i have a 2000 ford f250. ever since i bought the truck the brakes have been very weak, almost to the point that the truck wont stop. i have since changed the master cylinder, however this has not helped. what seems odd is that when you pump the brakes, on the third press the pedal feels like it hits something solid mid travel and the truck barely wants to stop. the brakes do feel spongy when the truck is running, but this has done this before the master cylinder was changed also. the master cylinder was bench bled, and all for wheels were bled also. any idea what could be causing this. thanks.

 

Hey jmorgan ... welcome aboard the FTE board. Some of the older generation owners have talked about their brake lines deteriorating to the point they start losing rubber material inside the connector lines and create blockages causing the brakes to pull or be less effective.

My truck pulls to the right and after replacing brake pads, calipers, disc etc. which were worn, the pulling still happens. I'm thinking the blockage thingy is happening to mine ... necessitating a change in lines connectors. Many who have done this upgrade to stainless steel conectors ... lots of posts and "how to's" about this. Keep us posted ... we always like when people close the loop with solutions. It helps the next person.

 

Well if you're sure your vacuum booster isn't the problem and you don't have any vacuum leaks causing the spongy effect, then I myself would go Old School and try the pinch method, because it sounds like a caliper problem you just have to find which one.

 

i also forgot to mention that the abs light has also been on since the truck was bought. like i was saying after about the third pump of the brakes, the pedal feels like it is stopping as if something is under the pedal and it wont press down anymore. it almost feels like when the abs kicks in when sliding on snow, and the truck does not want to stop.

 

Now that sounds like my chevy truck i use to have. It had a bad sensor on the front wheel but it only got hard like a brick and not want to stop when i was at a crawl like pulling into a parking spot. After going through 3 sensors i pulled the ABS fuse and had regular braking again. But the brake light was always on.

 

Do a service on the slid pins, do a full fluid flush, install new rubber hoses or upgrade to braided stainless. Also do the push rod adjustment which helps 200%

 

Troubleshoot vs tossing parts at it. Have someone put their foot on the brake while you crack each bleeder. If you don't get a stream of fluid from each and the pedal doesn't go to the floor you've found the problem area. Now try this. Have same person press hard on the pedal then let up. Within a few seconds crack each bleeder. See if you get pressure when there isn't a foot on the pedal. If so this indicates a blockage. Likely a flex line is bad. It could be a caliper(or two) a line(or two) or a bad new master. New doesn't mean good. Masters can be a real bitch to bench bleed. Get yourself a "Motive" or other higher quality power bleeder and give the system a good bleed. I recommend replacing the rubber brake lines every 10 years. Bleed brakes every other year or 35-40K. The power bleeder makes this a 30-minute job. Brake fluid is hydrophilic it attracts water and moisture. Always use fresh fluid never something sitting around. A spongy pedal indicates air or a bad rubber line or both. Verify the booster is holding vacuum. Shut off truck count to 10 and pull the vacuum line. It should see vacuum. If not the bladders gone.
Google Motive Products. Amazon has it for $45. You will need the Ford master cylinder adaptor too. I think it comes with one adapter? Mine came with the old school dual well master cylinder adaptor and a few other do-dads. Summit or Jegs list those part numbers. Amazon has the Ford adaptor for $25. best money I've spent on a tool in a while.

 

Isn't that what I said above? He has a 2000 and Im positive the brake fluid has never been flushed, it most likely has original rubber lines. So changing lines and a full flush should be done regardless if that's the problem or not. These are wear items and should be serviced and changed periodically

 

Change the calipers if they are original.

 

If you think it's the ABS kicking in, pull the fuse for the ABS and see if anything changes.

 

i checked the fornt calipers and some of the slide pins were froze solid, so i changed the pads and the brackets. the brake still feels exactly the same. i have used over 3 quarts of fluid checking for air, so i think the whole system has fresh fluid. i am going to try another master cylinder. i havent changed out the rubber lines, that will be next on the list. i order a scanner that reads abs codes, so i will see what that says.