left rear caliper drag?

[MasterofDisaster]

I installed Power Stop Z17 Evolution Plus Brake Rotor and Pad Kit; Front and Rear (11-14 Standard GT) on my 08 GT last week. I bedded the pads, and the brakes seemed great. The car sat in the garage all weekend.
This morning I drove about 12 miles, of which about 5 were interstate. When I arrived at the destination, the left rear wheel was really hot. None of the other wheels were more than ambient temp. The LR rotor appeared to be bluing, and the brake smelled hot too.
When I drove home, the LR rotor was slightly cooler, but still hot. [I checked - my e-brake was not applied at any relevant time.] When I drive at a low speed, I don't hear any dragging.
On the old brakes, only the LR pads were down to minimums. The LR sliders were in good shape. They weren't rusty at all; I just greased them and reused them. I torqued the bottom slider before I torqued the upper slider per the manual.
Any idea what's going on? Any idea how to fix? Just let it wear?

 

[rocky61201]

I just replaced my pads and rotors this weekend. Same thing. My left rear pads were significantly more worn than any other wheel. I don't think I have as much as a drag problem as you described but the pad wear in that wheel shows its dragging and I've never been able to prevent it. I've had my 06 for almost 12 years. Its always been that way. Only car I've ever owned or serviced with screw type pistons and I think this design is part of the problem. I think I may just replace that left rear caliper or rebuild it and hope that fixes the problem. If there is a cause and remedy for this problem I would love to hear it!

 

[MasterofDisaster]

Thanks. RR caliper I had to tap the jackscrew with a hammer to get the caliper tool to work. LR caliper I had to put a cheater pipe on the jackscrew handle. I wouldn't be surprised if the caliper was frozen all the way out, but by the time the caliper was compressing the last 1/4 of the way, I was able to turn the jackscrew without the cheater pipe.

 

[rocky61201]

I guess you're talking about the brake tool you can rent that compresses and turns the piston at the same time. Yea it is still a PITA to compress the piston using that. Even then I still get the same problem with the LR caliper dragging. Maybe another shitty design from Ford in a rush to start production on the new model??? Like 2 piece driveshafts, remote shifters, and the awesome plastic clutch master cylinder clevis???

 

[MasterofDisaster]

I think I remember the rear calipers on conversion kits for foxbodies having the same piston design. The family's Fusions have all had it. The Jeep Liberty has it.

 

[07 Boss]

did you double check that the back of the pad was properly lined up with the piston. There's a little slot that needs to match up with the nub on the pad otherwise the pad sits crooked. If it's not that it might just be a bad caliper. I replaced my drivers side rear when it got stuck. Probably could have rebuilt it but I went the easy route.

 

[rocky61201]

Yes I've always checked the piston was matched up with the brake pad.

Probably just a bad caliper since it's only my drivers side. For the past few years I wish I could have bought rear brake pads and check "1/2" for quantity because 2 is all I really needed in a box of 4 brake pads, lol. Guess I'll end of replacing the bad caliper eventually.

 

[MasterofDisaster]

Rocky & 07 are wise indeed. I clearly remember aligning the slots on the piston with the peg on the pad, but it was out of alignment when I checked.
I found that I was able to turn the piston face enough to align with a huge pair of channel lock pliers. The handles are a foot long.
Reinstalled the caliper and test drove the car. Problem fixed. Even after 10 miles of driving on a 90º day, the wheels and calipers were never more than warm, and the LR was no warmer than any of the others.
Still not sure how the piston worked itself out of alignment.
BTW - many thanks to Rocky & 07!

 

[rocky61201]

You're luckier than me. Installed new rotors and pads on Sunday morning and pin was aligned. After 3 days of driving my rotor is turning blue about 1/4 inch wide near the bottom of the pad contact area. But I know my pin is aligned with the pad. I'm thinking maybe years ago the very first time I installed new brake pads it was my first experience with screw type calipers. I remember trying like a mofo to push that piston in without turning it using whatever I could find for leverage. Probably an hour later I figured out the procedure for screw type pistons. Maybe I fucked up my left caliper way back then?

Wouldn't have been the first time I tried to substitute brute force for brains. And probably won't be the last.

 

[MasterofDisaster]

I'm guilty too. Definitely worth taking the time to pull off the caliper and check. Few things on our cars are easier to check.
I'm still not clear on how the peg could escape from the slot.

