My front brakes were neglected! What happened and how I fixed it.

I have been experiencing a creaking sound when stepping on the brakes all the way. The car can be off or on, it makes no difference. When I step on the brake pedal with some force and hold it there I can hear this creaking sound that is very annoying. I can play with pedal pressure at that point to almost get a tune out of the creaking. I've had that since I bought the car in July 2017 (it had 175K on it then, has 215K now). However, the sound has intensified a lot now and I felt that the braking became less effective, though still fully functional and safe. I did the sliding pin cleaning and greasing last year, but that did not get rid of the sound. So, yesterday I decided to get to the bottom of it. I took off the caliper, pads, the caliper bracket and the rotor off and discovered the following. The rotor's inner surface was worn very incorrectly. The part further from the center (about 1/3 of the area) was rusty and bumpy as if the pad made little or no contact there. The part closer to the center (2/3 of the area) was worn normally. The outer surface of the rotor looked perfectly fine (so looking at it with the wheel on would indicate no problem). The pads were interesting. The outer pad had very little wear and what wear it had looked perfect. The inner pad, on the other hand, looked awful. It was worn in a way that made it not parallel to the rotor. The part further from the center of the wheel was worn a lot (that's where the rotor was rusty and bumpy) and the other part was worn a lot less, making an incline plane. Upon removing the slide pins from the caliper bracket I saw very dry and caked up grease and the pins did not move easily at all. In fact, it took some effort to get them out and I tore up the rubber boots in the process.

I replaced the rotors, pads and rubber boots on the pins and used a synthetic caliper grease for the pins after cleaning everything of old grease with lots of brake-clean, paper towels and compressed air. Everything went back together nicely and the creaking is gone. I went out and performed a few hard stops to bed the pads to the rotors. I got to about 45mph, switched to neutral (in order to disable regenerative braking) and braked to a full stop in a fairly rapid, but not panic fashion. After the third time the braking felt perfectly smooth and very grabby.

Oh, and in order to avoid unexpected and unwanted brake actuation, I pulled the two ABS relay from under the hood relay/fuse box. I did not feel like disconnecting the battery and removing the relays worked perfectly.

Moral of the story is to check the slide pins and re-grease them regularly. I hope the grease I used is sufficient. It is not the enigmatic Toyota soap grease, I know, but I think this is not that complicated. These are normal floating calipers that are similar in design to just about every other floating caliper I have ever seen and worked with. The difference is they are used a lot less and disuse for brakes is bad. With all the regen our wonderful gen 2's have the front brakes can go neglected and it's a good idea to go in there and give them some love on regular basis. Lesson learned for me.

I will get some pictures of the rotors and pads for reference.

My parts were sourced from a local parts store/auto repair business I trust and have dealt with for many years. They have a shop and a parts store. I never used the shop, but have used the parts store a lot with good results. They specialize in Toyota, but work on everything, really. I had some discussion with one of the shop people and he told me that what I saw was fairly common, especially on gen 2. I purchased the rotors and pads that they themselves use in their shop (they have a very good reputation and would not use crap that makes people come back with recurring problems). The brand was "Original Performance", some sort of thing I never heard of before, but he said it was their supplier's brand and was proven to be good. Pads are ceramic, rotors are coated and vented. Everything made in China. Cost was $37/rotor and $32 for a set of pads. I also had to buy a set of those rubber boots at NAPA for $8. I had synthetic (moly compound) brake grease on hand.

 

Yes, I realize Toyota has a very specific grease for this that is very strangely named. However, this being NOT rocket science, I think most synthetic, rubber friendly, non-drying grease will work. I also intend to regularly check and maintain the health of this system now that I know it's vulnerable to this condition.

I am attaching pictures of the stuff I used. The black tube is what I used and the blue packet was what NAPA guy sold me as the right grease for the job. I did not use it, but used what I had instead just as an experiment as I think this stuff in the tube is the proper stuff. I used it on my Volvos for years and nothing ever dried or attacked rubber boots.

 

Yes, it does mention caliper pins. It's on the label. I've been using this stuff for years on the Volvo calipers that had the same basic design (Toyota did not come up with it and the special Toyota sauce is not necessary). The mechanic I spoke with told me that no matter what kind of grease I put there, I still need to keep an eye on it on regular basis and clean and re-apply the grease on the pins every year, at least. He said they use Permatex Ultra Dis Brake Caliper Lube (green in color), but he said as long as it's synthetic and non-drying and I maintain it on annual basis, I should be fine. I don't think over-thinking this is a good idea, so I just went with what I had. We'll see how it holds up. I will be keeping an eye on this now.

 

Well, I did tear the boots and bought new ones at NAPA. They fit great and felt like they were of good quality (sturdy), but came with no grease at all. The NAPA guy did sell me two pouches of grease that is supposed to be used for this purpose. I put the picture of the pouch in one of the posts above. I did not use that grease and used what I already had and used before. What I used seems to be made for the purpose I used it for and I did not have trouble with it before. I will check on this next spring for sure to make sure the brakes are wearing properly and pins a still able to slide easily. If things get caked up again, I will try the NAPA pouch since I already have that. I think the more important thing here is not the exact Toyota grease, but rather fairly frequent and regular inspection of this system. I am sure from the factory it will work fine for years with the Toyota pins, Toyota boots, Toyota grease, Toyota air, etc. But this car is 12 years and 215K miles old, so All that Toyota sauce is simply no longer there and trying to replicate it is not necessarily the best use of resources. This type of calipers have been in use for a long time and the lubricating products to make them work properly are fairly commonplace. It's just that in our beloved Prius the friction brakes get lazy and tend to suffer from disuse symptoms. My 1998 Volvo had a 5 speed manual transmission and an old school 80/20 front rear brake system. The rear disk brakes on that car were practically unused and went rusty and crusty within a year of installing all new components. They were a different design than front Prius brakes, but the point is that they were not used very much what with a manual gear box and old school 20% braking duty. Later Volvo (and most other manufacturers) changed that with advent of electronic traction control, etc. and rear brakes began to wear more and better.

This is my current philosophical stance on this issue. More important than the brand of grease is to be cognizant of the issue of lightly used brake system that can suffer from stuck slider pins. Appropriate cleaning and lubrication is also key, no question about it. I will try to remember to update this thread next spring when I take the brakes apart to examine them.

P.S. I cleaned everything that old grease touched with lots of brake cleaner, Q-tips and paper towels until I was satisfied that no old grease or gunk was anywhere near where I apply new stuff.

 

Thank you for that.

As I said, the Toyota rubber boots are history, I tore them and replaced with NAPA boots. So the chemical compatibility of glycol soap grease (what is even soap grease?) with the mystery NAPA rubber is just as questionable as silicone grease with Toyota rubber. And I really do not believe there are issues of chemical compatibility of metals involved and grease of any kind (I may be wrong, but my gut tells me no problem there). I used grease that was specifically made for slide pins, so I believe it has a good chance of working, but if it does not, I will try something else. That tube of grease I used is a quite a few years old (and it was not cheap) and perhaps better compounds have been invented since it was sold to me. And Toyota built a caliper that can't do without such compounds.

In any case, I may be in for a lesson, but at least I am paying attention and observing. It's kind of like science.

 

Thanks for the explanation. So when I am doing dishes I am creating a palmolive bacon grease?