All that work without bleeding the brakes all around?? Are you 100% sure it's the brake caliper?

 

Should have mentioned, did bled the brakes both times the caliper was changed. Not looking like it’s the caliper or the hose.

 

Okay...how are you determining there is excessive heat??

 

I keep an IR thermometer in the truck and take readings after various periods of time on the road. Generally if the temp on the driver side front rotor is around 50C the passenger side will be at 90 - 100C. On a long trip I’ve seen it up to around 150C on the passenger side with the driver side staying between 50 - 70. The rear rotors are both consistent and a good bit lower, which makes sense since there is less braking on the rear wheels. About half the time there is also a burnt smell during the trip when you stop for a light or stop sign and there is a bit of a draft from behind.

 

When you step on the brakes does the truck pull one way or the other? Please put that IR gauge away. I bet your a RVer. Those guys are the worst. I tow with mine 34' 5th wheel and I worried all the time about tire this brakes that not enough truck for this as well. I got tired of the crap from some of those guys. I have towed over 35,000 miles with my truck and still on the stock brakes. 15 F250. Those guys took all the fun out of RVing.

 

Well it could be the caliper dragging....but if there's a problem after changing the caliper then there's another problem to resolve. I'd consider using a Ford dealership to do the troubleshooting.

 

That’s what I was thinking, thanks!

 

LOL, we found the IR gun to be a great tool when visiting bus and trucking companies to address brake issues. It's not an unuseful tool. Vehicle tests had thermocouples embedded into the brake pads; no need for a gun.

Temp or dust can be a good tell of a dragging brake. However, just because it's a new caliper doesn't mean it is free of issues, especially if it's a rebuilt caliper.

Brake drag can be caliper pistons, caliper slides, pads not freely moving in the brackets, hose constriction (internal tear or twisted), or ABS valve hangup, usually in that order. It can also be excessive rotor runout or wheel bearing wear. The master cylinder is two-channel, so any issue there would affect both brakes on a Superduty axle.

When we had to solve a dragging brake issue professionally, it would involve a forensic disassembly. So it didn't matter if we only had 200 miles on a test rebuild. If a test showed a 100ºF disparity between the brakes on one axle, we would do that. Just make sure you are measuring the rotors at the same location. Rotors typically run hotter than the brake pads.

Open the bleeder to see if there is trapped pressure (Hose or ABS valve)​

Remove the caliper and check each piston for freedom of movement going back in​

Check the slide pins for freedom of movement​

Check freedom of movement of the pads in the brackets​

Measure the pad to see if there is tapered wear (can indicate piston or slide​

An ABS failure we never had in 25 years of testing.

With aftermarket pads, probably 25% of the time, we had to adjust the end clearance of the pads due to excessive paint or tolerance to the steelback. The aftermarket buys cheaper steelbacks and has +/- specs, whereas the OE has -/+0 specs.

 

Wow! Thanks for the incredibly detailed and helpful feedback! Glad to be able to rule of the master cylinder and ABS, and start following up on this with the garage next week.

 

Not ruling out the ABS, but it would be rare.

There should be about a 0.010" gap between the pads and rotor, at least when relatively new. The age and heat exposure to the calipers change that amount; the o-rings that pull the pistons back lose their resilience over time. Caliper slides with hysteresis can keep the outer pad against the rotor even if the pistons roll back appropriately.

This simple check is the easiest way to check for pads dragging on the rotors. I posted this a long time ago when this type of discussion occurred before.

The 1999-2004 brake caliper design from Akebono did not have the robust brake pad push-back that the later design TRW has, and this is how mine was based on the mileage noted in the description, a 2003 truck. 75k miles on calipers, 30k miles on pads.

 

If your brakes are dragging you would smell them. If they were getting hot then you would see hot spots on the rotor. Another thing is excessive dust on one wheel over another. Are there groves in the rotor?
I get it that a heat gun is a useful took. I use one in the kitchen LOL. I don't carry one in my truck.

 

Not necessarily either. Hot spotting occurs in the 1,000ºF region.

Very dependent on the quality of the brake pads and the curing stage during manufacturing.

• 550°F - 650°F
  Brake resin odor is present
• 850°F
  Brakes begin to smoke

So to have those, the OP had to have a severe dragging issue. Which you may not catch by the time you stop and get to where you can take all four brake temps.



Houston, we have a problem. The driver noted brake pulls by the end of the day, and he knew what was happening with a thermocouple in each outer brake pad. At the 100ºF threshold, you start to feel brake pulls due to the differential in friction coefficient side to side, especially with a Superduty with its high scrub radius.

AKA, 40 mph our two-lane road with traffic lights.

Two issues were noted during overtime after day 1. First, two of the brand new (OE) calipers had some resistance when first pushing the pistons back into the caliper body. Exercising them back and forth with pedal pushes then retraction helped with this. Over the years, this occasionally happens when the calipers sit on the shelf and the rubber o-ring adheres to the piston. The second issue was the pads had slight interference in the brackets, as I'm mentioned earlier. That we could not address due to the "test." But over the course of the test, you can see imbalance improving with wear-in of the steelback tabs.