66 Dart master cylinder replacement

-
Wrencher

Wrencher

Well-Known Member
Joined
Jul 20, 2010
Messages
271
Reaction score
9
Location
Alabama
OK, so I have a 66 dart with a slant six thats in surprisingly good condition, but I find myself shying away from driving it because of the antiquated braking system. It has four wheel drum brakes, which doesn't bother me, but the master cylinder is a single reservoir type, and that bothers me in a big way.

I would like to go to a dual reservoir master cylinder, so in the event of a failure...... I don't die:)

Here's the info I need;

1- which master cylinder can I use(for what vehicle).

2- do I need a proportioning valve? I'm assuming no, since its a disc brake part?

3- what do I need other than new plumbing. Junction block of some type I'm thinking

4- the wheel cylinders on this car are seized from sitting. I want to order new cylinders for the car but I can't remember if it has 9" or 10" drums. The 10" has the bigger piston and I'm going to order it for the extra breaking power. Chances are they bolt up the same way right?
 
Oh yea, this is a manual brake setup I'm reffering to. Is there a lot of work that needs to be done to get power brakes on these cars?
 
I picked up a master cylinder from Napa PN#36308,$115. You can go on-line to Napa Pro and find the dual M/C. I got a new distribution block from a 71 Dart PN# RBV001 $65.and bent some lines. Turned out real nice. The block you should be able to get from Fine Lines. The set-up is supposed to be suited also for disc brakes also if we decide to upgrade later.
 
I would get a modern aluminum master cylinder. Mopar Performance sells one, but you can do much cheaper. You can buy an adapter block ~$70 so the 2 bolt holes can be used with the 4-studs on your firewall. I plan to try just drilling 2 holes for an MC from a Breeze (no booster) on my 64 Dart.

To get power brakes (not essential with drums), you need the stand-off brackets w/ lever from any A-body. You can mount just about any booster and MC to the brackets. I used one from a 95 Breeze on my 65 Dart. I just needed to rat-file file the bracket holes slightly. Or you could buy an after-market set for ~$250. You don't need a proportioning valve with drum brakes. I used one to allow for future front disks. The one shown is ~$25 on ebay.

I suspect you can't use the 10" wheel cylinders in 9" drum brakes. I have both (65 Dart & 64 Valiant) and I recall the cylinders and rods are quite different. Many wheel cylinders are <$5 on rockauto, so I usually just replace them, but that is when rebuilding the whole suspension. I recall that in my 10" brakes I couldn't mount the cylinder without unbolting the backing plate, at least with my wrenches, so might be easier to hone the cylinder in place and install new parts (~$2). You should pull a wheel first and see which brakes you have. You should clean and repack the bearings, which requires a new hub seal, so you need to know. Most V-8's had 10" brakes and slants 9". My 69 Slant had factory air and 9" brakes.
 

Attachments

  • master cylinder & booster.jpg
    191.7 KB · Views: 648
You can do this with a master cylinder from a 68 dart/valiant. At RockAuto, it's $30. RAYBESTOS Part # MC36221. I did this to mine over the winter and all works good. That is the only part you need to buy other than new brake lines. No proportioning valve needed.

You will have to make up some new lines and run them but can use your current distribution block. You will have to plug one of the holes. Look at how the distribution goes and I'm sure you can figure it out. One line goes to the back and splits at the rear end.

Don't want to turn this into a big long response but if you need detail, PM me and I will get more detailed for you.

Dennis
 
thank you very much!!

This is exactly what i needed.

The newer aluminum master cylinder is intriguing, but I think for the time being though, I will put it in the memory bank for when i decide to go to a disc brake setup. The replacement unit for the '69 will suit me just fine. Its exactly what i had in mind, i just wasn't sure if i would be able to do it without swapping to disc brakes.




The reason i asked about the wheel cylinders wasn't really about price but more like performance. I had a 98 dodge ram 2500, and anyone whose had one and pulled loads knows how the rear brakes just don't perform well at all. Well after looking around, i went with a Chevrolet 1 ton wheel cylinder, which was much bigger (1in vs 13/16 i think?) the difference is very noticeable, and its slowed down the front pad wear quite a bit.
 
BillGrissom said:
I would get a modern aluminum master cylinder. Mopar Performance sells one, but you can do much cheaper. You can buy an adapter block ~$70 so the 2 bolt holes can be used with the 4-studs on your firewall. I plan to try just drilling 2 holes for an MC from a Breeze (no booster) on my 64 Dart.

To get power brakes (not essential with drums), you need the stand-off brackets w/ lever from any A-body. You can mount just about any booster and MC to the brackets. I used one from a 95 Breeze on my 65 Dart. I just needed to rat-file file the bracket holes slightly. Or you could buy an after-market set for ~$250. You don't need a proportioning valve with drum brakes. I used one to allow for future front disks. The one shown is ~$25 on ebay.
Click to expand...