 

[Windstang]

This thread has me interested. W few years ago, I noticed a "tshh,tshh,tshh" sound from the back of the car. I thought it might have been bearings or the diff. I took it to a car place, they put it up on the hoist and the noise was obviously coming from the brakes. They said probably no biggie. Fast forward a few years and I changed the brakes and had a bitch of a time getting the pistons retracted with the screw in tool. They just wouldn't retract. So I disconnected the brake hose etc. and took them to the bench. Again I tried turning in the pistons, and this time in they went really easily. So it appears to me that there could be a restriction further back in the brake lines - perhaps the ABS system that could be causing the pistons not to 'relax' when the brakes are not applied - almost like there is a check valve preventing the fluid from going backward although the brakes are not fully applied so there is obviously some retraction going on. My noise is still there and it is annoying but I am living with it. Does changing the calipers work for you guys to get them to retract or is the problem still there? Anyone have any experience in going further back up the brake lines to find a restriction. I was watching a Youtube video (South Main Auto Channel) and in one brake video he mentioned something about brakes not retracting - possibly from some damage to the brake lines.
Thoughts?

 

[rocky61201]

I haven't gotten far enough too let you know. My plan is to replace the caliper but it will have to be a stock type replacement because I'm not upgrading to Brembo's or anything like that. At that time I'll look at the brake lines back to front and look for what you're suggesting. I don't know when I'll get around to replacing the stock caliper. Maybe in the next month or two. Unless my whole rotor starts turning blue. Than maybe I'll rush right into the problem.

From what I've heard a lot of the restrictions are being loosened starting this Friday. So that means the local bowling alleys are opening back up. That's where I'll be spending the majority of my free time instead of underneath the Mustang like I have been for the past two months.

 

[MasterofDisaster]

Windstang - I think maybe the difference in effort is trying to hold the caliper in one hand and crank the piston tool with another. I had to press the caliper against a solid part and crank on the piston tool with a cheater pipe.
The tsh, tsh noise sounds a lot like a warped rotor.
I'd be surprised if the problem was a brake line obstruction. When you bleed the brakes, how does the fluid look?
When I pulled off my LR wheel, even using a bright light and a mirror under the caliper, I wasn't able to see the peg on the inboard pad. I was able to see that my sliders now slid great. Why don't you pull of your wheel and check your sliders? If they don't slide freely, pull them out, spray everything with PB Blaster, brush the holes with a rifle cleaning bore brush until they shine, wire brush the sliders until they shine, load them with grease, fit the rubber boot on the sliders and brackets, and check the slide.
While you have caliper off you can check the peg/pad alignment.
The slider bolts take 33Nm or 24lbft. Torque the bottom bolt first and then the top bolt.

 

[rocky61201]

For the record I just think the calipers suck. Good luck to you guys. I'm going bowling.

 

[Speeddmn]

Anyone have a inexpensive upgrade for the rears? Disc’s and caliper? I have a parts list for fronts but havent see an upgrade from stock size to a larger size.

 

[rocky61201]

All of the popular vendors have them. Start with American Muscle. Be prepared to spend some coin.

 

[Windstang]

Master - thanks for the ideas and comments. I know what you mean about holding the caliper in one hand and trying to turn it in with the other - it was awkward. But the pistons just wouldn't go in - until I put it on the bench with the hose off and it was dead easy. Also I don't think the rotors are warped because normal braking has no pulsing. It's almost like the rotors are just not relaxing enough but they aren't getting hot either. I'll take the brakes apart again and ensure the sliders are lubed up. Brake fluid is clean - I flush it every 2 years.

 

[MasterofDisaster]

The Powerstop Z17 kit from https://www.americanmuscle.com/ is an upgrade from stock. They're stock size and they're not slotted or drilled, but you may get a little more bite. I also like the coating that cuts down on rust. Before tax, etc, they were less than $220. It's hard to get decent rotors and pads for that.

 

[MasterofDisaster]

Windstang - thanks for the note. I'm not really sure enough to say anymore at this point. Please let me know what you learn.
The RR caliper had been reluctant to turn. I tapped the jackscrew on the caliper tool with a hammer. That loosed up the piston, and I was able to turn that one into the caliper without a cheater.

 

[Fly Navy]

Had the same problem as "master". The problem is easily Solved. I had to back the puck in all the way making sure i turned it the same number of turns. This sets the baseline for your brakes. I did not do for the left rear. The wheel would turn easily, but the very slight drag would heat the disk
excessively!