Classic cars forum & vehicle restoration.
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ukdave2002
Joined: 23 Nov 2007 Posts: 4104 Location: South Cheshire
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Posted: Thu Feb 27, 2014 7:38 pm Post subject: Sealed Bearings in a pre war gearbox |
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I rebuild a few box's for follk; on my 3rd Morris 8 box this year!
Originally the bearings were open but with a shield. The shields have to stay as they affect the position of the mainshaft, however.....
Recently I have been using "RS"spec bearings ie they are sealed, but I pick one of the seals out when the bearing is at at the "end" of a gearbox; this means that oil is restricted "out" of the box, but normal gearbox oil can flow to both lubricate and cool the bearings.
In the case of the Morris 8 and the Morris 10, the gearbox is over engineered, and nearly all bearing failure is down to contamination...I'm thinking of using completely sealed bearing in the future...
Any thoughts?
Dave |
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colwyn500
Joined: 21 Oct 2012 Posts: 1745 Location: Nairn, Scotland
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Posted: Thu Feb 27, 2014 8:39 pm Post subject: |
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Dave, I used to work on commercial mowers such as those you see dragged behind a tractor on a playing field. We used lots of bearings on the cutting cylinders which were meant to get greased every day. We experimented using sealed bearings to get around the occasional neglect and the very hostile environment. They did last a bit longer but not much. Quite often the sealing discs got pushed out in any case. |
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goneps
Joined: 18 Jun 2013 Posts: 601 Location: Auckland, New Zealand
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Posted: Fri Mar 07, 2014 10:35 pm Post subject: |
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Dave,
Why buy sealed bearings for a gearbox? Surely standard 'open' bearings are the correct choice?
Richard |
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ukdave2002
Joined: 23 Nov 2007 Posts: 4104 Location: South Cheshire
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Posted: Tue Mar 11, 2014 11:19 am Post subject: |
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goneps wrote: | Dave,
Why buy sealed bearings for a gearbox? Surely standard 'open' bearings are the correct choice?
Richard |
Mainly to reduce bearing wear, but also to help keep the oil in the box..
I recently rebuilt a high mileage modern box, the bearings were sealed and didn't really need replacing. Most people don't change gearbox oil very frequently; open bearings will get contaminated and wear accelerated.
Its probably a mute point given the low mileage that most of our cars do, but leaving a seal in the bearing at each end of the Morris 8 4 speed box should certainly help to keep the oil in .
Cheers
Dave |
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goneps
Joined: 18 Jun 2013 Posts: 601 Location: Auckland, New Zealand
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Posted: Tue Mar 11, 2014 9:44 pm Post subject: |
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ukdave2002 wrote: | Its probably a moot point given the low mileage that most of our cars do, but leaving a seal in the bearing at each end of the Morris 8 4 speed box should certainly help to keep the oil in . |
Hmm... This has a ring of desperation about it, Dave! If you really want to keep the oil in it's relatively simple to fit lip seals—but you know that as well as anyone.
And did you really mean to say "the Morris 8 4-speed box", or was that a typo? Either way, whether an 8 3-speed or E 4-speed, lip seals are the answer. In both cases there's still the matter of unsealed selector shafts going straight through into the bell housing.
Richard |
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ukdave2002
Joined: 23 Nov 2007 Posts: 4104 Location: South Cheshire
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Posted: Sat Mar 22, 2014 8:09 pm Post subject: |
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goneps wrote: | ukdave2002 wrote: | Its probably a moot point given the low mileage that most of our cars do, but leaving a seal in the bearing at each end of the Morris 8 4 speed box should certainly help to keep the oil in . |
Hmm... This has a ring of desperation about it, Dave! If you really want to keep the oil in it's relatively simple to fit lip seals—but you know that as well as anyone.
And did you really mean to say "the Morris 8 4-speed box", or was that a typo? Either way, whether an 8 3-speed or E 4-speed, lip seals are the answer. In both cases there's still the matter of unsealed selector shafts going straight through into the bell housing.
Richard |
Hi Richard
Not so much desperation but simplicity it struck me that whilst I have been machining bits of box's to keep oil in , that by using sealed bearings anyone could archive the same oil containment results without having to machine anything.
I called it a Morris 8 4 speed box as I thought most folk who run 8's would know it's from the Morris 8 SE !
Cheers
Dave |
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goneps
Joined: 18 Jun 2013 Posts: 601 Location: Auckland, New Zealand
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Posted: Sat Mar 22, 2014 9:36 pm Post subject: |
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Dave,
I wonder about the effectiveness of bearing seals in dealing with oil. After all, their principal job is to keep dirt out, and then to retain the pre-packed bearing grease. I wouldn't expect them to be as effective as a lip seal.
Richard |
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Miken
Joined: 24 Dec 2012 Posts: 544
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Posted: Sat Mar 29, 2014 9:01 pm Post subject: |
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I have fitted shielded bearings to many classic motorcycle gearboxes over the years.
I use a single shielded bearing with the shield outboard. then fit the actual oil seal in front of this as standard. I fill the gap between the 2 with grease. So the bearing is still lubricated with gearbox oil.
Its a belt and braces method of getting 2 seals . I have never had a British bike that leaks oil (from here).
Ive just done a similar mod to the rear hubs of my pre war Morris.. I have fitted double shielded bearings to the hubs and machined the hubs to accept modern lip seals to keep any diff oil that may get past the sealed bearings in. So replacing the original felt seals.
I am not expecting any leaks.
Mike |
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