[poy41]

disc brake conversion/distribution block/Proportioning valve


So i got this kit for my 1970 Lemans sport the other day and am just trying to figger out how to set up the proportioning valve with what i have stock in the car now.

my question is when hooking up the Proportioning valve, do i need to take out the distribution block, or can i just plum the lines coming from the master (in the car now) to the Proportioning valve.

as my car has drums all around now, this should be a distribution block and not a valve right?

Or, would it just be better to take it out and run some new/extensions lines?


the kit:

Chevy 1964-74 A, F, X Body Complete Stock Height Kit

tracked down some 69/70 shop manual pics:




distribution block in the car now:



Master in the car now:



Proportioning valve that came with the kit:




............

[cobalt327]

The new combo valve replaces the distribution block and hold off valves (if present- things were in flux in '70 w/GM brake systems). May require running some new lines.

[poy41]

theres no hold off valve present from what i can see. but in the manual for the Proportioning valve, it says i can plug one of the front outles and split it somewhere else. so is the distribution block in my car a real distribution block or does GM have some magic valves hiding in there? (lol)

just took a pic of the manual for the Proportioning valve:

[joe_padavano]

Just so we're all on the same page, the drum brake cars used a distribution block only. This is simply a tee fitting with a differential pressure switch that illuminates the BRAKE light on the dash if you lose pressure in one half of the system.

The 1967-70 disk brake cars used the hold-off/metering valve in addition to the distribution block. This is the same distribution block used on the drum brake cars.

The 1971-up disk brake cars combined the distribution/metering/proportioning functions into a single, cleverly-named combination valve. The brass item you have is one of these post-71 combo valves. As noted, it replaces all other valves and distribution blocks in the system.

[poy41]

Originally Posted by joe_padavano

the drum brake cars used a distribution block only. This is simply a tee fitting with a differential pressure switch that illuminates the BRAKE light on the dash if you lose pressure in one half of the system.

thats what i have now

so something like this should work, only have to hook up one of the wires tho.

[joe_padavano]

Originally Posted by poy41

thats what i have now

so something like this should work, only have to hook up one of the wires tho.

NO! Why would you want to do that? You have a combo valve. It REPLACES the distribution block. That's all there is to it.

[poy41]

Originally Posted by joe_padavano

NO! Why would you want to do that? You have a combo valve. It REPLACES the distribution block. That's all there is to it.

It would be easyer for me to do it like that. Its just undo two lines and hook them up. To remove the distribution block means replacing lines. Just looking for the easy way out ;-)

[poy41]

anyone have anymore thoughts on this? just doing the job now so.

[cobalt327]

After looking at this a second time, are you sure there will be adequate flow/volume from a single port of the combo valve to feed both ports out of the distribution block to the front calipers? I believe your better off plumbing it correctly, not "easily".

[Rosylab]

Hi. I just registered as a member and am a newbie at this posting thing so please bear with me. I noticed this old thread about distribution blocks while searching the net and was wondering if Joe's question was ever resolved. I am converting the drum brakes in my 69 GTO to discs and was wondering as well what to do with my old distribution block on the frame. A new combination valve will be installed on the MC so should I remove the dist block and plumb the "rear" output on the new valve straight to the "T" fitting at back axle and run new separate lines to each of the front wheels or can I block off one "front" port and run a line from the remaining "front" port to a "T" fitting and connect to my existing front lines?

[cobalt327]

Originally Posted by Rosylab

Hi. I just registered as a member and am a newbie at this posting thing so please bear with me. I noticed this old thread about distribution blocks while searching the net and was wondering if Joe's question was ever resolved. I am converting the drum brakes in my 69 GTO to discs and was wondering as well what to do with my old distribution block on the frame. A new combination valve will be installed on the MC so should I remove the dist block and plumb the "rear" output on the new valve straight to the "T" fitting at back axle and run new separate lines to each of the front wheels or can I block off one "front" port and run a line from the remaining "front" port to a "T" fitting and connect to my existing front lines?

You can do either, choice is yours.

See #3 under B) Line Connections: http://www.jegs.com/InstallationInst.../884-A0730.pdf

[Rosylab]

Thanks for the info Cobalt327. I think I'll replace the dist block with a T-fitting to service the front brakes and run a new line to the rear. Right after I install the new Edelbrock intake manifold and carb.

[joe_padavano]

Originally Posted by Rosylab

Thanks for the info Cobalt327. I think I'll replace the dist block with a T-fitting to service the front brakes and run a new line to the rear. Right after I install the new Edelbrock intake manifold and carb.

Why? The aftermarket combo valve already has separate outlet ports for the two front wheels. Just plumb from these outlet ports to each front wheel and from the rear outlet port to the rear wheel junction block on the rear axle. Discard the original distribution block. Problem solved.

[Rosylab]

Hi Joe. Ya, you're right of course. I guess I'm going thru the same thought process you did back in 2011 when you were upgrading your brakes. Just trying to save some time and work by not replacing both existing front brake lines. I was also hoping to avoid buying tube flaring and bending tools for a one time project. It's sort of silly, I know. The extra cost of the tools and tubing is minimal compared to the conversion kit cost.