Author Topic: Cb750f rear caliper  (Read 708 times)

Offline Snednil

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Cb750f rear caliper
« on: February 14, 2021, 10:01:19 PM »
Evening all,
Appreciate a  little advice if anyone can help....
Rear disc is sticking on caliper so either something in wrong place or missing!!
Hopefully pic below will help....

Offline hairygit

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Re: Cb750f rear caliper
« Reply #1 on: February 14, 2021, 10:30:33 PM »
Have you replaced the wheel bearings? If the disc is touching the caliper, it is possible that the wheel bearing on the caliper side of the shell has not been tapped fully home, resulting in the retainer ring not screwing home quite as far as it should, which in turn allows the disc to be located incorrectly in relation to the caliper.

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Offline JamesH

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Re: Cb750f rear caliper
« Reply #2 on: February 14, 2021, 10:56:27 PM »
Have you replaced the wheel bearings? If the disc is touching the caliper, it is possible that the wheel bearing on the caliper side of the shell has not been tapped fully home, resulting in the retainer ring not screwing home quite as far as it should, which in turn allows the disc to be located incorrectly in relation to the caliper.

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Looking at the picture I strongly suspect that hairy is bang on the money with his analysis..

Offline K2-K6

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Re: Cb750f rear caliper
« Reply #3 on: February 14, 2021, 11:07:25 PM »
Have you replaced the wheel bearings? If the disc is touching the caliper, it is possible that the wheel bearing on the caliper side of the shell has not been tapped fully home, resulting in the retainer ring not screwing home quite as far as it should, which in turn allows the disc to be located incorrectly in relation to the caliper.

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Looking at the picture I strongly suspect that hairy is bang on the money with his analysis..

Adding to this, try doing the axle nut up with a big enough spanner,  if the wheel bearing is not fully home this will push it into place by squeezing the the whole assembly. 

Offline hairygit

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Re: Cb750f rear caliper
« Reply #4 on: February 14, 2021, 11:14:02 PM »
I wouldn't advise the last suggestion as the spacer will be pressing on the inner race, which may well damage it. Safest to remove the wheel and bearing locking ring, then with a drift or large socket tap the OUTSIDE race home to its shoulder, then replace locking ring and refit the wheel, problem should be gone.

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Offline Snednil

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Re: Cb750f rear caliper
« Reply #5 on: February 15, 2021, 06:28:00 AM »
Thank you all for reply. Yes I have put new bearings in, will remove today and look into it and let you know how it goes.

Offline K2-K6

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Re: Cb750f rear caliper
« Reply #6 on: February 15, 2021, 09:32:12 AM »
I wouldn't advise the last suggestion as the spacer will be pressing on the inner race, which may well damage it. Safest to remove the wheel and bearing locking ring, then with a drift or large socket tap the OUTSIDE race home to its shoulder, then replace locking ring and refit the wheel, problem should be gone.

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While I'd agree that general principles would have the loaded race pushed to avoid going through the bearing's rotating components, these rear wheel bearings will easily take that side loading.

They are, in use, subjected to significant side loading which is why they are designed with retainers to prevent the wheel assembly "shuffling" across the bearings when ridden. Along with the bearing track engagement sufficient to accept that load path.

Offline Spitfire

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Re: Cb750f rear caliper
« Reply #7 on: February 15, 2021, 07:52:59 PM »
Looking at mine that retainer is sticking out a bit more.


Dennis
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

Offline Snednil

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Re: Cb750f rear caliper
« Reply #8 on: February 16, 2021, 09:33:02 PM »
Sorted, exactly as hairygit had described.
Cheers all

Offline hairygit

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Re: Cb750f rear caliper
« Reply #9 on: February 16, 2021, 09:49:19 PM »
Glad it's sorted, I've seen it a few times over the years. I've seen drastic bodges to deal with it as well, such as grinding the wheel to caliper spacer down, didn't sort it! The worst one someone took an angle grinder to the edge of the caliper to get clearance, then found that they couldn't get the inner pad in!

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