This was my ol’ ’Bird. Now it’s back, with a braking issue.
A couple years ago, I decided that it was time for a truck, and said goodbye to my T-bird, a 1996 V8 model, to make room for the ’Murlequin. I never did get around to introducing you guys to the ’Bird, but it’s new owner is none other than my own sister, which means that the car remains at least somewhat in my periphery. AMA if you want to know more about it.
She recently reported that despite making some repairs to the brake lines a year or so ago, the brake pedal once again went to the floor without so much as a drop on the pavement. But the reservoir was draining, so it had to be going somewhere...
So I had her pull all of the wheels off to inspect the lines, hoses, and calipers more closely. Everything was dry. She even unbolted the master cylinder to see if it was puking into the booster- nothing.
I went and took a look at it myself, and everything was indeed dry, until I got to the brake pressure control valve blocks tucked away between the headlamp and battery. There, I found a lot of peeling paint and rust. Oh man.
Turns out, this was a very small, slow leak, which snuck up on her as she admittedly hadn’t been keeping a close eye on the brake fluid level. It never accumulated enough to fall to the ground and leave puddles.
We re-bled all four corners to confirm the exact location of the leak, and none of the lines were burst. We didn’t even see it shooting out of either of the valve blocks. But a very slow gradual wetness appeared where the bottom of the blocks met the mounting bracket.
Sadly, these valve blocks are unobtainium now, available only in unknown condition from junkyards, as Ford no longer sells them. And if that wasn’t bad enough, trying to remove the old assembly resulted in two of the flare nuts twisting their respective lines during removal. Clearly, a good dousing of penetrating oil just wasn’t enough to get them to spin freely.
I managed to get one of the blocks off of the bracket, and continued with disassembly. Near as I can figure, one or more of the internal seals must have worn out enough for fluid to leak past the piston and pop out the little rubber cap on the end of the plug. No way that little cap could have ever held back hydraulic pressure. This must be an “indicator leak”, not unlike a weep hole as you would find on a water pump that tells you when it’s time to replace it.
The good news is, these blocks (F6SC-2B091-AA) are pretty clean inside, and suitable for rebuilding. The bad news is, nobody seems to offer a rebuild kit for this model.