Brakes Spongy

So, it seems that my brakes are becoming super spngy while I'm bouncing around on a 4X4 trail. I really don't have any problems on the street. Here's what I've checked/fixed:

2003 Tacoma 3.4L
140,000 miles


1. All new brake pads installed (1 pad was almost completely shot...)

2. Checked brake fluid, but did not bleed. The fluid is original and never changed.

Any idea's or suggestions?

 

You might want to flush the system and replace the fluid (obviously).

 

holy cow! 140k on original fluid?!

get that changed out asap, there is probably a ton of water in the lines (brake fluid absorbs water) corroding fittings and such. Also you most likely have some air in there causing the spongy feeling.