Deore brakes going to the bar

othello

I'm pretty certain this is an issue with air in the system, but I wanted to check first before I start fiddling around!

I've got a set of Deore 615 brakes, which have always worked well, with only the occasional quick bleed needed with the cup on the lever.

Recently I've noticed an issue when I get the bike out of the shed. The lever will go all the way to the bar when pulled and the brakes don't go on. I end up doing a fair few pumps of the lever and gradually the brake returns to normal. This also happened when I went o Bike Park Wales last year, every time I picked up the bike off the uplift trailer.

Is this air in the system, which gets pushed along if the bike is on its back wheel, being wheeled around etc? When level and the system pumped, it returns to normal?

Doing a full (top down) bleed should fix it?

Or are the brakes on their way out?

JBA

It sounds like air in the system so a full bleed should solve it.
It’s also worth checking for signs of fluid leaking anywhere.

steve_sordy

Epic Bleed Solutions are a good resource. Not just for parts, but for how to videos and great advice. The owner will respond to messages. The following link opens at how to do a 5 minute mini-bleed for Shimano brakes, but there is loads more to see if you have a look around.

https://epicbleedsolutions.com/blogs/guides/5-minute-shimano-mini-bleed

mully79

My deore M615s did exactly the same on the bpw uplift. Its the 1st sign you have air. it gradually gets worse until you do a full bleed.
Might aswell get the bigger tub of shimano oil. you'll use it.
M615's (or is that all shimano brakes) dont like being tipped up.

reaperactual

More than likely down to air in the sytem. Had the same thing happen last week on my SLX rear, that turned out to be a sticking piston on a nearly new caliper so hopefully just a build of of crud after a very muddy ride that day. Worth checking piston movement just in case.

I find a caliper up flush and bleed works better, spending a long time flicking the lever and tapping hoses etc is worth it for piece of mind that the bleed the best it can be. Finally making sure to properly fill the lever to the brim of the bleed port so no space left for air to get into system when bike is upside down etc.

othello

mully79 said:

My deore M615s did exactly the same on the bpw uplift. Its the 1st sign you have air. it gradually gets worse until you do a full bleed.
Might aswell get the bigger tub of shimano oil. you'll use it.
M615's (or is that all shimano brakes) dont like being tipped up.

Glad it wasn't just me then! Very disconcerting when you pick the bike off the trailer, about to do a run, and find you have no brakes!

othello

Thanks for the info everyone. I'll do full bleed and that sounds like it will sort it. No leaking oil anywhere so that must be it.

yearofthegoat

Did that sort it? Am interested as my/our bikes are stored front wheels up in our garage as it makes better use of the space. Cheers

wilberforce

Came across this video about bleeding Shimano brakes with wandering bite point and which may help
https://www.youtube.com/watch?v=piWBVDh1pTE