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Dish washer in rear hub assembly - is it needed anyway?
#1
I'm hoping somebody can help me over the issue of the washer which is supposed to go between rear hub inner and the bearing.  

I'm putting together an axle from bits and don't have any washers to look at. The question I guess is whether they are needed or not?   I seem to remember that they are needed to ensure correct fit of bearing in hub, but can't find confirmation of this. What I can't establish is whether the washer fits between hub and bearing or is it between bearing centre and axle casing? Obviously it can only fit tightly between one of the two!

I am using sealed bearings so leakage of oil/grease not an issue here. 

See Cornwall site for line drawing - unfortunately too low res to answer the question.

Sorry for wordy post.  Seeking guidance thanks..

Damian.


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#2
You will need the dished washer or a washer of the same thickness so that the bearing's outer track is pinched by the inner and outer hub parts once the hub setscrews and wheelnuts are tightened. Leaving it out would lead to the hub turning on the bearing outer sooner or later; something which seems to be a problem with some hubs anyway.
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#3
Thanks.  Does anyone supply them?

If not, is anyone able to measure thickness for me?
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#4
Sad 
I've just measured the only one I could find in a whole crate full of hubs  Sad it's .030" thick. Despite my experience, it shouldn't be hard to find these as they're a non wearing part.
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#5
(28-10-2018, 12:59 PM)Damian GT Wrote: Thanks.  Does anyone supply them?

If not, is anyone able to measure thickness for me?

Whilst there's no picture on his web site, I think David Cochrane's part number BO47 is what you're after, Damien. I bought a set some while back and I'm sure that's where they came from. I can't find them on Seven Workshop's site but might be worth a phone call also. 

Steve
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#6
Thanks both - really helpful...
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#7
As above, the assembled hub halves, with whatever gasket or substitute, and originally with the raised side of the washer against the felt seal, should clamp the race outer ring. The depths can be investigated with vernier calliper set. However, except as it affects seal operation, and with a sealed bearing will allow any oil past the outer ring, slight movement of the  bearing in housing is of little consequence. (Other makes have considerable freedom) At the front must be rigid. Hard thick paper will adjust itself nicely!

If using unsealed bearings, pack little more than the race whenever apart. Pumping the hub full as old handbooks is  folly unless regularly wading.
Sealed bearings are not intended to work as oil barriers although do.

As above axle tube ends are usually ridged and worn and I am surprised modern seals work. Ideally no diff oil should reach. modern wheel bearing greses very stable and used sparingly almost any seal will retain provided no diff oil.
Incidentally standard advice is to only part fill diff.
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#8
On my Ruby, I have got sealed bearings all round, at the front, I retained the felt seal & washer, but at the rear, on both sides, the washer prevented the bearing from seating satisfactorily on the inner hub, it would pop out very easily, so I omitted both the felt seal & washer. My outer rear hubs were new and fitted onto new drive shafts. So, my experience, there is a better clamping of the bearing without the washer. It has been like this for over 3 years now and I had to take it all apart this summer as part of other work and I thought I would revert back to re-fitting the felt seal & washer, but it just did not fit as well, so back it went again without - perhaps the sealed bearings are slightly different???
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#9
(29-10-2018, 01:05 AM)GK5268 Wrote: On my Ruby, I have got sealed bearings all round, at the front, I retained the felt seal & washer, but at the rear, on both sides, the washer prevented the bearing from seating satisfactorily on the inner hub, it would pop out very easily, so I omitted both the felt seal & washer. My outer rear hubs were new and fitted onto new drive shafts. So, my experience, there is a better clamping of the bearing without the washer. It has been like this for over 3 years now and I had to take it all apart this summer as part of other work and I thought I would revert back to re-fitting the felt seal & washer, but it just did not fit as well, so back it went again without - perhaps the sealed bearings are slightly different???

The bearing is half and half in the hub and 'Felt Housing'' and should be a good fit in both. 

If the bearing popped out easily from the Felt Housing the bearing seat is worn (or stretched ).

The felt washer (around the correct way) is necessary to fill the bearing space  as shown in the picture above- all wheel bearings sealed and unsealed are the same width.
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#10
Damian
Just to try and clear up some of what may be confusing terminology and explanations  in the posts so far.
The "inner hub" is actually properly called the felt housing.
The washer is dished around part of its inner radius so that it sticks out towards the felt seal and will not touch the inner race of the bearing so it is free to rotate with the felt housing and outer bearing race.
The outer radius of the washer is trapped between the bearing outer race and the felt housing.  If the washer is left out then the gap between outer race and felt housing would allow the hub outer, outer race and half shaft to move towards and away from the axle banjo direction (end float of the whole hub assembly)
It is probably difficult to see from that picture that the bearing inner race has a nut which tightens up against the front face of the inner race and pushes it back so that the rear face goes up against a shoulder on the axle case so holding it firmly in place against the axle casing.
The (outer) hub is held tight on the half-shaft taper and has screws which pull the felt housing (which is free to rotate independent of the axle casing) tight against the hub. The bearing sits half in the felt housing and half in the hub.
the only connection between inner and outer races are the balls of the bearing.
With the washer missing there is a gap between outer race and the felt housing; since the inner race is firmly held against the axle casing it will not move, but the half-shaft/hub/felt housing assembly can move in and out by the amount of the thickness of the missing washer such that with the inner race held tight and the outer race held in place via the balls the outer circumference of the outer race will slide in the housings of the hub and felt carrier (end float).
The outer race should be a good press fit in the hub and felt housing, so, as in one of the examples above with the washer missing it may not be obvious at first that there is anything wrong..........however this WILL lead in the end to rapid wear of the felt housing and hub as they slide in and out over the outer race so that the bearing becomes a sloppy fit in them resulting in ruined felt housing, hub and wobbly wheels. 
There should be no reason why a correctly machined hub and felt housing with correct washer would not fit together clamping the correct bearing in place.

GK5268 is making matters worse by not having the washer (which must be the dished type) in place.....perhaps he has the wrong too thick felts which will not compress sufficiently??  But eventually those nice new hubs and the felt carriers will be prematurely ruined.  Without the washer there is NO clamping of the hub/felt housing and outer bearing race

Where it is found that the felt carrier and hub housings are a bit worn so the outer bearing race is not an easy press fit but a loose fit then one of the LOCTITE bearing fit fluids can be used.....but do check up on which one to use as there are several to chose from according to how much wear there is.

Dennis
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