Well that went badly...Critical failure

[ArmedAviator]

I changed all four brake pads and rotors today. Three went flawlessly. The last one I tackled, the rear driver side, was problematic from the get go.

First, the lower slide pin would not come out. I had to beat on it after spraying some PB Blaster in the slide channel to free it. The rotor needed to be beat with a BFH as well. I cleaned the slide pin up real good of the dried on slide lube and reassembled. I cleaned the slide channels very well and of course used new brake grease.

Took it out for the test drive. Felt great. After 2 miles the rear driver side was smoking. Pulled off when I could and saw a BRIGHT RED rotor.

Well color me pissed and scared. It was probably very very very close to going up in flames. I had my roommate bring my tools and took it back apart on the side of a development side street. It appears that the upper slide pin with the rubber cap at the end had deformed. This was not the problem slide pin, though...

I have no idea of the rubber gasket on the end of the slide pin was the failure cause or a result of the failure (melted maybe)?

I removed the rubber gasket from the pin, reinstalled it after cleaning out the channel with some more brake lube and the brake was still seized! I limped it home very slowly and stopping often to cool it to get home.

My mechanic friend said that the failure can be with the caliper or with the hose. Ideas?

Either way, I'm going to need to replace the pads, rotor, and caliper. Any ways to test the failure mode of this to be certain?

I will upload pictures soon.

[Ilya]

Probably the caliper. If the slide pin was seized pre-work, my guess is the brake piston or whatever it's called was likely sticking already and finally gave out.

Did the piston go in easy when you pushed it in to fit the new pads?

[ArmedAviator]

The piston went in as easy as the rest. I opened the banjo bolt and used a C-clamp like the rest of the calipers. I probably didn't even need the clamp.

Does anybody know of any outlets that ship the calipers and hoses overnight? I need the car up and running ASAP.

[Ilya]

The piston went in as easy as the rest. I opened the banjo bolt and used a C-clamp like the rest of the calipers. I probably didn't even need the clamp.

Does anybody know of any outlets that ship the calipers and hoses overnight? I need the car up and running ASAP.

I'd call all the local parts stores and hope one of them can get you a caliper...no online place will get you one fast enough.

[ArmedAviator]

AutoZone has remanufactured Duralast calipers with the bracket for $70. They are not in stock locally but I'll go that route as going through Infiniti, they are upwards of $350.

Should I do both rear calipers at the same time so they're "even?"

[ArmedAviator]

Pictures of the failure are here. The picture quality is the best I could do being on the side of the road at night. I'll be taking it apart tomorrow in the garage. Please let me k ow how to diagnose the issue.

My main question is why did the pad wear so unevenly (visible in picture). I figure if the piston/hose was to blame than the pads would have been worn evenly.

Would this indicate slide pin issues? Would it indicate a bent caliper bracket (maybe from hammering the stuck slide out)?

I'm going to go to AZ tomorrow to order a caliper unless someone with knowledge has a different solution.

[Ilya]

Pictures are missing...

[ArmedAviator]

Whoops, forgot to hit CTRL+V haha.

Here they are

[BlackCat81]

Pictures of the failure are here. The picture quality is the best I could do being on the side of the road at night. I'll be taking it apart tomorrow in the garage. Please let me k ow how to diagnose the issue.

My main question is why did the pad wear so unevenly (visible in picture). I figure if the piston/hose was to blame than the pads would have been worn evenly.

Would this indicate slide pin issues? Would it indicate a bent caliper bracket (maybe from hammering the stuck slide out)?

I'm going to go to AZ tomorrow to order a caliper unless someone with knowledge has a different solution.

It's very common for the inner pad to wear faster than the outer, especially with a semi seized slide pin. For some reason, that's just how Infiniti pads tend to wear. I wouldn't worry about a bent bracket, unless you're the hulk. I always recommend people remove, clean, and lubricate the slide pins every 15k just because of that reason. It's also really important to make sure you get the rubber dust boot seated properly so it keeps the weather out.

