I did a junk yard disk brake conversion. 72' monte carlo. I am using my metering or distribusion block, and I am using a adjustable por. valve for rear bias. all new parts except for my metering block. my brakes are crap. soft pedal, it takes two or three pumps two firm up. master has been removed and bleed twice. brakes bleed several time using the two people method and vaccumed pumped. with air only being removed when the master was removed and reinstalled. what gives?? do I have to replace my metering block? I thought you could keep it. I just read you had to fix the rear bias difference problem. thanks for any help.

still got drums on the back or 4 wheel disc?

I have drums on back.
I just found a page that goes through all the parts and proper name and function of each. a distribution block is not a metering block and a proportioning valve is still different than the others. I have a stock distribution block that works on disk and drum set ups. the proportioning valve (on frame rail under driver seat) is different for a disk drum combo than straight drums. but when you add disk to the front you have to add a metering block (the round looking one next to master)to the front brakes system so that it can build pressure before they engage. can someone verify this before I spend the $90 on one.. thanks

They call the one on the frame rail a Hold off valve for the rear brakes, it's suppose to prevent brake lock ups I guess.
The round one is for the front brakes and I was told it's a Proportioning Valve. This setup was on 67 only I believe and
a distribution block too.
How does it stop?
Are they Power or manual?
If power is it a new Booster?

The round one is a Metering valve according to the firstgensite illustrated brakes webpage, but some also call it a hold off valve and it was used on 67-69 with front disk brakes. The rectangular looking block under and offset from the master cylinder is the distribution valve and also called the proportioning valve. And the one on the frame below driver seat is a Brake pressure regulator Valve some also call this a hold off valve. All in all too many darn names..lol That first link in this post (Metering Valve) is a little bit cheaper from right stuff then the $90.00 you posted and they are a good place to buy from, at least in my experiance.

yes, they are power brakes, and every thing is new other that distribution block. I'm going to check booster today for leak.
thanks for the info about Right Stuff, every thing helps. then I wait on parts to show up.

The residual pressure valve [thought I would throw in another name] is a check valve that keeps a bit of pressure/fluid in the rear brake line. I think it's about 2-5 psi but don't really remember. As the drum wears the shoes have to travel further to hit the drums which in turn takes more fluid. The valve reduces the amount of fluid needed to apply the rear brakes. Four wheel drums have a check valve in the master cylinder but disc brakes do not use the valve thus a separate one for the rear brakes.

Here's a thought, If your rear brakes are way out of adjustment they could be taking more fluid than the M/C can give in a single application causing you to pump the brakes to get enough fluid to get pressure?

Another M/C check - pump the brakes untill you get good pressure then just hold the pedal down if it [the pedal] slowly moves to the floor you have an internal leak in the M/C.

x2
Have had 2 brand new master cylinders that were defective in a row.

if you want a simple principal about this, check out the hot rod "Roadkill" episode where they rescue a badly modified merc. it had front disc and rear drums, but the master cyl was still a 4 drums master, caused the front discs to lock up because of the residual pressure valve.

my m/c is for disk brakes. this is my second m/c, first one seem to bleed by, never could get any kind of pedal feel. i couldn't make it to the shed today, hopefully wensday