Well, I replaced my master cylinder last weekend. We bench bled it, then popped it right on, no problem. When it came to the bleeding however, we had some issues. We initially tried vacuum bleeding it, no improvement. Two man bleed, nothing. Gravity bleed, nothing. Finally we bubbad our own pressure bleeder and voila, rock solid. That was friday night. Sunday on my drive back to school, I noticed the brakes got a little softer again. I just figured that was an air buble that had taken some time to work it's way down the system. Unfortunately, it was a leak somewhere. Of course I didn't realize this until I was driving back from school on Tuesday. For 3 hrs I hadn't needed to use my brakes so I didn't notice anything until I was comint up and off ramp at 60 mph. No brakes at all. Not the tiniest amount of resistance. I tried downshifitng as quickly as possible, but wasn't fast enough. As I rapidly approached the three cars at the stoplight in front of me I panicked, moved off the road and shifted to first too quickly which locked up my wheels. I turned sideways and skidded through the red light. My angel must have been working overtime to keep me alive and in tact. I quickly pulled over and waited for my heart to come back out of my throat. I had never been so scared in my life. I opened up the hood and took of the master cylinder cap to see that my front resevoir was completely empty. The rear one was fine, still full. As luck would have it, a local security guard came by and offered some help, he turned out to be a 16 yr plant supervisor at GM. We got some mroe brake fluid and pumped the brakes for probably 45 mins to get any semblance of resistance. Then I limped home on the side of the road w/ my flashers on. Now I have to find where on earth this leak is coming from. I guess when we restored full brake pressure we opened a weak spot that the earlier weak pressure hadn't bothered. Any suggestions as to where usual problems occur? The previous owner had replaced the lines w/ steel braided brake lines so I was surprised that those might bust so easily. Sorry about the rambling and thanks in advance :smash:

 

Thank goodness everyone is alright :eek: ! You must have been one scaried puppy going thru that intersection. On a side note, maybe the people that saw it just thought you've seen one too many Dukes Of Hazzard shows ;) .

First I'd check the connections where the brake lines go to the new master cylinder. Then if they look ok, check the calipers for any wet spots and if you don't see anything there, start tracing from the calipers back to the master cylinder.

Glad your still here with else :) .

 

Glad nothing bad happened! Brakes are the life insurance for you - remember! They MUST work OK.

Use proper line wrenches to tighten the lines to the caliper and hoses and master.

Check out the inner side of your front wheels - if there are signs of fluid on the wheels / tires moved outside due to rotation it should be the calipers.
If not, check the lines to the hoses.
Therefore you did nothing to the proportioning valve it should be OK.
Most likely there might be a loose connection anywhere you don´t expect!

Check with a proper light all underbody!

 

Thanks for the pointers. Yea, I'm sure a few of lesser intelligence thought "stupid 18yr old in a vette, what a showoff" :p: The connections at the master cylinder are fine, checked those. One problem is I had bought a chromed master cylinder cap, after taking it off i noticed it was leaking a tiny bit. So that didn't help the problem but the small amount it was leaking wouldn't cause the front resevoir to run dry. I'll keep y'all posted on what we find and thanks again for the help. :smash:

 

Whoaman that is Very frightening....Brakes are important indeed :eek: