Brakes "skip" as I press down. Whats goin on?

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I have a 65 Dart in Ct and it's likely your brakes saw the same type salty winters in NYC/NY that promotes rapid rusting.
Selecting a master cylinder that bolts directly in starts by looking at your tire size.
If you see a 13 inch tire then it's likely you have 9 inch brake drums and the master cylinder should have the small bore around 15/16 or 1" diameter and be labeled for manual brakes. Note Rockauto doesn't tell you the bore diameter for the three you are looking at......... You would have to call them to get that info. Do not buy the larger bore master cylinders. You don't want to start this job unless you have an experienced person who knows how to bleed the air out of the brakes after the master cylinder is changed. Let us know your tire size. Do not order a master cylinder until it's verified you have a certain size brake drum.
 
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BigBlockMopar said:
I agree with the above.
Also, before you start ordering stock replacement parts, go over the rest of the brake system first.
Wouldn't surprise me if everything needed attention, and, at that point I would advise in doing an upgrade at the same time. Like installing discbrakes for instance.
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I was gonna order it and then when I bring it to the shop, ask him if he would do a quick install
DonPal said:
I have a 65 Dart in Ct and it's likely your brakes saw the same type salty winters in NYC/NY that promotes rapid rusting.
Selecting a master cylinder that bolts directly in starts by looking at your tire size.
If you see a 13 inch tire then it's likely you have 9 inch brake drums and the master cylinder should have the small bore around 3/4" diameter and be labeled for manual brakes. Note Rockauto doesn't tell you the bore diameter for the three you are looking at......... You would have to call them to get that info. Do not buy the larger bore master cylinders. You don't want to start this job unless you have an experienced person who knows how to bleed the air out of the brakes after the master cylinder is changed. Let us know your tire size. Do not order a master cylinder until it's verified you have a certain size brake drum.
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Thanks, Yeah I do have 13 inch tires. I wasn't going to do the work myself to start> I was gonna order the part and then ask them to swap it out for me, when Im swapping out 4 new tires I bought.
 
66DartSedan said:
I was gonna order the part and then ask them to swap it out for me, when Im swapping out 4 new tires I bought.
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If it were me, I would have them look at it first and tell you what they find.........then get a quote to fix it, if you aren't doing the work yourself.. It's possible you need more than just a MC, it could have rusted lines, stuck bleeder screws that can and do break sometimes and bad wheel cylinders.

Best to know what you're up against before someone tears into it.
 
Warped drums. Most likely in the rear.

When you say it "Skips" do you mean the car feels like it speeds up and slows down as you come to a stop?
 
stretch said:
Warped drums. Most likely in the rear.

When you say it "Skips" do you mean the car feels like it speeds up and slows down as you come to a stop?
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all in one action: brakes applied...momentary freeze...continues to brake...momentary freeze...fully braked.
 
Sounds like the drums need machined..........................
 
Sounds like you are describing pedal pulsation. That is normally caused by warped rotors or drums. Obviously drums in your case.
 
That makes the most sense,warped drums. A partially engaged parking brake can warp a drum. A stuck brake cable is usually the cause. A two minute drive by someone with experience would pin down the problem.when you go for tires, have him take it for a drive. Then when he’s got wheels off maybe he can check brakes. A brake inspection isnt free,so be prepared to fork out some extra money. Also, it will have backwards threads on one side, be sure to mention that. You can verify this by checking the end of the wheel stud for an “L” stamped in the end of it. One side of car has left hand stud and nuts.

If you dont verify it,and mention it,and tire guy doesent think of it -it will cost someone some time and money.
 
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I'd check to see if you have a leaky wheel cylinder... brake fluid on the drum may cause it to grab then release.

These old cars can be a can of worms... dont just go throwing parts at it without some knowledgeable hands on advise. Todays techs know zero about working on old cars... you need to find someone who is in the biz and is fair and honest.

With al the rust and corrosion i see you would be well advised to soak every nut and bolt in PB Blaster, Kroil or another good solvent. I can guarantee those wheel cylinder bleeders are rusted tight. A $100 master cyl. Job can turn into a $1000.00 brake job in an instant.

Im not trying to scare you but to be aware of what can happen. These cars can be a blast to own...
 
Judging from the heavy rust around the master, and the description, you should do a complete stem to stern inspection and overhaul of the brakes, other than steering, the SINGLE MOST IMPORTANT system on the car. Also consider doing a little bit of replumbing and convert to a later model (67/ later) dual master cylinder.
 
X2 on the '67 and later dual reservoir master cylinder. You'll need the correct dual res. distribution block also. That is the brass chunk mounted on the frame rail where the brake lines from the master cylinder go, and where the front and rear lines go to their respective wheel cylinders. The '67/up block has two ports for the master cylinder lines. This is an excellent upgrade!
 
