ACK! Something let go in the brakes.

[KShortell]

I went to drive the Chevy to work today. Yes, she's still a semi-daily driver. Well, I got to the end of the block and went to hit the brakes. I thought I heard a pop or clunk and then the pedal went halfway to the floor. The brake warning light came on. Well, I turned 'er around and parked back at the house. I ended up driving the Jeep to work today.

The front half of the master cylinder is dry. The rear is low, but not sucking air like the front.

I've just been out in the dark with the flashlight looking over every inch of the brake lines; I found no wetness at all. I seem to find that leaks and such seem to show up better at night with a flashlight or worklight. Nothing apparent showed up in daylight earlier today, either.

I replaced the calipers, hoses, and right front steel line up front three years ago. The rear steel line (frame-mounted) was replaced last year.

My worry is that, in the absence of any external leaks, the master cylinder may have failed. The FSM and Haynes manuals that I have don't really give a great "real world" description of what it feels or sounds like when this happens.

So, any thoughts? I'm thinking of letting a shop tackle this one. I've got too many social events going on this month. I love my truck and get great satisfaction out of doing my own repairs, but the girl-chasing opportunities have to come first!

Thanks for your input!

Kevin
'86 Chevy Suburban C10 Silverado
350 SBC / TH700R4 / 3.73 / P235/75R15XL factory drivetrain

[magnethead]

my MC went out not that long ago..not sure about the pop sound, but undo the nuts that hold on the MC and pull it about half an inch or so out and look in the rod cavity with a flashlight...common sense should answer your question based on what you see.

[blaserman]

Have you checked under your dash? If the master is leaking it might be going into the cab.

[KShortell]

Found it! It was the crappy repair that Treadquarters did last year. This makes the second time their work has failed! I'd always meant to get around to fixing this properly. Now, it seems as there is no time like the present.

When they replaced the hard steel line in the rear, they left it loose, too long, and not properly secured. The shmuck just zip-tied the hose to the differential vent tube. Lazy as hell if you ask me. So, I now have a new brake hose and will tackle it in the morning.

I suppose it was a slow leak and the sudden event of Thursday was the master cylinder finally sucking air. I thought the front of the MC was plumbed to the rear and the rear to the front, but I couldn't remember. Now I'm sure!

This is what's called poor workmanship. The picture doesn't quite do justice as to how sharp the bends are in the brake hose.



Thanks for your input and help, guys!

Kevin