uniberp Posted January 15, 2012 Share Posted January 15, 2012 I had a shop press in a new rear bearing in October, and didn't think to do the seal, and it failed already. Had to do it again for another $100. I guess I thought the bearing was sealed or something. Not. Be sure to replace the seals. The innermost seal is a flush seating against the face of the axle. There seems to be a second inner seal, but I don't know the function of that one. At any rate, I had him replace all three and packed the whole thing solid with grease just to be sure, before I put it back on. Quote Link to comment Share on other sites More sharing options...
bheinen74 Posted January 15, 2012 Share Posted January 15, 2012 yep, the seal outer and inner is what protects the bearing from outside contaminants getting in. Always. would be like changing a timing belt and reusing the water pump etc. that is no no. new seals. yes. that shop failed, cross them off the repeat customer list. Quote Link to comment Share on other sites More sharing options...
hohieu Posted January 15, 2012 Share Posted January 15, 2012 If they're correctly pressed into and good knuckle, the bearings could theoretically last forever. It's often a bad seal that leads to bearing failure. Certain things can accelerate seal failure such as stuck and overheating brake calipers and corroded polished surfaces of the outer half shaft joint. An under/over torqued axle nut or poor installation procedures can also damage a bearing. On my '99 Forester, there are three seals for rear wheel bearings -- 2 inners and 1 outer. The innermost seal merely acts as a dust shield. NTN Bearing Co. recommends a grease fill of 30% of the the free space inside the bearing (see the bottom of this link: http://www.ntnamerica.com/product-support-and-training/frequently-asked-questions#g4 Overfilling will cause the bearing to overheat. Quote Link to comment Share on other sites More sharing options...
uniberp Posted January 15, 2012 Author Share Posted January 15, 2012 Thanks. I'll check the fill when the weather clears. Mostly short local driving in cold weather now. I blame myself. A square look at it would have told me it's not a sealed bearing and I should have requested seals. BTW I found 2 new NTN bearings in my parts box, so I could have saved myself even more $$. Still cheaper overall than having one done by an auto shop. If they're correctly pressed into and good knuckle, the bearings could theoretically last forever. It's often a bad seal that leads to bearing failure. Certain things can accelerate seal failure such as stuck and overheating brake calipers and corroded polished surfaces of the outer half shaft joint. An under/over torqued axle nut or poor installation procedures can also damage a bearing. On my '99 Forester, there are three seals for rear wheel bearings -- 2 inners and 1 outer. The innermost seal merely acts as a dust shield. NTN Bearing Co. recommends a grease fill of 30% of the the free space inside the bearing (see the bottom of this link: http://www.ntnamerica.com/product-support-and-training/frequently-asked-questions#g4 Overfilling will cause the bearing to overheat. Quote Link to comment Share on other sites More sharing options...
turboguzzi Posted January 15, 2012 Share Posted January 15, 2012 begs to ask what procedue are you using to replace the bearing. i've built a small set of turned spacers and drive it out/in with a 1" threaded nut as per the manual. Quote Link to comment Share on other sites More sharing options...
bork Posted January 16, 2012 Share Posted January 16, 2012 begs to ask what procedue are you using to replace the bearing. i've built a small set of turned spacers and drive it out/in with a 1" threaded nut as per the manual. Curious, which manual? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 16, 2012 Share Posted January 16, 2012 NTN Bearing Co. recommends a grease fill of 30% of the the free space inside the bearing (see the bottom of this link: http://www.ntnamerica.com/product-support-and-training/frequently-asked-questions#g4Overfilling will cause the bearing to overheat. VERY IMPORTANT! NEVER pack a sealed bearing completely full of grease. It has nowhere to go and WILL overheat. Grease is NOT what does the lubrication - the grease "drops" and turns to an oil that does the actual lubrication and protection. If further heating is allowed to continue the oil will cook just like you left it on a hot skillet over a stove. The NTN bearings that I install on a regular basis for the EJ's come pre-greased. That's all you need! If you want to replace the grease - pack ONLY the bearing cones and put a thin smear on all other bearing surfaces. Over-packing is second most common cause of bearing failure after grease contamination. I have replacement EJ wheel bearings going on nearly 100k miles of trouble-free operation using only the grease that was provided by NTN in them. GD Quote Link to comment Share on other sites More sharing options...
