Manual brake master cylinder

[lilcuda]

My newly acquired 67 Belvedere II (see my thread in the Welcome Wagon section) started getting a spongy brake pedal on it's first trip around the block after I got it registered. Got it into the garage and found the reservoir for the rear brakes was nearly empty. I bled the brakes and got a bunch of air out, but it takes one pump of the pedal to get a firm pedal. I haven't driven it yet since bleeding the brakes, so I don't know how well it stops.

Anyway a couple of my friends who are Mopar guys tell it's the master cylinder. I don't doubt it, it looks original. I've been looking around online and all of the manual brake master cylinders don't have studs. Mine has studs in the MC that go through the firewall.

Any ideas where to get the correct MC? Thanks!

 

[T2R9]

You tap the studs out of the old one and press them into the new one. A couple taps with a brass hammer will pop them right out.

 

[Fran Blacker]

Agree ^^^ and it doesn't hurt to put nuts on stud if you don't have a brass hammer.

 

[multimopes]

And if memory serves me; remember that you have to pre-bleed the master cylinder before you bleed it at the wheels. Good Luck!

 

[khryslerkid]

And if memory serves me; remember that you have to pre-bleed the master cylinder before you bleed it at the wheels. Good Luck!

Yep, bench bleed it first. They have a kit that you can rig to recycle the fluid. Make sure you push the piston all the way in when bench bleeding. Not hard just nice and slow

 

[khryslerkid]

Got it into the garage and found the reservoir for the rear brakes was nearly empty.

Could be that the rear shoes are pretty worn. That takes up the fluid. Once the reservoir gets too low it will allow air to enter the brake line. Adding fluid and bleeding the brakes will normally fix it. It doesn't fix the fact that the lining is worn or it could be the master cylinder is leaking out the back also or a wheel cylinder is leaking. All things to consider when you find your master cylinder low on fluid.

Good luck

 

[Ranger16]

I've been looking around online and all of the manual brake master cylinders don't have studs. Mine has studs in the MC that go through the firewall.

I think I bought mine from O'Reilly Auto Parts and it came with studs.

 

[khryslerkid]

I think I bought mine from O'Reilly Auto Parts and it came with studs.

Sometimes they do sometimes they don't.

I reused my studs taken from the old factory single reservoir and pressed them in the newer dual master cylinder. Same size.

 

[miller]

Since you don't know the condition of the rear brakes, you should pull the drums for a look.
Waste of time, if the brake shoes are wore out. Could wear out the drum itself, if the shoes are bad. You'll also be able to tell, if their self-adjusting, or not, and if there's brake fluid leaking in there.
If it's all good, just manually adjust the brake shoes, so the drums 'just' slip in place, and go from there.

If their manual adjust only...yes, you have to adjust them, for brake pedal height.

 

[lilcuda]

Pulled the rear drums today. Brakes are in pretty good shape. Actually, the passenger side was a little tight, so I loosened it up a few clicks. Wheel cylinders looked good as well. Decided to take it to my buddy's house to show the car to him. Now brake fluid is running down the firewall...so I need a master cylinder for sure.

Thanks for the input. I'm familiar with the fact that I will have to bench bleed it. Now on to order a m/c!

 

[1 Wild R/T]

Order one of these, you’ll never “bench bleed” a master cylinder again..

Do it on the car, faster, cleaner & better..

https://www.amazon.com/Cardone-10-5000MCB-Master-Cylinder-Bleeder/dp/B002JSM7HA

 

[Kern Dog]

Okay...But how does that WORK ? It looks like a syringe without a needle.
Also....DUMP the single reservoir style master cylinder and get a dual reservoir. The only reason to run the original style is for 100 % correct restorations.

 

[lilcuda]

Okay...But how does that WORK ? It looks like a syringe without a needle.
Also....DUMP the single reservoir style master cylinder and get a dual reservoir. The only reason to run the original style is for 100 % correct restorations.

67 is the first year for dual reservoir master cylinders, so mine already has one. Just need one that doesn't leak.

 

[BigEd]

I used a Wilwood 7/8's inch manual master cylinder and had my machinist make me this plate... it works great, have the same setup on my cuda too

 

[lilcuda]

Bought a reproduction mc on eBay. Got it today, but they forgot to include the pushrod retainer o-ring. Super annoying. Can't put the new mc in until I have the retainer.

 

[Kern Dog]

Use JB Weld.
(Don't do that)

 

[1 Wild R/T]

Bought a reproduction mc on eBay. Got it today, but they forgot to include the pushrod retainer o-ring. Super annoying. Can't put the new mc in until I have the retainer.

a 5/32" length of 5/32" vacuum hose is the common fix...

And as far as how you use the M/C bleeding syringe, bolt the M/C in place, It's a good idea at this point to put an old towel below the M/C to catch any fluid that spills.... Fill both reservoirs, leave the lid off, stick the tip of the syringe into one of the reservoirs & pull back on the plunger, now put the tip of the syringe uptight to the fluid port & push the plunger in... Initially you'll see lots of bubbles but about 1/2-2/3 of the way through pushing the plunger in you'll see the bubbles stop & the fluid will geyser in the reservoir... Pull the syringe away & screw the line in and tighten it..
repeat with the second half of the system....
Now have an assistant sit in the car & when you are ready the assistant will push the brake pedal down one time ...
You want a wrench on each line, crack them both loose & have the assistant step on the pedal, as the fluid is bubbling out tighten both lines.... If the brake system was operational before, you are done... Drive the car & you'll see the pedal should be perfect... If the system is new & hasn't been bled then you'll need to bleed everything...

 

[Fran Blacker]

For your retainer o-ring could try the tan surgical hose. It very flexible they use it for slingshots. Problem is finding it chain drug stores good luck. Surgical supply house.