Rear Brakes Rubbing

[MidwestT4R]

Had a problem with my parking brake a few days ago. Posted here. Got some feedback and fixed it.

But while it was all apart I noticed the regular brake pads were worn so I replaced them. But when I pulled off the wheel on the other side I found that the caliper was frozen. Needless to say the rotor didn't look so good and I have been getting some pulsing so I went back to the parts store to get rotors and calipers.

I've done this type of work before on all my cars so I wasn't particularly concerned. There was only one listing for rear calipers in the Autozone system (as compared to the front where you have to figure out what casting you have) and one listing for rotor size. When I got home I pulled the bad caliper and compared it to the new one just to make sure. Looked the same

But after lubing everything up, putting in new stainless steel shims in, putting the rubber boots on the caliper, and then assembling it all I took it for a test drive.

No more shimmy, nice smooth braking, but when I got home there was a distinct hot brake smell coming off both wheels. I did clean the rotors with brake cleaner so I doubt it was residue on the rotors.

I took a couple of longer drives and when I got back both times there was a thin haze of smoke coming off both rear wheels. I would also add that it seemed to me that the truck was slowing a little faster on it's own when I was coasting but that is just a seat of the pants observation.

So I pulled on wheel apart again to check.

- No rubbing from the SS shims. They were clear.
- Caliper bolts slid in easily when the caliper was placed over the pads.
- The pads are the right ones because they were replaced under a lifetime warranty from Autozone as I have replaced these pads once before. The guy pulled my history and pulled the same brake pads I bought before. Ceramic with a lifetime warranty.
- All bolts torqued to toyota specs.
- I did a visual comparison of the new vs. old rotors before installation and they looked exactly the same.
- I did not put the caliper bolts (new vs. old) side by side but they fit just fine.
- Bled both calipers with a buddies help. Nothing new here.
- When you screw in the brake line into the new calipers you bet a bit of brake fluid on them, but not a lot. There is no leaking at that connection as I checked it repeatedly. Even after a test drive.

Maybe I'm making a mountain out of a molehill on this, but the new calipers fit very easily over the new pads and I can't recall ever experiencing this with any other brake jobs I have completed, even the front full rebuild (both calipers frozen) that I did on this truck about three years ago. No smoke. Keep in mind it wasn't a lot, but you could still see it.

I have the old calipers bolts and will pull a wheel just to compare them to the new ones. I doubt this is the issue, but who knows. Maybe there isn't an issue.

Anyone else experience this? Is it the ceramic brake material seating? This truck is the first one I have ever used ceramic brake pads on. Any other suggestions on what to check? Or should I just drive the truck for a week and then revisit if I still get some smoke?

 

[ChaosStarter]

On the sliding pins that slide into the caliper mounting bracket from the caliper itself, how much lube did you use? I've seen that if you use too much, it's possible that it will actually lock the caliper up because you can't compress the lube. You can tell when this happens when you tighten up the caliper bracket mounting bolts, and the caliper pin boltss to spec, and that you won't be able to physically spin the rotor/axle. This is basically locking the pads up and when you drive it around, it will drag the pads around giving off dust, noise, smells, and 'hazey smoke' or what not.

If you then loosen your caliper pin bolts, and you can spin the rotor/axle, you know it's in the caliper pin part of the caliper. Remove some of the lube, and retighten the pins. You should be able to spin the rotor/axle fairly easily when everything is tightened up. Also, if the caliper piston is fully depressed into the caliper housing, you should be able to move the caliper back and forth over the pads with everything tightened up.



*not say this is your problem, just something i've noticed over the years and worth checking out. And I've only seen it if I used a little too much on rear calipers. Never have really seen this on the fronts ever.


*1 more thing: Those little ruber insulators on the caliper slide pins (1 per caliper), sometimes they'll also give you trouble. They're there manly for vibrations and tiny noises, but the system will work fine without them without any noises or issues that I've ever seen. Just add a little extra lube to make up for the lack of the insulator. They get old and brittle over time and can screw ya up.

