Sucky brakes

[Hobbs z]

I have a 74 duster 318 auto with pw steering and brakes. The issue at hand is my brakes are sketchy at best lol. I can apply the brakes and it will travel down about 2in before making a difference and when it finally does catch it goes from very little braking to almost immediately stopping within the next inch and a half. I'm trying to explain it the best possible way I can. Has anyone else ran into this issue before any suggestion would be greatly appreciated. Thanks in advance.

 

[toolmanmike]

Sounds like a power brake booster problem although I have never heard or experienced those symptoms.
tmm

 

[67Dart273]

Actually it sound to me more like the rear brakes are out of adjustment, or......

either front or rear (probably rear) section has a hydraulic problem

 

[Hobbs z]

Thanks for the speedy responses. by hyd problems do you mean a leak, air in the lines or what. Can you elaborate please. The break booster is about a year old. But it wouldn't be the first time I've got a bad part. How do I need to go about troubleshooting any of these possibilities.

 

[67Dart273]

You describe going from "no to full braking" which sort of indicates that the booster might be OK

Try pumping the brakes with the engine running, stopped. Does the pedal come "up" some? This could indicate rear brakes out of adjustment

Very first thing I'd check is the fluid level in the master cylinder.

Rears should be self adjusting, but this does not mean they are 'self adjusted'

Jack up the rears, and play with the adjusters one way will move the adjuster and "click" the self adjuster ratchet. Spin the rear wheels and adjust them up until they start to drag. See if that raises the pedal some

Frankly, as old as these girls are, it might be time for a full on brake inspection, stem to stern. Try to determine, IE ask previous owner, or inspect brakes. See what you have for pad wear, inspect for any leaks

About the first thing you should be doing is searching the www for either a CD or paper reprint of the proper service manual. You can download some here, but there is nothing new enough for 74

 

[Inertia]

Is the pedal higher if you give it a pump?

If the reservoirs have fluid, adjust the rear brakes before you do anything else,..

lol,, Del out-typed me,,

67Dart273's guidance will be spot on..

 

[MopaR&D]

It'll be a power booster problem if the pedal travels a bit with some force on the brakes ("good enough" for normal slow driving) but when you push the pedal hard to stop quickly it gets rock hard immediately but the brakes still aren't grabbing any harder.

That what you're trying to say? lol

EDIT: Also I agree with 67Dart273 100% a total brake job on these old cars is actually not a whole lot of work and well worth it (for your life lol).

 

[RedFish]

I've seen similar symptom before in front wheel drive applications. Mushy pedal with some braking then suddenly lock and slide one rear wheel. Master cylinder was the cause.

 

[jdsduster]

Actually it sound to me more like the rear brakes are out of adjustment, or......

either front or rear (probably rear) section has a hydraulic problem

x2

 

[mischiefdart]

First off pull all the wheels and check all the linings. Look for any obvious problems like leaky wheel cylinders or axle seals. Make sure the front wheel bearings are adjusted properly. Sounds like the shoes on the rear are way out of adjustment. Is it just the rear tires that are locking up?

 

[toolmanmike]

If your pedal comes up when you pump it, you have air in the lines. If the pedal is low, they need adjustment.

 

[toolmanmike]

The OP didn't mention whether his car has front disc.

 

[RedFish]

Actually it sound to me more like the rear brakes are out of adjustment, or......

either front or rear (probably rear) section has a hydraulic problem

That is exactly what I and everyone else thought, something not right about that left rear drum brake. The old guy said he had learned to drive the car without locking that wheel too often, that is until he tried to stop on snow. He did 360 degrees around through an intersection and was nearly hit. Scared the crap out of him. He left it with me and said find it and fix it no matter what it is.
I went to a parts yard and got booster and master from identical model. Of course I changed the booster first since I really don't like, trust, use, used master cylinders, plus I could change the booster without playing in brake fluid Booster didn't make any difference at all. The junk yard master cylinder fixed it.