I’m having a problem with the brakes on my 1997 Ford F-250. The problem is when I’m driving a decent distance without touching the brakes then I start using them to slow down they work fine. But if I’m in town or using the brakes often the pedal gets hard as a rock and I can barely stop. I already checked the vacuum pump line and it had suction. Any ideas on what this could be?

 

Sounds like the pump is working but weak.

 

So I should start with just replacing the pump?

 

NO. Get a vacuum gauge and check the vacuum. This sounds more like a brake booster to me but do a vacuum test first. You can borrow a vacuum gauge at the local parts house.

 

Rock-hard pedal means your problem is in the vacuum assist system, not the hydraulics. So it's NOT master cylinder, lines, fluid, calipers, wheel cylinders, bleeding, etc. Vacuum pump, brake booster, leak in another vacuum line could be the issues.

 

If you end up buying a brake booster get a zero loss one.