Is there a way to tell a disc/drum from a drum drum proportioning valve from the out side???


Keith

Heres a picture off my 69 chevelle, disc front, drum back. http://www.1969supersport.com/rockerpanel.html

Rob

Is there a way to tell a disc/drum from a drum drum proportioning valve from the out side???


Keith
I'm guessing we're not talking the same parts here. A Proportioning valve is a 4 year only part from 67 -70 when the car is equipped with front disc brakes. It's a valve positioned behind and slightly below the master cylinder on A bodies. The Unit I'm guessing you're discussing is known as a Distribution valve. This is the unit bolted to the frame below the firewall. Dist. valves look the same from 67 on until 71 when the general went to a combination valve which took the place of the dist/prop valve which served the same purpose as the combined 2 valves from 67-70 for disc brake cars. A combination valve will have a cylindrical appearance where a distribution valve will have squared ends. There is NO such thing as a disc/drum distribution valve. It's the same part irregardless of the vehicles brake option after 1967. Robs picture shows the frame mounted distribution valve which is a universal part for model years 67-70 on dual reservoir brake systems.

Heres a couple here,http://www.yearone.com/serverfiles/fbshopmain2.asp?input=proportional+valve&SM=1&SC=0

I guess there are different names, one is also called a combination valve, do you have a picture of one and where it goes Jason.

My car is all apart or I would put some on, it would be good to get some actual on the car pictures. This question comes up a lot on these forums.

Rob, the combination valve gets used as a factory application all 71 and later cars. It replaces the valve whose pictures you have posted originally on your website and gets bolted in the same location. It looks like the folks over at year onecame up with a good idea to mimick a factory style valve without the need for changing the top line set off of the master for those who convert their cars at a later date to power brakes. This is a great idea, because it doesn't sacrifice the look of originality and it saves some money by not needing to replace linesets or purchase the additional disc brake prop valve.

http://www.ss396.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=chevellecamino&Category_Code=VALVES
Rob, Fpv-7 and Fpv-89 shows a factory style proportioning valve used on disc brake equipped cars through 70. This valve is used in conjunction with the one you have photographed on your website.

metering/prop. valve
16451
dist. block
16452
comb. valve
16453

On 71 & 72 the distribution block and the combination valve look very similar, but the combination valve is about an inch longer.

Thanks guys, i guess what i wanted was the combination valve. I am thinking the disc brakes came off of a 72 monte carlo. It was 10 years ago and i can't remember if i changed the combination valve or not..I just got the car running last week.

J.wagner.Do you have an actual measurment of the disc/drum combination valve???

As you probably know, those valves came in cast iron and in brass. I have three '72s and they are all cast iron. The length of the iron body is 4.75 inches. This does not include the length of the fittings.

Thanks guys. i looked and it's only about 3 1/2" long. i looked at the one on my 66 and it is about 4 3/4" long and it's the round cast iron style. I am having problems with the brakes being soft. I am sure that is the problem. I will replace it with the correct one and see what happens. I did try a panic stop tonight and only the back tires locked up..

I wonder if i got one off a late model G body if that would work?? I know the calipers and wheel cylinders are the same part number as the 68/72 A bodys.

Keith