Air fittings...which one?

TBH unless there is a spec listed in specific in the manual or a good reason to use plastic i always use brass. Lasts longer usually in my experince.

Also this is the kit I use. https://www.kljack.com/products/ask...artVFCfUfzRMEuK3_UIKXYhy5tcS81EgaAuDiEALw_wcB

Its a LOT more expensive then the amaxon kits but the amazon ones are cheap for a reason and i always regret using their crap. These ones ive had exactly 1 fail on me in 4 years.

 

Brass is better. Plastics can crack and leak. Once you tighten a brass fitting down the compression guarantees a leak free connection. Those PTC fittings might be convenient in a tight place where getting a couple wrenches in is not possible but they're band-aids.

 

Just an fyi … fittings have to be DOT fittings, napa has them.

 

Several years ago, I went to a hardware store, and asked for 3/8 union compression fittings, and the dude said, unless they are used for non-automotive applications, he couldn't sell me one.

 

This should be what you need @gekko1323
https://www.fleetpride.com/parts/power-products-brass-union-n626

Non quick connect brass air line unions for platic air line use a steel insert to clamp the ferrule to the air line. Keep in mind, while you may see similiar style unions at a hardware store, they are made for copper line and do not have the steel inserts.

 

Brass compressing fittings, but I do have one of those plastic assortment kits for a just in case thing

 

Because anything on a truck has to have a dot stamping on jt

 

Brass with DOT on it is the best to go. I have a good amount of the cheap plastic fittings I carry with me for emergency on the road use.
I bought this a couple years ago https://www.amazon.com/dp/B083S3Q56V?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1