Author Topic: XTR internal spring not springing?  (Read 1252 times)

Matt2matt2002

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Re: XTR internal spring not springing?
« Reply #15 on: August 02, 2016, 06:04:27 AM »
XTRs are odd brakes. Hard to photograph, too - really needs manual focus, which my camera does have, if I could just remember which knobs... Anyway, maybe this is the spring of concern:


Yep!!
That's the spring.

I don't think I could photography it any better.

One side is definitely weaker. And I don't see how it can be removed and retensioned.

I'll strip down again and follow instructions offered above.
Many thanks folks.
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Matt2matt2002

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Re: XTR internal spring not springing?
« Reply #16 on: August 03, 2016, 05:02:57 PM »
Yes - I have the M970
I found the paperwork that came with the bike.



And here is that internal spring I was going on about.
It's not shown on the paperwork diagram and I don't see how it can be removed.




There is a zip tie end pointing to it.

Well folks, many many thanks for all your hints and tips.
After another strip down and clean, I put things back together and by tweaking the 2 adjusting screws things are much much better.

Now to clean up the rear brakes....!
Never drink and drive. You may hit a bump  and spill your drink

Matt2matt2002

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Re: XTR internal spring not springing?
« Reply #17 on: June 21, 2017, 08:56:32 PM »
Time clean the Xtrs.
Running blue Swisstops on CSS rims.
Had a squealing front brake for some time and needed to clean off accumulated dust/ muck.

Please refer to my last picture showing the instructions from Shimano. Middle diagram showing pad, washers and nut.

On removing all parts I realised that the washers on the ' spindle' had not been assembled correctly.

They sit within each other and allow toeing in.

Things greatly improved once cleaned up and refitted.
However.....
On the last set I cleaned up I noticed the the ' spindle' that goes into the ' bracket' that holds the pad, was wobbly.
I had removed the pad and found a little dust underneath. Nothing serious. Just wanted to be thorough.
All 3 other units had a snug fit of the spindle into the pad bracket. They just pull out. No nut or fixing mechanism.

So..... I have a squealing from the back brake. The one with the wobbly spindle.
Could this be the cause of the sequel?
Or maybe I need to do a little more toeing in?

I've been out on a 10 mile hilly run to bed things in. And still the squeal.

Also.....
On the rear left brake the gear shift mechanism located.
I didn't remove this.
Played safe.
Any tips for removing it and getting it back on in the same position?
Please excuse incorrect terminology.
Thanks folks
Never drink and drive. You may hit a bump  and spill your drink

Danneaux

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Re: XTR internal spring not springing?
« Reply #18 on: June 21, 2017, 10:41:47 PM »
Matt,

Pad squeal usually comes as a result of oscillation of the pad material against the rim sidewall under braking -- the pad catches, slips, and catches again. This cycle is usually what results in noise (though occasionally it can be caused by a poor match of pad surface to rim...old MAFAC 4-spot and even 5-spot black pads were notorious for the squeal even when used on other brakes).

Toeing the pads in reduces oscillation and noise. If your brake arms are worn or already flexible by default, then more toe-in is called for.

If one of your pads is held less securely, that is where I would look first to find a source of squeal. Look carefully for any mismatch in size or for something that is keeping the assembly from tightening fully. Worse comes to worst, you may have to add a bit more toe-in on that one brake to reduce noise, but I'm betting the most likely cause is a loose fitting, based on what you've told us.

Yes, the spherical washers have to be mirrored as shown in the instructions to get the full range of toe-in.
Quote
On the rear left brake the gear shift mechanism located.
I didn't remove this.
Played safe.
Any tips for removing it and getting it back on in the same position?
When faced with a similar situation, I look for the gap in the clamp and mark its location with a piece of tape stuck to the handlebar right next to it. That way, when reinstalling, the clamp and assembly not only slides on the same distance, it has the same orientation. When finished, I just peel off the tape and all is as it was before.

All the best,

Dan. (...who appreciates the photo of the elusive spring)

Danneaux

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Re: XTR internal spring not springing?
« Reply #19 on: June 21, 2017, 10:44:08 PM »
This link might be helpful to you, Matt:
http://www.myra-simon.com/bike/vbrakes.html

Best,

Dan.

Matt2matt2002

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Re: XTR internal spring not springing?
« Reply #20 on: June 21, 2017, 11:39:37 PM »
Great link Dan.
I'll run the bike a few more days and then take another shot at the rear brakes.
Never drink and drive. You may hit a bump  and spill your drink