Prius V -2012 rear brake caliper pins "seized"

Wow and I though my 'bad' pin was terrible...pic in this post :

Hi all, new Prius v owner | Page 3 | PriusChat

You win!

 

Public Service Announcement question: everybody who likes to take pins out for degreasing does remember to get the wide end of the boot securely tucked into the groove in the caliper, and the narrow end securely tucked in the groove of the pin, right? Right?

-Chap

 

I leave the boot connected at the caliper end, just rotate it in the groove at that side, and work a little (SilGlyde, in my case) brake lube in.

 

Yep. The odd thing is that my bad pin did have a secure boot. Maybe there was a pinhole sized in it? I didn't linger on it because I threw it out in disgust and replaced it. I wasn't a happy camper at the time.

 

I like the name of that jpg. Looks like it's been at the bottom of the ocean for a year.

 

Wow that's a super corroded bracket! I thought mine looked bad. Mine looked relatively good in comparison..pic here :

Hi all, new Prius v owner | Page 3 | PriusChat

 

If it weren't for the wretched pin(s) stuck in it, that bracket could be taken to your local zinc plating outfit for bead blasting and replating. The one near me has a minimum batch charge around $30, and will happily do three or four within that. The surfaces to clean up especially before dropping it off are the flat notches where the pad 'ears' go (flat file), and the pin bores (flex-hone is nice).

The zinc plating is what sacrifices itself to the oxygen gods to keep the steel from rusting, so once there's no plating left, things get ugly faster.

Last time I did some, I googled up some Toyota spec sheet that made it seem like they considered a B grade zinc plating to be 5 microns thick, and A grade to be 8 microns (0.00032 inch), so that's what I asked for. Had to hone out the pin bores again after plating until the pins fit.

-Chap

 

As in everything else, I guess they're thinking weight, material properties and compatibility, and cost.

There are times when I take zinc-plate bolts or nuts out of something, and use SS instead when I reassemble, just because it's cheap for me to buy a couple SS nuts, but I understand why they didn't build the whole car that way and then try to sell it for a profit. Anyway, would you make the bracket of SS too? That'd be a pretty penny.

-Chap

 

Use of stainless steel pins with an aluminum casting may create a galvanic/electrolytic reaction. Anti-seize paste may cure that, but why even go there?

 

Regardless of zinc plating and such, the best course of action is to just take the pins out and check & re-lube them every now and then. Also, making sure the boot it not compromised is key. The bad pin I had was caused by a pinhole breach of the boot.

I also think brake maintenance is one of the most neglected maintenance items with the Prius.

 

Anti Seize is not good for the pin lube, dries up fast. Either use the kosher Toyota stuff (@ChapmanF has the names I believe), or an aftermarket lube recommended for caliper pin lube, one that is also recommended for use with rubber, won't swell the O-rings.

Sil-Glyde Brake Lubricant is one that works. I've applied it tri-yearly on ours, no problems: the pins come out with the lube slightly darker, but fine, and no swelling of the rear brake O-rings.

I do use Permatex Anti-Seize on contact surfaces, pads to shims to calipers, but never on the pins or any rubber.

Yes. There's so many testimonials here, owners relating how their "brakes" have lasted 100K miles, but: the brakes are not just pad thickness. Regular disassembly, cleaning, inspection and relube is mandatory for any and all brake systems. Toyota recommends this (in the US maintenance schedule) every 3 years or 30K miles, but it seems like a lot of owners completely miss this. To be fair, the language in the booklet is VERY subtle.

 

Just for clarity, the caliper castings are aluminum (starting with Gen 2), at least in front (I'm not positive about the rears), but the brackets, in whose bores the pins ride, are ferrous.

So, still the potential for, um, galvanic potential, but it would be the one between SS and steel/iron, rather than SS and Al.

-Chap

 

They call it "Rubber Grease". You can buy a tube of it, or if you buy a kit of the rubber parts (nice to have around anyway, in case you ever do a brake inspection that shows a boot or seal problem, fix it on the spot, no waiting for parts or having to settle for chintzy ones because only the local auto chain is open), it comes with a little packet of the right grease included.

Yup, the best way to be assured of reaching those lovely high numbers is just to make sure you (at minimum) flip the silly things up once or twice a year, wiggle them in and out on the pins, and squint at them for any attention needed. Then flip them back down and drive....

-Chap