'79 brakes

My son's '79 lost its brakes yesterday, and we spent today fighting this: I can't get all the air out of the left-front line. We've run

8-10 ounces of fluid through the system, which is maybe 18 inches long on this wheel, and still there are bubbles with no end in sight. The system must be sucking air somewhere. There aren't any obvious fluid leaks, the flexible lines are intact, but we cleaned the entire master cylinder area and plan to look closer tomorrow---We made a bit of a fluid mess while replacing a line on the rear, which is where we thought the problem was.

The other symptom is that the pedal is firm if we hold it hard, but a soft push goes to the floor.

Last, the master cylinder reservoir squirts up if we hit the pedal hard...is that normal? (this is why we made the fluid mess)

We rebuilt the rear brakes in the spring, including new cylinders and one new line in back, and replaced the front pads a couple months ago, flushing the entire fluid system. It's been working fine since. No way am I an expert or even very experienced at this, but I'm pretty confident we're doing the bleed properly. What should I do next?

-John O

Reply to
JohnO
Loading thread data ...

"JohnO" wrote in news:1165799365.568310.24160@

73g2000cwn.googlegroups.com:

Replace the master cylinder. It's bad.

Reply to
elaich

Yep... tipoff is: light effort - pedal goes to floor, yet no leaks.

Reply to
Backyard Mechanic

Good, we can handle that. Thanks guys, for confirming what--for me anyway--was a wild guess.

-John O

Reply to
JohnO

Replaced the master cylinder last night, and the brakes now work perfectly. The bigger resevoir had a bunch of gunk in the bottom, maybe this was the remains of the seals breaking down, or what caused them to fail, whichever. Hell, they were 27 years old!

The job was a lot easier than I expected, especially since the old lines came off the cylinder nicely. Thanks for the help guys.

-John O

Reply to
JohnO

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.