My $800 junk car is on its final limb at 255k, I assumed sticking and squeaking was from low breaks / caliper pin sticking,
Now I’m worried that the master cylinder is the culprit, the pump still works and has pressure when I turn the car off and pump the breaks but is there any forsure way to know without a 60-140 dollar diagnoses ?
Brakes not breaks.
Fixed my problem thanks Volvo!
The lower case must of made the breaks stick.
No. The most common cause of sticking brakes isn’t either of those. It’s a faulty flexible brake hose; the one that leads to the caliper. Squeaking brakes are usually caused by the pads and rotors, not the caliper or MC. For a sinking brake pedal , if there’s no fluid loss that’s most likely a faulty MC. If there is fluid loss, wherever the leak appears is where the problem is located.
So if break fluid is full it’s the MC ? 90% chance ?
If the symptom you are trying to solve is that brake pedal slowly sinks to the floor as you push, and the hydraulics are known to be properly bled, & never had to add any brake fluid to top the system off, very good chance the problem is the MC. “Very good” does not equal “for sure” however. There’s always other possibilities. But if I had that symptom on eithe of my two vehicles and there was nothing else obviously wrong via visual inspection I’d replace the MC as the next step.
There’s the problem, the fluid is broken.
So it probably just needs a flush then?
It probably needs someone who knows what they are doing, looking at it. Brakes, aka breaks, in this instance, are nothing to play trial and error with.