Brake Fade – OLD Bull Trailriders

This topic contains 9 replies, has 0 voices, and was last updated by dennis da menace 12 years, 5 months ago.

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November 19, 2012 at 9:04 am #102094

John
Member

Went for a ride on the weekend and came to a downhill section that would have been about 500 metre long. Anyway i was on the brakes most of the way down. Nearing the bottom i went for the rear brake and there was nothing, thought i missed the peddle so had another go. Nothing.

Only had about a hundred metres to go so i went down just using the front. What happens next ? the front brakes failed. So i bailed off the bike. Picked it up and walked to the bottom clutching it.

What caused this and why? The first part i can probably answer myself but the why ??

November 19, 2012 at 9:11 am #232681

Scott Southwell
Member

Jak I suggested in your 5 year service thread to flush some new fluid through the brakes. Did you do it?

November 19, 2012 at 9:15 am #232684

John
Member

Scotty wrote:

Jak I suggested in your 5 year service thread to flush some new fluid through the brakes. Did you do it?

:blush: :blush: :blush: Point taken Scotty. :blush: :blush: :blush:

November 19, 2012 at 9:23 am #232682

Greg
Member

Your fluid probably boiled, Boiling produces gas bubbles as within any boiling fluid. Gas is compressible so boiling brake fluid leads to a “soft” brake lever with long travel. Overheated brake fluid can (and will) boil in the calliper. Brake fluid is hygroscopic which means it readily attracts moisture from the atmosphere, and over time it get saturated with water to the point where it lowers the fluids boiling point.
You can compress a gas but you can’t compress a fluid. When you pull the brake lever you create hydraulic pressure in the hydraulic brake system which acts on pistons at the wheel end that actuates the brakes, imagine a bubble of air in the hydraulic system. Remember you can compress a gas but you can’t compress a fluid, so if there’s a bubble of air in the system then when you pull your brake lever and instead of the hydraulic pressure acting on the pistons for the brake all your effort is going to be used compressing the gas instead of working the brake.

Change your fluid and probably your pads, gear down next time to reduce you relying on your brakes alone.
Check your manual to get the correct fluid, any quality one will do you and change it every 12 months

TB

November 19, 2012 at 9:23 am #232683

MARTIN TWINE
Member

Jak,

You have boiled the brake fluid. Flush the whole system out and switch to a higher boiling point fluid. Motorex do a 5.1 fluid. DO NOT USE 5 fluid,they are VERY differnt.
You can also run a rear resovoir extender,to increase the fluid capacity.
Also try to alternate your braking when coming down a hill,just to give either one a break.
Use engine braking as much as possible also to give the brakes a breather.
Cheers Marty

November 19, 2012 at 9:28 am #232689

John
Member

Thanks for that.

Its never happened before but had to change me jocks afterwards.

New brake fluid on the way :cheer:

November 19, 2012 at 10:42 am #232693

dennis da menace
Member

stop going sooo slow downhill

or try reducing the load on the brakes, by volume :whistle:

ADUJSTED TO BE JUST WITHIN THE PARAMETERS OF THE TECH THREAD AS THE REMAINING IS CORRECT

theboss

November 19, 2012 at 11:16 am #232705

nathan steele
Member

I found from experience cheap and nasty brake pads will fade very easily! ( had front brake pads smoking )

November 19, 2012 at 7:14 pm #232706

glenn
Member

Tech thread Boony AGAIN its not hard

theboss

November 20, 2012 at 8:49 am #232712

dennis da menace
Member

Boony wrote:

Tech thread Boony AGAIN its not hard

theboss

:laugh: :laugh: :laugh: :laugh: :laugh:
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