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Interesting find about caliper pin bolts - check it out
So I am rebuilding my calipers....new piston...seal...dust boot...pins ...pin boots....front and back.....i get to looking at the front caliper pins and comparing them to the back pins....they are the same pins ! ....only difference is the bolts that come in the kit....front kit has M8x1.25x25 bolts ....rears are M8x1.25x20 bolts
i then put the bolts in the caliper holes only to find there is not a whole lot of thread left on the bolts to engage the pin ( front and rear !! ) the bolts are not even using half of the available threads in the pin....i am thinking these 2 bolts are the only thing holding the caliper on and stopping your car and you are depending on a few MM of threads on a bolt !!!???
after a few measurement with my trusty dial caliper i then take the front bolts and put them in the rear ....perfect fit and 5mm more of thread from the bolt in the pin....curiosity gets me and i get some 30mm long bolts for the front.....yep....perfect fit
another thing i notice is the bolts that come in the kit have no grade on the bolt head....are these zero grade china bolts we trust to stop with ?????
i am lucky to have a Summit store close to me so i go and get me some ARP bolts in 25 and 30mm lengths .....the factory tq on the bolts for the pins is 24 ft pds so the ARPs will be properly pre loaded per ARP tq specs for M8 bolts.....if you do get some ARPs like i did be forwarned that the M8x30 bolt kit comes with 3mm thick washers...the M8x25 kit comes with thin washers....ARP does sell M8 thin washers ( i already had the thin washers from another job )
i sleep better at nite now with longer stronger bolts
i am thinking these 2 bolts are the only thing holding the caliper on and stopping your car and you are depending on a few MM of threads on a bolt !!!???
I don't believe these bolts are very critical. The bolts that secure the bracket to the spindle are much more important. Since the body of the caliper engages the caliper bracket directly, forces will go through the caliper body and bracket and not through these bolts. (They just need to hold everything in the right.)
Maybe. Although there have been some reports occasionally of caliper bolts backing out. I've never experienced this happen, but some have. I really don't know the length of the bolts on mine.
Personally I may not go so far as to use 12 point ARP bolts, but I could see upgrading the length of them.
sometimes you go to lowes....home depot....ace hardware.....you just cant find the bolt you are looking for.....go to Summit and they have most of the ARP catalog in stock .....plus it matches the other ARP bolts i have
06-24-2018, 03:18 AM
Interesting find about caliper pin bolts - check it out 