 

[MidwestT4R]

Thanks. I wondered the same thing. This is the rear calipers, not the front. One thing I did not do is try to insert the caliper pin into the caliper while it is off the caliper mount. This would probably give a good indication if what you described is happening. If I have to really force it in and it pops out when I let go then there is probably too much lubricant.

I used to spin the rotors after reassembly on other cars I have owned but my V8 runner is full time 4wd and I don't have a way to lift all four wheels in the air in my driveway. I'm probably going to take another look at the rubber inserts, but as these are brand new calipers I would prefer to make it work with them in.

One last note: After I posted this note I thought about how three years ago I did the same complete rebuild of the front brakes on the truck with new rotors, calipers, and pads. I did the job at my buddy's house about an hour away because he has a lift in his garage that lifts the entire truck up about three feet. Perfect for sitting on a chair and working on the brakes. I do remember spinning the tires after the work as I had the truck in neutral. They spun fine.

But now I recall that on the one hour drive home I noticed the same smell and yes, a bit of smoke. Not much just wisps of it. I just ended up driving the rest of the way home hoping it was nothing serious. By the time I got home it had stopped.

I wonder if it just had to condition the surface of the pad and in the time it took three years ago to drive home it did so. If wouldn't be the caliper pins because the front calipers are not floating calipers. Or maybe if the autozone rotors have so much oil protectant on them then even if you try to clean them you have it in the ventilation holes and such so it just burns off as the brakes heat up and over time it dissipates. The front brakes today are still good with no warping on the rotors and about half the life on the pad left. Both front and back pads are Autozone Ceramic Pads with a lifetime warranty.

Anyway, I'll give it a try when I get back home in a couple of days. If they seem to float nice and easy then maybe just drive it around a few days to see if it stops like it did on the front brakes.

 

[ChaosStarter]

Yea, the issue I was describing was just for the rear brakes. It's possible that it was just the new pads/rotors bedding in, but they shouldn't be smoking/hazing at all. I'm not sure how Autozone pads break-in since I've never used them, but I know when you properly bed-in the OEM pads/rotors, you don't usually get any kind of smells (unless you're an ******* who break-in pads by going 50mph-0mph-50mph-0mph).

Also, make sure none of the rubber (um... cushions?) or plugs or whatever the hell they're called on the caliper brackets themselves haven't popped out when you installed the caliper slider pins. I've seen that happen with too much lube as well. You go to install the slider pins, and it shoots those little rubber plugs at the end of the caliper slider pin slot out at 30mph.

 

[TechWrench]

One more thing to check. Did you replace, or get new brake pad slider clips for the calipers. I am talking about the small metal clips that fit in the caliper slots that the top and bottom tabs of the pad fit into. If these are installed correctly, you should be able to move the pads in and out (with piston fully retracted) fairly easily. If the pads bind at all in these clips, then they will not relax properly when the pedal is released and rub on the rotors.

 

[MidwestT4R]

Good suggestion. The brake pad kit came with a complete new set of the stainless steel clips. After the first drive where I noticed some wisps of smoke I pulled the wheel (after is cooled down) and then pulled the caliper so I could check them. All of them were nice and tight on the top and bottom of the caliper bracket. The pads also went in nice and easy into each of them. Sure, you have to maneuver them a bit to the pad into the bracket but once you get the inside front edge in the brake pad tabs just popped into the bracket. No forcing necessary. Nothing is really ever specified but I put a light coating of lube on the brake pad tabs before putting them into the bracket.

I'll check them again when I get back tomorrow. The more suggestions I get the more I keep coming back to the possibility that the brake rotors were heavily sprayed with protectant oil. I cleaned the surfaces where the brake pads contact and the inside area where the parking brake goes, but how do you clean out the ventilation ports on the disk? Maybe this particular manufacturer loads it up and what happens it the disk rotor gets hot and it all smoke/burns off.

We'll see. Tomorrow I'll be pulling both sides and checking the ability of the caliper pins to move easily in and out and also the SS shims again to see if the pads move freely.