bheinen74 Posted January 16, 2012 Share Posted January 16, 2012 ^exactly. and when things get warm in there, things expand, you don't want it packed full of grease, it will blow your seals out. Quote Link to comment Share on other sites More sharing options...
turboguzzi Posted January 16, 2012 Share Posted January 16, 2012 Curious, which manual? talking about one of those official manual appendix documents from good ole' endwrench lost both the bearing change pdf and the links to it, but i am sure the list for these manual updates is out there. Quote Link to comment Share on other sites More sharing options...
uniberp Posted January 17, 2012 Author Share Posted January 17, 2012 FWIW, these are not sealed bearings. There is no seal built into the bearing. I just looked at the new NTN bearings I have on the shelf, and they are not sealed either. The hub has have external press-in seals. 2 inner and 1 outer. VERY IMPORTANT! NEVER pack a sealed bearing completely full of grease. It has nowhere to go and WILL overheat. Grease is NOT what does the lubrication - the grease "drops" and turns to an oil that does the actual lubrication and protection. If further heating is allowed to continue the oil will cook just like you left it on a hot skillet over a stove. The NTN bearings that I install on a regular basis for the EJ's come pre-greased. That's all you need! If you want to replace the grease - pack ONLY the bearing cones and put a thin smear on all other bearing surfaces. Over-packing is second most common cause of bearing failure after grease contamination. I have replacement EJ wheel bearings going on nearly 100k miles of trouble-free operation using only the grease that was provided by NTN in them. GD Quote Link to comment Share on other sites More sharing options...
bork Posted January 17, 2012 Share Posted January 17, 2012 Well it sounds like I need maybe both rears. Do the rears seem to go more often? I hate the thought of junk yard parts, might last a while or just a month. OIY. If I buy new bearings & seals, where is best source for quality & good deal? Can I order from a bearing supplier, or best to get dealer only? Are all subies same? I have a 1999 impreza L 4 door. Quote Link to comment Share on other sites More sharing options...
uniberp Posted January 17, 2012 Author Share Posted January 17, 2012 (edited) Yes rears seem to take a bigger beating, I think due to water splash more than anything. For me they are a maintenance item. I've replaced 2 fullsets (plus 1) on the 99 Forester and one on the 97 legato. I don't think there is significant difference in quality in bearings. Someone mentioned Timken seals don't fit so well. I don't get all these guys claiming to replace bearing on the car without the use of a specialized tool like a hub-tamer, and there are lots of stories about busted knuckles (human ones, not so much the car ones). There may be a MY design change a '00. Getting the rear hub off can be a chore primarily due to the 140mm long lateral bolt. It rusts solid in the bushings and cannot be removed. I developed this method: http://www.ultimatesubaru.org/forum/album.php?albumid=304 Replacing the seals is mandatory, as I learned, and putting extra grease between the inner 2 seals will also prevent water incursion, which ruined one of mine in 3 months. I'm lucky to have a parts store with a machine shop in the back. I get the bearings for about $60 and the press for about $30. They may press in my sourced parts, but I like the quick turn service I get there, for the most part. Well it sounds like I need maybe both rears. Do the rears seem to go more often? I hate the thought of junk yard parts, might last a while or just a month. OIY. If I buy new bearings & seals, where is best source for quality & good deal? Can I order from a bearing supplier, or best to get dealer only? Are all subies same? I have a 1999 impreza L 4 door. Edited January 18, 2012 by uniberp Quote Link to comment Share on other sites More sharing options...
bork Posted January 17, 2012 Share Posted January 17, 2012 Once the long bolt is out, bushing is used over? or replaced? If replaced , I could torch out. Hate having spend the bucks on new bolts, because I see the dealer item, is a little pricey. The bearings & seals are the same on all models? I have a 99 imprezza L sedan. Are any part #s available? Quote Link to comment Share on other sites More sharing options...
