brakes - upgrade or bleed?

Mar 19, 2019
44
32
18
Cardiff
Ride
Looking for one!
#1
During last night's ride, on a tarmac section, I noticed that my rear brake didn't have enough power to lock the rear wheel, even if I put all my weight over the handlebars.

Even with me off the bike and pushing, with the lever pulled almost right in, the wheel wouldn't lock.

Both levers feel quite spongey too. They're the standard Shimano Deore M6000.

The pads have plenty of meat left on them. There's a small chance I might have contaminated them with GT85 - I was careful, but I can't guarantee none got onto the disc!
 

khorn

E*POWAH Master
Patreon
Jul 19, 2018
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Denmark
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Specialized
#2
During last night's ride, on a tarmac section, I noticed that my rear brake didn't have enough power to lock the rear wheel, even if I put all my weight over the handlebars.

Even with me off the bike and pushing, with the lever pulled almost right in, the wheel wouldn't lock.

Both levers feel quite spongey too. They're the standard Shimano Deore M6000.

The pads have plenty of meat left on them. There's a small chance I might have contaminated them with GT85 - I was careful, but I can't guarantee none got onto the disc!
Based on your description you seriously need a bleed and a good clean up of pads and discs

Karsten
 

MattyB

Well-known member
Jul 11, 2018
800
467
73
Herts, UK
#3
A bleed costs almost nothing compared to upgrading the brakes. Unless you were unhappy with their performance from new you need to grab a bleed kit and learn how to use it - not a difficult process. These guys offer very good and affordable kits...

Epic Shimano Bleed Kit & Oil - 9.99
 

Gary

E*POWAH Elite World Champion
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Mar 29, 2018
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from the internet
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ESommet VR
#4
Shimano?

My money's on a leaky caliper piston.
if I'm right and they're under 2 yrs old get them warrantied.

Clean everything up properly and bleed the brake, next fit new pads and bed the brake in (by riding, getting the pads/disc properly hot... not just doing stops on tarmac) then after your ride, clean the bike, remove your new pads and stuff paper towel in the caliper where the pads sit and leave the bike standing for a few days.

*dodgy shimano calipers leak fluid when not in use.
it's a common issue.

if you have a leaky piston seal it'll wet the paper towel

I'm not saying this is def what's wrong with yours I'm just telling you how to check
 

Andy A

E*POWAH Master
Patreon
Jan 13, 2019
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North Yorkshire
#5
During last night's ride, on a tarmac section, I noticed that my rear brake didn't have enough power to lock the rear wheel, even if I put all my weight over the handlebars.

Even with me off the bike and pushing, with the lever pulled almost right in, the wheel wouldn't lock.

Both levers feel quite spongey too. They're the standard Shimano Deore M6000.

The pads have plenty of meat left on them. There's a small chance I might have contaminated them with GT85 - I was careful, but I can't guarantee none got onto the disc!
The Shimano brakes on my new Jam2 felt that way they were OK but not great all I did was put some sintered pads in them and the difference is massive, they feel so much better now, of course yours might be faulty :)
 

steve_sordy

E*POWAH Master
Nov 5, 2018
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113
Grantham, UK
Ride
Focus Jam2 9.6 NINE
#6
The rear brake can often be a problem as it is so far away from the lever with lots of hose looping about the place. Even a conventional bleed might not shift the problem. Someone gave me a good tip that really worked for me.

Pump the lever and then immediately clamp it down to the bar. I zip tied it, but a strong rubber band, or even some string will do the job. Store the bike upright overnight on its rear wheel. Compressing the lever makes any air bubbles as small as they can go. Storing upright allows the bubbles to rise to the reservoir at the lever. Then do an easy mini-bleed instead of a full bleed (much quicker). See this vid by Epic Brake Bleeding Solutions.

5 Minute Shimano Mini Bleed

Epic have all sorts of products and videos for specific brake sets. I have found the guy that runs it to be very customer focused and responds quickly to emails.
 
Last edited:
Mar 19, 2019
44
32
18
Cardiff
Ride
Looking for one!
#8
Feel free to laugh at my expense, but before starting the bleed procedure I noticed the span adjusters - I wound them in so there's far less travel before the pads move (and they're the finned pads so it's easy to see!) and the action is much more positive. All good for a morning at BPW tomorrow :)
 

highpeakrider

Well-known member
Aug 10, 2018
410
171
63
Peak District
#10
Did you manage to route the cable without removing the battery and motor?
No, I unfastened the motor and lifted it about an inch, on mine and I guess all the hose was fastened with a tie wrap under the motor and I couldn’t pull it through.
An inch let me cut it and provided enough room to pull the hose through, some pics on here somewhere.
 

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