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'69 Mustang coupe...331, Fox / Explorer EFI, TK3550, MDL, SoT, TCP, Fays2 Watts, 94-04 Cobra discs
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Discussion Starter · #1 ·
Gang -

Does it matter where in the rear line an adjustable proportioning valve is installed?

It is easier (I think, based on some quick figuring) to mount the adjustable prop valve under the car, towards the rear, somewhere right before the metal line goes into the rear flex line.

Is it a problem to mount it this far from the master cylinder? I couldn't think of a reason why it might be but wanted to poll the experts...

Thanks,
Nate

PS: If anyone has any pictures of how they routed their brake lines coming out of the master cylinder, into the distribution block and prop valve that would be great. Email them to me or post them up here. Thanks!
 

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You're right, it doesn't matter where in the rear line the valve is mounted, however traditionally it is mounted soon after coming out of the master cylinder.

If you're using a prop. valve, why are you using a distribution block? Just for the brake warning light?

If you're not concerned with running the brake warning light.... Simply "T" the front lines coming off of the master. Run the prop. valve in the rear line soon after coming off of the master.

Dave
 

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'69 Mustang coupe...331, Fox / Explorer EFI, TK3550, MDL, SoT, TCP, Fays2 Watts, 94-04 Cobra discs
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Discussion Starter · #3 ·
I thought the distribution block was required?

I was just going to use the factory dist. block and put the prop valve inline in the line running towards the rear...

Nate
 

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On a stock brake arrangement, yes, the distribution block is required. The moment you plumb a prop. valve into the system, it negates the function of the factory distribution valve... other than the electrical signal for the brake warning light.

The factory distribution block is a "prop. valve" within itself. It splits the pressure to the factory front discs/drums and sends an appropriate amount of pressure to the rear brakes.

If you're not concerned with the brake warning light, having a factory distribution block and an aftermarket prop. valve is a waste of brake line plumbing.

In the below picture, the rear bowl of the master powers the front brakes. From the rear bowl, a line is run down to a "T" fitting. Each end of the "T" runs to a front disc. The forward bowl of the master is for the rear brakes. From the forward bowl, a line is run down to the proportioning valve inlet side. The prop. valve outlet side line runs back to the rear axle. It doesn't get any simpler than this.

http://i198.photobucket.com/albums/aa148/davesanborn/100_0806.jpg

Dave
 

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You are going to have to crawl under the car to adjust the brakes. Seems like a real hassle.
 

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'69 Mustang coupe...331, Fox / Explorer EFI, TK3550, MDL, SoT, TCP, Fays2 Watts, 94-04 Cobra discs
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Discussion Starter · #7 ·
Dave -

OK, dumb question...are you saying that the factory dist. block sends full pressure to the front? You seem to indicate this by saying I could just remove the factory dist. block, "T" the fronts off the master and put the prop valve in-line to the rears...

As far as I know, I don't have a brake warning light anymore...nor do I feel the need to have one. If the brakes go, I think I'll know...

Nate
 

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I could just remove the factory dist. block, "T" the fronts off the master and put the prop valve in-line to the rears...
That's exactly what I'm saying...

Dave
 

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DaveSanborn said:
On a stock brake arrangement, yes, the distribution block is required. The moment you plumb a prop. valve into the system, it negates the function of the factory distribution valve... other than the electrical signal for the brake warning light.

The factory distribution block is a "prop. valve" within itself. It splits the pressure to the factory front discs/drums and sends an appropriate amount of pressure to the rear brakes.
Dave,
I don't think that is correct for 1965/1966 Single Chamber master cylinders. There are two outlets from this MC: one goes into the distribution block, which splits the lines for the disk breaks left and right. The other outlet goes to the proportioning valve, which adjusts the pressure to the drum brakes in back.

The distinction may be in the use of the term "factory distribution valve" vs. factory distribution block. The 1965/66 blocks do not have any valves in them; only the proportioning valve does.

In later years, when two chamber MC's came about, one of the chambers has a valve built into it that reduces the pressure to the rear drums. This, of course, assumes a disk/drum system.
 

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kstang said:
My pictures are not as good But this is what I did,
with a disc/drum set up.

http://farm3.static.flickr.com/2408/1906486210_9c8512bc23_m.jpg
http://farm3.static.flickr.com/2408/1906486210_9c8512bc23.jpg

http://farm3.static.flickr.com/2349/1905645551_c3f92c5b52_m.jpg
http://farm3.static.flickr.com/2349/1905645551_c3f92c5b52.jpg
Sorry for my lack of words I was in class when I posted. We have a 65/66 style. With a single res MC. When we upgraded we went to a dual Res master cylinder. We took the rear wheels and set them straight to the Proportion valve that was supplied with the kit. We took the front and attached it to the distribution block that is original to the car. In that block we then found the correct plugs and plugged the hole that would originally feed the rear wheels. Sorry for the messy pictures. If you have any other questions I might be able to help.
 

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Dave,
I don't think that is correct for 1965/1966 Single Chamber master cylinders.
You're right. This procedure assumes a dual bowl master cylinder is being used.

Dave
 

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I've put a ratchet-style prop valve underdash, and when I do my dual M/C will probably move my dial prop valve to the seat riser to the right of my right thigh.
 

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DaveSanborn said:
Dave,
I don't think that is correct for 1965/1966 Single Chamber master cylinders.
You're right. This procedure assumes a dual bowl master cylinder is being used.

Dave
Yeah but I think what Randy is trying to say is that the dist block on 65-66 cars is nothing but a glorified T, there's nothing inside.
 

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This is a '65 fastback I adapted with a Fox 2.3L brake booster, SN95 V6 MC and a manually-adjustable proportioning valve about 4 years ago:
http://img237.imageshack.us/img237/2969/kieths65053pj8.jpg

If you have a manually-adjustable proportioning valve in tandem with a factory disc/drum proportioning/combination valve, Then the secondary side of the factory valve needs to be gutted and capped (valve spool and spring removed). Otherwise, you will have a rear brake circuit with 2 pressure knee-points of flow control to the rear brakes. --not good.

Mods needed to factory valve if you are using it with a manually-adjustable valve:

1. http://img297.imageshack.us/img297/294/valvemodificationhb6.png Another diagram: http://img297.imageshack.us/img297/9171/guttedproportioningvalvfm7.jpg

2. http://store.summitracing.com/egnse...rdSearch&DDS=1&N=700+4294908331+115&x=43&y=11
 

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My 67 is equipped with the dual reservoir master cylinder with the distribution block only(no proportioning valve) under the hood, and the stock proportioning valve which I replaced with an aftermarket adjustable proportioning valve is located in the brake line at the rearend.
 

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I have one of these:

http://static.summitracing.com/global/images/prod/large/ssb-a0707_w.jpg

but will be switching to one of these:

http://static.summitracing.com/global/images/prod/large/sum-g3910_cp.jpg

and replace my Dist block and mount this in the stock location. SSBC has an Identical piece, but its $10 more.

Summit racing prop valve link
 
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