Mods, if this is the wrong section, I apologize.

I have a 98 Explorer, 4 door, 4 wheel drive, 4.0l V6 OHV. I had to replace the ball joints in it. After that was finished, my truck had no brake pressure. Calipers were hung, not removed, no leaks at first. I had to pump the brakes to get pressure, then when I drove away, it would lose pressure again. Took it back to the shop, was told it was possibly a master cylinder. Had that replaced, brakes still didn't have proper pressure, pedal would sink almost all the way to the floor.

Checked again for leaks or vacuum problem, nothing. Took it back again, calipers up front were checked, everything up front looked OK. New brake pads up front. Still not adequate pressure.

Took the truck to another place, he bled the lines, got some air. Still having issues with pressure. He sent it out for an ABS diagnostics check. Everything appeared fine, but he found a small leak in the rear caliper. Had the rear caliper replaced, line bled again. The pedal originally would be strong from slight pressure and stay strong and only go down about a quarter of the way for a non emergent stop. Now, with all of that done, the pedal slowly sinks to about halfway, further than before, before it starts to grab now. Is this something I will have to just get used to, or might there still be a problem? All three mechanics said they don't know why the pedal travel has changed.

Any ideas or input? If I left out a detail, just ask, I will answer to the best of my ability.

 

check the play in the wheel bearings. excessive play in the front wheel bearing on those can cause the rotor to push the piston and fluid back into the brake system

 

Did the master cylinder itself get replaced or the brake booster as well? The seals tend to go bad in the booster and cause that exact same problem...

 

The master cylinder and the brake booster were replaced.

 

Are you positive that there isnt the slightest leak from the calibers. I mean even a wet residue The brake hose to the calibers have 2 copper o-rings. I would go through and check all four calibers. Signs and symptoms of air in the system caused by a leak somewhere.

 

I had 3 different mechanics take a look at it. The first guy who did the job, then another who I took it to for a second opinion. He had trouble figuring it out, but he did bleed the lines. He sent it to another guy, who did diagnostics check on the ABS and re-checked for leaks. He found a small leak only in the left rear caliper. He double checked and that was the only leak he could find. Sent back to the second guy, who replaced the left rear caliper and bled the lines again. I picked it up yesterday and the brakes still didn't feel right. But driving it this morning, they felt better.

But, with the weather we had, and all the melting snow, it's hard to diagnose a leak with all the water from melting snow. I will give it a few days and see what happens. If there is still a leak some where, I should notice it in the master cylinder, with losing brake fluid, correct?

Oh and thanks guys so much for your input.

 

If there is in external leak you MAY notice a drop in the master cyl reservoir. Not necessarily though. If it's an internal leak (faulty master) then you won't see a leak or loss of fluid anyway. I'm going to chance it's not the master though as it's already been replaced and it's hard to get that wrong. Especially if you build them everyday.

 

Like JP said, you might not see a significant drop in fluid. It can be so small that you will have what us army guys call a class 1 leak which is a wet residue. With that small of an escape route for the fluid to get out and air in it can be cause for a pedal to have too much play. You can get underneath the truck and wipe all calibers down and check that away after driving a few hours.