m2 Sportchassis cab bag leaks

[hemsteadc]

Found a couple pinhole leaks in one of my cab bags.  Does anyone have any quick/temporary fixes, like tape or glue or bicycle tube repair?  Not sure this is a DIY job, and having difficulty with shops in this area.

[Chad Heiser]

No good suggestions on a quick fix, but I do have a bit of experience changing the cab air bags on a Kenworth T2000.  The job itself is pretty easy.  The hardest part is access (which isn't bad on my T2000).  I can see access on an MDT being a bit more challenging, but I don't know for sure.  I use a small bottle jack (sitting on the frame and a 2x4 to spread the load on the bottom side of the cab) to lift the cab up to make access to the top and bottom of the airbags much easier.  Typically it is one or two bolts and/or clips and an air line to remove and then reconnect the new bags.

[hemsteadc]

On 5/11/2021 at 5:55 PM, Chad Heiser said:

 I do have a bit of experience changing the cab air bags on a Kenworth T2000.  The job itself is pretty easy. 

Sportchassis tells me they can do it in a half-hour.  Of course, everyone around here says 2-3 hours.  Sigh. Just not sure it's a job I want to tackle.  Thanks.

Of course I don't expect these leaks to stay small and will likely blow on me at the worst possible time.

Found a mobile mech who says he'll show up tomorrow.  I'll be amazed if he does.  With the bags. Good help is hard to find around here.    Yeah, it'll cost me, but I have more money than desire or mechanical ability.

Edit: Nobody here yet. No calls, nothing.  Why am I being lied to all the time?

Edited May 13, 2021 by hemsteadc

[ms60ocb]

Have you found a fix? Do you have the replacement parts or is that part of the problem.

4 years ago, Sportchassis replaced mine after Freightliner couldn't find the leak. Of course that Freightliner service shop had some other problems.  

Clay    2015 Sportschassis M2 106 only drove less than 2300 miles last year.

[hemsteadc]

On 5/23/2021 at 8:33 AM, ms60ocb said:

Have you found a fix? Do you have the replacement parts or is that part of the problem.

The fix will be taking it to the least incompetent truck shop. Mobile service said they'd show up, twice, never did.  Other shop was so disorganized I left. The last time I used a Freightliner shop they kept it for 3 weeks.  Parts are not an issue.

I found 2 pinhole leaks in one of the cab bags.  I'm actually considering covering the holes with Gorilla glue and hoping it holds long enough to see if they are the reason the rear axle bags are also deflating without actually having leaks of their own. Sportchassis said leaking cab bags can do that, but they also didn't know what LOF meant.

Edited May 24, 2021 by hemsteadc

[Darryl&Rita]

The only way that leaking cab bags can drain the suspension bags, is if the suspension levelling valve is passing backwards. If it's weeping pressure back into an empty air system, you'll end up with empty suspension bags. In warmer temps, our KW will sit for a week before squatting. Cooler, it'll drop faster. Our levelling valve is of unknown age, and I don't worry enough to change it.

[ms60ocb]

On 5/11/2021 at 10:56 AM, hemsteadc said:

 Not sure this is a DIY job, and having difficulty with shops in this area.

Where you located. This appears to be a job that is not impossible for the shade tree mechanic but extremely hard without a pit because my arms are not long enough laying under neath. The truck bed makes it more difficult but not impossible.

Clay

[hemsteadc]

5 hours ago, ms60ocb said:

Where you located.

NM

[TD1]

Do try to get it repaired as a long time diesel tech I can tell you that excessive air leaks in the chassis cause the air compressor to run or cycle more that is should and it will eventually take its toll on it, if you have access there usually easy to change. Disconnects the control and use it to overfill the bags a little the shove a precut block of wood in there for support and then swap them out refill and remove blocks. Reconnect control valve arm and your good to go

[hemsteadc]

On 5/31/2021 at 5:30 PM, TD1 said:

 Disconnects the control and use it to overfill the bags a little ..

I'm not sure what that means.  What control?

I'm getting more ready to try this myself, only first I have to have access under the truck without constant fear of it falling on me.  So I'm pouring concrete pads for ramps to elevate the truck enough to see if I can do this.  And of course that takes forever. 

[Darryl&Rita]

2 hours ago, hemsteadc said:

What control?

Ride height control.

 

2 hours ago, hemsteadc said:

only first I have to have access under the truck without constant fear of it falling on me

It can only go so far, like 4 inches. It won't "Lay frame", or crush you underneath, unless your a little "stouter" than most.

ETA: Instead of waiting for concrete, place wood blocking between the frame and axle, after you lift a little higher than usual, using the ride height trick posted above.