About time someone mentioned getting rid of that deathtrap single reservoir master cylinder.:D
 
that teapot MC is adequate for granny popping down to the Piggly Wiggly for butter in the slow lane of a side street but for 21st century driving, you want the 67 Dual MC and plumb the brakes as a dual circuit system. Its a matter of getting the 67 MC,a $15 proportioning valve from a bone yard from a drum/drum Mopar and maybe $8 in brake line. Put the prop valve down by the original 3 port distribution valve, and run the rear line directly into the rear port. Then run the 2 front lines into to the front ports and finally the one original feed to the inlet and the new feed into the other inlet. Plumb both inlets into the new M/C and bleed. Its not a difficult job but it does take an afternoon if you got all the parts handy.
PV6070FD-dims.jpg
 
If he is sticking with drum brakes, no need for a prop valve. In fact other than the warning switch, you can plumb the thing with what is there and some more tube and fittings. I forget? You disconnect the distro tee and run the rear tube to the front port of the master, then plumb the old master port to the tee to the rear port of the new master, then plug the remaining tee port.
 
Okay ya guys lost me. lol ....but I thank everyone for the input. My plan is this:

When I get back to NYC, Im picking up the car from the auto glass guy...Im gonna pop the MC open see if there is any fluid within eyesight, if so, fill it up with some DOT 3, if not....Ill be driving...very very slowly to the tire shop to have the brakes bled and tires swapped.

backglass1966dart.jpg
 
yeah, if he wants to run no prop valve, hell just extend the rear line up to the rear port and plug the rear port of the distribution valve and then run the fronts to the front reservoir.
 
Here's a picture when I swapped out my single pot for a dual reservoir. My original master cylinder was leaking and I wanted to upgrade. The dual will still allow you to stop should you have a severe brake fluid leak at one corner.

New MC Installed 2.jpg
 
66DartSedan said:
Okay ya guys lost me. lol ....but I thank everyone for the input. My plan is this:

When I get back to NYC, Im picking up the car from the auto glass guy...Im gonna pop the MC open see if there is any fluid within eyesight, if so, fill it up with some DOT 3, if not....Ill be driving...very very slowly to the tire shop to have the brakes bled and tires swapped.

View attachment 1715124168
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Basically, the dual reservoir splits the system frt & rear. It's the differential valve that moves towards the side that loses pressure & blocks the flow of fluid to the failed half
while simultaneously turning the warning lamp switch on. There is no extra safety without the differential valve, You would have pretty much zero brakes the same as the
single "death drive" master cyl. on there now. The rate of total fluid loss would be delayed slightly, but w/o the valve, it still ain't a good place to be.
 
Killer6 said:
Basically, the dual reservoir splits the system frt & rear. It's the differential valve that moves towards the side that loses pressure & blocks the flow of fluid to the failed half
while simultaneously turning the warning lamp switch on. There is no extra safety without the differential valve, You would have pretty much zero brakes the same as the
single "death drive" master cyl. on there now. The rate of total fluid loss would be delayed slightly, but w/o the valve, it still ain't a good place to be.
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Oh okay yes. I understand that. I did some more searching online and the most similar issue I see that compares to mine is "hard brake pedal" and Im seeing "lack of vacuum pressure ." as a common cause.
 
66DartSedan said:
Oh okay yes. I understand that. I did some more searching online and the most similar issue I see that compares to mine is "hard brake pedal" and Im seeing "lack of vacuum pressure ." as a common cause.
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OK, first We need to be clear, from the pic You posted You have a single reservoir non-power assisted master cylinder for a four-wheel drum system. No vacuum involved
at all, and no differential or proportioning valves either. If a wheel cylinder or hose or steel line fails anywhere in the system, You will have -0- pressure & -0- pedal, NADA!
This is why the above posts recommend a switch to a dual reservoir, but without the differential valve added to the system as well, You're not much better off.
The only way that car is going to "grab & release" is because the drum surfaces are screwed, it's manual unassisted brakes, regardless of the hydraulic conditions the
pressure ain't going to change itself no how no way. Certainly not in a rhythmic way. Either You've got a good pedal or You don't, it's that simple. If it's leaking/losing
fluid, don't operate that car at all, get it fixed before driving it....period!
 
Killer6 said:
OK, first We need to be clear, from the pic You posted You have a single reservoir non-power assisted master cylinder for a four-wheel drum system. No vacuum involved
at all, and no differential or proportioning valves either. If a wheel cylinder or hose or steel line fails anywhere in the system, You will have -0- pressure & -0- pedal, NADA!
This is why the above posts recommend a switch to a dual reservoir, but without the differential valve added to the system as well, You're not much better off.
The only way that car is going to "grab & release" is because the drum surfaces are screwed, it's manual unassisted brakes, regardless of the hydraulic conditions the
pressure ain't going to change itself no how no way. Certainly not in a rhythmic way. Either You've got a good pedal or You don't, it's that simple. If it's leaking/losing
fluid, don't operate that car at all, get it fixed before driving it....period!
Click to expand...
Ah. Okay, yes. Thank you. I guess Ill just have to tow it to my mechanic.
 
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