 

[TechWrench]

Good suggestion. The brake pad kit came with a complete new set of the stainless steel clips. After the first drive where I noticed some wisps of smoke I pulled the wheel (after is cooled down) and then pulled the caliper so I could check them. All of them were nice and tight on the top and bottom of the caliper bracket. The pads also went in nice and easy into each of them. Sure, you have to maneuver them a bit to the pad into the bracket but once you get the inside front edge in the brake pad tabs just popped into the bracket. No forcing necessary. Nothing is really ever specified but I put a light coating of lube on the brake pad tabs before putting them into the bracket.

I'll check them again when I get back tomorrow. The more suggestions I get the more I keep coming back to the possibility that the brake rotors were heavily sprayed with protectant oil. I cleaned the surfaces where the brake pads contact and the inside area where the parking brake goes, but how do you clean out the ventilation ports on the disk? Maybe this particular manufacturer loads it up and what happens it the disk rotor gets hot and it all smoke/burns off.

We'll see. Tomorrow I'll be pulling both sides and checking the ability of the caliper pins to move easily in and out and also the SS shims again to see if the pads move freely.

If you cleaned all the shipping grease from the rotor contact surfaces, you should be good in that area. I use a spray brake cleaner on new rotors. It cuts the grease, and dries quickly. If they got some of the grease on the inside surfaces of the rotor, then it could just be that burning off, and it should stop after a day or two.

 

[MidwestT4R]

UPDATE:

Finally got outside to check the rear brakes. I found two issues. First, the stainless steel shim kit that came with the brake pads from Autozone were slightly different than the shims from Toyota. I had a spare OEM set sitting in my work room and compared them. So I put the OEM on both sides. The inner pad on the driver side was also a little stiff in the caliper frame. I had to wire brush the frame to get every last bit of rust and old grease out of the spot where the shim goes to get the shim to sit flush. This made the pads on both sides move easily in their holder.

But the biggest issue was the rubber bushings on the calipers. One of them is just a collar that fits into one of the caliper pin holes on the actual brake caliper. The other one is an entire sleeve of rubber that has to be pushed through the hole in the caliper. I am not familiar with the OEM calipers. Maybe it's already installed, but on the Autozone calipers you had to put it in yourself.

On the passenger side the rubber sleeve that fits through the caliper had a hitch in it. I didn't feel it pushing the pin in the other day but when I tried to pull it out today it was really hard. Like it was stuck. So I ended up pulling the sleeve entirely out and cleaning out the bore in the caliper with a brass brush. Then pushed the rubber sleeve back through. A light coat of lube on the pin and it slid in and out much easier.

Put it all back together and went for an extended test drive. Got home. No rubbing. No brake smell. No smoke.

Lessons learned?

- Even though the surface might look clean you should probably wire brush all original parts like the caliper frame, especially where new shims go. If your car is more than a few years old it probably has some rust or old grease that needs to be removed.
- If you get remanufactured calipers you should not assume that everything is nice and clean, especially where bolts go through.
- Insert the caliper pins and always pull them in and out a few times before tightening down just to make sure that that they move free and easy.
- After inserting the pads try and move them around a bit to see how easy they move in their space. They should be fairly easy to move in and out. If they aren't take another look at the SS Shims and the area on the caliper frame where the shims go. You might need to clean it up again.

And maybe the biggest lesson. Don't rush. Even if you do these jobs all time you still need to watch the details. Nine times out of ten you might not have an issue. But I sure wasted some time on some stupid fixes because I wanted to go do other things besides sweating like a dog in my driveway working on the brakes. Ten more minutes a side and I would have probably avoided these issues.

 

[aha2988]

glad you got it figured out I was thinking perhaps the rear emergency drum brake wasn't adjusted properly for the new rotors. Its always a good idea to clean part store parts with a good brake cleaner before use. just dirt from shelf life can cause issues depending application.

 

[ChaosStarter]

I had a feeling it had something to do with those rear caliper slide pins.