Hello all, I thought I would share something that I have never seen before and Lord knows I have seen some “SH*#”! out there…
I was diagnosing what seemed to be a failed front brake caliper on a 13’ Toyota Corrolla… It was a friends vehicle who had just recently had front brake pads and rotors installed about 2 months prior… It was presenting with all the symptoms of a failed or sticking front brake caliper. Sure enough the brake pads were new on one side…and within a day of being metal on metal on the other. The rotor showed heat damage coloration…no doubt about it…she was locking up.
Upon inspection the caliper piston moved quite well with no signs of an issue. The caliper slider pins however seemed very sluggish despite having grease on them. So I cleaned the slider pins and greased them using the correct brake grease. Seemed to move and slide properly after that… Until I let it sit for a minute or two then the sliders would seem to lock up on me again. I found that extremely strange and never saw anything like it before in all my experience with caliper sliders. I cleaned and greased them again…they moved fine…after 5 minutes…I couldn’t get the caliper to slide again… Which prompted me to exclaim “Gosh Golly Gee, what in the Heck is going on with these crazy darn sliders?”…or its equivalent in Garage Repair Speak. I cleaned and greased them a 3rd time…they seemed fine until a few minutes passed and then they locked up.
So I took this as a personal affront and simply HAD to understand what was going on here.
I removed the entire caliper and its bracket and put the bracket in a vise and went to work. I could finally see what was causing this strange condition… It was the rubber slider pin dust boots!!! Some dust boots fit over a collar on the caliper body…some dust boots fit INTO a hole on the caliper body… This vehicle uses the second variant. The hole in the caliper body swells over time due to rust and the diameter of said hole can become constricted thus squeezing the caliper pin much too tightly…so tight it squeezes the grease off the pin…or scours the grease off the pin… So I cleaned the internal caliper dust boot rim internally with a small Dremel wire wheel (Not the slider pin well itself, just the initial entry where the Dust Boot meets the caliper)… For good measure I also Hogged Out the rubbed boot itself. Seemed both adjustments were needed actually. PROBLEM SOLVED… No New Caliper Needed!!
I have NEVER seen this before and thought it would be good info to pass on. This could save you a lot of money if you own this vehicle. Toyota Brake Calipers are not known for locking up very often …especially in a 5 yr old vehicle with 60K miles !
So be aware…what may seem like a bad / locking up caliper VERY well may be the caliper pin dust boot constricting around the slider pin and becoming very hard to slide… Not sure if the actual problem is a too thick dust boot or a too small hole in the caliper for the dust boot…but over time they both seem to conspire to lock up the slider pin…
Boy Howdy… After seeing this I went and did the same adjustment to the other side as well… I noticed the slide action felt sluggish as well upon closer scrutiny. So it was not just one caliper presenting with these symptoms, one was a bit worse than the other…so…this may be prevalent out there…dunno. I did all this because the caliper piston was NOT the issue in any way…
Just something to be cognizant of I guess… I’ve honestly never seen this before… Either tolerance on the pin boot hole is too tight or the rubber boot too thick… Or Both… Cleaned the boot collar rim and hogged out the rubber as well and both seemed to be needed… A Dremel Tool is a must for this and works flawlessly. After this adjustment all is well with no signs of any problem whatsoever. I am CERTAIN a shop would say your calipers were bad and needed replacement, which would be costly. Problem solved…
Never had this problem on my 2012 Corolla. Just did a brake job and everything slide like it should. I always clean and put a little synthetic brake grease inside the rubber boot before inserting the newly lubricated pins.I never had a caliper stick on my car.Just make sure you clean the slider holes with brake cleaner and a shop towel before you insert the pins.
I hate to be the bearer of bad news, but you didn’t solve your problem. Close, but no banana.
Rubber will absorb grease over time as it deteriorates. It is rubber after all and it will deteriorate over time just like a timing belt or other rubber parts. You need new boots and the best way to get them is to get a brake hardware kit. It will have the rubber boots and the thin steel sliders for the ends of the pads along with other miscellaneous parts that will make the caliper like new. It will not have a new dust boots or rubber ring for the caliper piston though, that would be in a caliper rebuild kit if you want to go that far.
Well the modification I had to perform DID indeed fix the issue, the sliders and rubber dust boots did have grease inside of them and I cleaned the slider wells as usual before re-greasing the pins . Also while I cannot disagree that rubber deteriorates over time, it usually does NOT deteriorate at 5 years of age, certainly not in the realm of Toyota. In my experience when rubber deteriorates, it usually crumbles and or shrinks in diameter, only if exposed to brake fluid will it expand, and in that instance it also softens and turns back into oil basically, so it gets out of its own way in that sense.
The condition I saw was entirely foreign to me, and I’ve been in this game a long time, which is why I thought it noteworthy of mention. If by some miracle the issue does return, I will surely replace the boots now that I am prepped for the issue… However, now, for me, this has cast a shadow of doubt on the boots themselves… Were they substandard? A cheap knock off? Could be a total fluke? I don’t know, all I know is that it was clear cut , a serious problem and in need of intervention. All this with no visible abuse markings to make me suspicious otherwise. I dunno really… All I know is how I had to get around it on a late Saturday afternoon with new parts unlikely…
Judge the method of the madness or use the info as a tool to possibly save yourself from mistakenly replacing perfectly functional brake calipers. It definitely had me scratching my head for a moment and fleas aside, not too many failure modes confuse me (albeit momentarily)… Like anything…problem solved…till it isn’t anymore
Of course Kieth, I cannot argue that the brake HW kit was what was needed and that is why I NOW have one in my possession… but at the moment of repair, those parts were not available and the vehicle was needed immediately and the caliper was not at fault. The owner also was in a bad financial situation and had asked for my help. I would have purchased a new caliper if I couldn’t figure out what was binding the pins, I was doing all this work for no charge already. What I did here, in this instance, was only to get out of a pickle.
At any rate, the brakes are still working properly now and they are using their original OEM parts, nothing is missing nor outwardly damaged. I ground off a very small amount of rubber inside the dust boot collar with a sanding drum and a Dremel, just to free up the slider action. So when time allows I will revisit this issue and install the new HW kit.