Brake Bleed/Bite point

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scarbs85
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Brake Bleed/Bite point

Postby scarbs85 » Sun Dec 16, 2012 17:20 pm

I've just bled my rear brake (Avid Elixir 5's) as it was pulling to the bar. Even when its been bled, the bite point is pretty close to the bar, especially now I have brought the reach in a little. Elixir 5's have no bite adjuster and so it got me wondering if you can adjust the bite point by pumping a little extra fluid into the system, or would it just run back out the minute you remove the syringe as it would be slightly under pressure.

The other possibility is I just haven't bled the brake very well, and there is still a little air in there. It doesn't feel spongy, but I have always found the longer hose of a back brake seems to have a little more squidge than the front brake.

Newfish
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Re: Brake Bleed/Bite point

Postby Newfish » Sun Dec 16, 2012 18:48 pm

Worn pads?
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scarbs85
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Re: Brake Bleed/Bite point

Postby scarbs85 » Sun Dec 16, 2012 19:02 pm

Sorry should have said new pads have gone in. Old pads were well worn and initially I thought that was the problem.

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The Rookie
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Re: Brake Bleed/Bite point

Postby The Rookie » Sun Dec 16, 2012 19:20 pm

Pads settled on disc or are they still having to close in first?

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supersonic
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Re: Brake Bleed/Bite point

Postby supersonic » Sun Dec 16, 2012 19:39 pm

Google 'advancing avid pads'.

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bennett_346
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Re: Brake Bleed/Bite point

Postby bennett_346 » Sun Dec 16, 2012 20:00 pm

It's called the deadband. Always a problem with elixirs from personal experience. I usually bleed in a bit of extra fluid but its really hard to change the pads like this.

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supersonic
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Re: Brake Bleed/Bite point

Postby supersonic » Sun Dec 16, 2012 23:15 pm

Extra fluid is a bad idea as will not allow the to expand when heats up, and due to the nature of the open system, actually does nothing unless overfilled to excess.

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bennett_346
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Re: Brake Bleed/Bite point

Postby bennett_346 » Mon Dec 17, 2012 00:11 am

True but i've never had it heat up enough to cause an issue, and it's been successful as a workaround to a degree.

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scarbs85
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Re: Brake Bleed/Bite point

Postby scarbs85 » Mon Dec 17, 2012 12:00 pm

Well I cable tied the brake lever over night to try and advance the pads. It seems like its made a little bit of a difference. I think I will have a ride on it before mucking about with much else. I'm hoping that out on the trail, the fluid should heat up a bit and reduce the deadband (you learn something new every day!).

Thanks for the advice chaps.

danlightbulb
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Re: Brake Bleed/Bite point

Postby danlightbulb » Mon Dec 17, 2012 13:21 pm

I've recently had this problem on my Elixir 3's with the rear brake.

Did you adjust the reach to where you want it before you did the bleed? If not then this needs doing first.

I just made sure that when I was doing the lever end part of the procedure that I gave it plenty of goes at vacuum pressure then plenty of squeezes on the syringe to make sure I got that fluid in. I did it with the wheels on as well, no problems.

The 'advancing pads' procedure didn't appear to make any difference for me. When I bled there was plenty air bubbles coming out and as the bike is quite new it was probably underfilled as was suggested here when I asked for advice.

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bennett_346
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Re: Brake Bleed/Bite point

Postby bennett_346 » Mon Dec 17, 2012 14:16 pm

danlightbulb wrote:The 'advancing pads' procedure didn't appear to make any difference for me. When I bled there was plenty air bubbles coming out and as the bike is quite new it was probably underfilled as was suggested here when I asked for advice.

Nail on the head there, the advancing pads method has never worked for me, as elixirs are simply underfilled from the factory.

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supersonic
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Re: Brake Bleed/Bite point

Postby supersonic » Mon Dec 17, 2012 14:55 pm

Well I cable tied the brake lever over night to try and advance the pads


That is not how you advance the pads. The procedure is near the bottom if this page:

https://docs.google.com/viewer?a=v&q=ca ... w4_bN4-N6Q

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mrmonkfinger
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Re: Brake Bleed/Bite point

Postby mrmonkfinger » Mon Dec 17, 2012 16:06 pm

scarbs85 wrote:I'm hoping that out on the trail, the fluid should heat up a bit and reduce the deadband (you learn something new every day!).


It won't.

Incidentally, temperature related expansion or contraction is precisely the characteristic you least want in brake fluid...


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