Replacing trans. lines, need advice.

S_Mazza

Registered User
Ok, so I think my stock transmission lines have a slight leak. They look pretty rusty anyway, so I want to replace them. I need some advice about the fittings. I bought 2 60" lengths of 5/16" brake line at the parts store. They are equipped with brass fittings, but I'm not sure the size (is there a standard size?). I have a tubing bender that I can use to shape the lines.

Questions:

1. Will I need to cut the fittings off the brake lines and replace them, or will they screw right into the radiator and transmission?

2. Is there a washer I should be replacing at either the radiator or transmission? If so, what type, and where should I get it?

Thanks in advance!
 
If you are going through the trouble of replacing the lines you might as well do a 3/8 line swap with an external cooler. You will need new case fitting for the transmission and new fittings for the radiator. If you decide to do what you are doing the transmission fittings are fine the line will connect directly to them. The ones in the radiator will have to be saved from the old lines or you will need new fittings for the radiator. Be careful not to kink any lines or you will cause restriction that will fry your transmission.
Alan
 
Thanks for your reply! The info is very helpful. I think I will keep the stock cooler for now, as I don't want to mount anything else in this cramped bay. I am planning to use high-temp teflon tape to seal the threads on each fitting. If any washers show up when I remove the fittings, I guess I can find a replacement at the hardware store or something. I will let you know how this goes when I get the time to attempt it. Thanks again!
 
S_Mazza said:
Thanks for your reply! The info is very helpful. I think I will keep the stock cooler for now, as I don't want to mount anything else in this cramped bay. I am planning to use high-temp teflon tape to seal the threads on each fitting. If any washers show up when I remove the fittings, I guess I can find a replacement at the hardware store or something. I will let you know how this goes when I get the time to attempt it. Thanks again!


They are flare fittings teflon tape will not help anything. I think you should reconsider a cooler if you want the trans to last a while.
Alan
 
Dirtyd0g said:
They are flare fittings teflon tape will not help anything. I think you should reconsider a cooler if you want the trans to last a while.
Alan

What Alan said. I would also toss the brake line tubing and install some 6AN braided steel hose instead. BTW, There has to be some provisions in the lines for engine movement..that's why the stock lines have a short section of rubber hose.

David
 
David Neibert said:
What Alan said. I would also toss the brake line tubing and install some 6AN braided steel hose instead. BTW, There has to be some provisions in the lines for engine movement..that's why the stock lines have a short section of rubber hose.

David

I just run them in 3/8 steel tubing,but I'm a cheap***. Always remember to bubble flare any lines you are going to connect rubber to.
Alan
 
Update:

The teflon tape may not make a difference at the flare compression fitting itself, but don't forget that there is an adapter fitting between the flare and the radiator. When I got under the car, I reconsidered the idea of replacing the entire line, because it looked less corroded than I thought, and because it looked pretty hard to access the fittings at the transmission. So, I used the teflon tape and resealed the supply fitting at the radiator. Judging from the clean cardboard on the garage floor, it fixed the leak. So, I think the teflon tape does work, if applied in the right spot.

Also, I found out that the fittings that came on the steel brake line do fit the radator adapter, but they are not long enough to compress the flare fitting. So if I decide to do the line replacement later, I will have to cut off the standard fittings and reuse the old ones.

Oh, and the thing that made me decide to forego the auxiliary cooler for now is that it doesn't seem to be running that hot. I used a thermocouple to take the temp. of the cooler lines just after my 50-mile commute from work. They were in the 130-140 range. Maybe I'll check the pan temp. sometime this week.
 
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