Howdy y'all I am new to this forum and apologize if this topic has already been discussed before.
I have a 97' OBS F250 w/ a 7.3 Powerstroke Engine
About 2 weeks ago I noticed the brakes go completely stiff as well as my parking brake light come on and loss of Cruise Control. I've had no issues with steering, Master Cylinder is still topped off, it seems to be getting sufficient vacuum but I don't have a gauge to fully verify, just the thumb over inlet test, oh and the parking brake IS released (I triple checked). The kid who owned her before has said he's redone the whole brake system few years back but had a consistent issue with the vacuum pump. Idk if it's that Chinese garbage or another issue which is causing the failure. Still runs & drives without any issues besides listed above, and I'm curious as to what else I can troubleshoot before throwing parts at it. I haven't had any issues with her until about 3 weeks ago when the Alternator went out. But she's made the 2400 mile move from ID to SC without a problem. I believe the Brake Booster may be the culprit but am curious on y'all's input before moving forward, thanks for your time!

-Cook

 

vacuum gauge on one of the lines. step on brake pedal. if the vacuum does not return to at least 19 inches almost immediately, the vacuum pump is bad.
if it does return immediately, i would be looking closely at the booster.
unfortunately these days new pump don't mean much and they are all made of cheap chinesium junk.

 

thanks buddy I’m going to look into that tomorrow, I’ve been able to run it as is just fine but would rather fix it than be sorry. I will post in here again depending on the results

​​​​​​-cook

 

yea, been there done that...
it is not a good feeling when you go for the brake pedal and it is hard as a rock!!!