General brake question: is it a sign of stuck slide pins if both pads on the rear LH are thin but the same thickness (and both are thicker than the RH side)? Or does that point to the caliper piston sticking? In other words, I always thought evidence of sticky slide pins was when one pad is thicker than the other but if both pads are thin then the caliper is sticking. Thanks in advance.

 

Since these 2 conditions aren't that difficult to verify, I'm not sure I'd hang my hat on the pad wear as the true indicator. Pull the caliper off and if you can move the slides with your hands, they're fine. If they're tight or sluggish, pull them out and clean/grease them. If they're frozen, get a new caliper/mounting bracket. While the caliper is off, try to move the piston. If it's one that has a built-in e-brake mechanism, spin it with the appropriate tool. If it's purely hydraulic, try to compress it with a tool or pliers. If using pliers, put a brake pad on top to protect the piston surface. Make sure you crack the bleeder before you do this.

One 3rd option is sometimes as rubber brake hoses age, they can collapse inside. Brake pedal force is enough to push fluid towards the caliper, but the square-cut o-ring in the caliper doesn't offer enough return-force to send fluid back through the constriction, so the bad hose winds up acting like a check valve. If your slides and caliper test good, put a hose on it. If you're doing the work yourself, worst case scenario is you're out 20-30 bucks for the hose, 10 bucks for the brake fluid, and you're in the same situation. Seems likely the issue is one of those 3 things though.

 

Thanks for that input Matt.

Over the weekend the left rear brake started making noise so I pulled over to inspect it and discovered it was extremely hot. I got it home and removed the rear wheel and caliper and discovered that the brake pads were both down to about 1/16" inch but they were the same thickness. I pressed the caliper back in and the piston had a little resistance but not too much. I did the same thing to the RH side to compare and that caliper went in easily but pretty much the same. The RH pads are very thick because I installed front and rear OEM pads and rotors about one year ago. The slide pins on both sides were basically stuck but I could push them in after a fair amount of effort to get them unstuck. I regreased them when I did the brake job but apparently the grease dried out (I'm kicking myself now for not using silicone grease). I'm leaning towards the slide pins being the culprit because the car has been well maintained, spent most of it's life virtually salt free and had brake fluid flushed on a regular basis.

For some reason, though, I had it in my mind that if both pads are thin BUT EVEN then it's probably not the slide pins...but thinking through that now I don't think that makes any sense.

 

Sticky slide pins are another item that can be overcome by brake pedal effort, but not returned to "rest" by the resiliency of the square cut o-ring in the caliper. If the pins are sticky enough to move with the brake pedal, but not "rebound" upon release, the inner and outer pad could still be applied evenly and then left to wear against the rotor. One thing to consider is that once the pins are all gunked and seized up within the pad hangers, cleaning only the pins may not fully alleviate the issue. The pad hangers are still full of dried up goo and sometimes rust (if that played a role in firming up the pin motion). When I worked at the dealership and would come across seized pins, I'd work them free, remove any lube with brake cleaner, and then gently hit them with a wire wheel on a bench grinder. After that I'd hit the pin bores with brake cleaner and wipe them dry with a rag, and then I'd follow up with a cylindrical wire brush. After I scrubbed them out, I'd brake clean them again and dry them with a rag again or blow them out with compressed air. If you only addressed the pins and not the bores in the pad hanger, it's possible there's still enough friction there to restrict movement.

And yes, best to use a legit brake caliper lube for the pins. Anti-seize works too, and I've used it plenty of times, but my favorite is the Permatex stuff in the white bottle with a red label. The blue label bottle is much cheaper, and still better than anti-seize. If you don't do brake jobs for a living, of course, you can just get the little foil packs your local PepBoys or Advance sells for like a dollar each. It's still legit caliper lube, just at a quantity that a normal person would use.

 

Matt, thanks for your detailed response. That's pretty much what I was fishing for and now I have good info to use to make a plan and move forward. 👍

Your procedure above is very thorough and is normally what I do including using the cylindrical brush. However, I did the brakes at my brother's house because it was in the middle of winter 2022 and my brother has a heated garage. We were also running out of time and I "had" to get it back together and we all know what happens when we get in a hurry. Yesterday I referenced my notes and it appears that I didn't clean the caliper brackets (which I normally do) but rather just relubed the pins and kept moving forward. I think that's what came back to bite me. Thinking about it a little more this morning, this Saturday I'm going to quickly free up the slide pins then reassemble and test drive. If the heat goes away then I'll assume the caliper is good and then I'll disassemble, redo the rears with new pads (picked them up yesterday) and will also fully clean out the caliper brackets and use a different lubricant than last time. I'll probably also redo the front caliper brackets the same way. I agree 100% about the pad hangers and will clean them out too. For lube, I normally use silicone grease or Sil-Glyde but this time I used the black CRC brake caliper grease on the pins. That gets dry over time and I should have stuck with silicone on the pins and used the black CRC only on the back of the pads to dampen vibration. I tried searching for your recommended caliper pin grease...would you mind sending a link? What is the difference between the red label and blue label?

 

Quick update: the caliper was the culprit. I came to this conclusion after using a small channel locks to push the piston back into the caliper body and felt the resistance. I did this on the LH and RH sides and on the RH side (the good side) I could easily squeeze the piston back into the caliper using one hand on the channel locks. On the LH side (the bad side) it took two hands. I intentionally used a smaller channel locks to limit the leverage so I could get a good "feel". I reconditioned both rotors with 60 grit sandpaper (the LH rotor was blue from heat) on my DA sander so hopefully the new pads will seat well. I also went through each caliper bracket (front and rear), cleaned out the black CRC brake grease I used previously from the slide pin bores and used silicone grease on the pins. Just for kicks, I did the channel lock test on the front calipers and they are both the same and both a little difficult to push back in so I might be replacing them in the future. Now I'm wondering if my brake fluid (rated Dot 3 & 4) might possibly be swelling the caliper seals. Thank-you again to everyone for responding to this post.

 

Sorry for the delay. Been a pretty busy week! I think the only difference between the 2 permatex products is the heat tolerance (probably based on ingredients/chemical makeup), though I'd have to do some product research to be sure. For general daily driving purposes, I'm sure either would be more than sufficient.

I'm glad you figured out the issue! Many more miles ahead for this CR-V I'm sure. I would doubt the DOT fluid would be swelling your seals. All brake fluid I've ever seen for sale meet DOT specification of one level or another, and DOT5 is the only one that really differs substantially in formula. Given that they all meet DOT rating, they'll all be safe for DOT brake systems (again, DOT 5 being the exception).

The most common cause for a locked up caliper is just the formation of rust and pitting between the caliper piston, and the bore that it rides in. This can happen quickly when fluid is neglected, but even well cared for stuff isn't immune to time. If it is in fact the piston/bore interface that's causing the issue, it'll probably occur again as you continue to drive since even though you got the piston moving, the surface imperfections are all still there. If you find it dragging again, I would suggest just replacing the caliper. They aren't too terribly expensive, and doing so will give you the opportunity to flush your brake system. Then you know you'll have fresh fluid throughout.

 

No worries Matt, I've been swamped too. I'm curious, so as soon as I get some free time on a Saturday I'm going to disassemble the calipers to inspect for rust in the bore. I replaced both rear calipers so I (hopefully) shouldn't see this issue again. I am also going to look into the Permatex caliper pin lubricant that you mentioned.