I am leaving mine alone. They seem to do fine unless you go racing. If you can re-pack them, confident that they will not be dirty or leak, OK, but they were not designed for that, and you may do more harm than good.
Any more thoughts on this? I thought I saw a post a few years ago on how to repack the 88 front hubs. It seems to be a good idea to replace 31 year old grease.... perhaps I am wrong
Has anyone actually done this successfully and documented it? I have a couple of sets of 88 front hubs that are fine and I could experiment with one
I always repack them when I get them. It is a preventive maintenance thing. They will eventually fail... that is a guarantee. It is simply a matter of time (and I drive my 88 8-10K miles per year). If you can properly repack the bearings with fresh grease vs. 30 year old grease, that should give you additional service life from the OEM bearings.
Originally posted by Gall757: If you can re-pack them, confident that they will not be dirty or leak, OK, but they were not designed for that, and you may do more harm than good.
That logic makes sense for newish parts, but I disagree for 30-year-old+ dried grease time bombs.
At some point, these late-model maintenance practices (don't maintain "sealed-for-life" stuff) become unsustainable. As the Fiero matures into a classic car, what works for most cars on the road (i.e. sub-15-year-old cars) no longer applies.
Do you think a bearing can operate for 40 years without fresh grease?
[This message has been edited by pmbrunelle (edited 09-19-2019).]
The simple answer to that, is that the "sealed" bearing isn't hermetically sealed, especially as it ages and dirt helps to abrade things between the seal / journal.
It is considered good practice to repack wheel bearings after fording water with a car/truck... it is assumed that water can enter wheel bearings during fording. If the bearing is leaky, then the volatiles can leak out.
Once, I bought an industrial surplus gearmotor that was about 20 years old. It looked like it spent its life indoors, and wasn't scratched up. In that case, when I opened up its gearbox, I was greeted with a pile of thick goop, and a pool of liquid. Apparently the grease separated into its components. In that case, the gearbox stayed sufficiently well sealed to contain all of the ingredients.
I don't think an automotive wheel bearing with water and dirt exposure remains a "closed system" over its lifetime like my industrial gearmotor example.
[This message has been edited by pmbrunelle (edited 09-19-2019).]
I checked out Fieroguru's pictures on his old link.
If someone happens to be re-packing 88 front bearings soon, would you mind making a video and posting it on youtube or elsewhere? It would be very handy. I think it would be great to be able to replace 31 year old lubricant with fresh and extend the life of these bearings. Much appreciated
The simple answer to that, is that the "sealed" bearing isn't hermetically sealed, especially as it ages and dirt helps to abrade things between the seal / journal.
It is considered good practice to repack wheel bearings after fording water with a car/truck... it is assumed that water can enter wheel bearings during fording. If the bearing is leaky, then the volatiles can leak out.
Once, I bought an industrial surplus gearmotor that was about 20 years old. It looked like it spent its life indoors, and wasn't scratched up. In that case, when I opened up its gearbox, I was greeted with a pile of thick goop, and a pool of liquid. Apparently the grease separated into its components. In that case, the gearbox stayed sufficiently well sealed to contain all of the ingredients.
I don't think an automotive wheel bearing with water and dirt exposure remains a "closed system" over its lifetime like my industrial gearmotor example.
Obviously the seal is going to live longer if it's unused as with your gearbox. Also, had your gearbox been used, the grease would not have separated. Since it was all still there, it just needed to be mixed back up...
If the seal on a sealed hub actually fails and lets grit in, then hub failure follows shortly. If the hub is still in operating condition, then the seals aren't bad, or if bad have not been bad for very long.
Replacing the grease is a precautionary measure. The hub won't live forever. Overloading the hub beyond its design loads (ie, mount large sticky tires and USE them) will kill it no matter what grease is in it.
[This message has been edited by Will (edited 09-20-2019).]
