Need recommendation for a Disc to Disc Proportioning Valve for a 1970

[Rich Ackermann 174]

I have installed front and rear disc brakes (Granada up front and CPP setup in rear) on my originally all drum 70 Mach.  I have a 7" (Bendix like) booster with a dual master cylinder.  I am starting with Inline tube Disc to drum brake line kit, knowing it will need a little modification at either end.

All that said, Ideally I would like to get a 1970 disc to drum style Proportioning Valve for a Disc to Disc application to minimize the modifications needed to the valve mounting location, line mods, and brake light switch plug. I have found NPD and CJ selling a GM style disc to disc/drum Proportioning Valve but it will need mounting, line and brake plug mods to work.

What are you using for your conversion?

Thanks All!

Rich

 

[barnett468 418]

you don't run a disc/drum prop valve on a disc/disc system, and in fact, you may not need a prop valve at all. you could try it without one, then if you need one, add it then. irregardless, a basic prop valve from wilwood "should" have enough adjustment for your app.

i never heard of the brake line kit you have or why it would affect braking bias.

you should check to make sure there are no residual valves in your master cylinder.

if you add 2 lb residual valves to the brakes, it will reduce pedal travel slightly but may also cause your brakes to wear a little faster.

[Rich Ackermann 174]

5 minutes ago, barnett468 said:

you don't run a disc/drum prop valve on a disc/disc system, and in fact, you may not need a prop valve at all. you could try it without one, then if you need one, add it then. irregardless, a basic prop valve from wilwood "should" have enough adjustment for your app.

 

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Thanks Barnett468. I did not think I could do without a Proportioning Valve entirely. I always thought i would need disc to disc valve, but I am hoping that I can find one that mounts and connects like the stock disc to drum valve does to minimize the brake line mods. I found that CJ Pony Parts lists a GM style Proportioning Valve from CPP (see pic) that claims it can work with either disc to disc or disc to drum. It look similar to a stock valve, but it still will require mods to the lines, switch, and mounting location..

 

[barnett468 418]

2 hours ago, Rich Ackermann said:

Thanks Barnett468. I did not think I could do without a Proportioning Valve entirely.

I always thought i would need disc to disc valve, but I am hoping that I can find one that mounts and connects like the stock disc to drum valve does to minimize the brake line mods.

I found that CJ Pony Parts lists a GM style Proportioning Valve from CPP (see pic) that claims it can work with either disc to disc or disc to drum.

Many older cars that came stock with ft and rr discs, do not have a prop valve, but their caliper sizes are designed so they don't need one.

You will have to do brake line mods.

C J Pony parts is lying to you.

[Rich Ackermann 174]

6 minutes ago, barnett468 said:

Many older cars that cam stock with ft and rr discs, do not have a prop valve, but their caliper sizes are designed so they don't need one.

You will have to do brake line mods.

C J Pony parts is lying to you.

Thanks. I would not be the first time....

[aslanefe 333]

7 hours ago, Rich Ackermann said:

I have installed front and rear disc brakes (Granada up front and CPP setup in rear) on my originally all drum 70 Mach.  I have a 7" (Bendix like) booster with a dual master cylinder.  I am starting with Inline tube Disc to drum brake line kit, knowing it will need a little modification at either end.

All that said, Ideally I would like to get a 1970 disc to drum style Proportioning Valve for a Disc to Disc application to minimize the modifications needed to the valve mounting location, line mods, and brake light switch plug. I have found NPD and CJ selling a GM style disc to disc/drum Proportioning Valve but it will need mounting, line and brake plug mods to work.

What are you using for your conversion?

Thanks All!

Rich

 

I used the GM style prop valve for disk/drum when I converted my 69 to front disks. Summit and other vendors sell a disc/drum and a disc/disc GM style prop valve (different part numbers) that makes me think that there is a difference inside the valve, maybe a different spring. I made a bracket to mount the prop valve to stock location on fender well. Had to bend the original lines to rear and front brakes a little bit to attach them to the valve (but did not have to cut or make new lines). Bent premade lines from mc to prop valve. Brake warning switch connection was easy, the original plug to switch has 2 pins and wires but they are jumped on the original switch ( if you look at the pins on the original switch closely, you can see the jumper inside) so I jumped the pins of the original plug and attached it to the one wire from the GM style prop valve.

[Rich Ackermann 174]

On 4/8/2020 at 12:01 AM, aslanefe said:

I used the GM style prop valve for disk/drum when I converted my 69 to front disks. Summit and other vendors sell a disc/drum and a disc/disc GM style prop valve (different part numbers) that makes me think that there is a difference inside the valve, maybe a different spring. I made a bracket to mount the prop valve to stock location on fender well. Had to bend the original lines to rear and front brakes a little bit to attach them to the valve (but did not have to cut or make new lines). Bent premade lines from mc to prop valve. Brake warning switch connection was easy, the original plug to switch has 2 pins and wires but they are jumped on the original switch ( if you look at the pins on the original switch closely, you can see the jumper inside) so I jumped the pins of the original plug and attached it to the one wire from the GM style prop valve.

Perfect. Thanks for the info. I'll check for the jumped pins.