What is the size of the Breeze power booster? Will it fit on a V8 early A?
 
I'm doing the exact same thing this week on my '66 Barracuda. Got a Napa NMC P1874M master cylinder and the distribution block from Year One.

Its my understanding that for manual drum brakes you don't need a prop valve, you only need the distribution block for a duel reservoir master cylinder car.

The distribution block from year one was 39 bucks. Here's the link: https://www.yearone.com/Product/DisplayProduct/226822

It seems to be high quality and bolts right in the stock location so I should be able to reuse the old brake lines since they were all replaced about 3 years ago. I'll let ya know how it all works out!
 
That's great do update me on that. Sadly, I don't have a Napa within 30 miles of me, so its either internet or auto zone/advance. The car is sitting on the original 13" wheels with some terribly bad dry rotted tires. I've been looking here on the forums for a set of rally wheels to put on it. Once I find something I'm going to drive it all summer, now that I have a direction to go on these brakes.

The proportioning valve I kinda knew wasn't needed. Since its function is simply to temper the fluid flow to the fronts, which on a caliper has a gigantic piston as compared to the wheel cylinder
 
I used a distribution block from a 67 B-body (off my parts car) to install a dual reservoir master cylinder on my 65 Barracuda. Works fine.
 
Started ripping into the brakes on my '66 Cuda today. Ran into a couple of hitches . . . first of all the brake peddle push rod was stuck in the old master cylinder so had to unbolt it from the brake peddle to get the old MC out. Put the dang thing in the vice and after some good hammer blows it still wouldnt come out, ended up having to use a cut off wheel on the MC piston and split it in half to free up that push rod. Ugg . . . old cars . . .

Second bit of fun was taking the old brake lines out of the original distribution block in prep for the duel res master cyl distribution block from year one. Just an FYI . . . the mounting bracket from the year one block is backwards. I used a grinder and carefully ground down the brass that holds the mounting bracket in place, popped it off and flipped it around. It seems to hold strong but maybe a little JB weld will be in order just to be safe. I'll try to get some photos of what I'm talking about incase anyone else has the same issue.

Going to hook up the lines and finish the new MC install tomorrow. . . . old brake lines suck
 
I have my parts on order and I sure do hope I don't run into that problem. Sounds like a big pile of suck....lol
 
http://www.earlycuda.org/tech/dualmaster.htm

I ran across this site last night. I think my new plan of attack is going to be to run a coupler to extend the rear brake line directly to the MC and use a rear axle brake line "T" from the MC to the L and R front brakes. Upon further review it looks like using the year one block will be more problems than its worth since I want to use the brake lines that are already on the car. If you're going to run new lines it shouldnt be an issue however.

Good luck on yours, ill keep you posted on my progress this weekend.
 
Call the ram man. He rebuilds and specializes in Mopar brake systems. He can hook you up with the proper master cylinder and prop valve. He can set you up with a master cylinder for manual disc or any drum brakes you may go with.

http://www.theramman.com/
 
I ran into the same problem with the piston and the MC. Just used the old distro block so no problems there. Just gotta be patient and plan on running into snafu's along the way. These cars are 40+ years old and you have to realize that not everything is going to go smoothly on them.

Along with the usual wrenches, sockets and screwdrivers, you need cut-off wheels, chisels, torches and a bfh sometimes to work on these old relics. Dennis
 
I picked up a set of flare wrenches today so hopefully that'll help from rounding off these dam things. Im just going to run the rear line up to the MC and use a T for the front lines, that year one MC is goofy, hopefully I can return it. Im running all 4 manual drum brakes so dont have to worry about any prop valve.

Ya along with a a BFH to beat stuff i love my "big fuzzy screwdriver" and my foot long half inch socket extension with a nice deep well socket to use as a breaker bar on the 3/8 ratchet handle.
 
mcnoople said:
That is a v8 in his post. From his carlist on his tagline I would say it is a early a.
Click to expand...
Yes, a 1965 Dart w/ 273, standard thick motor mounts. I forgot the diameter of the Breeze booster, but recall ~1/4"D less than a 73 Dart Midland-Ross booster I have (currently on my 65 Newport). I have only ~1/4" clearance to my Wiend valve cover (taller than stock?). My trans mount might be sunk and the engine may come up a bit when I replace it (good since my Pitmann stud barely clears the mini-starter). If my booster then hits the valve cover, I have a smaller one I can swap (for 4 bolt MC, but can adapt). BTW, I managed to repair the original Midland-Ross booster in my Newport by cutting a ring of neoprene rubber for use as a diaphragm. I found no place to buy replacement diaphragms. Haven't put on the car yet, but tests OK w/ engine vacuum.

