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runaway parents

Cab air bag Disaster

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Don't let this happen to you guys.  So I found out I had a air leak in one of my cab air bags. Figured since I had to change one might as well do them both. Supplier had to order them in.  Took a couple days. Didn't have to seeing that I already had the collets and o rings but I thought I would change out the ptc fittings with new ones. BIG mistake the new ptc fittings came with thread sealer on them. This was a very hard red substance caked on the threads.  I asked  parts salesman if I had to put thread tape on them. He said no. Sealant on fittings will be just fine.So I put every thing together. Went to air it up nothing all the air was leaking out of the bottom of my new air bags. Took them back apart to find out  the thread sealant had actually cracked the bottom of the air bag where the ptc fitting screwed into it. Not only did this to one but both of them. Took air bags back to supplier they seem to think they can warrantee them out wont know till tomorrow we will see. So fare the seem to a purity good outfit to get truck worked on . Did not realize the bottoms of these things where made of plastic seems kind of od. 

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13 minutes ago, runaway parents said:

Don't let this happen to you guys.  So I found out I had a air leak in one of my cab air bags. Figured since I had to change one might as well do them both. Supplier had to order them in.  Took a couple days. Didn't have to seeing that I already had the collets and o rings but I thought I would change out the ptc fittings with new ones. BIG mistake the new ptc fittings came with thread sealer on them. This was a very hard red substance caked on the threads.  I asked  parts salesman if I had to put thread tape on them. He said no. Sealant on fittings will be just fine.So I put every thing together. Went to air it up nothing all the air was leaking out of the bottom of my new air bags. Took them back apart to find out  the thread sealant had actually cracked the bottom of the air bag where the ptc fitting screwed into it. Not only did this to one but both of them. Took air bags back to supplier they seem to think they can warrantee them out wont know till tomorrow we will see. So fare the seem to a purity good outfit to get truck worked on . Did not realize the bottoms of these things where made of plastic seems kind of od. 

That red stuff was probably LocTite Red.  You can’t break it loose easily  without heat which would probably melted something.

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Ptc fittings screwed rite in buy hand and gave them about a quarter turn with wrench and I think that was all it took. Split the female fitting on the air bag three ways. It two was plastic.

Edited by runaway parents
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The air bags on a Freightliner have a push in fitting, no threads, nothing to tighten and break. Plastic airline just slides in. Release it by depressing the ring. 

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19 minutes ago, beyerjf said:

The air bags on a Freightliner have a push in fitting, no threads, nothing to tighten and break. Plastic airline just slides in. Release it by depressing the ring. 

My old 1984 Peterbuilt still has the flare fittings with rubber air lines. I did just put in new seats and the new valves had push fittings. The old girl will hold tank air for a week-suspension over a month. Thinking tank air loss is comming from transmission. Even still has air wipers. I like old.

 

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A lot of fittings come with thread sealant pre installed. The rule of thumb is to never put a metal fitting in plastic. They make renenforced plastic fittings probably best to use those if you can.

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35 minutes ago, Lance A Lott said:

The rule of thumb is to never put a metal fitting in plastic. 

This is also a Code rule in both plumbing and electrical codes. For this exact reason. 

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Second attempt got replacement air bags today this time I rebuilt old fittings with new o rings and collets put wet thread sealant and screwed them in HAND tight so far so good it is holding air no leaks .

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