[ArmedAviator]

The inner pad was worn unevenly like the outer (pictured) but not nearly as much. It seems most of the loading on the rotor was from the outer pad and both were worn at a significant angle.

The dust boots were seated.

The wear/failure seen in the pictures linked in my above post were taken with 2 miles of use.

[Altered]

That angled pad wear is really unusual, never seen that before... I would think they had to be seated properly when you installed them because otherwise the caliper would barely fit over them. Maybe the pad mounting shims had some defect as well. It definitely seems like a stuck caliper is the initial issue but the uneven wear on the new pads is tricky. Were the pads both worn more on the top or bottom? Or were they worn in a 'staggered' (one top/one bottom) orientation?

Regardless if it were me I'd go with a dealer caliper, pads rotor and shims. I know its easy to recommend when it someone else's money, but I don't trust OE "replacement" brands personally. Sad situation but at least you caught it relatively early.

[ArmedAviator]

I took both rears apart again to try to figure it out. I also ran a few trials/tests.

I believe that the original issue was caused by the insertion of the rubber gasketted slide pin had caught it and cut it causing the original deformation. This deformation cause the slide pin to stick just right but it would only be noticeable with the slide pin tightened down in the caliper. At that point, I would have noticed it if I had tried to spin the rotor.

This morning I had cleaned out the channels better than the side-of-the-road-repair. I had gotten a bit more rubber gunk out of the bottom of that channel. I re-assembled the brake WITHOUT LUBE (as a test) and it worked fine. No more sticking and the brake worked when the pedal was depressed and released correctly when pedal is let up.

The wear pattern makes sense for this scenario, too. The upper, and inner corner of the outer pad had significant wear. If that pin was not able to slide all the way in, the caliper would be forced to put pressure on that corner of the outer pad. The inner pad has a little wear, also uneven, but not nearly as bad as the outer.

Since the intense heat could have damaged the piston seal in the caliper, and who knows what else, I opted to replace the whole caliper (including slide pins, boots, gaskets, bracket). I tested the function of the hose and it seems fine. To order it through Rock Auto, it would have cost 3x as much to ship it next day than the cost of the hose. I also ordered new pad mounting hardware for both rears, new boots and gasket for the right rear, and new boots and gaskets for both fronts. I'm also going to switch to a different grease as online reading points to the Permatex green bottle that I've used causes rubber to swell. I'll find some silicone brake grease. Of course a new rotor and pads are also on their way as well.

The parts arrive Thursday and I will have that evening to try my best to fix it. Here's hoping it works out. I won't be able to test it until Friday evening when I'll be able to have a friend help bleed the caliper and follow behind me incase of more issues on the test drive.

I also hope the wheel bearing continues to hold up after being heated so much. The paint on the brake cover behind the rotor bubbled up and flaked off.

[Mjkkb2]

good detective work, looks like you're on the path to getting it behind you.

I will be tackling my sport brakes in the next month or two. Should the moral to this story be to spin the wheel/rotor before putting the rim on and bedding the pads?????

[ArmedAviator]

That is an excellent moral of the story. I'll always pump up the brakes and then try turning the rotor from now on. This will ensure the slide pins are sliding and the caliper piston rebounds properly to ensure proper clearance.

My parts should all arrive and be installed tomorrow. I'll update when complete. I will have to wait until Friday to bleed the caliper and test drive as I will need a partner in crime. This time I'll have a fire extinguisher with me....just in case.

[BlackCat81]

That is an excellent moral of the story. I'll always pump up the brakes and then try turning the rotor from now on. This will ensure the slide pins are sliding and the caliper piston rebounds properly to ensure proper clearance.

My parts should all arrive and be installed tomorrow. I'll update when complete. I will have to wait until Friday to bleed the caliper and test drive as I will need a partner in crime. This time I'll have a fire extinguisher with me....just in case.

