master cylinder out of a 80's Diplomat fit in my Valiant?

-
M

moparfreak77

Well-Known Member
Joined
Sep 24, 2006
Messages
567
Reaction score
2
Location
Ontario Canada
I have power brakes in my 77 aspen but the master cylinder/booster is out of an 80's Diplomat. Can I take the master cylinder, dont care about power, and put it in my valiant? if not, what will it take? thanks
 
does your valiant have power brakes or manual now?? if it bolts on the fire wall easly enough (it shuld) then your only issue will be the length of the brake pushrod. manual ones are not adjustable and basicly are matched to the car model and its master cyl. I have cut them and also welded on extra material before (a short piece of a bolt) but this was for a race car , not a street car. not that it makes much difference.Be sure that your pushrod CANT FALL OUT OF THE MASTER CYL!! if it doesnt fit properly this can happen..its a really bad thing!
there is a chance that the proportoning will be off, unless your useing the aspen/diplomat stuff to update to disks, then it would all match up and i would suggest useing the diplomat master cyl.its a pretty simple upgrade as long as some care is taken
 
I believe the vintage car you are talking about as a doner has two bolts holding the MC to either the firewall or booster. And, your valient will have 4.

You can purchase an adapter and an adjustable push rod but that will cost a bunch more than just going to the local parts store and purchasing a rebuilt for the car you need it for.
 
The bore size will affect pedal pressure. It'll either be 1 1/32" or 15/16" of an inch. The 15/16" bore will give you a lighter pedal. The larger bore will give you a stiffer pedal, which is what I prefer. That's the old size.
 
the valiant doesnt have power brakes and I dont care if i have them. The booster is off an 80's diplomat and i put it on my aspen because it didnt have power brakes. I noticed today that they bolt up different like dgc333 said. I can make the adapter plate myself. so how do you know the proper pushrod length? this is the rod that goes in the master cylinder and bolts up to your brake pedal right? the main reason i'm doing this is to get rid of the one reservoir. I will be keeping my 4 wheel drum setup for now. thanks
 
From what I know, you will need a longer pushrod because an adapter will put the master cylinder that much further away from your brake pedal. Mopar Performance makes an adjustable length one.
 
ok thanks. what about the proportioning valve? will the one on my valiant work or should i use the aspen one? the aspen one will be from a no power setup but disc upfront.
 
If you buy the adapter from RMS or mopar the push rod is the correct length and bolts rite in. Dave
 
Still don't understand why you would want to go through all that trouble when you can get the correct master cylinder rebuilt for $20 at the local part store.
 
yes the mid 80's diplomat master syl will fit if you use the 4 bolt to 2 bolt adapter.. the 2 bolt master cyl push rod bore is bored more shallow then the 4 bolt so the adapter takes up the difference and works out great... i didn't have to change the rod on mine..
 
You must log in or register to reply here.
-

Back
Top