1973 Commando rear drum brake assembly

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MLW9110

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I'm reinstalling my rear wheel after putting a new tire on. Items 30, 45 and 46 in the parts diagram are missing. The felt washer and retaining washers are missing from between the wheel hub bearing and the brake drum also.

Are these felt washers and retaining rings removed for some reason?

Item 21, brake plate backing washer is missing too. It looks like that one goes between the dummy axle and the hub. It would be captured inside the assembly. Is that correct?

Mike
Bremerton, WA



I
1973 Commando rear drum brake assembly
1973 Commando rear drum brake assembly
 
I'm thinking that because the bearings have been replaced with sealed bearings, the felt seals aren't necessary.

The bearing installed is a Fafnir 5203KDD3. Now I think the brake drum has been modified to use a slightly wider bearing.
 
Last edited:
MLW9110 said:
Item 21, brake plate backing washer is missing too.
Click to expand...
MLW9110 said:
It looks like that one goes between the dummy axle and the hub.
Click to expand...
That part was fitted as required marked "AR" in the parts books so if it's not there then it probably doesn't need to be. It fits between the dummy axle and the brake plate which I assume is what you actually meant.

I'm thinking that because the bearings have been replaced with sealed bearings, the felt seals aren't necessary.
Click to expand...

Correct.
 
L.A.B. said:
That part was fitted as required marked "AR" in the parts books so if it's not there then it probably doesn't need to be. It fits between the dummy axle and the brake plate which I assume is what you actually meant.



Correct.
Click to expand...
Thanks! On to my next conundrum!
 
L.A.B. said:
That part was fitted as required marked "AR" in the parts books so if it's not there then it probably doesn't need to be. It fits between the dummy axle and the brake plate which I assume is what you actually meant.



Correct.
Click to expand...
Is the AR shim for creating clearance of pllate to drum and the drum rivet heads? I think Paul Henshaw on his you tube channel recently needed to shim a norton rear hub that was making a scraping sound and witness marks on drum rivet heads.
 
Tornado said:
Is the AR shim for creating clearance of pllate to drum and the drum rivet heads? I think Paul Henshaw on his you tube channel recently needed to shim a norton rear hub that was making a scraping sound and witness marks on drum rivet heads.
Click to expand...

Yes, the shim 21 is to provide additional clearance when necessary.
 
I have a couple of related questions: my double row bearing in the hub is sealed, so it appears I don't need the felt bits. But if I did put in the washer, felt and dished washer - how do they stay in? The dished washer is not a tight enough fit to hold everything.

1973 Commando rear drum brake assembly


Next question: the diagram shows the speedo spacer inserted from the outside of the gear, but it does fit very snugly into that recess on the inside of the gear.... Can someone please confirm it goes from the outside and that the recess has nothing to do with the spacer?

1973 Commando rear drum brake assembly
 
OK, I have one like that in the box.
Should the felt be greased or oiled before inserting it? Are these parts totally unnecessary with sealed bearings, or would they still serve to keep crap out, so should be used since I have them anyway?
 
MLW9110 said:
I'm reinstalling my rear wheel after putting a new tire on. Items 30, 45 and 46 in the parts diagram are missing. The felt washer and retaining washers are missing from between the wheel hub bearing and the brake drum also.

Are these felt washers and retaining rings removed for some reason?

Item 21, brake plate backing washer is missing too. It looks like that one goes between the dummy axle and the hub. It would be captured inside the assembly. Is that correct?

Mike
Bremerton, WA



IView attachment 120927View attachment 120926
Click to expand...
The drawing is confusing about #21. It goes on the dummy axel where shown but is directly behind the brake plate to space it out a little. In other words, between the dummy axel and brake plate.

If the drum and brake plate rub without it, use it. You can use more than one if needed to stop the scraping but if you need two or more, your brake plate is probably bent. One is almost always needed.
 
Do you have the inner and outer dimension for the retainer so I can check please?

I guess the purpose is to stop the felt getting drawn into the bearing, so the correct one would be good. If I don't have the right one then my decision to not fit these bits can be made
 
When refitting the wheel, take care not to use the workshop booked spec'd 70ft-lbs on the axle nut...it can squash the potmetal of the speedo drive unit, which can force it into contact with the alu hub cover plate, leading to self-machining and sufficient heat build up to liquify the drive's grease, giving the infamous "Black Star of Death" streaks over the hub. Hot tip is to go with 45 to 50 ft-lbs max on axle nut.
 
GraemeH said:
Do you have the inner and outer dimension for the retainer so I can check please?

I guess the purpose is to stop the felt getting drawn into the bearing, so the correct one would be good. If I don't have the right one then my decision to not fit these bits can be made
Click to expand...
However although I don't have a spare here's an old picture of it in position so you can hopefully see it's not the same as the one in your picture, this is from my Mk3's front wheel as the Mk3 rear wheel doesn't have that felt retaining washer.
1973 Commando rear drum brake assembly
 

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