So, as described in ->this thread<- the rear brake caliper bracket bolt GM 11589201 is discontinued/not available. This is an M12-1.5x28.5 flanged bolt with a 15mm head. The service manual says to discard the old bolt when removed.

I'm looking for an alternate flanged bolt with the same 15mm socket size but coming up short. Anyone have a source for these?

I've been able to find a flanged bolt with a 16mm head (OEM is 15mm) in 25mm length (OEM is 28.5mm). I can also find a non-flanged bolt in 30mm depth and could use a washer to give roughly 28mm of thread engagement depth. Is a 3mm shorter flanged bolt ok, or should I settle for the non-flanged 30mm bolt with washer? Should I go with black oxide or zinc plated?

Out of curiosity, does anyone know the actual technical reason why the service manual would says to discard the rear caliper bracket bolts when removed, but the front caliper bracket bolts don't need to be?

Thanks all for your expertise!
NMH3

 

In all my years I've never tossed the bolts. I personally just reuse them. You do you though. Jmho

 

Serviced many many many H3/H3Ts rear brake calipers and I have always used the OEM original bolt.
It is not a TTY bolt so I have no idea why it should be a single use bolt.

If you are that concerned why not just buy the kit?

 

Thanks guys - I guess that was my question, reuse or replace? I don't know why the manual says to replace them once removed. If they were cheap and easy to find I wouldn't be asking.

@TAINTER - the Dorman kit includes only the caliper guide pin bolts (and the guide pins), which the manual does not specify as single use. The bolts in question are the caliper bracket bolts that get torqued to 100 ft lbs.

 

I ended up getting these bolts here from Bel-Metric and cut the length to size.

Those OEM caliper bracket bolts are not TTY or TTA bolts and it is confusing why they only want the rear bolts replaced.
I ended up replacing the caliper bolts because it is too easy to do so.

https://belmetric.com/oem-hex-flange...BF12X1.5X35GEM

 

The pic of the Dorman kit sure appears to include those bolts, but I haven't bought it, so...

 

Those are the caliper slides & bolts, not the bracket mounting bolts.

 

Hummerz is correct, those are caliper slide pin bolts and caliper bolts in that screen capture.
What NMH3 was asking about was the caliper bracket bolts - M12 1.5 X 28

 

That's a weird setup. Never seen slide pins with separate bolts to hold them in. Interesting.

 

2pc floating caliper slide pins design has been around for many decades. I've replaced thousands of brakes and many times found slide pins seized inside the bracket requiring a gas wrench to get it out, without breaking the pin or damaging the caliper seals/dust boot. With the 2pc slide design, simply remove the bolts holding the caliper to the slides and move out of the way to prevent any damage from the torch. WARNING, when heating the bracket with a torch the seized pin WILL release and become a PROJECTILE. I don't have a video of the damage I caused over the years removing seized caliper pins, only a video to show you the design: