which master would you use?

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mopar56

mopar56

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OK, I read through the old post here I think I got it but want to be sure, I am converting the front drum brakes on a 70 Duster to disc brakes from a 73 dart, so would you use the master cylinder from the 73 dart or one for the 70 Duster, as I understand it the 70 was the only year that came with the four piston brake and the 73 is single, dose that make a difference?, is the bolt pattern the same?, my thoughts are use the one for the 73 dart, BTW the car is a manual brake car and I am keeping it that way, sorry if this has been posted before I read through 6 pages of post and couldn't quite see the exact question being asked before. oh and yes I am using the proportion valve from the 73 dart to.
 
One for a 73 dart with front disc brakes will work the way it's supposed to.

Can also buy the adapter and run the newer style master cyl but it's not necessary.
 
Thanks that's what I thought, this is my sons car, he is on a bit of a budget so I think we will stay with the 73 one as there only about $50.00 but just out of curiosity why do some members here like the newer style ones?,
 
mopar56 said:
Thanks that's what I thought, this is my sons car, he is on a bit of a budget so I think we will stay with the 73 one as there only about $50.00 but just out of curiosity why do some members here like the newer style ones?,
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In general, you should be matching your master cylinder bore to the bore size of your calipers.
Since you are using a 73 disc setup, I would go with the 73 MC.

The newer MC is aluminum, making it lighter. The bore size is more than likely different as well.I have one in one of my Darts, and notice no difference in braking.
 
Thanks JD but surely there must be more to it than weight difference as they are really only a few pounds any way but if that's it then I cant see the advantage for a street car?
 
mopar56 said:
Thanks JD but surely there must be more to it than weight difference as they are really only a few pounds any way but if that's it then I cant see the advantage for a street car?
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Lighter is better, for the street. Aluminum intakes, heads,wheels, etc. Anything to shave weight,every pound counts.

The other difference is bore sizes.
Not going to get into that right now, hitting the rack. Im sure someone else will chime in.
 
Transfer everything from the 73 and it will be golden.
The only science in Disc brake-M/Cs, of this era, and factory calipers, is the bore size. Everything else is negotiable. On the street, run what you brung.If you don't like it on account of it takes too much leg power, or it travels too far to affect a good stop, THEN swap it out for another M/C with a different bore size. Really I've tried 'em all and like the 15/16 inch bore. Others will tell you they like the 33/32 bore. Run the 1973, and see what you think.Measure it before you install it, in case you think on swapping it out later; then you won't have to pull it at that time.
 
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Make sure the 73 has fluid in it at the time of removal. If they sit for long empty, they will suck up atmospheric water and that's not good.If there is any rust in the reservoirs, at all, there's a good chance the unit is no longer serviceable.
If it's good, and you won't be refreshing it in a day or three, bag it!
 
..if it's not too late and you are exchanging your callipers for rebuilds get the later ones with
2 3/4" pistons ('76 Cordoba?).Your '73 callipers with 2 5/8" pistons will still work well,but the 2 3/4" will provide more pressure at the rotor with the same amount of "leg" and are a little nicer.
..as AJ says 15/16" work well and 1" is o.k. too.
 
mopar56 said:
Thanks JD but surely there must be more to it than weight difference as they are really only a few pounds any way but if that's it then I cant see the advantage for a street car?
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Aluminum is lighter and stays purty. The plastic reservoirs don't leak like many experience w/ the old cast-iron ones. They also have a level sensor you can wire to your dash lamp. I use an MC for a 95-99 Breeze w/ ABS (7/8" ID bore) on all 3 of my 60's Mopars. I had to buy a 4-2 bolt adapter plate ($30), except on my 65 Dart where I used the Breeze booster (see avatar). The first one I got cheap at the junkyard, and bought the others new on ebay for ~$25 ea, plus a spare for the shelf. A late 80's Dodge truck MC is used by many, and same PN sold in sometimes pricey upgrade kits.
 
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