Went to change my front brake discs today and the caliper bolts just wont budge. Gave them a good spray of WD-40 and left it to penetrate. Went back and still no give in them. Any advice?
for difficult bolts i recommend using a tight fitting 6 sided socket & breaker bar cos a normal 12sided loop spanner or especially an open C-spanner will certainly round it off and you end up grinding the head off then replacing parts
if there's no space, you could try unbolting the caliper carrier bracket from the hub (17mm), unbolt the brake line from caliper pull the carrier/caliper assembly away off the disc so you could then clamp the carrier on a big vice to loosen the caliper bolts with breaker bar
i,m guessing its the 17mm ones he,s struggling with ?
a hot air gun will do sweet FA fwn and they should have blue threadlock on the threads (critical bolts )
so i would,nt advise lubing them with copperslip
I've never used thread lock on caliper bolts in more than 30 years never had one come loose