Hello, so I have a problem with my 2000 f250 powerstroke where the rear disc brakes keep locking up on me. I feel like I've diagnosed it at this point but just want to hear some extra thoughts before I dump my money and time into a fix I might not need again. So I bought this truck a couple months ago and it's been doing fine, after a couple weeks it kinda felt sluggish but it was still handling itself on road so I thought it was fine. Then one day while heading back from work I felt myself slowing down considerably on the highway, it was struggling to do 55 and when I let off I would immediately slow down. When I finally got home I noticed the rear brakes were very very hot, both sides were smoking it seemed to be the right a little more than the left but the fronts were absolutely fine. I took everything apart and it seemed like caliper pistons were sticking out a bit too far so I pressed them down with a c clamp and called it a day. Then the next time I took it out it did it again but this time it was more locked on the left side so I said screw it and decided to replace both the rear calipers with brand new ones and even got some new rotors since the last ones were probably warped from all the heat. I greased everything up and made sure all the surfaces were clean and bled the brakes but then it locked up on me again so I did some searching. I wound up finding some threads about the push rod in the hydroboost being too long for the master cylinder and not allowing fluid to return and they suggested to check this I needed to take off the two bolts holding the master cylinder on and sure enough they started acting fine again and it got me home but they locked up soon after. I tried to get in to adjust the push rod but due to an immense amount of corrosion I was unable to remove the master cylinder from the hydro boost and believe me I tried everything, from pb blaster to heat to hammers and brute force. Anyways I have a feeling that if I want to adjust the push rod I'm just gonna need to buy a new hydroboost and master cylinder. Nobody follows up on threads once their problem is fixed so I'm not sure if this even is the problem or what else I could try to fix or diagnose this before I wind up spending a lot of money. Any thoughts or ideas would be appreciated because I'm kind of stuck at this point.

 

I'm not familiar with issues with the hydroboost/master cylinder but hopefully you'll get some responses on that one.

There may be another step or two at the rear axle you could try for the brake dragging. I recently had a sticking rear caliper, and my issue was solved with a caliper replacement. Some folks have needed to replace the soft lines at the calipers, as collapsing inner liners on those hoses can cause the calipers to stay engaged. One person had corrosion in the hard lines on the rear axle, and replacement of those solved his issue.

Here's my maintenance thread on the subject as a starting point. @Sous and @FordTruckNoob and @SkySkiJason have some experience with the axle side brake issues.

https://www.ford-trucks.com/forums/1...l#post19834761

Sous' thread:

https://www.ford-trucks.com/forums/1...reading-2.html

 

Change all of the rubber hoses that go to your brakes. The insides are degrading and 'flapping' and holding the brake fluid in the calipers, even if you have released the brakes at the pedal. Also, something that may cause a 'drag' is the emergency brake..... may have tightened it's self too much

https://video.search.yahoo.com/searc...f&action=click

 

Definitely something worth trying, the e brake cable was the tiniest bit applied on the left side but I hammered it back into place and it's definitely the calipers that are locking rather than the e brake. Thanks for the idea though probably going to be a lot easier than jumping straight to the hydroboost.

 

I had the same problem and replaced the rubber hoses to all the calipers which fixed my problem. There is also another rubber hose that feeds the back brakes before they split which I did not replace but I intend to. Worth a shot as it's not too expensive either. It's got to be done some time anyways

 

@MedShark , @Brother Les has got you on the right path. A hyrdoboost issue would affect all the brakes. not just the rears. Like you, I had brake issues when I first bought my truck. I eventually had to replace all the brake lines including the hard ones starting with the flex hose from frame to rear axle and all the way out to the calipers.