Yup, I'm new to the site, but not new to 4-wheelin'. I have a 94 4runner (work in progress). Brake pedal keeps going slowly to the floor, then no brakes. Especially when it's warmer out. I suspect master cylinder, but want to be more sure before I buy a rebuild kit. Help?

 

doesn't sound to complicated, check all your lines for leaks, and have someone step on your pedal while listening to your master cylinder. Also have you checked your levels consistantly in your brake fluid resevior?

 

Thanks bro,
have checked for leaks... none. reservoir levels are constant at full level. What noise am I listening for with the master cyl? This is driving me crazy.

 

well on my old jeeps master cylinder i had the same problem, but the seal has blown in the back of the MC, and when I was trying to diagnose the problem i heard it hissing when my buddy hit the brakes for me. but if your not losing fluid, then it means you either have air in your lines or your MC isn't uping your brake pressure.

 

Thanks bro. That helps. I did bleed the lines and same prob, so I am gonna swap out the MC with a rebuild and see what happens. Cheers

 

Good luck

 

It was the MC. Bad scouring and metal shavings in the front piston bore. Replaced, bled brakes... gooder than new! : ) Thanks

 

I have had the same problem on my 1993 Toyo 4x4 V6 xtra cab 5speed! Just replaced all brake lines. Wifey and I bled brakes. Still no pedal! Goes to floor. Bled rear right side and left. Do you think there is air in the front lines somewhere. No air bubbles come out at rears. Plenty of brake fluid in Reservoir master. What next? Very confusing. Don't know what else could be bad! Anyone had this problem?