trans cooler line to radiator fittings

[mminneman]

Hello, I think I am missing a fitting. 69 Roadrunner 440/727, ordered new trans cooler lines, 3/8" female fittings on both ends. The 727 has some male fittings coming from the trans case that the lines connect to. However, the old lines ended at the radiator with male fittings (3/8" 45* double-flared hard line). I think I am missing a coupling fitting. Seems like it should be a 3/8" male-to-male inverted flare coupling, but nobody seems to have such a fitting.

Does anyone know what fitting goes here? I found another trans cooler install thread with a close-up of the cooler lines going into the radiator and it looked like there was a fitting in there. Obviously the radiator is a female fitting. I assume the previous owner cut the female end off the line tossed a normal male tube end on there, which I don't want to do.

Thanks.

 

[Revhendo]

You sure that's 3/8th line? Mine are 5/16th. All you need is to go down to your local parts house and get a 1/4 NPT to 5/16th male line adapter.
Check here for the male connector http://www.plews-edelmann.com/brochure.cfm?brochure=1867&location_id=2516 #148540

 

[mminneman]

Thanks for the reply, I will check that out. The lines are stock, I'm sure you're correct on the size. I eyeballed it so I will take your word for it. I was surprised to see there was no mention of these fittings on year one, it seems like everyone would need them. The 6bbl fuel hard-line fit into them, and to your credit, I do believe those are 5/16th as well.

I was not able to test the radiator thread size. I'll trust you on the 1/4" NPT. It did have tubes going in there directly from the previous owner, but I know that was not the correct setup. Do tube nuts run the same thread as NPT fittings, minus the flare? I can't believe this wasn't leaking.

Is that the same fitting that would also go into the case on the 727 trans? I might as well replace them all. I apologize for the questions, I was in the middle of trying to get this together when I left on business, so I don't have access to the car for the next couple days.

I greatly appreciate your help! Thanks.

 

[Revhendo]

Pipe thread and tubing threads are different. Pipe threads actually have a taper to them, that's why the fitting gets tight when you screw it into the manifold, head, radiator, whatever. Pipe thread fittings should always get some sort of sealant (even sending units, just check for ground when you've tightened them). I prefer teflon paste myself. The sealant acts as a, well, sealant, but it also lubricates the threads. This allows the fitting to be tightened without galling the threads.

Tube nuts are a regular SAE pitch thread. They actually rely on the inverted flares to do the sealing job. If you ever see a line nut with thread tape on it, slap the yahoo who did the job. I always suggest using anti-sieze on line nuts and also on the back of the flare that the line nut turns against.

727 trans fittings are 1/8NPT to 5/16th male inverted.

Hope this helps. Sorry if it's a bit long winded. Way too much coffee this morning.