Brake Problems

[geomuf]

I have an 02 Explorer with some brake problems.
I purchased the truck 2 years ago and replaced the pads on all 4 wheels at that time, no issues. A couple of months ago we started to notice a heavy pulsing when the breaks were applied. No problem, I pulled off all 4 rotors and had them turned. The pads were still good but I replaced them anyway. Now the pedal goes to the floor. I blead the breaks several times and still nothing. I am concerned that the master cylinder is shot.

When I was replacing the break pads I did the standard push the caliper cylinder in with a c-clamp. I normally do this very slowly to not cause any damage. I may have got in a hurry on the last one (driver side front) and I heard a squishing sound at the master cylinder when pushing one of the cylinders in.

Did I blow a seal in the master cylinder? Is there something with the ABS that could be causing this?

Thanks, George

 

[thunderhorse]

When you were bleeding the lines, did you have a 2x4 or something under the pedal to keep it off the floor? If the pedal went to the floor chances are the master cylinder is toast.

 

[mikeh44]

warped rotor get it turned down

 

[geomuf]

No, I didn't. The pedal was going to the floor before I blead the brakes. I thought maybe there was air in the lines, so I blead them. I have never experienced a master cylinder go like this. It was fine before I did the brakes. I did not open the system during the job so there should not have been any air in it. While bleading the system I really did not notice any air coming out so I figure it must be the master cylinder.

Thanks,
George

 

[geomuf]

I had all four rotors turned and installed new pads, hopefully that solves the pulsing problem, now I have to fix the very soft pedal issue.

 

[MadExplorer93]

I had all four rotors turned and installed new pads, hopefully that solves the pulsing problem, now I have to fix the very soft pedal issue.

Is the brake fluid in the master cylinder LOW or Leaking?

If so and no wheel cylinders are leaking or lines, then it could be the brake booster as that will also make a soft pedal and SWOOSH SWOOSH sound when brake pedal is pushed either engine running or not, but worse when running and harder to stop.

You could also have a AIR LOCK in the master cylinder or wheel cylinders or line.

 

[Nocturnall]

Typically, at least when it's me, whenever my brakes pulse or anything is happening that a warped rotor could be the culprit I just replace the rotor instead of having it turned down. It's just gonna warp again. As far as the soft pedal I just had this happen, pedal would go right to the floor and would barely stop the truck. Replaced the master cyl, well actually just threw parts at it as I didn't have time to properly diagnose so new brake booster and master but the master ended up being the cause of my soft pedal.

 

[geomuf]

Well I located a new master cylinder and plan to replace the old one. Hopefully that will fix the problem.

I find no leaks around the master cylinder or any of the other brake components. The brake booster appears to be operating correctly and the check valve checks out ok.

I am not sure how I would have air-lock in any of the system since it has never been open. I blead the system at all four corners and the master cylinder and found no air anywhere.

Thanks,
George

 

[MadExplorer93]

Ok then it maybe a bad master cylinder if no leaks around it or lines or wheel cylinders.

Also inside under the pedal towards the firewall, check for a leak as i blew my master cylinder on my checy truck and it was leaking inside on the firewall area behind the pedal.

It would be a good guess your master cylinder is damaged by your description and your process of elimination.

 

[geomuf]

Thanks everyone for the help, I found the problem.

Before I changed out the master cylinder, I thought I should test it. I removed the lines and installed plugs in the master cylinder. When I stepped on the pedal it was rock hard and held.

I decided to backtrack to where the problem first occured. In order to determine where the pulsing problem was I did the rear brakes first and test drove, better but not completely gone. It was after replacing the front pads and turned rotors that the problem showed up.

I decided to take off the front calipers to look for a problem. when I looked at the pads I noticed that one edge was crushed. After some more looking I noticed that the pads were binding on the caliper body. The new pads had a couple of tabs sticking out of the edge that the originals did not have. These were hitting the caliper and binding causing the caliper to not clamp straight on the disk.

I gathered everything up and ran back to the NAPA to try and exchange the pads. The guy at the counter asked what year Ranger? I said these are for an Explorer. Turns out the previous guy had grabbed the wrong box. It was strange, the slipper pads and the pads themselves fit right in the caliper mount, it was not until I bolted on the calipers that the problems showed up.

The pedal was much more solid. After bleeding the system everything was good again.

Lesson learned do not go looking for additional problems, go back to look for the last mistake. I noticed those tabs and that the caliper was a little tight going back on, I did not think much of it assuming that I had the correct part.

Thanks again
George