Can brake fluid evaporate? And if so, can it do it in a sealed system? The last time my camaro moved was about 3 years ago, the brakes were mushy at best, but still worked. The master cylinder was full, and the car stopped when I pulled into the garage. Now I'm trying to bring her back to life and the brake pedal had almost no pressure, doesn't quite drop the floor under its own power...but it doesn't take much at all to push it down. I figured it just needed bleeding since it was mushy before anyway, so I popped the M.C. cover off to fill the fluid up & start bleeding, and the front reservoir was 1/2 full and th back one was completely dry! I've searched the entire system for evidence of a leak...but can't find anything anywhere. I added fluid to the m.c. and gave it a few pumps, still no sign of leaks anywhere. Couldn't bleed it yet because I couldn't find a rubber hose anywhere, but went & picked up a bleeder kit today so I'll try bleeding after work.

I'm kind of anticipating the brakes to bleed perfectly and work fine after I bleed, just because thats usually been the case in the past for cars that I thought had no brakes left at all. But, that doesn't explain where all the fluid went in the first place, and with something as important as brakes I kind of feel like I should know where all that fluid went before I assume the whole system is okay. Can it just evaporate & I have nothing to worry about, or has it leaked & soaked into somewhere that I need to know about?

I don't know the answer as to evaporation, but did you check the inside wheel rims on both rear tires? A leaking wheel cylinder can be hard to detect until it's soaked the brake shoes (if you're driving it), but in your case, it make have leaked just to the bottom of the inside of the drum....and would run out at in the inner wheel. If the fluid does evaporate, this would be my best guess....but I still think you'd see/feel residue on the inner wheel.

I am going to guess this car has power brakes.

If I am correct the fluid has leaked out the rear of the master and into the booster.

agree with both those statements!

rear brakes look dry from visual inspection...haven't pulled the drums off, but you can usually see it dribble out the bottom like you guys say, and the wheels are bone dry still.

Strick, you're correct about power brakes, its 4 wheel drums. Should I remove the MC & booster & check for fluid in there before anything else, or am I okay to try bleeding 'em & see what happens when I get home tonight? I assume the inside of the booster should be bone dry when I open it up if there's not a problem, right?

If its the master cylinder and/or booster, that'd be kind of good actually. If I'm replacing 'em anyway, might as well go ahead & convert to front discs while I'm at it, right? :D

You can pull the master off the booster a few inches pretty easily and check for leakage there.

Pull the drums off too.

Inspect the floor under the car as well. Brake fluid doesn't evaporate, but the "dust and crud" inside a drum brake will hold a startling amount if the leak is slow, and the stuff will soak right into unsealed concrete. Looks for stains, not puddles.

You absolutely have a leak, in the rear brakes somewhere. If nothing else, you'll find it when you start bleeding them.

Sorry it was so long before I posted a followup on this, but I found my problem. I bled the brakes all around, starting at the M.C. then right rear left rear right front left front, had great pressure & a solid pedal. About 2 days later I went down to the garage & saw a puddle of brake fluid on the ground under the master cylinder. All wheel cylinders are still dry, all lines look good, so I think the M.C. is my only problem. The leak comes out between the M.C. & power booster, so it looks like Strick wins a gold star. :thumbsup:

Now, the question is...do I go the cheap budget route & spend 70 bucks on a new M.C., or do I use this as a good excuse to do what I've been wanting to do anyway, which is the front disc conversion? The kit from Ground Up restoration is like 700 bucks, and I just joined Team Camaro so they'll apparently give me a 10% discount if I read the membership page right, that seems like a good investment for the safety & appearance of the car.

My car is not, will not, and cannot ever be numbers matching original...so I don't have to worry about compromising its originality. Will adding disc brakes to it increase its value? I've never done a conversion before, but I've worked on disc brakes and I've worked on drum brakes, so I assume I take the disassembly half of what I know about drums, and the assembly half of what I know about discs & I'll be fine...right? I've got all the tools except a pickle-fork attachment for my air hammer to pop the spindel off & a spring compressor which I think I can borrow from Autozone. BUT, the car is on 14" rims right now, so I need to figure in an extra grand for wheels & tires if I go to discs also. All told, I'm guessing I'll wind up finding a way to spend near 2K instead of 80 bucks. Does the safety, investment value, and appearance really make that worth while?

Disc brakes will make the car more desirable and safer, but you'll never get out of it what you put into it, except to drive the snot out of it to repay the labor spent.

My 2 cts.

I would do the front disc conversion if they fit under your 14" rims. I now feel safe to drive at a normal following distance behind newer cars. Do you have rally rims or aftermarket? I've got 14" cragars and my brake kit worked fine. My power disc conversion kit cost me about $400 after everything was said and done. Let me know if you'd like the details. For $400, I think that increases the value of the car at least by that much.

Yes I'd definately be interested in hearin' about your conversion...$400 is definately better than the $700 I was about to spend for it. My rims are 14" American Racing chrome rims, don't know what type but here's what they look like:
http://i165.photobucket.com/albums/u51/billrush5/vroom/100_0301.jpg

If I get new rims I'm getting 17's and will try to sell these to recoup the cost of rims & tires anyway, so it might not be such a huge net expense...

Leave the drums - they will stop your car just fine.
Not like you plan on doing any Rallye racing are you?

The problem with drums is they get hot faster, then fade -
that is not a problem in normal driving usage.

I have this discussion all the time with the Corvette guys.
My 63 with 4 wheel drums, stops just as fast as my 66 with 4 wheel discs.

I can lock up my brakes at any time on both cars - so both are suitable.
Leave it how it came. :thumbsup:

Bill,

Here's the link to the ebay auction:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=260165226835
I didn't want the crossed drilled or plated rotors so he took 50 bucks off of the price since he pays some guy $50 to do it. I'm guessing he will do it for you to. Just ask.
475+65(shipping) -50= $490

I also used my existing spindles and used an angle grinder to cut 0.61" off of the mounting hole. I then sold the spindles that came with the kit on ebay for $100.
End cost for a power front disc conversion WITH brake lines = $390

My guess is that the kit will work on your 14" rims since they are aftermarket. (I can't see the pic because I'm behind a firewall). There's got to be someone in your area with a conversion kit. I've heard that most , if not all, of the kits on ebay are the same.

So, other than $200 of course...whats the difference between that kit and this kit? http://www.ss396.com/mm5/merchant.mvc?Screen=PROD&Store_Code=camaro6769&Product_Code=FM-1790

Oh, and back to the original topic of the post..."where did my brake fluid go"...YES, unsealed cement absorbs it like crazy. The big puddle under my car, its gone now. There's almost no stain left behind either because brake fluid is nearly clear with an amber tint, and my cement has a slight yellowish tint to it...so if anything it just looks slightly cleaner where the puddle used to be. Within about a week it went from half an M.C. of fluid all over the floor to bone dry. That explains why it was so hard to find before...

The kit that I got looks just like that one. My guess is that it's the same exact kit. I thought that the price was too good to be true but it turned out to be a great buy.

Have you looked at Belair Bob's kit? He's in Georgia I think. He's a sponsor and his kits are cheaper than ground up.