Hello All,

I've searched, but with such common terms, I can't find a similar situation.
1992 pickup, 3.0L V6 4wd, automatic transmission, 150k miles. Stock everything.
Driving down some hilly roads the other day with a small load (~300lbs) in the back, my brakes felt very weak when going downhill. The pedal seemed normal--it wasn't overly mushy or hard, but it seemed like it took forever to stop. I pulled over and noticed a horrible smell, and then checked for leaks. I couldn't see anything from any of the brakes, but there was fluid being pushed up and out of the brake fluid reservoir (at least that where it looked like it was coming from). The fluid level is normal, so I didn't lose a lot. Fluid is clear.
After unloading the truck, I drove it around slowly, and the brakes then appeared normal, but I never thought the brakes were great.
I replaced the rear wheel cylinders about 5,000 miles ago, and in the process basically replaced all of my brake fluid. At that time, I checked the front pads, and they had about 60-70% of the pad left.

Anyone have any ideas what is going on here? How can I further diagnose and fix this?
I'm contemplating upgrading the front brakes (T100 rotors and 95 4runner pistons) soon. Maybe the time is right.

 

Figure out just where the fluid is leaking from ?/

Is it brake fluid or something else?/

The only way it can push out the top of the reservoir is if you have a major blockage and the fluid can go no where else .

Your emergency brake keeps the rear brakes adjusted does it work and do you use it??

 

If you're actually pushing brake fluid back into the reservoir, I would suspect a leaky master cylinder. That might also explain weak brakes. (Though a leaky master cylinder rarely corrects itself.)

Clean everything up (water works for just brake fluid, though a little spray degreaser will clean it up all the grease too) and find the leak.