I have a 1994 Isuzu Trooper 4x4 in excellent condition. It has approx 95K on it and has been well maintained. I've had a recently-developing problem with an increasingly spongy brake pedal. When I step on the pedal, I get the feel that the system is engaging, but no real braking occurs until I get the pedal almost to the floor (about 2 inches from it - really, even with the accelerator, which is a BIG problem). The fisrt 3/4 of the brake pedal press, no significant braking really happens. The brakes have obviously been replaced a couple of times over the life of the car, but nothing has been done recently, and the pads are fine. No leaking fluids, etc. I'm not a mechanic, but can do some things on my own. Any suggestions/diagnosis, recommendations/help? Thank you!

You have fluid correct?

The only other thing that it sounds like to me is your brake booster thingy is dying.

check your lines under the truck too , if it rusted under there somewhere and you have a pinhole , that could cause it , getting slight air bubbles in there , and also a slow slow leak.

If you don't find any leaks, I would try bleeding the brakes and replacing the fluid (you could have water in the fluid). Bleed them very well (about 20 pumps per wheel).

Your seal on your master cylinder can also be starting to go out on you slowly , just enough so that its starting to get that spongy feeling to it.I think there is a bearing in the part just before it joins into your brake booster , and that is the part ot look into.

Check to see if all the caliper slides are moving freely, if one slide is frozen then the pads will wear unevenly this will cause exsesive piston travel and flexing of the caliper. The volume of the calipers compared to the master cylinder is probably about 10:1 so it takes alot of pedal travel to move the calipers a very small amount. I see alot of cars come into my shop with this problem. Also be sure to use a pure silicone grease to lubricate all your slides and hardware, if you use a petrolium based grease it will will damage ruber seals and bushings. Good luck.

Thanks. This makes sense, in that the brake fluid has probably never been replaced. How to do this is the question for me, cause I've never bled a system before.
Any suggestions/Help?