carguy123
carguy123 UltimaDork
4/14/17 6:16 p.m.

Warning: Long post

I posted a couple of months ago about putting new brakes on my F150 and almost popping the pistons out of one caliper. Things worked out OK . . . or did they?

I suddenly heard a grinding noise in the passenger front wheel that didn't go away when I stepped on the brakes and the truck didn't pull right or left ever. I quickly stopped and saw a little scoring around the outside edge of the front rotor. I couldn't see the brake pad but since they were new I presumed a rock must have gotten stuck in the top of the caliper so I went home and parked the truck.

I realized I'd need to replace the caliper so decided to replace both, as that's prudent. They were outrageously expensive at O'Reillys, etc. so I ordered them online expecting the worst.

A few days later when they arrived I jacked the truck up and began looking in Earnest.

I found that the outside pad was completely gone but all 3 other pads (both wheels) looked brand new. I have no idea if the pad blew up or there was a caliper malf.

So I tried to get a caliper rebuild kit, but no one carries them. They do carry new calipers (ouch) but I bought one on the off chance there was a caliper problem left over from before.

I replaced everything with new, bleed the brakes extremely well (that means 3 different times and over a bottle of fluid with no bubbles).

But the pedal feels slightly soft, not bad, but still not what I expected. I can't activate ABS and there's this very bad brake smell even tho I've bedded in the pads which makes we worry that whatever was wrong the last time is still wrong. Everything looks nominal!

What else should I check?

jstand
jstand HalfDork
4/14/17 6:57 p.m.

Sound like the slide pins are not moving freely.

One pad wearing down quickly while the other doesn't is usually a sign of binding in the pins or the anchor bracket.

Remove the pads, reassemble, and make sure the caliper can slide freely in both directions.

If that doesn't show any binding reinstall the pads, and check for binding. One way to check it so spin the rotor and have a helper press and release the brake pedal.

This will let you see if the caliper is twisting (piston pushing off axis), pads are hanging in the anchor bracket, or pins not sliding freely.

If you don't find any mechanical issues, press and release the brake pedal so it's binding, and then crack the bleeder to see if the brakes release. It's possible the rubber hose isn't letting pressure release.

carguy123
carguy123 UltimaDork
4/14/17 10:32 p.m.

The new caliper had new slide pins and the new ones and the old ones were moving freely. One thing that had more sticktion to it than I liked were the pad ends. The little spring clip you install on the bracket that the pads reside in had touch too much friction for my tastes, but I played with and didn't see any solution.

I forgot to mention it's not pulling either way when I apply the brakes, but it also didn't pull when it was destroying the other pad.

I've seen uneven wear side to side before and this was nothing like anything I've seen before. It was all other 3 pads looked almost like they didn't have any wear and this one pad was completely destroyed. Now there was a small amount of more wear towards the outside of the steel plate (where there used to be a brake pad) than at the inside.

I've got a helper coming over tomorrow so maybe we'll pull the wheel and look for deflection.

The truck stops well enough in normal situations but it bugs me that I can't activate the ABS because that says it's not stopping as well as it should. What if I have a car cut in front of me or something? Will I be able to stop?

If it weren't for the ABS portion I'd think I was just being overly sensitive due to the last issue, but I have new rotors, a new caliper and new pads.

If it's the brakes not releasing what would cause that? I've not touched any adjustments at the pedal end so I wouldn't think it was not releasing at the Master end.

NGTD
NGTD UberDork
4/15/17 7:27 a.m.

Are the pads able to move freely in their guides? I find that I have to file down the "ears" on any new pads otherwise they hang up and cause uneven wear.

iceracer
iceracer UltimaDork
4/15/17 9:35 a.m.

ABS only activates when a wheel starts to slide.
Try braking on dirt or grass.

AngryCorvair
AngryCorvair UltimaDork
4/15/17 11:14 a.m.

NGTD is on the right track. 0 Pads should never take more than one finger push to slide in the rails. I have had to file the ears on many new aftermarket pads to get the slide force to an acceptable level.

sergio
sergio Reader
4/16/17 7:22 p.m.

we aware that on some fords the inner and outer pads are not the same. bad E36 M3 happens if they are installed wrong.

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