Brake Master cylinder- My 98 4runner seems to have a sinking brake pedal but, it hasnt been consistant. Sometimes it holds fine. I havent been trying to push it through the floor but occasionally when holding on a hill it seems to sink further towards the floor than I'm comfortable.
Ive done some searching on master cylinder and this doesnt seem to come up very often. Ive got about 120k miles on it.

So my main reason for the post: Is they something else I should be looking for? I wil be pulling the rear wheels to check for wheel cylinders leaking. Wondering if I should just bleed the brakes and put fresh fluid in to see what happens? I know what happened with my crx is I eventually had a pedal on the floor and and needed a m/c. Getting ready to take atrip and since Im headed to the mountains in the winter I was not planning on taking the s2000.

Thanks in advance

 

hey pal!!!!!
i almost crash today because of the pedal sinking,check my posts

 

2008 my bad!

 

Yeah ,im going to do the full breaks service it was a really scary moment

 

Pull the ABS fuse and see if it gets better. if it doesn't improve, you have eliminated one part of the system. Check for leaks at the calipers and cylinders. Is the resevior full?
Check the rubber lines from the frame to the wheels. Have someone pump the brakes while you look at each one. If the hose is weak, you may see it balloon under pressure.