Leaky Seat Height Adjustment Air Valve

[hitchn2go]

My seat height adjustment valve is leaking. Trying to find a part number for the valve/ switch but Dynamax changed the seats out from stock?

Anybody had this problem that can point me in the right direction? Or has anybody replaced with an suitable substitute?

[KRedburn]

Standard Freightliner part NTS 235522 01
Available direct from Freightliner parts.

The seat riser is a standard Freighliner assembly. The swivel and seat are different.

[hitchn2go]

Originally Posted by KRedburn

Standard Freightliner part NTS 235522 01
Available direct from Freightliner parts.

The seat riser is a standard Freighliner assembly. The swivel and seat are different.

Thanks for the part# and the info!

This was the same# that the parts guy had (using my VIN) but I couldn’t find a pic of it so was not sure.

[EdandShelley]

We had the issue for quite a while. Tried a new air switch but issue continued.

Use some windex and spray it around where the airlines attach. That is where we had the leak. We used some in weld them out the airlines in. Let it set for 24 hours. No more leaks.

[hitchn2go]

Originally Posted by EdandShelley

We had the issue for quite a while. Tried a new air switch but issue continued.

Use some windex and spray it around where the airlines attach. That is where we had the leak. We used some in weld them out the airlines in. Let it set for 24 hours. No more leaks.

Good idea. Did you pull off the airline or just put it around the outside? I will have to cut the tube anyway if I have to install a new one, so worth a shot.

[EdandShelley]

Originally Posted by hitchn2go

Good idea. Did you pull off the airline or just put it around the outside? I will have to cut the tube anyway if I have to install a new one, so worth a shot.

After spraying the Windex we could clearly see the leak coming from around both airlines. Was causing the seat to loose height while driving and secondary air gauge pressure to fall.

Pulling off the lines will be a little difficult. Found that scoring the outside of the line where it connected allowed me to get it off. Then cut the line so you have a clean area to reinstall. Out the JB weld around the brass nipple on the switch being careful to not let it get near the air opening. Reinstall the lines and put a little extra JB around the end of the air line. Did the trick. Has been working great fir 6 months.

[hitchn2go]

Originally Posted by EdandShelley

After spraying the Windex we could clearly see the leak coming from around both airlines. Was causing the seat to loose height while driving and secondary air gauge pressure to fall.

Pulling off the lines will be a little difficult. Found that scoring the outside of the line where it connected allowed me to get it off. Then cut the line so you have a clean area to reinstall. Out the JB weld around the brass nipple on the switch being careful to not let it get near the air opening. Reinstall the lines and put a little extra JB around the end of the air line. Did the trick. Has been working great fir 6 months.

Same symptoms. Yep, those lines are on pretty good. I am going to give it a try...thanks!

[EdandShelley]

Originally Posted by hitchn2go

Same symptoms. Yep, those lines are on pretty good. I am going to give it a try...thanks!

Be careful with the airline that goes to the seat. Only so much line available to cut and still have adequate slack to work. Replacing it requires removing the seat to get to the airbag underneath. I learned the hard way.


Other (supply line) has a coupling behind the seat so easy to replace if needed.

[hitchn2go]

Originally Posted by EdandShelley

Be careful with the airline that goes to the seat. Only so much line available to cut and still have adequate slack to work. Replacing it requires removing the seat to get to the airbag underneath. I learned the hard way.


Other (supply line) has a coupling behind the seat so easy to replace if needed.

Ok. I used the windex test and it was bubbling. I just raised the seat to the max and stuck something in the scissors to keep it from collapsing when seat airbag deflated. Only cut off about 2 inches and reseated both tubes. Used the E6000 on the control module post. Hopefully, this fixes it...will update in a couple days!

Thanks again for responding to the post!

[EdandShelley]

Originally Posted by hitchn2go

Ok. I used the windex test and it was bubbling. I just raised the seat to the max and stuck something in the scissors to keep it from collapsing when seat airbag deflated. Only cut off about 2 inches and reseated both tubes. Used the E6000 on the control module post. Hopefully, this fixes it...will update in a couple days!

Thanks again for responding to the post!

Anytime. This Forum has been an incredibly valuable asset. One of the primary reasons we went with a Dynamax.

[hitchn2go]

Just for Thread completeness, I took the control module out of seat frame to make it easier to work on, took a picture to document which tube went where, and used a potato chip clip to keep deflating the air so as not to bubble the sealant.

[EdandShelley]

Originally Posted by hitchn2go

Just for Thread completeness, I took the control module out of seat frame to make it easier to work on, took a picture to document which tube went where, and used a potato chip clip to keep deflating the air so as not to bubble the sealant.

Nice work... will be easy to check for a leak before reinstalling.

[hitchn2go]

Since this is my Sunday project, decided to study this a bit more to understand what is going on....

Looking at the part of the tubes cut off, noticed abrasions on each of them near the brass nipple connector. Comparing to the passenger seat (still working on drivers seat), noticed the seat frame rails are really close to the nipples. As the seat is further deflated, the air tubes get distressed as the frames descend upon each other. Over time that seems like what is causing the edge of the brass nipple to cut into the air lines. It may be more than just a leaky connection point.

I am going to have to find a way to limit how far the seats descend before the lines get distressed or this will just happen again.

[EdandShelley]

Originally Posted by hitchn2go

Since this is my Sunday project, decided to study this a bit more to understand what is going on....

Looking at the part of the tubes cut off, noticed abrasions on each of them near the brass nipple connector. Comparing to the passenger seat (still working on drivers seat), noticed the seat frame rails are really close to the nipples. As the seat is further deflated, the air tubes get distressed as the frames descend upon each other. Over time that seems like what is causing the edge of the brass nipple to cut into the air lines. It may be more than just a leaky connection point.

I am going to have to find a way to limit how far the seats descend before the lines get distressed or this will just happen again.

We found the same. There are two rubber bumpers at the base of the seat. One of ours was tipped to the side allowing the seat to crimp the air hose. Started our issue.