uniberp Posted January 18, 2012 Author Share Posted January 18, 2012 (edited) sOnce the long bolt is out, bushing is used over? or replaced? If replaced , I could torch out. Hate having spend the bucks on new bolts, because I see the dealer item, is a little pricey. The bearings & seals are the same on all models? I have a 99 imprezza L sedan. Are any part #s available? Yes the bushing was preserved and used again. Equal difficulty to push the cut-off bolt out or push a new bushing in, IMO. I don't like the torch idea on welded links or just the idea of fire. I got used bolts from pick-a-part, and nobody but dealer has that 145x14mm(?) size. But like I said, you can get the front lateral arm off the bolt, undo all other bolts and brake lines, and you may be able to slide the knuckle forward off the bolt, leaving the bolt stuck intact in the rear bushing. The rear is the problem because you have no place to lever it. The front arm and knuckle can be levered against the rear bushing collar. See the 3rd pic of my link. Any parts store has the listing for the part. There's a couple expert ebay specialist sellers too. Edited January 18, 2012 by uniberp Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 18, 2012 Share Posted January 18, 2012 (edited) I replace rear bearings (yes Forester's too) using the FWD service set from Harbor Freight ($89 or so) - never remove the knuckle. I've done dozens of them. I have yet to have a repeat failure. I use NTN bearings ($34) and the grease that comes with them. New seals too of course. GD Edited January 18, 2012 by GeneralDisorder Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 18, 2012 Share Posted January 18, 2012 FWIW, these are not sealed bearings.There is no seal built into the bearing. I just looked at the new NTN bearings I have on the shelf, and they are not sealed either. The hub has have external press-in seals. 2 inner and 1 outer. The seals on the hub CREATE a sealed cavity. If you pack it full of grease then you have the same problem. For all intents and purposes the bearing IS sealed inside the knuckle. GD Quote Link to comment Share on other sites More sharing options...
bork Posted January 18, 2012 Share Posted January 18, 2012 (edited) I replace rear bearings (yes Forester's too) using the FWD service set from Harbor Freight ($89 or so) - never remove the knuckle. I've done dozens of them. I have yet to have a repeat failure. I use NTN bearings ($34) and the grease that comes with them. New seals too of course. GD So HF has the FWD set. Is that what they call it? what does it include? any pic links to such ? Where is the best source for the NTN bearings & the seals? On edit, are most of the failed bearings dry, inside? If "yes" any way of using a hypodermic needle, to get a few drops of oil into bearing? (to but a little time, if bearings not real loud yet) Edited January 18, 2012 by bork Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 18, 2012 Share Posted January 18, 2012 (edited) So HF has the FWD set. Is that what they call it? what does it include? any pic links to such ? Sure: http://www.harborfreight.com/fwd-front-wheel-bearing-adapters-66829.html It works fabulously. The only thing it can't do is remove the outer bearing cone from the hub. But that's easily accomplished with a bearing splitter and a bit of ingenuity. Such as this one: http://www.harborfreight.com/bearing-separator-and-puller-set-93980.html And remember - you can buy these and return them within 30 days. Harbor Freight is really good about that. I use mine all the time and they have more than paid for themselves. I also have to say that Harbor Frieght has really excellent customer service. I recently called to order a new lead screw and replacement washers for my FWD bearing set and the cost was $14 shipped for two lead screws and six washers (ordered extra for future wear and tear). Where is the best source for the NTN bearings & the seals? Being a professional mechanic I have a business account with a local supplier - unfortunately that probably won't help you. I would find the part number and google it - probably find them on Amazon or rockauto, etc. On edit, are most of the failed bearings dry, inside? If "yes" any way of using a hypodermic needle, to get a few drops of oil into bearing? (to but a little time, if bearings not real loud yet) No - most of the failed bearings are not dry inside. They are usually just chewed up and loose. Sometimes the bearing cone's will spin on the hub and eat material off it. Then you have to go searching for a used hub. I've done tons of these bearings - never taken a knuckle off the car for it unless it was already off for another reason (usually front knuckles), and the whole job takes about an hour. $34 for a bearing, and $12 for all the seals typically. I've got a customer with 89k on one of the first bearings I did with this tool set. Still going strong. He just blew a driveline u-joint the other day and I had it on the lift - I checked out that bearing just for kicks and it's still tight like the day I installed it. GD Edited January 18, 2012 by GeneralDisorder Quote Link to comment Share on other sites More sharing options...
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