Hydro locked slide pin

[merc3065]

Is it common for caliper slide pins to hydro lock on the ones with the rubber bushings even after cleaning everything out of the slide pin bore and re-greasing everything?

Reason I'm asking is that I recently did a brake servicing and one of the calipers decided to seize up. Took it into a dealer since I was out of the area.

Was told today by the Mazda tech that the permatex silicone synthetic grease I am using caused the bushing to swell and hydrolock the pin causing it to stick and not release. So was charged for $50 for the work to free up the sticky pin and was told I was using incorrect grease. They instructed me Instead to use wurth silicone synthetic grease. I'm confused since I've been using the permatex brand for years on all of my cars with no ill effects.

Did I use too much grease maybe or is it fact the permatex is reacting with the rubber that Mazda uses??

 

[MikeM.]

Too much grease will not cause rubber bushings to seize, the wrong kind of grease can. Synthetic "rubber" bushings, o-rings and seals are made of different compounds to suit specific needs (high heat, resistance to abrasion, etc.). I would never assume a brake from one make/model/year is the same as a brake from another make/model/year. Always use lubricants meeting manufacturers specs for the specific application.

I don't know what happened in your particular case but I would tend to trust the explanation given by the Mazda service tech.

And if he got your bakes working after you botched the job for only $50, I would say you got off easy.

Be glad.

 

[merc3065]

I would like to agree with you, however, the specs on the synthetic brake grease I used and the grease used by the mazda dealership are identical in heat ratings and are both safe for use with metal to metal and rubber to metal.

And yes, I am glad, however I now have to redo all 4 brakes and replace the slide pins on both rear calipers because of the grease I used. As I said, it's confusing because no other issues on the other 3 calipers for the last 3 brake servicings either.

This sticking problem also occurred with the mazda factory grease which prompted an early brake cleaning the first time which also required the rear pads and rear rotors to be replaced.

So I'm not convinced I botched anything unless someone can prove to me that permatex synthetic caliper grease is not safe for use on Mazdas. According to the information I recieved from permatex, it meets OEM specs for temp range and use.

Perhaps there's something wrong with that one brake assembly.

Edit: after reading more about permatex, even though it states right on the package, that it will not cause rubber to swell, people have reported that it does cause swelling sometimes. Though there's little in the way to back up their claims as well as in what context(age of brake parts, condition etc). I'll have all the replacement bushings in hand by this weekend and will be using a different lube called sil glyde from Napa.

 

[Kedis82ZE8]

It just says rubber grease in FSM.

Looking around some say this works fine...