I have a 70 Malibu, It is had the power drums, I changed it to a factory disk set up in the front. I bought the disk/drum prop. valve from OPG. I also changed the Master Cyl. to the disk/drum. Ran all new stainless lines on the car. I just can not seem to get it all to work right.. Is there a different "stroke" in the pedal or booster for the drums compared to the disk.. Where have I gone wrong???? Any Ideas..... :confused:

Scott,
You don't specify what you mean by "can't get it to work right".
I'm assuming you have bled them. One thing to check is to be sure the rod between the booster and MC is the correct one for the MC. SOme need a long rod and some use a short rod. If I recall, my power drum setup had a short rod. Be sure that the new MC uses a short rod, or you will need to replace it with a long one.
John

Also, make sure the bleeder screws are pointed up!

And bleed the system properly.

Did you get all the lines right to the combination valve?

Joe

I know the rod from the booster is supposed to be on the lower hole in the master cylinder. Could be the problem?

I know the rod from the booster is supposed to be on the lower hole in the master cylinder. Could be the problem?
The rod from the booster to the pedal goes in the lower hole on the pedal for power cars. There is also a rod between the booster and MC, which actually works the MC. You can't see it when the MC is mounted to the booster. In some setups it is short (about 3")and some setups longer (about 5"). The booster will work with either setup, the MC determines if you need a short or long rod.
John

you can also make sure you don't have the front and back lines reversed on the MC.

Ive heard that some MCs have the rear port feeding the front and some have the rear going to the rear.

Not sure how you can tell which is which, though.

anyone have any info on this?

Originally posted by cperrell:
Ive heard that some MCs have the rear port feeding the front and some have the rear going to the rear.

Not sure how you can tell which is which, though.

anyone have any info on this? Starting around '73 (at least that's when I've noticed GM going to the reversed reservours at the 'yards I attend) GM started doing this. It makes you wonder if they anticipated the need for a quick take up MC. But, that's for another story...

You can tell by the size of the reservours. The big one feeds the front brakes and the small one will feed the rear brakes.

The '73-'77 15/16" bore MC that is used in Baer's kit is the reversed reservour design. My website has the AC Delco part number if anyone is looking for a small bore iron MC, but beware that it features a deep pushrod hole. Baer machines a spacer to fit inside the MC bore to make it a shallow MC for their applications.

Joe