Sealed bearings

Discussion in 'Mechanic and Repair' started by 1grnlwn, Feb 23, 2003.

  1. 1grnlwn

    1grnlwn LawnSite Bronze Member
    Posts: 1,261

    I am looking at new mowers(pls no mwr recomds) the exmarks I looked at have sealed bearings on the spindles. I was pretty shocked! The dealer piped up yep there guaranteed for 3 years. This doesn't impress me since my mowers get pretty low hours and if all bearings fail at 3 years two months. Is there a good history for sealed bearings on spindles?

    Thanks

    Mark
     
  2. mower17

    mower17 LawnSite Member
    from la
    Posts: 26

    Yes the sealed bearing last quite long. Keep in mind that if you prefer the bearing with a grease zerk on them all you have to do is remove one of the sealed bearings, pop off one of the side covers on it and drill a whole in the side of the spindle housing and install a grease zerk. Then you have a normal greaseable spindle. I have seen this trick done several times. Many people say the greaseable spindles lasts way longer so it is up to you. If you are hard on them I would go for the greaseable ones. But be careful, some people don't clean the zerk off before putting grease and then they get dirt in the spindle and they won't last long that way. Hope his helps.:D
     
  3. djsmokin

    djsmokin LawnSite Member
    Posts: 127

    Sealed bearings make a guy wonder how long they will last, but the car manufacturers have been doing that on wheel bearings now for many years. We used to pull bearings at about 25,000 miles and pack em. Now I have heard of them going 175,000 miles.
     
  4. proscaper

    proscaper LawnSite Member
    Posts: 40

    Same thing with U joints. I have a chevy van with factory sealed U joints and it has 190,000 on the original set.

    Josh
     
  5. 65hoss

    65hoss LawnSite Fanatic
    Posts: 6,360

    Hey Mark, all my eXmarks have the sealed bearings. I've not had one single failure.
     
  6. 1grnlwn

    1grnlwn LawnSite Bronze Member
    Posts: 1,261

    Thanks, I will keep looking and thinking. It would save some time. I am not a religious greaser (pls forgive me) anyway.
    Mark
     
  7. allenandinga

    allenandinga LawnSite Member
    Posts: 33

    Exmark chose to go to sealed bearings in an effort to stop rapid spindle bearing failures that had been plagueing them for years.

    The problem was not the greaseable bearings they used to use and the problem was not solved by changing to the sealed ones. This problem was solved by a blade bolt change. The older bolts (on the 52'' decks for example) was a standard thread bolt that was threaded all the way to the head (the threads on the bolt centered the blade). After the blade spins on the threads a few times (there is nothing to hold the blade still but the tightness of the bolt), the threads get worn down resulting in a bolt that is now too small to fit the hole in the blade tightly (blade runs out of balance from not being centered causing premature bearing failure). When the same bolts are reused after bearing replacement, the problem appears again sooner than it should. I have found this to be the case on every Exmark mower in my shop that has had a rapid bearing failure problem. Since I found this to be the cause and sell Toro instead of Exmark, I have only told my uncle about this (he bought a used Exmark from one of my other customers and has had this problem repeatedly). We put a new set of blade bolts on his mower after the last bearing replacement and I told him to keep a check on the bolts every time he has the blades off and replace as needed with grade 8 bolts. Every time I see him I ask him how his bearings are holding up. He has not a bearing failure yet. It has been 2 yrs since the last time his bearings were repleced. Prior to that it was every 3 months.

    The new bolts Exmark is using are not threaded all the way to the head so it has a solid shoulder now to center the blade that will last much longer the threads did before it gets worn down and has to be replaced.

    If they really wanted to fix this problem, they should use a welded-to-the-shaft saddle to hold the blade locked to the shaft like Toro does. Toro has never had this problem.
     
  8. Mr.Wrench

    Mr.Wrench LawnSite Member
    from N.H.
    Posts: 65

    Allen, Exmark is also only selling complete spindle assemblies. If you try to order new bearings seperately they will not sell them to you. At the last meeting they said that they were finding that at the service shops the assemblies were not going together perfectly straight and there was to much sideload being put on the bearings when people tried to press the assembly back together. They got rid of the grease fittings becuase the were a source of not only grease, but dirt and water as well. If you drill a hole in the new housing and pack it full of grease it won't do you much good. The new bearings are sheilded and won't take grease. The new bearings are also speced by exmark to be fully packed with grease, instead of only half packed as with standard sealed bearings. We have a ton of Exmarks out there with sealed bearings. mostly Lazers, Lazer Hps, and Turf Tracers. We have only had 2 failures due to other causes, no fault of the bearing itself.
    A lot of the problems with the bolts came from people not torquing the blades properly. We see this 10 times a week in the summer from our landscapers. They send the bolt home with a 1/2" impact gun. When they hit a rock or whatever they come accross the blade actually tightens the bolt to twice it's specified torque value. Sometimes they will snap, and sometimes you need to cut the head off to remove the blade.
    Josh
     
  9. allenandinga

    allenandinga LawnSite Member
    Posts: 33

    I have replaced ALOT of these bearings myself and don't know what they could possibly be talking about by saying they're not going back together straight. There is only one way they will go back together right. The only thing you could do wrong is not put the parts back in the right order in which case you probably couldn't get it to go back together at all. Exmark is not the only place you can get bearings to replace the old ones with. You can the exact same bearings they were built with from a parts house. Same manufacturer, same part #. Snapper also sells a bearing that is the same size and will work and costs less than buying from a parts house.

    I agree with everything you said about the bolts being tightened by hitting something and this is also the cause of the threads being worn down. Bolts getting to tight is another reason Exmark should put a blade saddle on the bottom of their shafts like Toro. The saddle would fix that problem too.

    In case you don't know why they don't, the reason is they say when you weld a saddle on the bottom of the shaft, there is no way for it to come out perfectly square like their machined pinch-tight shaft (sounds like someone at Exmark can't weld to me). As a master welder myself, I can vouch for the fact that this is not at all true. There is a very easy way to make sure it comes true. They also say that if you have the blade locked to the shaft and hit something, the shaft will bend much easier causing a more costly repair. I have never seen a Toro with a bent shaft. I have seen blades almost doubled over but no bent shaft.

    BTW Exmark is only selling whole spindle assemblies because they want you to buy a more expensive part. I hope you don't think that no one can replace the bearings in their spindles correctly.
     
  10. Mr.Wrench

    Mr.Wrench LawnSite Member
    from N.H.
    Posts: 65

    Allen, I agree 100% with everything you said. Its all about the warrantee:D.
     

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