Distribution block and proportioning valve testing

[napa68]

I'm in the process of doing some brake work to the car. After rebuilding the front calipers, I am not impressed with the brake fluid pressure or volume at the calipers when bleeding. I took the car for a road test and again, I am not impressed.

So, is there a way to test/check the distribution block as well as the proportioning valve? I know replacements are available. I would just like to keep the original parts on it.

I also posted this in the thread for the car.

Thanks!

Tim

http://i1043.photobucket.com/albums/b437/napa68/Harry%20Mann%2068%20L78%20-%20L88%20Camaro/IMG_20160621_195602423_zpsij6n2kaz.jpg (http://s1043.photobucket.com/user/napa68/media/Harry%20Mann%2068%20L78%20-%20L88%20Camaro/IMG_20160621_195602423_zpsij6n2kaz.jpg.html)

http://i1043.photobucket.com/albums/b437/napa68/Harry%20Mann%2068%20L78%20-%20L88%20Camaro/IMG_20160621_195511313_zpsecypxjei.jpg (http://s1043.photobucket.com/user/napa68/media/Harry%20Mann%2068%20L78%20-%20L88%20Camaro/IMG_20160621_195511313_zpsecypxjei.jpg.html)

http://i1043.photobucket.com/albums/b437/napa68/Harry%20Mann%2068%20L78%20-%20L88%20Camaro/IMG_20160621_195451152_zps24ivmgme.jpg (http://s1043.photobucket.com/user/napa68/media/Harry%20Mann%2068%20L78%20-%20L88%20Camaro/IMG_20160621_195451152_zps24ivmgme.jpg.html)

http://i1043.photobucket.com/albums/b437/napa68/Harry%20Mann%2068%20L78%20-%20L88%20Camaro/IMG_20160621_195408335_zpse0mcsfje.jpg (http://s1043.photobucket.com/user/napa68/media/Harry%20Mann%2068%20L78%20-%20L88%20Camaro/IMG_20160621_195408335_zpse0mcsfje.jpg.html)

http://i1043.photobucket.com/albums/b437/napa68/Harry%20Mann%2068%20L78%20-%20L88%20Camaro/IMG_20160621_195402610_zpskaqanb4h.jpg (http://s1043.photobucket.com/user/napa68/media/Harry%20Mann%2068%20L78%20-%20L88%20Camaro/IMG_20160621_195402610_zpskaqanb4h.jpg.html)

[cook_dw]

I literally just finished doing the same thing on the green L78 car last night.. I had an issue with the metering valve at the beginning as it was leaking along with the master. After replacing the master with another WT mc (father put discs on it back in the 80s) I rebuilt and reinstalled the metering valve I couldnt get a good pedal and realized it was leaking fluid out past the rear seal.. Pulled it back apart and there was a very small chunk of rust down in the crevice were the seal seats. Got in there with a pick and cleaned it out and I now rock hard pedal. Not sure itll be your problem but was the answer for me.. As far a bench test of the parts... When I pulled the metering valve apart it was frozen together and you could tell it wasnt working properly.. Not sure about the distribution block. Also do you have a proportioning valve down on the frame? Also might look at the wheel cylinders making sure they are leaking or bleeding off. Just some thoughts.

[Zman1969]

Both Ricks and Heartbeat sell rebuild kits for the hold off valve although they call it the Proportioning valve(thats down on the frame) HB also offers a reman/exchange unit too. This valve has a button on the rear that can be pressed while bleeding this valve hold off pressure to the front brakes until rear pressure is 30 lbs or so. you may try pushing the rear button and see if this helps your bleeding - you may want to remove the dust boot as as old as they are it will get damaged

[cook_dw]

Im not sure what button you are referring to??<<GRAEMLIN_URL>>/dunno.gif


https://www.musclecarresearch.com/articles

http://www.camaros.org/brakevalve.shtml

[Zman1969]

Darrell, on your first link under &quot;67-69 3905525 Metering valve rebuild&quot; the end with the rubber cap (left side of the picture) is the button that can be pushed in I've used a screwdriver and pried against the booster to allow bleeding with pedal pressure
https://www.musclecarresearch.com/sites/default/files/styles/large/public/images/3905525-15.jpg

and the end can be seen in this picture
https://www.musclecarresearch.com/sites/default/files/styles/large/public/images/3905525-2.jpg

[cook_dw]

Ok so you the button as you are calling it is the end of the shaft. Gotcha.. You are basically blocking the fluid from going to the front brakes. Im following what you are saying now. The way you wrote it wasnt registering in my simple brain. <<GRAEMLIN_URL>>/beers.gif