Kelsey hayes front rotors correct master cylinder

[440DART1970]

Is there a correct Kelsey hayes 4 piston caliper sbp brake master cylinder that i need to use with my front manual drum to disk conversion?.... I had thought I had read something about the bore size has to be correct

 

[66fyssh]

I used a 73 (IIRC) master cylinder when I did my m/c from the one pot to a dual. I had factory K-H. The 73 has a 1 1/16 (inch and a sixteenth) bore and I wish I would have gone with a little smaller, maybe 7/8. The 7/8" is probably a little easier on the leg!

Nice looking setup you got there!

 

[440DART1970]

What about a 1-1/32 bore?

 

[BillGrissom]

1-1/32" manual MC would be OK for an NFL linebacker. Most here like the 1980's Dodge truck alum MC w/ 15/16"D. Can buy a 2-4 bolt adapter plate ~$30 (ebay) or one place sells them packaged. 7/8"D would yield an even easier pedal, w/ downside of more travel.

 

[440DART1970]

How do I know which 1980s Dodge truck master cylinder get

 

[BillGrissom]

Many posts, search. I know there was at least one post in the last few months showing the kit (MC + adapter plate) from Dr Diff or such. I find searching from Google works best.

 

[davescuda]

Do you want original? or what will work?

 

[Mattax]

What Dave asked is important too.
Street use vs. road course. On a road course the less movement will feel much more reassuring especially when the brakes get hot. Racers modulate by pressure and not having to move the foot and leg much.

I've been using the stock 1" bore, 1" stroke and find its fine (and I'm not a linebacker :LOL: ). Also the selection of pad and shoe material makes a difference in feel and pedal force. I've used some that required more initial force on the pedal than others.

 

[Mattax]

FWIW here's my work in progress crib sheet for Original A-body Master Cylinders & Bore.
Feel free to add, question or correct (especially if you have a documented source).

years___Application_____________p/n_______Bore
1966... Fixed Ft calipers, Manual................1"
1966... Fixed Ft calipers, Power..................1"
67-70.. Fixed Ft calipers...........2808600.....1"
71-72.. Fixed Ft calipers...........3461178.....1 1/32
73-74.. Floating caliper, Manual..3580146.....1 1/32
73-74.. Floating caliper, Power.. 3580112........15/16

1976?...............................____4647..........15/16

 

[66fyssh]

Thanks Mattax, I think I used a 73 m/c which would put mine at 1 1/32" It takes a little effort, but its not scary hard (I was an inside linebacker in junior high school!)

FWIW here's my work in progress crib sheet for Original A-body Master Cylinders & Bore.
Feel free to add, question or correct (especially if you have a documented source).

years___Application_____________p/n_______Bore
1966... Fixed Ft calipers, Manual................1"
1966... Fixed Ft calipers, Power..................1"
67-70.. Fixed Ft calipers...........2808600.....1"
71-72.. Fixed Ft calipers...........3461178.....1 1/32
73-74.. Floating caliper, Manual..3580146.....1 1/32
73-74.. Floating caliper, Power.. 3580112........15/16

1976?...............................____4647..........15/16

 

[BillGrissom]

... I know there was at least one post in the last few months showing the kit (MC + adapter plate) from Dr Diff ...

If somebody did search, please post the link for everybody.
For example, I typed "Dr Diff" w/ "Master Cylinder" in Google and easily came up with this FABO thread
www.forabodiesonly.com/mopar/threads/dr-diff-master-cylinder.348853/
with link to
www.doctordiff.com/aluminum-master-cylinder-kit.html
Finally, a screenshot from Dr Diff's page. Pick 15/16"D or 1-1/32"D (if feeling manly).
There is also a recent post about those reservoir caps leaking, and suggestion to replace w/ Dorman caps from most auto parts stores, but I'll let someone else search for it and post the link.