Brake lines for disk/drum prop valve?

[jimmydean]

So I have the prop valve and the lines that run from the M/C to the valve. But the stock lines are 3/8 and mount to the bottom, where the new valve has one on the bottom (and it's 1/4") and one in the back. I have been to every parts store and nobody has a 3/8 to 1/4" reducer, or a male to male union so I can run a short line to the back.

Where can I get these parts? Did anyone else have these issues when swapping the front to discs? Man, what a pain!

[70GMCer]

Maybe 70c10 (Jim) can chime in here on this. He went through the same problem last week......

[NitroMike]

I ran into the same thing and got the required reducers/adapters at my local NAPA store. They always come through with the right quality pieces.
Good Luck.

[jimmydean]

NAPA was the first place I went. I will go to the bigger NAPA tomorrow and see. I figured if anyone had it, it would be them, guess just not in my little town.

[krue]

Could one of y'all post pics of your setup, 'cuz I swear I think I have mine backwards.

[jimmydean]

Front to front, rear to rear for 1/2 ton, reverse for 3/4 ton. There is a pic on here somewhere when I asked about hose routing.

[krue]

After doing a little reading, I think I'm gonna rob the booster/ m/c /prop valve off a 84 and put on mine, I hate the rusty, leaky m/c and ugly prop valve in the way on mine.

[70c10]

Dave, I went to every parts store in town for the reducer fittings in the rear of the prop valve. I finally found it at Napa but I don't know the part number. I used two fittings (inverted flares) to make it work. The front line reducer fitting was easy to get. The brake conversion is on hold right now so I haven't been able to see if they will leak. I will post a pic of the fittings later today.

[boraxman]

I went through the same thing...so I ended up upgrading to stainless brake lines.

[jimmydean]

Originally Posted by 70c10

Dave, I went to every parts store in town for the reducer fittings in the rear of the prop valve. I finally found it at Napa but I don't know the part number. I used two fittings (inverted flares) to make it work. The front line reducer fitting was easy to get. The brake conversion is on hold right now so I haven't been able to see if they will leak. I will post a pic of the fittings later today.

The back is where I'm having issues right now. I went a few towns over to a bigger napa and got the 1/4 to 3/16 reducer and a 1/4 x 8" brake line. So it looks like I'll need to do some funky 5/16 to 1/4 conversion with some pipe fitting in between.

[jimmydean]

So I got it all connected, but the prop valve is nowhere near mounting like it's supposed to. The prop line and bracket kit I got was about 3/4" too wide where it mounts to the M/C. Then when I got that together, the rear line was too close to the booster. Man, what a mess.

I'm guessing I will be replacing it all very soon anyway, but I will bleed it tomorrow and see if it's at least functional.

[70c10]

Here is the pic showing the two fittings between the prop valve and existing brake line fitting. NAPA just started selling a new type of coated brake line that is bendable by hand . It's very nice and you can bend it like a pretzel without kinking it!

[pound41]

Got mine at home depot in the plumbing section

[jimmydean]

After looking at the pic on GMC Paul's site, I noticed they are way different than the ones I got.



My guess is the ones I got are for a different year. I can't find the paperwork, so I'm not sure what they said they were for, but they sure are these.

I was able to get the 3 fittings to connect the back, it's just wicked ghetto. I'll post a pic tomorrow. I am looking to replace everything soon anyway, but this should get me on the road.

My bracket looks like the one above but my lines look like these:



No wonder they didn't fit!