to return later. Also, seemed to imply the noise is harmless (my biggest concern is making sure nothing about the system is beating itself to death) and that I could leave it alone and be fine.

What do you guys think? Leave it alone and turn the radio up or try to find a dealer (possibly Lexus dealer?) to bleed the system?

I would take out each sway bar bushing and inspect before messing with bleeding. A cracked or worn bushing can cause knocking, it did for me and replacing the bushings fixed it. Mine was cracked behind the bracket strap, couldn't see it without pulling it out.

 

[dhatcher]

I would take out each sway bar bushing and inspect before messing with bleeding. A cracked or worn bushing can cause knocking, it did for me and replacing the bushings fixed it. Mine was cracked behind the bracket strap, couldn't see it without pulling it out.

Interesting! My 4Runner only has 30K miles on it but I'll definitely give that a look! Maybe time to see if there are some tougher sway bar bushings for these vehicles.

 

[Jivewalker]

Interesting! My 4Runner only has 30K miles on it but I'll definitely give that a look! Maybe time to see if there are some tougher sway bar bushings for these vehicles.

Put a jack under the piston before unbolting brackets, do one at a time, they can be a pita to get lined back up. Also, it's very easy to cross thread the end link bracket bolts. Use your jack to manipulate the piston up and down to get the end brackets to roll away from mount one at a time. Research a little before you do it.

 

[ayeyothisiskyle]

Put a jack under the piston before unbolting brackets, do one at a time, they can be a pita to get lined back up. Also, it's very easy to cross thread the end link bracket bolts. Use your jack to manipulate the piston up and down to get the end brackets to roll away from mount one at a time. Research a little before you do it.

Yep. Thats the reason why I have two in the garage as spares.

OP: Do a lot of research before you change out the bushings. That bar is darn hefty and difficult to get into place. when the brackets are off. Helpful tools include a long screwdriver or rod to use for bracket alignment, and if you have them, multiple jacks to support and align where needed.

 

[dhatcher]

Yep. Thats the reason why I have two in the garage as spares.

OP: Do a lot of research before you change out the bushings. That bar is darn hefty and difficult to get into place. when the brackets are off. Helpful tools include a long screwdriver or rod to use for bracket alignment, and if you have them, multiple jacks to support and align where needed.

Will a regular 3 ton floor jack and the oem bottle jack suffice for persuasion purposes? (I have a decent sized pry bar, few smaller crowbars and multiple screw drivers handy).

 

[dhatcher]

(Reading through some of the KDSS / sway bar bracket threads on here is definitely revealing that a lot of patience and careful attention will be required with those M12 x 1.25mm bolts).

 

[Jivewalker]

Will a regular 3 ton floor jack and the oem bottle jack suffice for persuasion purposes? (I have a decent sized pry bar, few smaller crowbars and multiple screw drivers handy).

Unless you lift the wheels off the ground, the bottle jack is all you need. Place it under the piston and lift a little. remove the two passenger side end bracket bolts. Lower the bottle jack slowly and the bracket will roll away from the mounting point. The bracket has two tabs on the bottom that slide over the bottom of the mount, but you should be able to just pull the bushing out carefully without freeing the two bent tabs, if not push down on the bar to clear the bottom. Inspect or change the bushing (bushin is split to allow removal and installation), raise jack to roll back into position, insert screwdriver or drift pin through alignment hole at top of bracket, CAREFULLY reinstall the two bolts and torque to spec. Once you do the passenger, you will have a good understanding of how to manipulate the piston and what it does to the bar and brackets. Study it first and it will make sense! It's not that hard, just don't rush the bolts back in. Worn bushings and/or cracks are known to cause the knocks. Good luck!

Adding that it is probably wise to keep the jack under the piston to keep it from fully extending and hanging there. Not sure that hurts anything, but no reason not to support it.

