Author Topic: Sloppy Foot Brake Repair?  (Read 1174 times)

pinholenz

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Sloppy Foot Brake Repair?
« on: October 16, 2017, 05:08:32 PM »
I have a lot of wear in the aluminium casing where the foot brake pedal shaft protrudes through the casing. Have others engineered a cure for their sloppy foot brake with a bush or similar?
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pinholenz

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Re: Sloppy Foot Brake Repair?
« Reply #1 on: October 17, 2017, 05:12:36 AM »
Chewing it over I have decided to  have the brake side plate hole machined out and a bronze bush pressed in.

The brake spigot (with the spline on) has a diameter of just under 20mm. Therefore I will insert a bronze bush with an ID of 20mm, OD of 24mm and a length of 40mm. I have picked this up from my local bearing wholesaler for the princely sum of NZ$15.

Self lubricating plastic bushes would be cheaper but aren't available locally;  a self lubricating sintered bronze bush would be a sexy option too. However the heat generated by my foot brake shaft is hardly likely to get the oil in that type of bush moving.

I figured metal on aluminium has done OK for the last 35 years; the plain old bronze bush repair should be good for at least another 50 years. Long after I am dead!

I started to get annoyed with the wear when I noticed that the sideways movement in my brake pedal was marking up the clutch housing.
« Last Edit: October 18, 2017, 12:52:19 AM by pinholenz »
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Walt_M.

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Re: Sloppy Foot Brake Repair?
« Reply #2 on: October 17, 2017, 08:32:42 AM »
That seems like a good solution. Should last a long time.
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Rikugun

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Re: Sloppy Foot Brake Repair?
« Reply #3 on: October 19, 2017, 09:38:18 AM »
I'm a little surprised there is so much wear in that direction. Is some of the play in & out? That can be addressed with little to no cost and may be sufficient to keep the pedal off the case. Also, if the lever has been bent by a drop on that side that may be exasperating the problem.

As I write this I've realized how thorough you have been in your XZ journey so I'm guessing you're diagnosis is spot on. I'll leave my post up just to mention another area to look for slop for those who might otherwise rush into a more expensive repair without exploring all options.
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Kenny

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Re: Sloppy Foot Brake Repair?
« Reply #4 on: October 20, 2017, 08:18:10 PM »
     Funny,

 But I rarely use the back brake excepting in town or on gravel!
      Cheers Ken S
               
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Rikugun

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Re: Sloppy Foot Brake Repair?
« Reply #5 on: October 21, 2017, 08:25:33 AM »
     Funny,

 But I rarely use the back brake excepting in town or on gravel!
      Cheers Ken S
             
Me too which is why I was surprised at the wear. We might be in a small percentage of the motorcycling community though. I think safety training courses often advocate using both.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

pinholenz

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Re: Sloppy Foot Brake Repair?
« Reply #6 on: October 22, 2017, 06:42:37 PM »
This problem was definitely from wear in the aluminium housing causing a fore and aft slop. It had been there since I had the bike and I mostly ignored it because it hadn't really affected my ride. I thought it might have been cured with a thin thrust washer on the shaft but that wasn't to be.

Like most of you, I tend to use the rear brake only occasionally - emergency stops, hill starts, and in gravel.

The bush I used ended up having an OD of 25mm. This meant that I had to take a bit more meat out of the casing than I would have liked. It was a nervous time pressing in the bush. I was afraid that the casing might split on the underside. With hindsight I should have had the bronze bush turned down to a thinner OD say 24mm, or even less, to reduce the risk, then machined the casing to suit.

Very happy with the outcome but the overall cost ended up being nearly NZ$100. This could have been more profitably used on some new s/s braided brake lines or better quality brake disks.
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Rikugun

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Re: Sloppy Foot Brake Repair?
« Reply #7 on: October 23, 2017, 09:27:46 AM »
Sorry it was so expensive but it sounds like a quality repair, nice work.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

pinholenz

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Re: Sloppy Foot Brake Repair?
« Reply #8 on: October 23, 2017, 07:51:58 PM »
If I did this again it would be a low cost repair done by myself instead of a precision machined one done by a pro.

The bronze bush was cheap enough. Next time I would simply drill the aluminium casing in a drill press to the required size, pop the bush in with some loctite and peen the bronze bush into the aluminium casing at a couple of points on each end.

Its not going to go anywhere and it doesn't get enough work to have justified the expensive solution that I over-engineered.

Sigh....
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motoracer8

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Re: Sloppy Foot Brake Repair?
« Reply #9 on: October 24, 2017, 08:29:12 PM »
That's the  way to fix it. The gear change pedal got alittle sloppy on mine. I made a small bushing and pressed it in after boring the pedal out alittle. 
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