Thread size on brake line splitter

[JohnnyD111]

On my 1972, M300 chassis, from the master cylinder, a line come off into a splitter (mounted on inside of frame), then goes 4 ways.  im replacing the line that lead to the rear.  that being said, I thought it was standard 7/16 24 thread, this doesnt seem to work.  could it be a metric size?  the parts and service manual say nothing about size.

[DaveVA78Chieftain]

Not sure about yours (mine is a 78 M400) but when I just replaced one of the lines from the master cylinder to the proporation valve/brake light warning switch (thats the splitter your reffering too) I had to make one from 3 seperate lines.  The 2 end sections were about 12" long with a 1/2-20 nut on one end and a 7/16-24 on the other (suprisingly small 3/16" brake line).  The center section had matching 7/16-24 on each end.  I spliced it all together with 7/16-24 inverted flare unions.  This was the only way I could do it as they do not seem to sell long sections of tubing with different size ends.   Only way I found this all out was by going back in the back of the store and looking to see what was available.  Counter kiddy didn't have a clue what to do especially since there is no motorhome listings   D:oH!

I will be replacing my lines one by one because the failure I had was do to rubbing at the frame holddown clip.  I am sure other places on my rig are doing the same thing.  Better safe than sorry.  This time I was lucky.

Dave

[JohnnyD111]

thanks Dave,

you go beyond helping all the time!  time to get this puppy on the road.