 

[dhatcher]

Unless you lift the wheels off the ground, the bottle jack is all you need. Place it under the piston and lift a little. remove the two passenger side end bracket bolts. Lower the bottle jack slowly and the bracket will roll away from the mounting point. The bracket has two tabs on the bottom that slide over the bottom of the mount, but you should be able to just pull the bushing out carefully without freeing the two bent tabs, if not push down on the bar to clear the bottom. Inspect or change the bushing (bushin is split to allow removal and installation), raise jack to roll back into position, insert screwdriver or drift pin through alignment hole at top of bracket, CAREFULLY reinstall the two bolts and torque to spec. Once you do the passenger, you will have a good understanding of how to manipulate the piston and what it does to the bar and brackets. Study it first and it will make sense! It's not that hard, just don't rush the bolts back in. Worn bushings and/or cracks are known to cause the knocks. Good luck!

Adding that it is probably wise to keep the jack under the piston to keep it from fully extending and hanging there. Not sure that hurts anything, but no reason not to support it.

Awesome! Thank you for the tips. I'm waiting to get the 4runner back from the dealer (airbag recall) and then I'll give the bushing replacement a go and report if it fixes the knock issue.

 

[Jivewalker]

Awesome! Thank you for the tips. I'm waiting to get the 4runner back from the dealer (airbag recall) and then I'll give the bushing replacement a go and report if it fixes the knock issue.

Did you fix your knock?

 

[dhatcher]

Did you fix your knock?

Haven’t had the chance to work on it yet. I need to find a shop that’s willing to swap the cv boots on one of my axles so I’m kind of focusing on that at the moment. Kind of surprised how many mechanics have turned down that job so far but, maybe I shouldn’t be.

 

[Mutant138]

Put a jack under the piston before unbolting brackets, do one at a time, they can be a pita to get lined back up. Also, it's very easy to cross thread the end link bracket bolts. Use your jack to manipulate the piston up and down to get the end brackets to roll away from mount one at a time. Research a little before you do it.

Yep. Thats the reason why I have two in the garage as spares.

OP: Do a lot of research before you change out the bushings. That bar is darn hefty and difficult to get into place. when the brackets are off. Helpful tools include a long screwdriver or rod to use for bracket alignment, and if you have them, multiple jacks to support and align where needed.

(Reading through some of the KDSS / sway bar bracket threads on here is definitely revealing that a lot of patience and careful attention will be required with those M12 x 1.25mm bolts).

Why not use the relief valve on the system like you're "supposed" to? Correct me if I'm wrong but you wouldn't have to wrestle nearly as much and prob save yourself the annoyance and cost of stripping bolts.

This but in between the process you do pull the sway bar apart.

YouTube

 

[Jivewalker]

Why not use the relief valve on the system like you're "supposed" to? Correct me if I'm wrong but you wouldn't have to wrestle nearly as much and prob save yourself the annoyance and cost of stripping bolts.

This but in between the process you do pull the sway bar apart.

YouTube

Because there is no need to. The risk of a lean, or other problem with KDSS can be very expensive, especially if you don't know anything about it and since most dealers give you a blank stare when you ask about KDSS. For a tech with full toyota support and KDSS knowledge, sure, it may be easier. I did it the way I described by myself and had zero issues and wouldn't really consider it wrestling, just smart manipulation and understanding basic leverage and how the components move. Changing the shocks without a spring compressor and no helper on the other hand, now that was wrestling!

 

[Mutant138]

Because there is no need to. The risk of a lean, or other problem with KDSS can be very expensive, especially if you don't know anything about it and since most dealers give you a blank stare when you ask about KDSS. For a tech with full toyota support and KDSS knowledge, sure, it may be easier. I did it the way I described by myself and had zero issues and wouldn't really consider it wrestling, just smart manipulation and understanding basic leverage and how the components move. Changing the shocks without a spring compressor and no helper on the other hand, now that was wrestling!

