I was towing a horse trailer yesterday when my brakes all of a sudden became hard to push and I did not have any stopping power. They will not stop the vehicle on their own and will not press down. I have an automatic and have to down shift to get it to stop. What do you guys think would be a good place to start to solve the problem?

 

Is your brake light on?
If so probably your vacuum pump has gone out.

 

No lights are on in the dash. I did pull the line on the top off the brake booster out and held it against my hand and it had suction on it. The truck continued to run while I held it to my hand also. I did see someone try this before and the truck would start running rough, but I think it was because it had a vacuum leake somewhere but not sure. I alsodisconnected the trailer just to be sure that is was nothing to do with it, and the problem continued.

 

X2 on the vacuum pump failure.

 

vaccume leaks only make gassers run rough, OBS powerstrokes have a belt driven vaccume pump.
it may not be sucking hard enough or you may have a bad booster. do yo uhave access to a vaccume gauge?
are your heater controles working fine?

what year and modle is your truck? the older f450s and superduy 250 and 350s have hydraulic assist brakes

 

both my vac pumps would create suction when they failed, but the hand over the hose test is just not accurate enough. a guage is really the best way to diag the problem.

if you find that it is the pump, i strongly recommend staying away from NAPA pieces. i had 2 fail on me within a 1 year period. i put a ford part on there and its been good for over 5 years now.

 

My truck is a 1997 F-250 4X4 crew cab. I have been hearing some chattering under the hood for the last week, but could not determine where it was coming from exactly. I guess this explains where it was coming from. It sounded like a bearing was trying to go out, but I could not figure out where exactly. I will check the heater inside and see if it blows warm air.

 

what should the vacuum gauge read if it is good or bad? Can I do this project myself or do I need a true mechanic to do it?

 

Its the vacume pump and after you take it off pull it apart and you will see why your hearing the noise. The cam on the pump is all chewed up.

 

Thanks Guys!!

 

17-21 in-Hg is what my book shows =57-70 kPa<O</O
At idle below 10in for more than 7 seconds will illuminate the brake lamp.
Most vac leaks i have found have been at the heat/ac control.

Its really easy to change the pump: Remove belt, remove three bolts, (10mm IIRC), disconnect single vac. hose on rear of pump, and its out! A word of advice is to remember to install the bolts into the new pump BEFORE you put the pulley on, otherwise the pulley gets in the way of the bolts, and you have to pull it off again. Hope this helps!

 

i have found that a good working pump on a system with small or no leaks will peg right over to 30inches.

excellent advice about the bolts!