How to "fix" Brake Fade

Gringo

Esteemed Pedelecer
Jun 18, 2013
1,346
842
Northampton
Just a thought
There's a lot of good advice related to constantly soft or spongy breaks but from what you have said I gather your breaks are good, then fade down long hills and recover once they've rested.
To me this sounds like there overheating the fluid. When the fluid is hot enough it releases gas " boiling" this gas is easly compressed/squashed, hence the spongy feal, once it cools down the gas is re absorbed into the fluid and results in the return of better breaking.
You'd be hard pushed to get this effect riding normally.

if your breaks are dragging they will be running warm before you even stat to apply them so With the tyre off the ground see if your wheel spin freely.

Also if you are keeping a constant light pressure on the break leaver, (just enough to take the edge of your speed). By riding this way they never get a chance to cool down.
Next time they stat to fade, stop as quickly as yo can and see if the caliper is very hot not buy put your fingers on it
 
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shemozzle999

Esteemed Pedelecer
Sep 28, 2009
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E-Bikes are heavy so brakes do a lot of work.. Today I totally ran out of brakes on a long steep hill, probably due to my going too fast. Back brake faded out first and then alarmingly the lever went soft as well so I was able to easily pull it in to the bars and pump it!! Thinking I had a leak and didnt want oil everywhere I used only the front only to pull up, Well, I couldnt pull up so heart in mouth made it to the bottom!! By this time rear had cooled down a bit and was back to normal, working fine and as it should.. Perplexed I am!!
I often get a bit of fade at the back, so just favour the front a bit more till the rear comes back, but never before has the lever gone.. Only to return! Is it a pad thing? Do different pads suffer fade differently? Has anyone experienced this lever issue before?
Fading mentioned at the end of the piece:

http://www.epicbleedsolutions.com/blog/how-hydraulic-brakes-work/
 

Gubbins

Esteemed Pedelecer
Hi All
Thanks for all the info and advice which is well received! Putting everything together..

Brakes are not binding and work exceptionally well, in fact far better than the originals ever did and I do tend to apply a constant light pressure to the rear on hills , but hill in question is fairly long, narrow and steep with a hairpin bend on its steepest part at 23.6% Gradient (according to Strava) and as I was letting it run a bit fast. (30-35 mph) the effort to slow to a walking pace for the bend has overheated the brakes to the point of boiling the fluid at the back, and fading away at the front . Wow, who would have thought on a push bike!!
I think the problem is mostly self created as I am surrounded by hills and get a big buzz from these mad twisty descents.
Note to self... Slow down and change my braking technique.
 
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Phil... your brakes should cope with that. People use those brakes on bikes in "proper" mountains in the Alps / Canada etc etc, and offroad where you can't let off anywhere on a 60 minute offroad descent really. They won't be getting that hot in anything round here, even with really bad technique.

there will be some small air bubble, or simply just not enough fluid in the reservoir. Visit your LBS and buy some pink Shimano mineral fluid. Try the tip I've suggest, based on years of racing downhill mountain bikes with Shimano brakes and top up your reservoirs and they will be spot on moving forward.
 
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Gubbins

Esteemed Pedelecer
Phil... your brakes should cope with that. People use those brakes on bikes in "proper" mountains in the Alps / Canada etc etc, and offroad where you can't let off anywhere on a 60 minute offroad descent really. They won't be getting that hot in anything round here, even with really bad technique.

there will be some small air bubble, or simply just not enough fluid in the reservoir. Visit your LBS and buy some pink Shimano mineral fluid. Try the tip I've suggest, based on years of racing downhill mountain bikes with Shimano brakes and top up your reservoirs and they will be spot on moving forward.
Will do.. I will have a ride over t'ill and see what they say..
Thanks..
 
unless they have a VERY good mechanic - they will simply tell you that you're brakes need bleeding, and either offer to charge you and do it for you, or sell you a bleed kit.

I'd REALLY suggest, just walking in and buying some fluid and doing it yourself, the problem you have could just be a little bit to low a fluid level, but more than likely its a small bubble in the caliper or lever that just needs "jiggling" (tech term ;) ) out.
 

Kinninvie

Esteemed Pedelecer
Oct 5, 2013
907
415
Teesdale,England
Your brake fluid has reached boiling point(I had this problem years back on a Suzuki T500 I used to race but my problem came from brake drag due to a dodgy caliper.
You need to replace the fluid with new or risk it happening again !!
I found that out the hard way at 120Mph at Cadwell Park.
 
Your brake fluid has reached boiling point(I had this problem years back on a Suzuki T500 I used to race but my problem came from brake drag due to a dodgy caliper.
You need to replace the fluid with new or risk it happening again !!
I found that out the hard way at 120Mph at Cadwell Park.
no it hasn't....

its just a small hill in Yorkshire...
 

Kinninvie

Esteemed Pedelecer
Oct 5, 2013
907
415
Teesdale,England
So are you saying you cant boil your brakes in Yorkshire?
 

awol

Esteemed Pedelecer
Sep 4, 2013
1,216
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I do the cadence style braking when it's wet and find it very effective for a quick slow down also when I get disc squeal I find it helps get rid of the squeal for a while.
 

Kinninvie

Esteemed Pedelecer
Oct 5, 2013
907
415
Teesdale,England
No. He is saying I am a bit of a wuss and should shut up and do as I am told. ....
I used to live in Oxenhope and know of quite a few hills round there that can cause brake fade!!