Brakes / A Crazy Leak?

[joejakegrace]

Someone here must be able to help!!

#791 with 18,000 miles - Run monthly, about half the time put 5-50 miles on it. Warm it up until the idle settles down and pull out of the garage - The first significant brake usually ends up with a modest aww shi% moment as the peddle goes rock hard to the floor. A bit of pumping and some RPMs and the brakes are relatively normal.

Coincidentally (or not), after a decent ride (more than a few miles), I'll usually detect a very small amount of what appears to be brake fluid (we're talking ccs here) distributed around the outside of each front rim. Splatter distribution as if someone put a thimble or two of fluid on the hub as she turned. I have to think the two are related.

The fluid in the resevoir is full/near full. It is a little old and I'm going to drain/replace/bleed soon. But I'd prefer to figure out what's going on first! - Obviously, if there is a leak, want to fix that first. The car is stored on a four poster and I've looked 20 times and found NO evidence of brake fluid near either caliper or on the lines from the master cylinder. (a drip or two occasionally from the rear main but that's another story).

This weekend I put it up on the four post, and removed both front wheels to get a better look. Both calipers, bleeders, lines, everything are dry as a bone!
I put the wheels back on after cleaning them up on the inside along with the whole brake area, dropped it off the jack (having seen nightmares about people opening F body doors while cars are jacked) and pumped the brake like crazy. Reinspected and still dry as a bone!

So what gives??? Something internal to these calipers?? Something else? A gremlin??

Ideas (to save me an hour or two) appreciated. My garage has cable and a beer fridge so anyone close enough is welcome to stop over to partake in a thank you.

 

[chopped39]

Im confused. Is the pedal rock hard or does it go to the floor. Does the brake light go on when pedal drops? The light should come on due to pressure differance if there is a leak. Did anyone top fluid with something other than brake fluid? Sounds like the master is going bad intermittently.The only thing is the pedal should drop right to the floor if the master is bad. When you loose assist that is when the pedal gets rock hard.If there is no leaks and there is brake fluid on rims you want to have an exorcism performed:biggrin:

 

[joejakegrace]

That makes two of us that are confused. The pedal goes about 1/2 way to the floor but is rock hard - as if there is no assist. By light, I assume you mean a dash light? I saw none.

What you point out is what is perplexing me. I was headed toward a) fluid flush then, if necessary b) MC problem - but the evidence of a little fluid on the rim makes me dumbfounded.

I've even searched high and low for other evidence of fluid - thinking maybe it was tranny or PS fluid - but a) I can find it no where else and b) the both front rim thing kind of points toward brake fluid.

At least the car is up on the lift and I can poke around trying to isolate it.

 

[chopped39]

with the car in the air have someone push the pedal and see if the brakes are holding if fronts are and rears are not or vice versa. The way it sounds the booster may be the culprit.that is rare for the booster to break internally did you check valve in vacuum line from engine? are you losing fluid? master dropping.I would pull all the wheels and make sure there isnt any leaks. pull the calipers and pads and install 2x4 where pads would sit and pump pedal. the 2x4 will not let piston come out all the way.inspect boots for brake fluid.If none is found pinch boot with your fingers and pull it away from piston and see if there is fluid in the boots.Dont use a scewdriver or pick.there should be no fluid in boots.If there is fluid the square cut seal is leaking.Did you check operation of booster? Start car and let run for a few mins and shut car off pump pedal about ten times while holding pedal start car and see if pedal drops.If it does it should be good. Check your iac counts . If you have a vacuum leak in booster you will see low to zero counts .If so disconnect line and plug and restart car and watch iac. if normal walla booster time. good luck.If you were around chicago I would look at it for you. good luck

 

[joejakegrace]

Fluid may be down ever so slightly in the MC - barely discernable but the amount of fluid I see on the wheels is pretty modest at best. I had both fronts off and found absolutely no leaks around the calipers so, if a seal is leaking, I don't know how I couldn't find evidence and I can't imagine why it would appear on BOTH sides. I'll check the operation of the booster - symptom wise, it feels like the booster is an issue. Once the rpms, etc. are up, brakes are fine. Now the modest fluid....I'm lost.