was coming home from store and lost my power brakes limped it home then went back out and they were working fine also my ac went to defrost is this a vacuum pump going bad or maybe a check valve hose issue

 

Could be vac pump. There should be a rubber union in the line off the pump that feeds the vac tree on the firewall, somewhere in the middle, where you can put a gauge on it to see how it's doing. It could also just as easily be the power steering pump, but you'd notice the steering change too. It could also be the hydroboost (hopefully not, expensive part, PITA to change) and there are a few different symptoms that could all point to that, and this is one of them. Sometimes if there's a little bit of debris in the fluid it gets caught in a valve on the hydroboost, and eventually blows through which would do exactly what you're experiencing although again, usually the steering is affected as well. Flushing the living heck out of the whole system might not be a bad idea. I'm leaning towards a vacuum issue though since the AC went to defrost. Could be a coincidence, but probably isn't.

 

well i checked the vacuum and was a steady 27 and not a hydro boost truck has the updated recall check ball could the vacuum lines be bad internally and cutting it off intermittently or is this what a vacuum pump does when its on its way out

 

I've never heard of a vac pump going intermittently, but I suppose it's possible. If you don't have hydroboost though, it can't help but be narrowed down significantly.