2011 Subaru Impreza - Floating Pin Seized In Caliper Bracket

[Number_35]

This is regarding my friend's 2011 Subaru Impreza, on which we replaced a drive axle (torn CV boot) and ball joint.

When putting things back together yesterday evening, I removed the top caliper pin, cleaned off the old grease, relubed it with purple Permatex, and reinstalled it. No problem at all.

However, I could not remove the lower pin (or move it at all). The head will not accommodate a socket, only the flats of an open-ended wrench, which slips off. Vice grips didn't work either.

I wish I had checked for movement when the caliper bracket was off. Could have clamped the head of the pin in a vise, and used the bracket for leverage. Coulda-woulda-shoulda ...

We put the brakes back together with the seized pin, because my friend needed the car back.

Strangely enough, the brake pads were wearing evenly, and the rotor looked good.

How did the pin seize? The top pin had no anti-rattle rubber bushing, so I suspect the bottom one did.

Given that a previous owner had spray-painted the calipers Brembo yellow, I could easily imagine him also lubing the pin with an incompatible grease that would swell the rubber bushing.

Anyway, it's a problem for another day ...

 

[sxg6]

How did the pin seize? The top pin had no anti-rattle rubber bushing, so I suspect the bottom one did.

Using a brake lube that wasn’t rubber safe caused the bushing to swell, and seize.

 

[Geekhead]

Using a brake lube that wasn’t rubber safe caused the bushing to swell, and seize.

Or moisture got by boot/pin interface. Have a Corolla that my Dad owned with upper pin corroded internally. Now I use a nice bead of Silglyde to seal that boot after my yearly brake clean/service.

 

[sxg6]

Yeah, always a good idea to clean and lube where the red line is so the pin seals up against the boot

 

[Geekhead]

Yeah, always a good idea to clean and lube where the red line is so the pin seals up against the boot
View attachment 292294

Exactly, thanks for your 1000 words explanation

 

[slacktide_bitog]

When you replace the calipers, get all-new calipers. Most of them are coated, too

Yeah, I never know that kind grease you can use on the brakes besides Sil-Glyde

 

[D60]

Using a brake lube that wasn’t rubber safe caused the bushing to swell, and seize.

Ya know I was just into the rear brakes of an FJ Cruiser and the lower pin on each side was VERY difficult to slide, but no rust. These pins ride in a full-length rubber boot and it never occurred to me someone probably used the wrong lube. Good thinkin'!

 

[D1dad]

Permatex purple isn’t safe for anything that isn’t metal. I’m not even sure it’s worth using on metal honestly. My slide pin with the rubber on the tip was completely froze in less than a year after using that garbage. I had to melt the rubber with a torch from the outside of the caliper and use a pry bar to get it out. Anywhere I applied that sludge turned into a solid and provided no lubrication at all. About the only place I’d use that stuff is on pad ears that were knocking around in the caliper mounting bracket. When mixed with dust and road grime it essentially turns into job weld. Straight up silicone paste is all I use after that debacle.