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General Category => General Discussion => Topic started by: sign216 on September 12, 2019, 09:10:37 AM
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Changing the front wheel tube on my '65 Sears/Gilera 106SS, and the brake drum was press-fit tight onto the axle, such that I really had to hammer it out. So tight I could never change the tube on the road w/out taking a hammer along.
Was this designed this way, to hold the axle stationary, or is it a flaw?
I.e. can I relieve the brake drum hole, to stop this death-grip?
Joe
P.S. This isn't my brake housing, but an example photo.
(https://i.ebayimg.com/images/g/yI4AAOSwUWpa394C/s-l500.jpg)
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Well, I'm not really an expert, but, I'll put up my opinion.
Decades of experience with drum brakes on motorcycles and have never seen a pressed in axle on the brake drum or backing plate.
I did have issue with my Norton axle once due to corrosion. I had to cut the axle to remove the wheel then press the remains apart, new axle received a good coating of grease on install.
Two things I would explore. Verify you have the correct parts combination, if possible. Clean up the bore and axle. The fit should be a loose sliding fit. As previously mentioned grease on install.
Axles are normally steel, brakes alloy. This sets up conditions for dissimilar metal corrosion leading to a press apart fit.
Best of luck, let us know the results.
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Oddly enough I've actually performed the exact same task , don't remember it being more than a snug fit . Removing a couple of thou from the axle hole won't harm anything , I would also polish the axle with some Emory cloth , and apply a very light amount of grease when reassembling .
Dusty
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It's not really "press fit" just crazy tight. Gilera, to their credit, put a steel bushing in the alum brake housing.
The axle is smooth, and no corrosion.
I was going to sand the housing hole a little, but wanted to make sure this wasn't an intentional design element.
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It's not really "press fit" just crazy tight. Gilera, to their credit, put a steel bushing in the alum brake housing.
The axle is smooth, and no corrosion.
I was going to sand the housing hole a little, but wanted to make sure this wasn't an intentional design element.
It needs to be snug so the drum stays true , it doesn't need to be so tight that force is needed to remove the axle . Wrap some fine Emory cloth around the chuck end of a drill bit that fits snugly in the hole and give it a few spins , check the fit , repeat until it feels right. If you don't have a bit that large , a short length of PVC will work .
Dusty
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Also Joe , wouldn't hurt while you have the axle out to make sure it is still dead straight. I use my cast iron table saw platen and a flashlight, a pane of glass works well too. Doesn't take much of a warp to make a tight fit well, you know. Sears, h'mm lifetime warranty? Good luck with it.
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Also Joe , wouldn't hurt while you have the axle out to make sure it is still dead straight. I use my cast iron table saw platen and a flashlight, a pane of glass works well too. Doesn't take much of a warp to make a tight fit well, you know. Sears, h'mm lifetime warranty? Good luck with it.
Dave,
Good idea. I'm not so sure this cycle has the lifetime warranty. But if the axle isn't true, I'll see what they say.
Dusty,
I'll give the housing a touch w the dremel. Thanks,
Joe
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On Loopframe Guzzis, there is (supposed to be) a washer between the shoulder of the axle and the brake backing plate. When this is missing, the axle bore of the backing plate can become distorted (smashed in) by the axle and the result is the axle fits very tightly.
Shouldn't happen on your Sears/Gilera though if it has a steel sleeve.
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Dave,
Good idea. I'm not so sure this cycle has the lifetime warranty. But if the axle isn't true, I'll see what they say.
Dusty,
I'll give the housing a touch w the dremel. Thanks,
Joe
Not sure using a Dremel is wise , too easy to remove more than intended . Just find something close to the inner diameter of the hole, wrap some Emory cloth around it , and spin it by hand . You want to keep it round so the drum stays true . Remember , you are working on a soft alloy , not steel .
Dusty
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Not sure using a Dremel is wise , too easy to remove more than intended . Just find something close to the inner diameter of the hole, wrap some Emory cloth around it , and spin it by hand . You want to keep it round so the drum stays true . Remember , you are working on a soft alloy , not steel .
Dusty
It's not really "press fit" just crazy tight. Gilera, to their credit, put a steel bushing in the alum brake housing.
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Dusty and Antietam,
My mistake, although it looks like a separate bushing, it's actually aluminum and part of the housing.
Antietam,
It sounds like I may have issued you described re the washer. Could you explain what this problem is?
Attached is a parts diagram of the wheel.
Joe
(https://i.ibb.co/XZ5XFQZ/Front-Wheel-diagram.jpg) (https://ibb.co/XZ5XFQZ)
flip a freebie (https://freeonlinedice.com/)
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Sign, looking at your diagram I would think the fit of the shaft to the housing should be the same as the fit of the bearing to the shaft. When lubed, a nice smooth fit with no rocking or tight spots. My $.02
Paul B :boozing:
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Dusty and Antietam,
My mistake, although it looks like a separate bushing, it's actually aluminum and part of the housing.
Antietam,
It sounds like I may have issued you described re the washer. Could you explain what this problem is?
Attached is a parts diagram of the wheel.
Joe
(https://i.ibb.co/XZ5XFQZ/Front-Wheel-diagram.jpg) (https://ibb.co/XZ5XFQZ)
flip a freebie (https://freeonlinedice.com/)
Although your parts diagram doesn't show one fitted originally, it might be a good idea to slip a washer on the axle before it goes through the backing plate, if there's room. The washer spreads the load over a wider area instead on it being concentrated around the shoulder area of the axle. When the axle nut is torqued down tight (especially if done up too tightly) the shoulder can deform the backing plate and effectively "crimp" the outer edge of the hole inwards slightly.
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Although your parts diagram doesn't show one fitted originally, it might be a good idea to slip a washer on the axle before it goes through the backing plate, if there's room. The washer spreads the load over a wider area instead on it being concentrated around the shoulder area of the axle. When the axle nut is torqued down tight (especially if done up too tightly) the shoulder can deform the backing plate and effectively "crimp" the outer edge of the hole inwards slightly.
Antietam,
There's precious little room, but maybe I can fit a thin (or shim) washer in there. Thanks for looking at this.
Joe