Disc/Drum Combination Distribution Valve - where to buy that DOESN'T LEAK??

[CoronetDarter]

I suspect the fittings on the lines. The ones from my master cylinder are originals from a 73-76 front disc A body car so they are maybe 50 years old. The threads do get worn after multiple on/off sessions.
If your fittings are "seasoned", your problem may lie there.

The hard lines were all replaced during the restoration. But it doesn't mean they're holding fluid. The car is still up on the lift so I'll check the fittings each day.

 

[Bird 426]

I have had nothing but trouble with reproduction dist blocks. Incomplete machining, top port from master at an angle , lines extremely difficult stop leaking. The next time it comes up, it's all going into the trash and will see what the aftermarket world has to offer. Never had a problem anywhere else in the system. Also, I use dot5, not dot4. Not repainting another engine compartment or firewall over that again.

 

[CoronetDarter]

I have had nothing but trouble with reproduction dist blocks. Incomplete machining, top port from master at an angle , lines extremely difficult stop leaking. The next time it comes up, it's all going into the trash and will see what the aftermarket world has to offer. Never had a problem anywhere else in the system. Also, I use dot5, not dot4. Not repainting another engine compartment or firewall over that again.

If I have to start replacing brake system components, I'm switching to DOT 5 too.

 

[Kern Dog]

If I have to start replacing brake system components, I'm switching to DOT 5 too.

It sure ain't cheap...The single quart of NAPA brand DOT 5 was $35 compared to $8 or 9 for the DOT 3.
I went through a LOT in the past couple of years when sorting out my brakes.

 

[CoronetDarter]

It sure ain't cheap...The single quart of NAPA brand DOT 5 was $35 compared to $8 or 9 for the DOT 3.
I went through a LOT in the past couple of years when sorting out my brakes.

It's not cheap. But I have to repaint the inner fender because the m/c brake line leaked a few years ago. The paint costs more.

 

[Bird 426]

Yes, the paint is expensive, but look at what you have to do before and after the paint. The cost of dot 5 is higher, but not compared to the possible alternative. Yes, and it's not if it happens, but when. Two of my cars had to have the engine bays only, redone because of master cyl failure. I don't know, it's always got to be something!

 

[CoronetDarter]

It looks like the line has fluid on the tube nut threads. I would double check that first before blaming the valve. A minute leak may take a long time to make a drop. I would clean it and blow it off well and look every day to be sure. . Remember a leak does not drip from the top.

Turns out three of the fittings were able to be tightened about 1/8 turn. That could be the difference, we'll see.
BTW, last week I picked up this set of crow's feet flare nut wrenches. They were a game changer, as regular wrenches wouldn't have fit with the headers right next to the distribution block.

 

[RJ Squirrel]

I finally found an all in one combo valve like the one I have that has good reviews. I'll let you know how it turns out. Thanks.
Right Stuff Detailing PV71 Right Stuff Detailing Brake Proportioning Valves and Blocks | Summit Racing
View attachment 1455355

Hey 68 SS looks like you have had this on your car awhile, is it still working well? No leaks? I have the two piece one on my RR that leaks and sucks air into the front brakes- looks like this may be the fix?

 

[68 Sport Satellite]

Hey 68 SS looks like you have had this on your car awhile, is it still working well? No leaks? I have the two piece one on my RR that leaks and sucks air into the front brakes- looks like this may be the fix?

yes, still working well with no leaks. I don't drive it much though, but probably 1000 miles since install.

 

[RJ Squirrel]

I just removed the smaller holdoff valve for the front brakes and plumbed them directly into the combination valve, there are 2 ports for front brakes and one is plugged when using the holdoff valve. It works great now, firm pedal and I can make the dog slide off the seat. (He wont wear a seatbelt)
The little holdoff valve is not necessary, just a source for leak and suck in air.

 

[68 Sport Satellite]

I just removed the smaller holdoff valve for the front brakes and plumbed them directly into the combination valve, there are 2 ports for front brakes and one is plugged when using the holdoff valve. It works great now, firm pedal and I can make the dog slide off the seat. (He wont wear a seatbelt)
The little holdoff valve is not necessary, just a source for leak and suck in air.

You bought the new combination valve or used your old one?

 

[RJ Squirrel]

I have this style disc/drum valve, mine was leaking/ sucking air at the pin on the bottom of the smaller metering valve.
I removed the metering valve and kept the larger proportioning valve in place. Works great.

 

[68 Sport Satellite]

cool, so you didn't need to buy the single piece unit, instead you got your 2 piece unit working with a slight modification. I'm not familiar with that type you show above. Since you removed the metering valve, it's no longer sucking air, but I wonder what they purpose of the metering valve is and with it removed if there will be situations it may not work properly? Maybe others can chime in here.

With it working well now, braking sounds like it's good. Is your car power brakes? If so, how is the pedal feel? Is it very light before it gets firm braking?

 

[RJ Squirrel]

The metering valve is simply a spring loaded foot that allows the rear drum brakes to build enough pressure to overcome the springs before the front calipers are applied. I now get a tiny bit of nose dive before the rears start to grab, barely noticeable. A big improvement over spongy or non existent front brakes for sure. Mine are manual, pedal is firm now and does not take much force to get very firm braking.