Yesterday I had my front brake pads and callipers replaced and both rotors machined. (1/4 ton van BTW)
Today I drove for about an hour and a half from one town to another. Upon arriving and getting out, there was a distinct smell of burnt brakes. Both front brakes appeared to be smoking (steaming?) a little. I felt the outside of the wheel hubs near the brake vents and they were very hot. I was not riding the brakes during my trip and I was not pulling a trailer.
A friend has just told me that sometimes when the brake pads are replaced that the new pads actually are in constant contact with the rotors for the first little while until they wear down a little (producing the heat and smell). This sounds like a plausable explanation to me but then again IANA mechanic.
I expect that there are mechanics on these boards who can confirm this theory or provide another explanation.
I’ve recently had new brake pads put on my car and though I haven’t witnessed any steaming, I do hear some strange noises. My SO who works in the auto industry says it is true that sometimes the pads rub up against the rotors and until they wear down I will hear that noise.
In addition to the increased tolerances, you almost certainly have self adjusting calipers, which you have to reset by pushing the pistons all the way back into the caliper. If they weren’t pushed back in the whole way, that might also be part of the problem.
OK disc brake 101 here.
The pistons have to be fully retracted into the calipers or the new pads won’t fit between the calipers piston and the rotor. Since the pads were installed, ergo the pistons were pushed back far enough. Ya can’t put a two inch pad into a 1 inch space.
Disc pads run at a very very tiny clearance from the rotor. When you step on the brake, the pison pushes forward, the seal distorts slightly and the pads press against the rotor. When you remove your foot off the brake, the seal returns to its normal shape and the pads retract slightly. I have never seen a spec for pad to rotor clearance, but I would guess about .004" or so.
Getting back to the OP.
Sometimes new pads do smell the first time they get hot. If you drive again and it happens then I would take the car back and have it inspected. If the pads are hot and you have NOT been riding the brakes, or using your left foot on the brake pedal, I suspect that There is an issue with either the caliper slider mechanism (if equipped with sliding calipers) or there may be a front wheel bearing issue.
OK disc brake 101 here.
The pistons have to be fully retracted into the calipers or the new pads won’t fit between the calipers piston and the rotor. Since the pads were installed, ergo the pistons were pushed back far enough. Ya can’t put a two inch pad into a 1 inch space.
Disc pads run at a very very tiny clearance from the rotor. When you step on the brake, the pison pushes forward, the seal distorts slightly and the pads press against the rotor. When you remove your foot off the brake, the seal returns to its normal shape and the pads retract slightly. I have never seen a spec for pad to rotor clearance, but I would guess about .004" or so.
Getting back to the OP.
Sometimes new pads do smell the first time they get hot. If you drive again and it happens then I would take the car back and have it inspected. If the pads are hot and you have NOT been riding the brakes, or using your left foot on the brake pedal, I suspect that There is an issue with either the caliper slider mechanism (if equipped with sliding calipers) or there may be a front wheel bearing issue.
I do a fair number of brake jobs and don’t recall ever noticing, or having a customer relate noticing, smoke or a burning smell. I don’t think it’s normal. What you describe sounds like the pads were dragging on the rotors. Unless the new pads were thicker than they should have been to the point where they had to be forced into place (which is extremely unlikely), they shouldn’t drag.
Old or new, the pads are in constant “kissing” contact with the rotors. This is why disc brakes, unlike drum brakes, are essentially unaffected by going through water–the pads wipe it right off the disc (rotor). If you spin the wheel, you can hear the slight swishing sound this causes (retract the piston and move the pads away from the rotors and you then won’t hear it). But there is not any PRESSURE applied if the calipers and caliper slides are working properly, and there should be no smoke, burning smell, or excessive heat.
Although I wouldn’t rule out new pads possibly having some smoke or odor while breaking in, I would think an hour and a half drive would be way more than enough for that to cease. Sounds to me like a problem with the calipers and/or caliper slides.