brake pedal bout went to the floor!

99 taco 2.7ltr, 4X4, 5 spd. got done driving my truck a few hours ago, came back home, hopped in it to go to town & the brake pedal bout went to the floor. slammed brakes on going down the road, stopped at a store, got back in it, seemed normal on the way back home. checked the brake fluid & it was fine! should i bleed my brakes or anything? front brakes & rotors were changed maybe 6-8 months ago. thanks in advance!

 

I had something similar happen to me with an 02 that we got a few weeks ago. We drove it all the way from Florida to New Mexico with no problems. Then one morning, I started it and the brake pedal went about 3/4 of the way down. The brakes would still work, but the pedal was way down. That came and went for about two weeks.

Finally, I went to bleed the brakes, found the fronts to be normal, but no fluid came out of the rear at all. The guy that was under the car had to crack the line to get the air out and fluid to the rear cylinder, then bleed both rears and the fronts again. There was a huge air bubble in there someplace, and it was obvious upon closer inspection that the rears had not been working for a while. The truck had stopped very well with just the fronts. We bled everything, replaced the front pads, and readjusted the rears. Everything has been normal so far. That was about a week ago. My question is, where did that air come from. No leaks of any kind that I can see. Maybe someone had gotten air in at some point, I don't know. We will be monitoring them closely for a while.

Hope that helps.

 

yeah man, that helps! ill try & bleed the brakes tomorrow, & see what happens, if i get the time. thanks man, hope ur truck is back to normal! during this, did u have any hopping/vibrating going on when applying the brakes?

 

Bleed the brakes, it's air in the line. Air could have come from a brake cylinder seal or hose fitting failure somewhere in the system, or a bad bleed valve. Depending on the age/condition of your brakes, it could be any of those locations.

Vibration is likely a warped rotor. Have it turned (machined) if the problem persists.

 

I'd look for leaks..... air doesn't suddenly get in the system.

If you're sitting in your truck with the engine running (in park, nuetral or whatever). Put your foot on the brake as hard as you can. Can you feel the pedal moving downward at all?

If yes...you've definately got a leak. Start crawling underneath and looking for leaks. I'd first suspect the rear drum brake area and go from there.

You can bleed the brakes now and that will probably do well for a while. If you have a leak, it'll eventually get air in the system again and the problem will come back.

 

No hopping or vibrating or other problems. You could pump the brakes up a bit, and again, they were still powerful, but it did begin to feel like mostly just front end braking - turned out it was all front end.

If the air pocket never returns, I will suspect it was let in by someone during some type of brake work. You had work done a while back too. We can't find any evidence of a leak, but time will tell.

Just an update, to get the air bled out, what my friend did was open the bleeder or the proportional valve that is mounted on the left rear of the frame. Once the valve had brake fluid again, then it fed the rear cylinders, and we were able to bleed the whole system. It was important to bleed the front again at the very end.