Showkahn

Hello gents. I have a 71 Cutlass S 455. My grandpa converted this car to disc some years ago. I recently inherited the car. It was sitting for about 5 years. I’m fixing it up and I finally got it driving again! The breaks are pretty soft. It will stop the car but I have to leave myself about 30 feet to stop. I attached the video of the master cylinder. I’m not too smart on the brakes and need help. Does this look correct? This is me pressing the brakes and holding the pedal down.

Vintage Chief

Congratulations taking ownership of your Gandpa's car. The MC reservoir looks fair enough. If the brakes are actually "working" and you can stop the car, I'd suggest you evaluate each wheel brake caliper for smooth unabated freedom of movement and evaluate each brake for general movement. Check your brake pads for wear. Check your brake rotor for cleanliness - nothing wrong with wiping down the rotors w/ a healthy dose of brake fluid after years of storage - that dirt, grime, oil & grease can impede a firm grip when pads meet the rotor.

Vintage Chief

I forgot to mention checking the rear brake drums for adjustment (assuming he upgraded the front drum>disc and the rears are still drums). Rear brake drums should not turn freely without a little pressure from yourself in turning them - IOW, you want some drag on the rear drums - not a ton mind you, but you do want some drag. Did Grandpa upgrade all four brakes to disc or just the fronts?

Showkahn

Thank you! I’ll give that a try.

Vintage Chief

Put the MC cover plate back on the MC before you go any further on evaluating anything on the car.

Vintage Chief

Here's the right amount of drag you want on rear drum brakes (if you still have rear drums). Finally, after you've evaluated the condition of your brakes at each wheel, it's not uncommon for air to seep into the system after a long storage & you might want to bleed the brakes if you don't see any issues with hardware. Keep folks informed and they'll provide sound advice for you moving forward. Good Luck.

oldcutlass

I moved your post to it's own thread.

Showkahn

He upgraded to disc all around.

sysmg

I wouldn't wash down drums or discs with brake fluid. That will contaminate the brake pads/shoes. Wash the rotors/drums with brake clean.

Vintage Chief

OMG!!! Neither would I!

Typing far too fast…I completely meant to say Brake Cleaner.

Holy Crap thanks for catching that!

Showkahn

I figured that’s what you meant.

Vintage Chief

Thanks for responding & being receptive to my brain fart.

Showkahn

Well I pulled all the break and bled and cleaned them all. Every break seems to be working fine with the exception of the driver front. The pressure is really low in that one. There was trash in the lines and a lot of built up dirt on all the pads and calipers. They’re all cleaned now and the brake is still soft but it is definitely better. I can actually stop within 10ft at 40mph. Thanks for all the advice!