carguy123
carguy123 PowerDork
11/5/12 10:23 a.m.

If I had mine apart and even if it only had 30K on them, I'd just replace them. It's easy now, but tough later.

joey48442
joey48442 UberDork
11/5/12 10:25 a.m.
Wonkothesane wrote: Just out of curiosity, do you guys repack your wheel bearings? I'm waiting on a package from Flyin' Miata to arrive, so I have the complete suspension disassembled and ready for paint, but that got me thinking: These wheel bearings are original (I presume), which means 1991, 150k on them. I'm worried that tearing them apart would upset the delicate balance of whatever is holding them together and seems to be doing fine..

I think they are sealed on the Miata. I've got over 200k on mine and no noise yet...

Joey

DaveEstey
DaveEstey SuperDork
11/5/12 10:52 a.m.

140k on mine and 5 years as an autocrosser without issues.

That said, if I had the car apart I'd replace them.

codrus
codrus Reader
11/5/12 10:55 a.m.
joey48442 wrote: I think they are sealed on the Miata. I've got over 200k on mine and no noise yet... Joey

The official Mazda line is to replace the front bearings and hubs as a unit, not repack them. Spec Miata racers eat them up very quickly, and have worked out how to repack them (theory being that the OEM grease isn't good enough for track duty).

Writeup on repacking here. You can also buy pre-repacked hubs from a few places.

I had to replace a front one after ~50K miles and a lot of track days, at 80K miles it needed a rear one too.

z31maniac
z31maniac PowerDork
11/5/12 11:23 a.m.

I just bought the ART hubs from FM when I had the suspension apart and the rear hubs from Planet-Miata.

A bit of added expense up front, but I should theorectically never have to touch them again.

Ian F
Ian F PowerDork
11/5/12 11:59 a.m.

I repacked the bearings on my GT6 shortly after buying it hoping to fix a squeak. I've repacked the bearings on the g/f's Spitfire and 1800ES when I had them apart. Everything else we own has sealed units except for the rear axle bearings in the Dodge which are lubed via the axle oil.

914Driver
914Driver MegaDork
11/5/12 12:00 p.m.

Repacking some now, waiting for new seals.

motomoron
motomoron Dork
11/5/12 1:57 p.m.

If they're original at 150k and the car is apart, you'll feel a little regret if you're removing both rear hubs to do 'em in a year.

If you're really pressed for funds to the degree that $70 in parts is more valuable than a day of your life, leave 'em.

I'm going to live exactly once, so I did 'em while mine was apart.

914Driver
914Driver MegaDork
11/5/12 2:02 p.m.

Is there a difference in greases?

Dr. Hess
Dr. Hess UltimaDork
11/5/12 2:47 p.m.

Yeah, there's a difference in greases. Genuine Harley Davidson Wheel Bearing Grease is the best. I use it for all extreme duty applications like wheel bearings.

Keith Tanner
Keith Tanner MegaDork
11/5/12 3:02 p.m.

Redline has a grease that's very well regarded.

I wouldn't be worried about the rears. Just leave them alone. If your Miata is mostly street driven, go ahead and keep the fronts if they're not giving trouble. But if you do autocross or track the car, it's a good plan to bung a new hub/bearing set in there or at least take a look inside. They're not hard to change out later if they do give you trouble, a Miata endurance race team can swap a failed front bearing in a 4 minute pit stop.

Curmudgeon
Curmudgeon MegaDork
11/5/12 3:19 p.m.

I got to where I really like Maxima's waterproof grease. It looks a lot like apple jelly only it's blue and it lasts forever.

motomoron
motomoron Dork
11/5/12 11:39 p.m.

Re. The grease itself: I used Amsoil synthetic forever, but since drinking the Redline Koolaid I've been using CV2 and the tub stuff. I've looked at bearings at the end of a season and they're indistinguishable from when I packed 'em.

RexSeven
RexSeven UltraDork
11/5/12 11:47 p.m.

My N/A FC's front hubs were sealed. Mazda wanted $450 a pop for new ones, and that's WITH the Mazdaspeed discount! I had a shop heat the old hubs with a welder and use a BFH and chisel to whack out the old bearings (Big PITA, according to the guy who did it). I get to do it all over again with my Turbo if I ever get it out of storage.

As for grease, the FSM specified moly grease (the gray stuff), so that's what I used. I think it was Valvoline brand.

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