Rebuilding Calipers

[texaxile]

Hi,
Just half way through a rebuild of a set of front 4 pot calipers for my Impreza. I have split them down, cleaned etc, but before painting and re assembling them I'd ask if I need to put a dab of threadlock on the bolts which join them together.

When I took them apart, there was a white power residue on the end of each bolt, so not sure if they are threadlocked from the factory or if it is from something else.

Cheers
Pete

[tapkaJohnD]

Threadlock usually only required for parts that rotate, but for a safety-critical item like calipers, why not? You won't be having them apart again soon!

[InitialDave]

It's probably not a bad idea, though most threadlocker breaks down by about 250 degrees C, so may not be doing as much actual locking with heavily used brakes.

I think Loctite's extra high temp one (2620?) is good to over 300 degrees though.

[littleredrooster]

I certainly would, if for no other reason than it seals the ends of the thread against water and therefore corrosion. Ironic that something designed to make it more difficult to strip things down actually makes it easier in the longer term!

[aka_kerrly]

Wouldn't the white powder residue most likely be aluminium oxide from steel bolts inside alloy calipers. There is no harm in thread locking brakes, hopefully once refurbished you won't be taking them apart for quite a while so the peace of mind knowing there is that little extra help on the brake bolts can't be a bad thing.

[Chris32345]

InitialDave said:

It's probably not a bad idea, though most threadlocker breaks down by about 250 degrees C, so may not be doing as much actual locking with heavily used brakes.

I think Loctite's extra high temp one (2620?) is good to over 300 degrees though.

The brake caliper shouldn't get anywhere near the temp
At 250c your brake fluid will be boiling so the theadlock failing will be the least of your worries



Only the disc and pads should reach high temps

Theres a nice thermal view of disc brake here
https://www.google.com/search?q=brske+caliper+mak+...

[InitialDave]

Fair point, yes, I was thinking in terms of "brake temperatures", but of course the calipers would be cooler.

[texaxile]

OK , Dab of threadlock it is then, I think though that the calipers are cast, not alloy like the Brembo's on an STi, so not sure what the white powder was, but it's not really that important anyway.

I've cleaned all the bolts up and blasted all the threads out with an airline, so should be good to go this weekend.

Thanks for the advice chaps.

Edited by texaxile on Wednesday 3rd June 00:54