Peterbilt keeps breaking airbag studs

Installed a new air bag in our freightliner a year ago. A Good for a Year with a plastic base.

A year later, the driver reported a loud explosion. Pulled over, thought it was a tire.

The bottom of the air bag base was completely disintegrated.

He pinched off the line, finished his load to the farm which was only a mile away and came back empty.

I figured it’s gotta be the plastic base so since then I’ve been ordering aluminum base air bags from that point on.

I even type in “must be aluminum base” in my parts order to the supplier.

We do have trucks with plastic base air bags but they will be swapped to aluminum when it’s time to replace them.

It’s only $20 more.

I think plastic airbags needs a good sized surface area for a stable mount or it’ll bust out the studs.

Our stepdeck trailer for example is plastic base but has a base plate that’s the same size as the air bag base for a good support.

For our freightliner, the plastic base is trying to stay center on a small spring surface area. So all the load is transferred to the stud which rips out.

 

I would not go by pterbilts specs. Those dont take into account for worn front and rear springs, front tire wear and rear tire wear, worn out wear pads, etc etc. . Those specs are brand new factory specs. I use a driveline analyzer to measure pinion angles. My truck calls for a little over 11" ride height from pete. If i do that, those bags get awfully pumped up like yours. My ride height is set at 10.25 inches. That little bit difference maeks a huge difference on how high your bags are pumped up. My truck also has no drivline noise. Turn your radio off and everything else with windows up, drive your truck about 65mph, check if you here any noise. Ill bet those bags are way over pumped and you need to lower that down a bit. Looks like thats your problem

 

I think you’ve hit on something that makes good sense. The plastic base has never been a problem on the traditional Air Trac or AiR Leaf because they have such a large solid pad to sit on. Low air leaf does not.

The only problem I see with the aluminum in the long run is the corrosion that builds up between it and the rubber spring causing it to rot a little faster. But that has always been an issue with the other suspensions as well.

 

SmallPackage: You’re correct with corrosion of aluminum also being an issue as well.

 

The freightliner that did blow the plastic base does have a air bag position misalignment which did not help the plastic base at all.



It is scheduled to go to a suspension shop shortly to correct the issue.

The OP’s post already stated he had the suspension work done and still have air bag breakage.

So I’m guessing it’s likely the supplier of the air bag with the material the base is made of or how the stud is put into the base.

 

My guess is depending on the brand of airbag, the plastic air bag base is garbage.

The manufacturer may have gotten cheap.