Newer plastic style master cylinder

-
73dust340

73dust340

Well-Known Member
Joined
Jan 31, 2009
Messages
112
Reaction score
0
Location
Pittsburgh, PA
I always see these installed, the kind of master cylinder with the metal bottom with plastic reservoir. Where is everyone getting these and what is required to swap over to one? I have all stock brakes. Front discs rear drums with power.
 
wilwood sells one or you can order one for something like a 85 diplomat. you also need the $30 adapter plate..


product_image.php
 
BTW thats not the website i got my brakebooster from, its the same one, but mine was like $50 cheaper
 
You will also need an adjustable push rod or lengthen the one you have.

Most of the people I know who have done this swap used a mid 80's Dodge truck master cylinder, the bore is an 1/8" bigger and gives you a quicker response with less pedal travel, it also makes the pedal a little harder but not enough to really notice.
 
Strange Engineering makes one. I got mine from Mancini. It was $110 and 30 or 40 for the adapter.
 
You will also need an adjustable push rod or lengthen the one you have.
Click to expand...

didn't need one on mine. it was totally bolt in. the newer master cly has a shallower rod hole but the adapter plate used to mount it makes the 73 style rod fit perfect.
 
abodyjoe said:
didn't need one on mine. it was totally bolt in. the newer master cly has a shallower rod hole but the adapter plate used to mount it makes the 73 style rod fit perfect.
Click to expand...

Try grabbing your pedal and pulling it towards the seat, all the stock rods I have seen will fall out of the master cylinder if this happens, they are about 3/8" short because of the adapter. there is only an O ring that holds it into the master cylinder, it is pretty snug but it wouldn't take much for it to pull out and loose your brakes.
 
all the stock rods I have seen will fall out of the master cylinder if this happens, they are about 3/8" short because of the adapter.
Click to expand...


nope the rod is perfect. like i said the new master cyl is drilled shallower then the original 73 up style. that same distance as the spacer. i have the wilwood master cyl. but i believe the 85ish diplomat are built the same way.

and how hard you you be pulling the pedal up to get it past the brake light switch?? gotta really yank it to do that i would imagine. that thing isn't just gonna fall out i can tell you that.
 
Mine's manual, but I just got a master cylinder and reservior for a late 80s D100 at the parts store. It was super cheap. I did need the adapter, but my stock pushrod worked fine.
 
abodyjoe said:
nope the rod is perfect. like i said the new master cyl is drilled shallower then the original 73 up style. that same distance as the spacer. i have the wilwood master cyl. i believe the 85ish diplomat are built the same way.

and how hard you you be pulling the pedal up to get it past the brake light switch?? gotta really yank it to do that i would imagine. that thing isn't just gonna fall out i can tell you that.
Click to expand...

I never seen two different length A-Body rods, I've used the 73 up master cylinders on the older cars with no other changes, how long is the rod you have? What master cylinder are you running? I have one out of a 85 Dodge truck but I mocked the car up with a used one out of a 80 Diplomat, both were identical. My adapter is 3/8" thick and when I mocked it up the pedal was a little too low for the brake light switch and when I pulled it up to see how far off it was, the rod fell. The company I bought my adjustable rod from said that they do fall out, that and to get the pedal height correct is why they made the adjustable one.

Some cars may not need the adjustable rod but I would double check before you test drive the car, this is not an area that should be over looked.
 
Blownfish said:
I never seen two different length A-Body rods, I've used the 73 up master cylinders on the older cars with no other changes, how long is the rod you have? What master cylinder are you running? I have one out of a 85 Dodge truck but I mocked the car up with a used one out of a 80 Diplomat, both were identical. My adapter is 3/8" thick and when I mocked it up the pedal was a little too low for the brake light switch and when I pulled it up to see how far off it was, the rod fell. The company I bought my adjustable rod from said that they do fall out, that and to get the pedal height correct is why they made the adjustable one.

