1998 Ford F-150 4x4 Noticed today my brakes lock my rear tires up only when I need to stop quikely or when I push a little hard I'm good on brake fluid. Looked around on brake lines a little didn't see any leaks and checked after driving all day after topping the brake fluid off (it was a tab low) and still at same as when I topped it off.I just got truck two days ago and has done it just noticed when I use brake it feels hard then goes soft but doesn't go all the way to the floor. Did the owner I got it from possible not bleed the brakes and maybe need redone by starting with the front to the back(bleeding)? No rubbing or grinding as if bad pads or rotors and seems to be no pulling as if there's a caliper locking up and not releasing. Feels like my mothers car after changing her brakes and didn't get them bleed it's just not as bad and doesn't go to floor.........so try to bleed them???? Thanks in advance!!!!

 

I would start by bleeding them front and back. This will take 2 people.

 

Kinda figured that's what it is due to no leaks and holds its fluid and nothing completely holding a grip

 

Now heres a bigger question. Is your truck 4 wheel ABS/disk? Rear drums may be too tight on there.I had a to stop on the highway from 60 to 0 quick. I never had a tire lockup, only in ice and the pedal give me feedback like a **** when it happens.

 

Yes it is a 4x4 witch works VARY well and idk if it's disk or drum all I know is it's a 1998 F150 4.2 V6 4x4

 

Check that for me, if its rear drums that is indeed your problem.

 

Okay thank you I'll find out In morning and get back to you.

 

It's drums! They didn't make disc until late '99. Rear drum lockup, especially first time use, is somewhat normal. If the truck is new to you. I'd check the rear brakes to make sure they are done correctly. IE: adjusters the right way and parking brake isn't partially on, one side. Check rear brake adjustment. If anything isn't correct the rears will lockup. Once everything is correct and adjusted, bleed brakes and retest.

 

Check wheel cylinders in drums for leak or weeping...

Check axle seal for leak or weeping...

Either of these is most likely the issue... little amount of fluid (gear oil or brake fluid) will cause the brakes to lock up...

 

A7X is exactly right...lining contaminated.