Brakes leaking? Can't bleed. Problems!

[johnwohl]

Hi all. A few days ago, I was driving and my brake light came on. I checked the fluid and it was a little low so I figured a slow leak. I checked it again a day or so later, and it was lower but not by much. Then the other day my girlfriend was driving and she came home with little to no brakes. The fluid container was dry! I got her up on jack stands and took off the wheels and inspected all of the lines and hard lines but no sign of any brake fluid. I also went from the back wheels under the car to the front and the hard lines were not leaking. So I figured I would bleed the system and then pump the brakes to see if I could get it to leak again under pressure. I bled the brake master as per the shop manual. I am using a vacuum type bleeder system. I tried it as the recommended, attach the pump assembly to the bleeder screw and with the screw closed, pump 10-13 time and then open the bleeder screw and close it again when the fluid level in the jar reaches about 2 inches. No such luck. With the bleeder screw closed all the way I am still getting bubbles and a bit of fluid and the vacuum goes down slowly instead of holding. Then when I open the screw all I get is air and a little fluid. I also tried just pumping the vacuum with the screw open but the air just keeps coming.. I seriously did this for like an hour and I only had to refill the fluid once and it was barely to the top of the float. Maybe I am sucking in air from around the bleeder screw? I don't know how to fix it if I am. All the lines look good. I don't have much experience with brakes so I would appreciate any help very much. Thank you.

 

[fr33b1rth]

sounds like the master cylinder is bad, like it's letting air in.

try bleeding it the traditional way before you go off replacing anything though.

 

[Old Mitsu Tech]

Master cylinders can leak at the input shaft. This usually winds up being a hidden leak. I've never had it on a Mitsubishi, but on a couple of others we had to compress the calipers to remove everything and then with them being held back with c-clamps, bleed the lines and such in a normal manner. If all else fails.

Try opening the bleed screw and having the person to push the pedal to the floor. Once it's there, lock off the bleed screw. Repeat. Just remember to put a vacuum line on the bleeder and immerse in fluid to as to help alleviate any air being sucked back in.

Good Luck

 

[oddrob]

Stick you head under the dash and check the master, usually if its going bad you can pull back the black rubber boot around the shaft and see signs of leakage.