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Packing front wheel bearings and caliper bracket torque
Hey everyone,
I was going to make a write up of changing the front and rear brakes for my GSL-SE since there are a few oddities and required tools, but had some questions:
1) Are you supposed to fill the ENTIRE cavity between inner and outer bearings? I see it mentions not to over-pack the bearings (not sure how that's even possible unless you just dunk it and don't wipe it off), then to fill the hub cavity. I've seen people saying don't fill it at all, fill 1/3-1/2, and to completely fill the gap. Anyone have specific experience with this to chime in?
I know it's the FC, but this writeup doesn't seem to mention doing so, but the FC FSM doesn't mention such a step either.
For what it's worth, I'm replacing everything (rotor, races/bearings, brake pads).
2) What on earth are the torque specs for the caliper bracket mounting bolts for front and rear? I can't seem to find them anywhere, so I'm torquing them down to ~50 ft-lbs to be on the safe side. A general range would be helpful, in case the specs are unusually low or high.
1 > no, don't over pack, just work the hi temp grease into the bearings and the outer ring. Don't use an air gun to spin the bearings although it is fun to watch
2> brake caliper brackets bolts (lock washers are nice), I tighten mine to feel using a 10 inch ratchet. Also use anti seaze.
3> tightening front wheel bearings is tricky, I tighten mine until I barely start to feel resistance. Then back off slightly. Check them out after driving a less than one mile. Then check for looseness of the wheel. Then might need tightening. Then a week later I check them again. With the car jacked up and the disc pads not touching the rotor. If you initially over tighten them, and then back off, then they will have a slight flat spot, and eventually fail. If you leave slight play in the bearings, they will eventually fail. They're temperamental.
As long as you grease the bearings using a tool or the palm of your hand, they'll be fine. Use the races that came with the bearing which is obvious if you just installed them in new rotors. Be careful not to over TIGHTEN the bearings, or you get brinnelling which is flat-spotting on the races. Better to be a little loose and risk wheel play than to over tighten. As the other posters mentioned, recheck your preload settings after driving on them a bit. I like to set 5lbs of force to rotate the rotor when pulling on any of the studs, this is easy to estimate and sets enough load to preclude any looseness. When you install the castle nut, note that it can be installed either tight to the cotter pin or to allow loosening when the wheel turns. You want to find the castle nut position that holds the cotter pin such that the nut can't be turned, as the coarseness of the threads will throw off your preload with as little as 1/16 turn of the spindle nut.
Torque on the caliper bracket is "gutentight". Probably around 40-50ft/lbs, but I don't use a torque wrench on them. Good luck,
I've always just properly packed the bearings. Slopping grease in the middle is just wasting grease.
Of course I could have been doing it wrong for the last 20 years.
Something interesting I found after pulling the rotors. While the center cavity was definitely packed full of grease, it looked brand new and almost untouched. You can see some of the black dirty grease on the edge of the bearing and how it compares to the yellow stuff in the middle. So I guess while recommended, its basically wasting it like you mentioned lol. I'll put a light coat in the middle just to keep everything greased, but don't plan to pack any in.
Originally Posted by midnight mechanic
1 > no, don't over pack, just work the hi temp grease into the bearings and the outer ring. Don't use an air gun to spin the bearings although it is fun to watch
2> brake caliper brackets bolts (lock washers are nice), I tighten mine to feel using a 10 inch ratchet. Also use anti seaze.
3> tightening front wheel bearings is tricky, I tighten mine until I barely start to feel resistance. Then back off slightly. Check them out after driving a less than one mile. Then check for looseness of the wheel. Then might need tightening. Then a week later I check them again. With the car jacked up and the disc pads not touching the rotor. If you initially over tighten them, and then back off, then they will have a slight flat spot, and eventually fail. If you leave slight play in the bearings, they will eventually fail. They're temperamental.
I tried using my hand, but as usual, I thought it would be as easy as it looks on Youtube and miserably failed. I put grease in a plastic bag and gently pushed it full of grease, then wiped the excess off the outside with my glove.
I was actually missing random lock washers on the bolts and picked some up from Ace today. Interestingly, the lock washer for the caliper bolt and bracket bolts appear to be the same.
Hopefully I dont mess up the torque
Originally Posted by LongDuck
As long as you grease the bearings using a tool or the palm of your hand, they'll be fine. Use the races that came with the bearing which is obvious if you just installed them in new rotors. Be careful not to over TIGHTEN the bearings, or you get brinnelling which is flat-spotting on the races. Better to be a little loose and risk wheel play than to over tighten. As the other posters mentioned, recheck your preload settings after driving on them a bit. I like to set 5lbs of force to rotate the rotor when pulling on any of the studs, this is easy to estimate and sets enough load to preclude any looseness. When you install the castle nut, note that it can be installed either tight to the cotter pin or to allow loosening when the wheel turns. You want to find the castle nut position that holds the cotter pin such that the nut can't be turned, as the coarseness of the threads will throw off your preload with as little as 1/16 turn of the spindle nut.
Torque on the caliper bracket is "gutentight". Probably around 40-50ft/lbs, but I don't use a torque wrench on them. Good luck,
I'm always amazed that there's a word for every possible sort of wear and tear or failure of metal. Thanks for my word of the day!
But...5 lbs!?!?!?! I bought a shoddy spring scale just to get in the ballpark, and it was ~.5 kg and ~.2 kg of force on each side with what was currently on there (calipers and pads removed). Granted, I assume that means it was possibly too loose. 2 lbs, as mentioned in the FC article, seems a bit more reasonable. It wouldve been reaaaally nice if Mazda gave us aballpark idea of the actual torque, instead of "check oil seal drag and add .4kg". Haynes manual is even more obvious and just says "check for sideways movement".
I've always been a little nervous when tightening down the hub nut as well. My dad taught me to tighten it down enough to cause resistance but you don't want it to be tight and burn out the bearings. Very interesting on that resistance setting, good to know! Will keep that in mind when I redo mine eventually.
02-13-19, 06:24 PM