Some cars may not need the adjustable rod but I would double check before you test drive the car, this is not an area that should be over looked.
Click to expand...


been driving the car a ton since 2006 with it set up this way.

i already stated that i am running a wilwood master cyl. (looks just like the mopar one). and i believe the rod hole is the same depth (not 100% sure but pretty sure) not sure how long the rod is. whatever the 73-up disc brake cars have. i'm not sure if there are different length rods i was just stating what i have in case there were.

only reason i went with the wilwood master cyl was out of all the local places i could only find one alum master cyl and that thing looked like they hit it with a hammer or something. its a crap shoot when you order one if you'll get an alum one or a cast iron one. i didn't want to wait so i called RMS and i had the master cyl the next day. i asked about the rod being too short because of the spacer and bill said it wasn't a problem because the master cyl. hole is about 3/8" shallower then a stock 73 style master cyl. which would actually make the rod too long. the spacer being 3/8" corrects that and puts everything in the proper location. atleast it did in my case. it all worked out fine. that rod is really in there. be tough to pull it out on a work bench let alone just tapping it by accident driving down the road. and then the brake light switch is there too. you would have to really pull hard and bust the brake light switch all the hell up to get that rod to fall out of the master cyl. but hey man everyones car is different i guess. maybe its the wilwood master cyl that makes it work but it worked on my car and i have a lot of miles on it since doing it in 2006.
 
The adapters that I build are designed to work with the stock pushrod. The combination of the master cylinder and adapter thickness put the pushrod cup in the stock location.
 
i went down to the local auto store and got a new master cylinder for an 85 diplomat, and you need an adapter of course. mine doesnt leak at all.
 
Where did you get the adaptor arron? This is the first I've heard about needing an adaptor.
 
I got my mine from summit.1 1/8 bore it was like 50 bucks and 25 or 30 for the 4 to 2 adapter plate. I just used the stock rod the whole set up just bolted right in.Nice simple set up that I thought was a big improvement over the stock power brakes.
 
AndyF said:
The adapters that I build are designed to work with the stock pushrod. The combination of the master cylinder and adapter thickness put the pushrod cup in the stock location.
Click to expand...

well there ya go. i got mine from RMS which is probably andy's piece.
 
needsaresto said:
Where did you get the adaptor arron? This is the first I've heard about needing an adaptor.
Click to expand...


the adapter is to go from the 4 bolt set up to a two bolt master cyl. and to put the push rod at the proper length. give bill at RMS a call he stocks them.. Phone - 570-443-7440
 
i got mine from sum hick at mopar nats last year i seen it in a pile and paid 5 bucks for it / i have had a lot of turbo dodge cars and have a master from one of them but have not installed it yet waiting on winter to be over :cheers: soon ya
 
AndyF said:
The adapters that I build are designed to work with the stock pushrod. The combination of the master cylinder and adapter thickness put the pushrod cup in the stock location.
Click to expand...

So who sells your adaptor? And how much?

Love your book btw!
 
abodyjoe said:
well there ya go. i got mine from RMS which is probably andy's piece.
Click to expand...

Yes, Bill sells my adapters. So does Doctor Diff, Firm Feel, Mancini Racing, etc. Basically everyone sells my adapter except for Mopar Performance.
 
At the time I bought mine, Dr. Diff had the best deal on aluminum MC and adaptor. I initially tried an iron truck MC with 1.125" bore. Too much leg effort for my taste and comfort level. Dr. Diff's was 1.03" - a big improvement.

You're not likely to get an aluminum unit going the reman route - they'll be iron. Rebuilders had issues refurbishing the aluminum bores.

Oh, and Andy's adaptor is very nicely made.
 
alsdemon said:
i have had a lot of turbo dodge cars and have a master from one of them but have not installed it yet waiting on winter to be over :cheers: soon ya
Click to expand...

Couldn't tell you why, but I've always heard NEVER put a FWD master cylinder on a RWD car. Might be an old wifes tale, but thought I might at least let you know.
 
You must log in or register to reply here.
-

Back
Top