1969 to 1970 master cyl disc brake question

[resq302]

Ok, I after just going through the joy of rebuilding my rear axle and differential again, I now have another gremlin I have to fix.  While taking the car out for its second break in of the differentials, I noticed an odor of something burning and pulled over only to find my rear wheels smoking.  I was close enough to drive it back home and the wheels were super hot to the touch.  After letting them cool overnight, I pulled the rims and drums and started the car.  I pushed gently on the brake to see if the rear shoes went out then returned back.  Well, they went out but did not go back.  At least I found my problem.    I thought the rubber flex hose for the rear brakes might be collapsing so I replaced it, no change.  My next thought is the master cylinder.  I have heard that the suction cup like piece inside the master cylinder could go bad and not cause a suction to pull off the brakes yet mushroom out enough to cause pressure to be applied in the line when it was pressed. 

My parts store had a listing for my 69 Master cylinder with disc brakes but when it arrived in, the master cylinder was for a drum brake car, not a disc brake.  They looked up 1970 year and found that hte master cylinder was a different part number as the part number they had for 1969 disc brake was actually the same part number for the power and non power drum brakes in 1970.

Are 1970 and 1969 Power Disc Brake master cylinders the same part?  Can they be interchanged and work the same?

Thanks,

Brian

[Shakey]

Ok, I after just going through the joy of rebuilding my rear axle and differential again, I now have another gremlin I have to fix.  While taking the car out for its second break in of the differentials, I noticed an odor of something burning and pulled over only to find my rear wheels smoking.  I was close enough to drive it back home and the wheels were super hot to the touch.  After letting them cool overnight, I pulled the rims and drums and started the car.  I pushed gently on the brake to see if the rear shoes went out then returned back.  Well, they went out but did not go back.  At least I found my problem.    I thought the rubber flex hose for the rear brakes might be collapsing so I replaced it, no change.  My next thought is the master cylinder.  I have heard that the suction cup like piece inside the master cylinder could go bad and not cause a suction to pull off the brakes yet mushroom out enough to cause pressure to be applied in the line when it was pressed. 

My parts store had a listing for my 69 Master cylinder with disc brakes but when it arrived in, the master cylinder was for a drum brake car, not a disc brake.  They looked up 1970 year and found that hte master cylinder was a different part number as the part number they had for 1969 disc brake was actually the same part number for the power and non power drum brakes in 1970.

Are 1970 and 1969 Power Disc Brake master cylinders the same part?  Can they be interchanged and work the same?

Thanks,

Brian

Maybe this thread will be able to help you a bit Brian.  I posted a chart that lists the different master cylinders available.  I found mine at a salvage yard in CA earlier this year.

http://www.dodgecharger.com/forum/index.php/topic,9884.0.html

[daytonalo]

Don't waste your time , keep it origanal . Rebuild you orig . if you can take a rear drum off , you can rebuild a master cyl .

[resq302]

The problem is the master cylinder is not the original one.  I would like to find an original one.

[daytonalo]

Good luck , GRASSHOPPER!!!!!!!!!!!!!!

[resq302]

Well, I searched around and found some parts stores that has some master cylinders that look like originals and have casting numbers like originals also.  Here is a pic of the m/c that I believe is correct.  Feel free to chime in if it is not correct.

Also, disc brake cars had the master cyl and cap painted gloss black I think right?  Or were they natural cast iron with the gold cad lid like in the picture?

[Shakey]

This might help you Brian.

http://www.dodgecharger.com/forum/index.php/topic,13667.0.html

[resq302]

Ok, I thought I remembered that thread with the power disc m/c's being black.  Just wanted to be sure I had it right and didn't need to pull it off yet once more to get it right.