You can bleed it yourself with one person. You can either put a piece of rubber hose through the top of a Gatorade bottle and run it down to the bottom of it. Put a little brake fluid in the container so the hose is submerged. The other end goes over the bleeder. Pump the brakes with the bleeder open. As long as the hose is submerged it won't suck air. You can also gravity bleed it by cracking the bleeder open and letting gravity do its thing for about 15 minutes or so. Done and done.

[BlackCat81]

good detective work, looks like you're on the path to getting it behind you.

I will be tackling my sport brakes in the next month or two. Should the moral to this story be to spin the wheel/rotor before putting the rim on and bedding the pads?????

Your sport brakes don't have slide pins, so as long as the Pistons retract, you're fine. I've also never seen a seized sport caliper. The single piston regular calipers are the ones with the issues.

[BlackCat81]

That angled pad wear is really unusual, never seen that before... I would think they had to be seated properly when you installed them because otherwise the caliper would barely fit over them. Maybe the pad mounting shims had some defect as well. It definitely seems like a stuck caliper is the initial issue but the uneven wear on the new pads is tricky. Were the pads both worn more on the top or bottom? Or were they worn in a 'staggered' (one top/one bottom) orientation?

Regardless if it were me I'd go with a dealer caliper, pads rotor and shims. I know its easy to recommend when it someone else's money, but I don't trust OE "replacement" brands personally. Sad situation but at least you caught it relatively early.

Dealer calipers are extremely expensive, and have a one year warranty. With the rear caliper issues that Infiniti has, your best bet is an aftermarket caliper for 1/3 the cost and a lifetime warranty. I agree with the rest though, Infinti pads and hardware only.

[Mjkkb2]

Info much appreciated. Thanks!

[EdBwoy]

good detective work, looks like you're on the path to getting it behind you.

I will be tackling my sport brakes in the next month or two. Should the moral to this story be to spin the wheel/rotor before putting the rim on and bedding the pads?????

Your sport brakes don't have slide pins, so as long as the Pistons retract, you're fine. I've also never seen a seized sport caliper. The single piston regular calipers are the ones with the issues.

Genuine curiosity here.
Could someone please take some pictures of the sport calipers if an oport unity presents itself.
If the brakes don't have slide pins, what controls the bracket's straight line motion and spring-back to disengage the pads?
Do the pads even sit on brackets or do they just clamp around the rotor like traditional bicycle brakes clamp on the bike rim?

[ArmedAviator]

They have pistons on both sides of the rotor.

[ArmedAviator]

Well the parts are here. I already have my front wheels and calipers off ready to install the new rubber parts boots and gasket on the slide pin. I want to be sure that on the front brake, the slide pin with the rubber gasket goes in the lower position. Is this correct?

On the rear, I am 99% confident that the rubber gasketted pin goes in the top position.

[ArmedAviator]

My parts arrived today! I relubed all caliper pins on all brakes using Sil-Glyde which was the most recommended to prevent rubber swelling. I replaced the bushing and boots on all 3 corners as well. The new caliper install was easy peasy. I ordered too many parts even, but doesn't hurt to have on hand.

Bled the caliper, dropped the car and rolled it to test for lockups. After that, I took it out on a very short trip around the block with the wi does down again. No issues. Took it to the gas station a mile past where I got off the main road last time. No problems. Did about 12 miles total.

I did not bed the brakes in yet but they already stop amazing. I'm happy with the results.

[Altered]

Well its good to see you appear to have it sorted out, I believe you are supposed to bed them first but at least nothing is locking now.

[ArmedAviator]

Yeah bedding is supposed to happen early on but I wasn't about to go ruin more parts without a thorough check of everything. Everything has been bedded now and works wonders.

And let me tell you that they grip HARD, especially when the engine downshifts and helps braking.....that extra vacuum on the brake booster is unexpected and kind of annoying when I don't want to stop that hard.