Re comments on wheel cylinders and proportioning valves, not smart to swap parts willy-nilly. Too big a wheel cylinder can make the rears lock-up and the rear spin out on a turn. 4 drum cars use no proportioning valve as far as I know, with the ratios designed into the wheel cylinders used. That part in ~68+ drum cars probably contains just a "pressure imbalance" warning switch. In earlier single-tube MC's like my 65 Dart, it is just an open distribution "T". In a disk/drum car (73+), the proportioning valve decreases pressure to the rear drums (plus warning switch). They never decrease front pressure. While disk calipers have a real big piston, they need that because disk brakes don't have the "self-generating" effect of drums where the shoes get jammed into the drum by the braking force. An after-market adjustable proportioning valve like in my photo might be best ($25). Adjust on a wet road until the rears lock up first, then back off.

For this simple upgrade from single to dual MC, nothing is trivial. In my 65, the single tube is 1/4", while I think all duals are 3/16". Therefore, you must install a 1/4 male to 3/16 female adapter in the top port of the T (or use a 3-port 3/16 T). Plug the port that went to the rears and use an in-line coupler to the rear. You can get these parts are Autozone in the bubble packs. Count on some rusty tubes breaking, so have a double-flare tool ready (not a cheapy). Note that even with 3/16" tubing, different size nuts are often used so one can't mis-wire at the MC. Always inspect the tube size of inverted flare fittings. Just because the nut fits doesn't mean it will seal. I removed 2 manual MC rods recently. In both, I had to hold the MC in a vise, put a socket extension thru the rod hole and beat real hard with a hammer until it popped out. An O-ring secures the tip in the MC piston, and gets hard. It might be a square ring (never found enough pieces left to tell). Look in the faucet seal section of the hardware store for something to work. I expect the rubber just keeps the MC from rattling. The rod can't come out of the piston once assembled in the car.
 
BillGrissom said:
I removed 2 manual MC rods recently. In both, I had to hold the MC in a vise, put a socket extension thru the rod hole and beat real hard with a hammer until it popped out. An O-ring secures the tip in the MC piston, and gets hard. It might be a square ring (never found enough pieces left to tell). Look in the faucet seal section of the hardware store for something to work. I expect the rubber just keeps the MC from rattling. The rod can't come out of the piston once assembled in the car.
Click to expand...

The best way to remove the MC brake rod is to remove it before you take the MC out of the car. First remove the brake light switch/bracket. Now just pull back on the brake pedal (Pop) the brake rod is out. No hammers,vises,cutting torches,jack hammers necessary.

The rubber grommet is to secure the rod in the MC. Do not get it at the hardware store. Get the right part,we are talking about brakes here,stopping is important.
Usually the rubber grommet will come with a new/rebuilt MC.

Side note: If you were going to buy just 1 new part for your car, a "New" master cylinder should be the first choice.
 
Well I was starting to question my sanity during this brake job. . . The Reman Napa 68 dart MC i was using was bad. it was weird, i bench bled it and bled the brakes so many times went through 3 or 4 BIG bottles of fluid. It kept sucking air into the MC, no leaks but it must have been a bad MC. I said screw it and bough this:
http://chucker54.stores.yahoo.net/ma1bowimoha1.html

Its MUCH better now! Got the adapter plate for a 2 bolt MC and the 10psi residual pressure valves from mancini's also. I'll get some pics soon. Everything went together perfectly and only had to do about 4 or 5 cycles of "pump pump pump pump pump, hold . . . bleed" on each wheel. Now its got a super solid peddle. Those residual pressure valves make it really nice too, it keeps the springs from pulling the shoes all back in so the peddle travel isnt far at all, its "right there" and she stops like a champ. Highly recommend this set up.
 
1974DartSwinger said:
Well I was starting to question my sanity during this brake job. . . The Reman Napa 68 dart MC i was using was bad. it was weird, i bench bled it and bled the brakes so many times went through 3 or 4 BIG bottles of fluid. It kept sucking air into the MC, no leaks but it must have been a bad MC. I said screw it and bough this:
http://chucker54.stores.yahoo.net/ma1bowimoha1.html

Its MUCH better now! Got the adapter plate for a 2 bolt MC and the 10psi residual pressure valves from mancini's also. I'll get some pics soon. Everything went together perfectly and only had to do about 4 or 5 cycles of "pump pump pump pump pump, hold . . . bleed" on each wheel. Now its got a super solid peddle. Those residual pressure valves make it really nice too, it keeps the springs from pulling the shoes all back in so the peddle travel isnt far at all, its "right there" and she stops like a champ. Highly recommend this set up.
Click to expand...

Hi; How is your upgraded master cylinder working out for you? I was wondering if you were still going to post any pictures of the installation? Regards.
 
You must log in or register to reply here.
-

Back
Top