It's a closed loop system it's not very complex and the instructions are very clear and documented. As for introducing lean idk if that statement had validity or not I haven't dug that deep. The video I sent is a supposed correction for lean although I have heard it's a band aid and usually comes back (idk about it causing lean tho). All I know is there is a servicing procedure for the KDSS system and plenty of people use it when doing their lifts with no issues. Just follow instructions closely it's literally just turning two or three bolts a few turns .

As for the spring compressor thing...
YouTube

 

[Jivewalker]

It's a closed loop system it's not very complex and the instructions are very clear and documented. As for introducing lean idk if that statement had validity or not I haven't dug that deep. The video I sent is a supposed correction for lean although I have heard it's a band aid and usually comes back (idk about it causing lean tho). All I know is there is a servicing procedure for the KDSS system and plenty of people use it when doing their lifts with no issues. Just follow instructions closely it's literally just turning two or three bolts a few turns .

As for the spring compressor thing...
YouTube

Simply following the procedures shown in the FSM is not always the best or easiest way to accomplish the task which Is what makes this forum great. The video you just linked is case and point. BTW, that's the way I changed my shocks. I researched a ton before touching the KDSS and made my decision to go the route I did after reading some others issues with the method you say is easy, and am glad I did so. I offered advice based on my experience of doing it, and I stand by that advice. To me, the way I did it was easier than pissing around with the KDSS, it simply isn't needed if you support the cylinders and then raise/lower them to line up the sway bars. Easy stuff. But to each his own, OP can make his own decisions and do his own research, which is what he was doing.

 

[Mutant138]

Simply following the procedures shown in the FSM is not always the best or easiest way to accomplish the task which Is what makes this forum great. The video you just linked is case and point. BTW, that's the way I changed my shocks. I researched a ton before touching the KDSS and made my decision to go the route I did after reading some others issues with the method you say is easy, and am glad I did so. I offered advice based on my experience of doing it, and I stand by that advice. To me, the way I did it was easier than pissing around with the KDSS, it simply isn't needed if you support the cylinders and then raise/lower them to line up the sway bars. Easy stuff. But to each his own, OP can make his own decisions and do his own research, which is what he was doing.

I haven't done any suspension work on this truck yet so I can only speak so much. I'll just take take your word for it.

I do think it would be unsafe to try and jack up on the LCA (to compress the springs) and the kdss piston bracket at the same while the truck is up on stands or a lift. But without the truck sitting wheels off in front of me it's hard to visualize.

 

[Jivewalker]

I haven't done any suspension work on this truck yet so I can only speak so much. I'll just take take your word for it.

I do think it would be unsafe to try and jack up on the LCA (to compress the springs) and the kdss piston bracket at the same while the truck is up on stands or a lift. But without the truck sitting wheels off in front of me it's hard to visualize.

I had 3 wheels on the ground, hub of wheel off supported with a 2x6 at lug nuts, KDSS cylinder supported with a bottle jack, and used the floor jack to lower the LCA away from the hub. It would only lower so far, so had to insert an old floor jack handle in and pry and hold it down enough to insert new shock and bolt up. Then raise LCA with floor jack and spring compresses. Worked like a charm, but really had to wrestle with holding the LCA down while inserting the new shock. If you unbolt the LCA where the alignment cams are, it would be much easier, but I had to wait a week or 2 before I could get the alignment, so I chose not to. Others have used the same method with success, hope this helps somebody else out!

 

[Mutant138]

I had 3 wheels on the ground, hub of wheel off supported with a 2x6 at lug nuts, KDSS cylinder supported with a bottle jack, and used the floor jack to lower the LCA away from the hub. It would only lower so far, so had to insert an old floor jack handle in and pry and hold it down enough to insert new shock and bolt up. Then raise LCA with floor jack and spring compresses. Worked like a charm, but really had to wrestle with holding the LCA down while inserting the new shock. If you unbolt the LCA where the alignment cams are, it would be much easier, but I had to wait a week or 2 before I could get the alignment, so I chose not to. Others have used the same method with success, hope this helps somebody else out!

You could have marked the cam. That prob would have got you by.