[barnett468 418]

33 minutes ago, Rich Ackermann said:

Perfect. Thanks for the info. I'll check for the jumped pins.

The prop valve in your photo looks like it is for drum rear brakes. The prop valve for rest discs should not have the check ball/black fitting on the end.

[Rich Ackermann 174]

2 hours ago, barnett468 said:

The prop valve in your photo looks like it is for drum rear brakes. The prop valve for rest discs should not have the check ball/black fitting on the end.

Here is a picture of the one I ordered. As you stated it does not have the check ball on  the end. .

Thanks for pointing that out.

 

[unilec 57]

Also a good idea to get the piston locking device you see in this short youtube clip.

 

[Rich Ackermann 174]

3 hours ago, unilec said:

Also a good idea to get the piston locking device you see in this short youtube clip.

 

Good info. Thanks

[Rich Ackermann 174]

My new GM Style discs to disc Proportioning valve came and I spend Saturday evening bending and fitting the brake lines. I am using the stock inline tube kit. What I discovered is you need a bunch brake line adapters of various sizes... well actually two adapters if you are making your own Master Cylinder to Prop valve lines. That was the second aha moment, the two Inline tube stock Master Cylinder to Prop valve lines that come with the kit are useless. The rest of the kit will work with some bending and the aforementioned line adapters. The front LH line needed the most reshaping and is hard to bend because of the outer (double) tube on the section that needs bending.It a short line, so in hind sight I could just made my own there too.

Also, the rubber brake that came with my Front Granada discs also need an line adapter to mate up with their respective stock inline tube brake line.

Now I need to tackle the rear line across the axle. I don't like the aftermarket setup much as it requires cutting the tubes shorter at each end. So I am going to use a Banjo to 3/8" female inverted flare, instead of the rubber hose and straps in the kit. This way I will only have to bend the brake lines at each end and not cut them. It will also look more like the stock brake line setup which I like. I realize that removing the rotor and or caliper with require me to disconnect the line from the rear calipers and then bleed the lines when I reassemble, but I can live with that. I would be a frequent occurrence. We will see how it goes.

 

 

[barnett468 418]

you should not have the front line running upward because it can trap air and not bleed it out.

[Rich Ackermann 174]

8 hours ago, barnett468 said:

you should not have the front line running upward because it can trap air and not bleed it out.

I'll have to figure out how to eliminate the big bend in the left front line. The rest are fine. Thanks

[ralt962 11]

With this GM style system that front line points up.  Unless its very low in the car,  it will be hard to not have the upper bend.  I'm about to do a conversion to disc front.

The original proportioning valve also had an upper loop.  Likely will be hard to bleed it with just pedal pressure.  But not much choice in these.  

[rr03cobra 3]

hey Rich. I'm converting my drum/drum to disc/disc system from MP Brakes. My original brake lines come straight up from underneath.  It looks like I may have to bend the front brake lines to connect to the valve. I don't have the original setup so I can't look at if for a reference. My question is did you buy new front brake lines or modify the old ones?  Are these pictures the latest setup that you did?

 

Thanks.....Rich R

[Rich Ackermann 174]

7 hours ago, rr03cobra said:

hey Rich. I'm converting my drum/drum to disc/disc system from MP Brakes. My original brake lines come straight up from underneath.  It looks like I may have to bend the front brake lines to connect to the valve. I don't have the original setup so I can't look at if for a reference. My question is did you buy new front brake lines or modify the old ones?  Are these pictures the latest setup that you did?

 

Thanks.....Rich R

Hi Rich,

I replaced all of the brake lines. Don't use 50 year old lines with your new brake system. I bought the 1970 Mustang kit from Inline Tube. All the lines will need some modification. I prefer to use Stainless Steel. but it is much harder to work with...hard to bend, and if you need to trim them, it is impossible to flare the ends with hand tools. So I would recommend using Steel lines.

The line from the rear to the Proportioning valve will need some bending to line up, as will the two front lines. The lines from the valve to the master cylinder will need to be bent. My conversion kit cam with rubber lines to connect the two rear lines to the rear disc caliper, but I chose to go all hardline instead. The rear lines after the junction "T" on the axle will need to be  trimmed and bent to line up with eh rear calipers. The critical part for me was finding the Banjo to 3/8" female inverted flare to connect the existing hardline fitting to the rear caliper. 

My front Granada disc brake assembly came with the flex lines. I needed to add an adapter to connect the hardline fitting to the flex tube. I also need to install a mounting bracket to secure the hard line and flex tube to the frame.

Finding all the right fitting adapters took a lot of time a searching and some trial and error. If you have access to a hydraulic flaring tool and know someone who can help you make the tubes with the right flares and fittings, then that may be a good route to take.

Finally, you will need to make some mods to the parking brake cable ends to adapt it to the rear brake calipers. Also you will need a GM Proportioning valve Brake Warning light plug. Our Mustang have two wire plugs and the GM plug is one wire. Just twist the two wires from you Ford harness together and connect it to the GM one wire.  Let me know if I can provide anymore info.

[rr03cobra 3]

looks great.. thanks for the reply I really appreciate the help.  I was able to make the old lines work for a temporary solution. I will redo them all when I get the car home. going to tackle the fuel lines tomorrow.