Rekateer Posted February 27 Report Share Posted February 27 I'm back! I have become generally confident with piecing my brakes back together on my 74 620 but I've hit a roadblock with the fittings of my master cylinder ends. The original, I think it's original, fittings are what I believe to be m16-1.0 threading but my new ones from dorman are m10-1.0. I'm struggling to find an adapter with the proper threading to just plug these things back in. Do other brands have the original threading fitment? Am I going nuts and my threading isn't actually m16-1.0? I can't for the life of me find an adapter for this line. I've ordered thread checkers and I think I'll have them tonight but if anyone here just KNOWS this info I'd be eternally grateful. I might end up answering my own question soon but I appreciate any help. Quote Link to comment
datzenmike Posted February 27 Report Share Posted February 27 Take the master into the store and find the correct fittings. Most auto stores have stacks of pre-made brake lines of various lengths. I just buy the shortest one and cut and remove them... unless you can buy them separate. Trim the ends of your lines, remove the old, slip the correct fittings on and flair the pipe ends. Make sure the flair matches what's needed on the master end. There are double flair and bubble flair, maybe more. Quote Link to comment
Rekateer Posted February 27 Author Report Share Posted February 27 46 minutes ago, datzenmike said: Trim the ends of your lines, remove the old, slip the correct fittings on and flair the pipe ends. Make sure the flair matches what's needed on the master end. There are double flair and bubble flair, maybe more. I was sort of trying to avoid this option. As much as I want to work with the brakes, the level I'm having to do this work is a bit much for my skills right now. I'm thinking I'm gonna have to take it to a shop at this point with how mangled this system is. One day I'll fiddle with the brake system but not today. Thanks again for the info Mike, I do really appreciate it! Quote Link to comment
iceman510 Posted February 27 Report Share Posted February 27 M16 would be extremely unusual size for for a brake fitting thread. Even modern cars rarely use larger than 12, and 14 is possible on power steering fittings. Is there a bushing missing from the master cylinder that should have the actual m10 x 1.0 thread for the line? 1 Quote Link to comment
Rekateer Posted February 27 Author Report Share Posted February 27 26 minutes ago, iceman510 said: Is there a bushing missing from the master cylinder that should have the actual m10 x 1.0 thread for the line? As it stands the fitting ON the brake line itself is m16-1.0, and it matches with the old master cylinder. I checked it on a thread checker, and that's kinda why I'm so confused. Maybe that's also why I'm struggling to find adapters for it because some dork a while back just threw it together. I also noticed the obvious size difference when I started putting the master back into the engine bay. Idk why or when this happened to the truck but it's a pain in my butt that's for sure. Edit- I have some afterthoughts I'm gonna find some m16 Brakeline fittings at my local place and try those. I shoulda thought of this. Maybe they don't even have it and that's why I'm struggling with it. Quote Link to comment
Rekateer Posted February 28 Author Report Share Posted February 28 I've asked around town with some mechanics I've gone to before and they're also generally confident I can do the snipping and fitting replacement myself. I'm terrified of major mistakes on this truck and making it worse for myself, but there's no other way to learn at this point. I'm ordering a flare kit and tracking down the proper fittings. Quote Link to comment
mklotz70 Posted March 2 Report Share Posted March 2 Do you have any pics of the m/c where the lines connect? Kinda sounds like you're missing pieces off the m/c. The fittings would be m10-1.0 if I remember right. If you haven't done any flaring before, this vid will get you started, but there's probably better ones on youtube. These are old, crappy vids, but it will show you the fittings at the bottom of the m/c that I think you're missing. http://www.bluehandsvideo.com/brake-master-cylinder-anatomy.html Quote Link to comment
Stoffregen Motorsports Posted March 2 Report Share Posted March 2 A pic would help. 16mm threads are not common on any brake line. Are you sure the bushing that holds in the residual valve is there? It has a giant thread. See the pic where those giant bushings are attached at the bottom? Quote Link to comment
EDM620 Posted March 2 Report Share Posted March 2 Get as good quality of flaring tool you can, cheapo tools will frustrate you and possibly lead to a leaking fitting. 1 Quote Link to comment
Rekateer Posted March 9 Author Report Share Posted March 9 Thank you all for the replies! I bought an eastwood kit and it appears to have worked well. Easier than I expected, maybe I'm just a nervous person. Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.