67 Dart brake change

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67DART340

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I have a 67 Dart. The car was originally from L.A. and came with a slant 6. It now has a 340/4speed with 5 on 4 1/2" right hand thread studs on all 4 wheels. The front now has disc brakes and the rear has 10" X 2" drums on an 8 3/4 rear. The brake pedal sometimes goes to the floor when pumped. I filled the reservoir and pumped it several times. There appears to be no leaks at any of the wheels, flexible lines, or hard lines. I'm thinking the problem is that it's the master brake cylinder. But, now with mixed parts, I'm not sure if the master cylinder is the right one (original) or has been replaced when the brakes were changed. The master cylinder has an equal reservoir body and cover which makes me think it's for 4 wheel drum brakes. See picture. There appears to be no equalizer either. Should I have a different master cylinder or an equalizer? And how about a newer style master cylinder? Any suggestions would help. Thanks.

Mastercylinder.jpg
 
67DART340 said:
I have a 67 Dart. The car was originally from L.A. and came with a slant 6. It now has a 340/4speed with 5 on 4 1/2" right hand thread studs on all 4 wheels. The front now has disc brakes and the rear has 10" X 2" drums on an 8 3/4 rear. The brake pedal sometimes goes to the floor when pumped. I filled the reservoir and pumped it several times. There appears to be no leaks at any of the wheels, flexible lines, or hard lines. I'm thinking the problem is that it's the master brake cylinder. But, now with mixed parts, I'm not sure if the master cylinder is the right one (original) or has been replaced when the brakes were changed. The master cylinder has an equal reservoir body and cover which makes me think it's for 4 wheel drum brakes. See picture. There appears to be no equalizer either. Should I have a different master cylinder or an equalizer? And how about a newer style master cylinder? Any suggestions would help. Thanks.
Click to expand...

The master cylinder in the pic is for DRUM brakes. You need one for disc. The disc MC has one small (forrear brakes) and one large (for front disc) resivior. Not only does the drum MC not have adequate fluid capacity for the front disc, there is a check valve in the port where the line connects to keep residual pressure in the lines. This will burn up your discs in no time since they will drag.
 
What do you think of this proportioning valve? It's a KH Disc brake proportioning valve for 11" front disc brakes with 11" X 2.5" drums in the rear. This was from a 1978 pickup. And here is a photo of a new master cylinder that I would use as a replacement. What do you think of that? Am I heading in the right direction? Short of going to the junk yard and looking for the parts (which I would love to do, in warmer weather) , but I might think it would be rather hard to find some decent parts around here. Thanks guys. Do appreciate the help.

PROPORTIONING VALVE.jpg


MASTERCYLINDER.jpg
 
67DART340 said:
What do you think of this proportioning valve? It's a KH Disc brake proportioning valve for 11" front disc brakes with 11" X 2.5" drums in the rear. This was from a 1978 pickup. And here is a photo of a new master cylinder that I would use as a replacement. What do you think of that? Am I heading in the right direction? Short of going to the junk yard and looking for the parts (which I would love to do, in warmer weather) , but I might think it would be rather hard to find some decent parts around here. Thanks guys. Do appreciate the help.
Click to expand...

MC will work as long as it will bolt up to the firewall and has the correct cup for the brake pedal rod. Make sure you put the grommet on the rod so it doesn't come out (Safety). The Prop vale is iffy. They are normally set up according to vehicle weight and weight ratio front to rear so you may get rear wheel lock with it. Go to your Chrysler dealer and get one for a mid 70's A-body. They are still available. Just got one about 4 months ago. Naturally you will have to be lucky enough to find a parts guy willing to look thru a real printed parts manual for the part number.....

Larry
 
Time out there fella's. The master cylinder he has in his car is for a KH 4 piston manual disc brake car, and in the absence of a booster appears to be what he has. Although your mention of the fact that you have the 4 1/2" bolt circle might indicate that you may have the later single piston sliders. I'd be willing to bet that the problem is the master cyl., and I am 100% sure that the master cyl you have is correct for a 69 dart with KH manual disc. Included is a picture of the same master in my car. If you have the later single piston calipers you may need the later style MC, but if you have the KH 4 piston discs, that is the correct MC. If you need brake stuff, call Craig Studnick the Antique Auto King out of New Jersey. He knows Mopar brakes like no other person i've met. His number is (516)1935. Good luck with your brakes, Geof

100_1121.jpg
 
I agree with cosgig, my 67 barracuda f/s has the same master
cylinder as pictured. Manual front disk brakes. He may have air in the lines
or a bad master.
 
72bluNblu, pettybludart, lhearold, cosgig, 69DartGTS, thanks for the help. The pedal when pumped in succession, holds most of the time, but maybe every third or 4th pump goes to the floor. With the pedal going to the floor, I would expect to see some fluid accumulating somewhere on the ground, but I don't see it happening. That makes me think it's the master cylinder. I don't know how old the MS is. Back in the day, I seem to remember that if there was air in the lines from the MS it tends to clear it self as the air rises and is replaced by the fluid from the MS. And the car is a jigsaw puzzle of parts, so I just want to get it right. The car might be in a movie, so I want it to be able to stop & go. Thanks guys. Chaz.
 
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