Edited June 7, 2021 by Darryl&Rita

[hemsteadc]

Got the last of the concrete poured today, so soon I'll get 'er up and get  under there and see what's what.  My favorite mechanic will absolutely not do air bags at my house.

I do not understand this truck.  For the last couple months the rear bags have been going down in concert with the cab  bags.  Now, last night, the cab bags deflated (2 known leaks) but the rears remained up.  Huh?

Edited June 8, 2021 by hemsteadc

[hemsteadc]

On 5/31/2021 at 5:30 PM, TD1 said:

. Disconnects the control and use it to overfill the bags a little 

Can I fool a lever or valve to think the bags are full?  In other words, stop air going to them?

Edited June 14, 2021 by hemsteadc

[Darryl&Rita]

2 hours ago, hemsteadc said:

Can I fool a lever or valve to think the bags are full?  In other words, stop air going to them?

Yes, disconnect the control rod and pull the arm in the direction of too high. Should be down. Air will be shut off, and bags will deflate.

[hemsteadc]

2 hours ago, Darryl&Rita said:

Yes, disconnect the control rod and pull the arm in the direction of too high. S

thanks

[hemsteadc]

Got the cabs bags replaced for 'only' a couple hundred bucks.  I didn't do the rears because they hadn't been leaking.  Now, after getting the cab bags replaced, the rears are leaking again.

I don't know how bags can leak intermittently.

[Darryl&Rita]

14 minutes ago, hemsteadc said:

I don't know how bags can leak intermittently.

Push to connect fittings are known for this, levelling valves can also do it. Less likely is the threaded portion of the fittings.

[hemsteadc]

6 hours ago, Darryl&Rita said:

Push to connect fittings are known for this, levelling valves can also do it. Less likely is the threaded portion of the fittings.

thanks.  Oh how nice.. all the bags are staying up and she's only leaked about 10 pounds in two hours.  Yay!

[hemsteadc]

Oh Joy! 

Both cab and rear bags stayed inflated all night, and the system lost only 50lb.  I don't know what you guys experience, but losing 'only' 50lb overnight' is a major improvement for this truck.  

Edited June 26, 2021 by hemsteadc

[hemsteadc]

Got to the Q and things started leaking again.  Mainly the rear bags.  ARRGGGHHH!  

Was all set to have the Love's repair shop replace rear bags, but upon further inspection I heard the drain valve on the rear tank hissing.  Pushed the pin a few times, got it to leak less, but not completely stopped.  Ordered a reman valve which should be here next week. 

[rpsinc]

Carry some kids soap bubbles.  They are the best to find air leaks, they bubble up more than dish soap.  And if you carry a compressor on board, use it to fill up the system with low-mid pressure without having the engine running.

[hemsteadc]

16 hours ago, rpsinc said:

Carry some kids soap bubbles.  They are the best to find air leaks, they bubble up more than dish soap. 

I've been fighting air leaks for 8 years on this thing.  Maybe someday I'll get them stopped.. for a few weeks.  Perhaps I need to learn to live with them.

Edited October 29, 2021 by hemsteadc

[rpsinc]

I think that any truck with air will have some leaking, its a matter of how much leaking is acceptable.  Or perhaps how much you are willing to accept.  It should always be a part of maintenance and part of a regular routine to mitigate those leaks.  There are just so many places that air is connected and used.  It is a chore to stay on top of them, and just when you think you got them all fixed, well, you take it for a drive and there ya go, another one pops up.

[hemsteadc]

3 hours ago, rpsinc said:

I think that any truck with air will have some leaking, its a matter of how much leaking is acceptable.  Or perhaps how much you are willing to accept. 

The only leaks I've felt comfortable fixing are the push-pin drain valves on the 2 tanks, and those are hard enough to remove.  I'm not doing air bags, nor messing with that multi-connection junction box near the rear axle.  Nope,  it's $hop time, and that's a whole other problem.. finding a reliable shop that knows what it's doing and doesn't take 3 weeks to do it.

The one leaking that really drives me nuts is the rear bags.  If I want to camp and remain hitched up, I don't want to have a  sag of 3" or more by morning.

 

Edited October 29, 2021 by hemsteadc

[ms60ocb]

My continuing leaks have been more Seat related. Driver seat had length hose that to short. Looking at it wasn't suspected to be a problem but connector was a repeating occurrence. The Passenger seat has a minor leak that I haven't solved. Turning the air at that seat solves the problem. My cab air bags were replaced when leaking about 70 lbs a hour ( a respected couldn't find the problem), 4 years ago a 25,000 miles. I drove up to Clinton OK and boys replaced the air bags and did a once over on the truck.

Clay 2015 Sport Chassis M2-106.