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I feel like I have no luck with road bike hydraulic brakes. No problems with mtb ones (all SRAM Codes of varying flavour).
Shimano brakes (r785 di2 levers with ultegra flat mount calipers) worked fine for first few years. Then I had micro leaking calipers - switched to Hope RX4. Rear worked fabulously for a few years, but had problems with the front leaking randomly. Then got leaky piston seals.
Gave up and went back to Ultegra last year (new ones at both ends).
Front has been grand - rear starting howling for the first few big stops about a month ago - but always gets its bite back after that. Haven’t spotted any micro leaks yet.
A few nights ago I noticed in the garage that the back brake lever was pulling to the car without biting. For no apparent reason. I stuck an elastic band round the lever overnight and the problem was fixed this morning when I used it to commute to work. Cycling home it was back to ****.
I haven’t got time to look at it tonight so will revisit tomorrow night. I guess a full bleed is the first step and really thoroughly check no caliper piston leak.
Any idea what the cause/ fix could be? Air in the system that wasn’t a problem for a good few months before?
what is the frame? IR? air can get trapped and move around, assume you've done the multi position lever bleed? Bite/contact adjustment wound out when you bleed?
When you say annual bleed they’re not a year old yet - probably been on the bike about 8 months I’d guess. On the basis the front is still perfect and previously they’ve not needed an annual bleed / other brakes I’ve had haven’t required this it seems odd to me.
shimano don't require an annual bleed if they are bled well first time as the oil doesn't absorb water. Shimano only recommend a fluid change when it is discoloured
Pull the pads out and look for fluid stains on the backing plate. Mine took a while for the leaks to become apparent
It’s internally routed - doesn’t have any flex on the caliper hose to move it around. I had a go at bleeding it at different angles with the bike rotates in the bike stand. That bloody stupid funnel make it awkward though - having to loosen / spin the handlebar to keep it upright. Feels like it would be easier as a 2 syringe job on the road bike.
Needing an annual bleed? Why would they need that, I’ve not bled both my code rsc in 4 years and they’re like the day I got them.
It’s just Shimano doing what Shimano do.
The funnel doesn't stay upright if you are doing it properly. At various points it's around 35-45 deg tilted forward or backwards. The bike doesn't rotate, just the bars (it helps if you have one of those devices some work stands come with to hold the bars straight). If you tilted the bike then tilted the bars to keep the funnel upright then you'll still have air in there.
@airvent because dot fluid absorbs water. Exactly the same reason car brake fluid should be regularly changed.
Shimano don’t use DOT fluid and that wouldn’t cause a sudden issue overnight.
I was referring to your codes. But no even with a dot system that would not happen overnight.
It sounds like the reservoir is underfilled, which may be due to badly worn pads. I'd check the pad wear first and replace if necessary. Then fit your funnel to the reservoir and keep squeezing the brake on an off. This should allow the reservoir to fill properly - just make sure that the lever is angled so that the funnel is at the highest point and air can flow out.
Such a pain, mine were awesome for two years then went bad- swapped to RX4 and fine since.
The last bleed I did I tippped my fluid over just before a big trip, ended up reusing dirty looking oil and even that was fine.
Thanks all - will have a go at bleeding it tonight. I thought bleeding it at different angles was to get air out of the caliper rather than the lever. Will do the bleed at different angles and try not to pour oil out of the top of the funnel. It feels like it would be better to have a syringe instead of the funnel to make this easier.
When I originally bled it the pads were brand new and I haven’t done anything since to the brakes. I don’t think they’re particularly worn but I’ll check.
Next time I lose a caliper to micro leaks (if outside of warranty) I’m pretty sure I’m going to try one of the Magura flat mount calipers instead.
No the angles are to release air from the lever. I think Shimano calipers have been designed now so that there aren't places for air to get trapped.
Good luck. It's not actually too bad, just don't leave the funnel overfilled.
Thanks - I’m going to need it. The only bleeds I find easy are a 2 syringe job on sram with bleeding edge. That’s such a clean job without brake fluid floating about everywhere.
Everytime I try and bleed Shimano road brakes it’s just a load of b*ll*cks quite frankly.
Can barely get any pressure in the rear brake lever. Either I’m terrible at brake bleeding or something isn’t right.
I’ve just ordered a genuine Shimano bleed kit (been using an Epic one) and 1 litre of genuine Shimano mineral oil and going to try again on the weekend. Will have to drive or get the train to work tomorrow.
If I can’t get it sorted I’m tempted to just sell the ultegra (di2) groupset and pickup a SRAM AXS one of some description. Never had an issue with bleeding sram brakes, or variable bite point, or micro leaking seals or the brake just stopping working overnight etc etc.
I never get into the big ring with the smallest 2 sprockets. I do however use the small ring with the biggest cassette cog.
To be fair on them, despite having ostensibly an easier life, my road bikes suck up maintenance time far more than my MTB's simply because they do more miles. A big day out on the MTB is 40 miles, 40miles of a big day on the road is stopping for second breakfast. Even the fixie seems to suck up more of my time being fixed than the MTB's which just trundle along.
pickup a SRAM AXS one of some description
I have an AXS 1x drop bar hydro groupset for sale if you’re interested…
pickup a SRAM AXS one of some description
I have an AXS 1x drop bar hydro groupset for sale if you’re interested…
Shimano brakes doing shimano brake stuff. Such a shame as when they work they’re ace. Current grx have not needed anything but pads in nearly four years but have had plenty of issues with mtb brakes from them
It’s just so frustrating. This recent problem came out of nowhere. They’d been working fine for 8 months, not low on pads etc.
So I had a massive go at the brake last night - had bought a new genuine Shimano bleed kit and a litre of genuine oil to rule out any bleed kit issues etc.
I put the bike in the stand completely vertical and twisted the handlebar accordingly upright to start.
I followed the shimano bleed instructions exactly step by step - ignoring various different ways of doing it on YouTube videos.
I now have a brake lever that seems to be working - it’s firmer I think than it was before it all went near shaped but it’s still not as firm as the front lever.
I tapped the lever / caliper / hose etc to encourage air bubbles out, let loads of oil flow through in the gravity bleed (topping up the funnel several times). I did the whole pull the lever to the bars and quickly open and close the bleed nipple. I then did the lever squeeze bit with the lever at various different angles.
It’ll do for now - see how it rides to work tomorrow / rest of the week. Hopefully that’ll sort it for a while until I feel the need to have another pop at it.
I can’t help feeling it’s such a stupid fiddly process (although not as bad as with the Hope RX4 calipers which are stupidly messy with oil) - and ending up with a little zip lock bag full of oil is ludicrous.
I can’t help feeling it’s such a stupid fiddly process
Yes, they are fiddly to bleed. Key thing is making sure the reservoir is full and doesn't have air in it, that seems to be the cause of the wandering bite point problem.