Ok, Its a 95 2wd automatic v6 4runner sr5.

When I bought it, the brakes were kinda mushy and so I replaced the master cylinder and the front brake pads and calipers. Also replaced the rear shoes.

I took it on a 10 hour trip and the pedal is now kinda mushy again. I cant see any evidence of leaks or of the master cylinder having any signs of fluid loss

What I hear is an audible thunk on occasion from the Drvr side Front wheel. I am thinking that at 230K miles it could be a possibly worn out Rotor itself allowing the pistons to extend to far when braking. It does it in reverse and in Fwd, and only intermittently.

I am going to get some Dot3 and pour it through in a free bleed and purge all the old fluid in the system. I bled them excessively about a year ago and that will probably firm them up some but it seems indicative of a larger problem. Anyone got any tips or similar experiences that will help point me in the right direction. Thx.

 

when you say mushy how far does the pedal travel could it be free play because of slightly less adjustment in the rear brakes. could be a very very small leak in a line somewhere under the truck check around all the brackets holding the line in place they are common for holding moisture and rotting lines slowly. also does the truck have a valve on the rear lines over the rear end to compensate for extra weight?

 

Thanks never saw the valve till today. I bled it also. I Bled all four corners with minimal evidence of air and minimal contaminants. It still has more mush to the pedal than I would prefer. When braking it comes within an inch or two of the floor.

I gave the lines a cursory once over and found NO apparent leaks and no real fluid loss.

I am leaning now 'twords the vacuum booster itself being sub par. I thought we checked it last time, but it seems like a likely possibility.

After bleeding them today they are better but still softer than I want them to be. I remember them being better than they are now after I replaced parts last time.

Fluid is in good shape, not dirty so I am leaning twords mechanical ... booster or vacuum line from intake.

Thanks for the help though..... I learned something.

 

For the clunk I'd check that your caliper bolts are there and tight. Also make sure the pins that go through the pads are there. Caliper has to practically spit out a pad for the pistons to come out too far. When they do you will lose lots of brake fluid and it won't stop. Doesn't happen with the Toyota's with pins going through the pads.