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2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Part number for caliper mounting bolts to knuckle?
These things really shouldn’t be reused and I’m a little nervous getting the car ready for track season as I’ve had the calipers on and off a number of times in the past couple years. Have read some horror stories about these fatiguing and letting go, catastrophically. Was just about to do it again tonight to put in new rear studs and didn’t have any spares. Can’t find the part numbers anywhere. Thx
Also I’m seeing torque spec of 135ft/lbs which seems pretty aggressive. I think mine are on there now at 85.
Yeah, I'm curious as well. When I did my front brakes, 135 ft-lbs seemed really high. It feels like you are going to break them. I would have liked to have replaced them.
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Originally Posted by Mort
This is what I found for torque.
Self locking bolt brake caliper to steering knuckle M14 180NM. Converts to 132.76 ft-lb so 135 ft-lb works.
Source: Alldatadiy.
Yup that was a rough conversion thx. Also learned that the bolts are not exactly TTY, however they do stretch by design (“self locking”). This is why they should not be reused.
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
My thread title is wrong. I meant caliper to adapter bolt. And torque. Got the bolts. Still don’t have a good answer to the torque spec.
In the rear there there is no adapter if I remember correctly. Caliper bolts directly to the knuckle. Does anyone have the bolt part numbers and torque specs for those too? Just going to re-do all of them.
My thread title is wrong. I meant caliper to adapter bolt. And torque. Got the bolts. Still don’t have a good answer to the torque spec.
In the rear there there is no adapter if I remember correctly. Caliper bolts directly to the knuckle. Does anyone have the bolt part numbers and torque specs for those too? Just going to re-do all of them.
Jim, you are correct, Rear Caliper bolts directly to Rear Knuckle. Bolt Part Numbers for Rear Caliper to Knuckle are above - they are different than the Front Caliper Bracket/Adapter/Retainer to Front Knuckle.
The Bolt attaching Front Caliper to Caliper Bracket - there is a difference in length between our Racing Brake supplied bolts, and the OEM bolts IIRC.
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Originally Posted by MBNRG
Jim, you are correct, Rear Caliper bolts directly to Rear Knuckle. Bolt Part Numbers for Rear Caliper to Knuckle are above - they are different than the Front Caliper Bracket/Adapter/Retainer to Front Knuckle.
The Bolt attaching Front Caliper to Caliper Bracket - there is a difference in length between our Racing Brake supplied bolts, and the OEM bolts IIRC.
Yes, that’s right. I had reused the longer OEM red painted bolts, but now have the shorter RB bolts in there at 135ftlbs. If that turns out to be ~50ftlbs too much, I may have damaged the threads in the aluminum RB adapter. Still no definitive torque spec on these.
Should there be loctite on the Allen bolts? I ask because even before my track day it appears they were backing out on one side after being reinstalled three months ago.
My thread title is wrong. I meant caliper to adapter bolt. And torque. Got the bolts. Still don’t have a good answer to the torque spec.
In the rear there there is no adapter if I remember correctly. Caliper bolts directly to the knuckle. Does anyone have the bolt part numbers and torque specs for those too? Just going to re-do all of them.
Did we ever get the specific torque spec for REAR caliper bolts to knuckle? I was in there last night inspecting some things, had to pop off the endlink to get a wrench on the bolts, and I don't know what kinda torque wrench you guys use but there was no way in hell my torque wrench would fit in the wheel well space and allow me to lever on it.
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Yeah you ideally have to get it up in the air. Like on a lift. Very difficult with car on stands. I managed with a short extension on the reverse-hex socket and a 3/8” torque wrench (my Precision has a v long handle). You’ll be crouching and pulling up on the drivers side and will have trouble keeping the socket on the bolts while getting enough leverage. It’s ripe for a chin whacker.
Mine are are all still at 135ft-lbs. No problems so far. Will redo all of them over the winter when I install new rotor rings and use the 100ft-lbs spec and blue Loctite.
I was just watching youtube. She installed caliper studs to replace the bolts we have been talking about. She has a GT350 but the caliper mounting is fairly similar to ours. I wonder if anyone makes a set of caliper studs that would work on our cars.
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
I think that caliper studs would be a real pain in the ***. I’d rather have all that thread in the adapter or knuckle than a nut on the end with a dozen threads holding it on that would be more likely to spin off. Plus, it’s tight in there. I think this is an instance of trying to stud something for no benefit. If race cars don’t use studs then why would anyone do this? I just don’t see a benefit, only drawbacks.
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