Acura MDX front rotor glazing

[Hokiefyd]

When we first got our MDX a few years ago, I put new pads on all around (with OEM Advics and Nissin pads). I also put new front rotors on, which are ProStop brand. I liked these particular ones because they had a nice coating on the hat area of the rotor (which still hasn't corroded away).

Anyway, this car will glaze the front rotors repeatedly when the weather gets hot. There's a visible stripe on each front rotor near the middle of the pad contact area. I've removed them twice now and had them turned and the problem is gone for a few weeks, but the stripe will eventually come back. This happens every summer when the weather gets hot, and it's about that time of year again. When I was driving it the other day, I could feel the front brakes start to "grind" on a long downhill stop (that's the symptom they give when they've begun to glaze over).

I've read discussions on here that brake problems that are often perceived to be rotor problems are really pad problems. I have an open mind about this, but do submit that the only non-OEM parts of the braking system are the front rotors, and these are the only items that *appear* to have problems. I'm certainly open to the fact that the pads could be dodgy and could be glazing the rotors or depositing some bad material onto the rotors.

If this were your car, what would your first move be? My plan is to replace the pads and have the rotors turned once again. Sound good? Should I replace the rotors also? I don't want to spend the money on replacement rotors if I don't have to; I have other jobs coming up on this car this summer, like new spark plugs and a timing belt change.

Cheers,
Jason

 

[SteveSRT8]

My first question would be are these multi piston calipers?

Usually when I get glazing it's the pads not the rotors. The pad gets too hot and the material gets glass-like and starts making noise and vibration. A stripe that is smaller than the swept area means something is wrong in the clamping force distribution in the caliper/pad.

I would also note that on my trucks even if I buy Genuine GM parts they are NOT the same pads as the truck shipped with.

If the rotors are still thick enough via measurement then you can turn them again, but repetition of the same process will likely yield the same results!

 

[Andy636]

Just my .02 but why spending money on resurfacing the rotors when you can do it yourself with a wire brush or some sandpaper?

 

[Hokiefyd]

The front calipers are dual piston calipers, but they still are sliding calipers. The stripes are different on either side. The passenger side has a nearly 1" wide stripe around the circumference of the rotor, nearly centered in the pad contact area. The driver side has somewhat of a split stripe around the circumference of the rotor. It's still about an inch wide, but seems to be split into two separate striped areas. I believe this may be pad material being deposited onto the rotor, but I'm not sure. The rotor surface DOES feel different on these stripes, almost lubricated slick instead of a "dull smooth" that the rest of the rotor feels like. Hard to describe.

My gut feeling is the stripes that I'm seeing are pad material being deposited onto the rotor in a very uneven fashion. Is this likely a defect in the pads themselves? Or is this likely a defect in the metallurgy of the rotors, making the contact surface of the rotor heat unevenly?

The reason I would have the rotors turned is it's not worth my time to clean them myself. For 10 bucks/rotor, I can have them turned by a local garage. The stripes on the rotor, whatever they are, are thick enough that it would take me a long time to fully remove it, if I could remove it at all by hand.

I will attempt to photograph the stripes and post them here this evening.

 

[Hokiefyd]

Here are some pictures of the glazing or pad deposits on the rotors. The first two are of the front passenger wheel, with the flash on and off. The third is of the front driver wheel. The third picture appears to show some uneven brake dusting on the wheel, but that's just an artifact of the light.

I described the driver side wheel pattern as somewhat of a "split stripe" about an inch wide, and that's what it was last time. Apparently, the pattern is a little tighter this time, but still in that same vein. The patterns are not exactly the same each time I have the problem, oddly.

What do you all think I have going on here?

 

[mechtech2]

You said the pads are a few years old.
I'd get new ones and of course roughen up the old rotors to help seat things quicker.
Get premium pads, to be sure.

This is what I would do if it was my own car, but unfortunately I can not promise a fix.
If you have to dig deeper, then it's rotors or calipers.

 

[The Critic]

I see those on a lot of cars, I probably would not worry about it until the pad deposits turn into a shudder.

Also, the Beck/Arnley Nissin pads you purchased were made by the same supplier, but may or may not be the exact same pad.

Lastly, you may want to check the pad retainer clips to make sure they are squeaky clean. If there is gunk on them the pads may not slide properly. Lubricating the slide pins with a high-silicone content grease (such as Motorcraft XG3A) may be a good idea.

 

[Hokiefyd]

Thanks. I just ordered a set of Akebono Ultra Premium Ceramics from Advance Auto Parts. Order code PRE4 on orders over $50 saves 20%. Got 'em for $65.90 with tax. Will hopefully install them tomorrow, if I can brave the insane heat and humidity. They're calling for the highest recorded temperature ever tomorrow here in central North Carolina.

 

[Hokiefyd]

Brakes fixed, at least so far. The old pads were glazed pretty smooth. There was definitely some caliper sticking on the passenger side. One of the sliding pins was very sticky, and wasn't moving much at all. I had to work it loose, and work plenty of fresh lube through it. I then cleaned the bore out well and applied a nice consistent layer of lube on the pin and it slides nice now.

Pictures of glaze on the rotors, new pads, and finished job below.

 

[The Critic]

It sounds to me, like the sticky pin was the cause of your problem.

How/what did you use to clean out the bore, and how did you prevent the fresh lube from accumulating inside the rubber boot (and not reaching the bore) while reinserting the greased pin?

I just bought a tube of Motorcraft XG-3-A silicone paste as I understand this is the preferred type of slide-pin lube by OEMs. It is supposed to be longer lasting than the OTC permatex and CRC offerings.

 

[Hokiefyd]

Good questions. I used a small wooden dowel to clean out the bores in the caliper mounts. There wasn't much in there, so not much came out. I took the boots off the mounts, then lubed and inserted the pins to lube the bores. I got them sliding nice before taking them back out, reinstalling the boots, then inserting again. So far, they slide nice. I will check again next time I rotate the tires, which will be in 3,100 miles.

 

[mechtech2]

Pads and rotors are supposed to be smooth - glazed.

 

[DuckRyder]

My experience with Hondas/Acuras is that factory pads are best for street duty... Incidentally they are probably also cheaper (~57.00) and come with the requisite shims and silencers.

Hopefully this fixed you up, but if not give the Acura Pads a try...

 

[Hokiefyd]

The previous pads were Advics, which are supposed to be the OEM pads. If not the factory pads, at least what comes in the Acura box at the parts counter. Oh well. So far, so good. I'll certainly have to wait a few hundred or a thousand miles, after a good amount of pad material has transferred to the rotors, to make any sort of conclusion.

 

[The Critic]

Originally Posted By: Hokiefyd
Good questions. I used a small wooden dowel to clean out the bores in the caliper mounts. There wasn't much in there, so not much came out. I took the boots off the mounts, then lubed and inserted the pins to lube the bores. I got them sliding nice before taking them back out, reinstalling the boots, then inserting again. So far, they slide nice. I will check again next time I rotate the tires, which will be in 3,100 miles.


That sounds like a good strategy, as opposed to use a brush. What lube did you use? My understanding is that some of the synthetic caliper lubes dry out, which is why OEMs typically recommend a high silicone type lube.

 

[mechanicx]

It looks like the Akebonos came with caliper pin grease. It maybe M-77. Did you use the grease they came with the pads? It's probably decent stuff.

 

[The Critic]

Originally Posted By: mechanicx
It looks like the Akebonos came with caliper pin grease. It maybe M-77. Did you use the grease they came with the pads? It's probably decent stuff.

NO!

It has been reported many times that Molykote M77 will cause pins to seize up over time when it dries out. Overtime, M77 becomes a sticky, dry paste - which is why it is best for metal-to-metal surfaces such as shims.

Honda specifies in the FSM, to use Honda silicone grease on the caliper slide pins. M77 is to only be used for the metal-to-metal areas: shims and pad ears.

 

[Hokiefyd]

The Akebonos came with a super-small envelope of grease. It appeared to be very dark, almost metallic-like (a graphite appearance), and not very viscous. I used that on the ears of the pads themselves, where they slid in the clips in the caliper mounts.

On the pins themselves, I use a small thing of Permatex ceramic-based lube. It was in a small purple envelope.

Permatex Ceramic Extreme Brake Parts Lubricant

 

[mechanicx]

My mistake you're right about no molykote on the pins. That packet looked like molykote. I haven't used the packet of molycote on pins because I use a bottle CRC silicone.

I wonder though if the problems with synthetic caliper pin geasing drying out might be because of a compatibility issue with the OE silicone grease that wasn;t cleaned out?

 

[mechanicx]

I think on this application the upper caliper pin has a bushing and is different from the lower pin.