Aplogies for asking a simple question but looking to learn/avoid a trip to the LBS for something potentially simple! My front brake’s suddenly gone all soft with the lever pulling to the handlebar and 1/4 the usual stopping power. I’ve taken the pads out, refitted and aligned them and there’s plenty of wear left. What should I be checking next? If it’s likely to be air then is there a simple process to try before giving up? I’ve read the cheap ways to blewed the brakes but wil probably just fire it into the local LBS if that’s necessary. Thanks

Check the full hose length and threads, make sure you don’t have a leak.

Something sudden usually means you have somehow got air in the system somehow

hi deepreddave try taking thr peds out and puttin the blocks in or something that will stop the pistons closing over and remove the resevoir cap and tying down the lever to the grip and leave it overight.thats what i done on my m575 shimanos and it made a hell of a difference.also cleaned my rotor too.hope this helps you.H

They need to be bled. Have you had the bike upside down recently -that can sometimes allow air in? As snakebite says if the deterioration is sudden then perhpas there is a fault but the most likely culprit is air

Thanks all. I didn’t realise inverting the bike would be a prob as assumed the system was airtight – obviously not tho 🙂
Will try the overnight option then maybe just get my walet out at the LBS.

For a fiver’s worth of mineral oil, some plastic tube and a bit of researcb on the web you could do it yourself in less than half an hour.

Shimano brakes are very easy to bleed.

After seeing the havoc wreaked on brake systems that have come into contact with even the smallest amount of the wrong fluid(even just residue left after a thorough wipe-out of the caliper shell), i’d be very wary of using the same bleed kit with both types of fluid, the parts and labour bill will easily negate the savings made.