I've searched this forum and others quite thoroughly and have read everything that was posted about the power brake booster on my 2nd gen ('94 4runner). What they claim was happening to me is the same symptoms that i have and so therefore i believe its the brake booster.

I will just re-iterate my problem and my search for what it is/was.

First off I have a great '94 4runner. She has less then 150k and I bought here over a year ago. She runs great. Minus a few oil leaks, which are on my list of things to do, she has really only needed minimum work. I changed both front axles, all 4 tires, brake pads and rotors about 9 months ago. I put the best ceramic pads that o'riellys had and mid-grade rotors. She runs great.

Then last week I was driving about 120miles to go pick up a boat and drive her back home. On my way to get the boat, on the highway about 25miles in, I get to the toll booth warning bumps and slow down (55mph is first bump) brakes work fine. I get to the 35mph bumps and my brakes are heavy, hard to push down, then barely respond when pressed all the way down. I'm like crap, wth?
So I get her pulled over in the parking lot at the toll booth and inspect everything. I look for fluid, check the master cylinder, inspect all the lines and hoses, and find nothing. Everything checks out.

So I decide it has something to do with my master cylinder or power brake booster. I get her towed home and do a deeper inspection. I am missing no fluid. I search the forums and find the exact wording of my problem and they claim it is the power brake booster.

I did not find anyway to test for it? My brother is out of town until tomorrow and he has all my tools and stuff, so until then I can't get the wheels off and inspect the pads, but I just changed those 9 months ago, less then 10k miles.

I have been towing a boat on and off since I got the 4runner, doing all the maintenance that is suggested on the forums and the chilton. The boat weighs less then 1300 lbs.

You guys have any ideas on how to test if it is the brake booster or the Master Cylinder? and if it is the brake booster how to test it once you take it off? and from what I read, if I get the brake booster off without emptying the MC do I still have to bleed the system?

Thanks, any info would be greatly appreciated.

'94 4runner man in KC