Blatant clickbait title but it’s truthful!
Given up on hope RX4 and stuck an Ultegra flat mount caliper back on my road bike. This is on an 11 speed di2 lever - can’t remember which model.
I’ve got the caliper filled etc and the lever is firm but it bites too close to the bars no matter what I do with the reach and bite point screws.
Any tips on how to get it biting further away from the bars?
I had the reach dialled out as far as it goes and the bite point screw 4 turns from fully shut when I did the bleed per park tools instructions. Should I do something different like have the reach all the way in to the bars instead?
Dunno, sorry - I have an oldish shimano brake on the front of my road bike. I did nothing clever to it and the bite point seems bang on.
Maybe you could re-bleed with a thinner spacer between the pistons ?
Assume you've bled as per Shimano instructions? Should bite around 10mm from initial pull.
3 positions for the lever to be bled to chase the bubbles out
Page 18 on the tech doc iirc
I’ve got the caliper filled etc and the lever is firm but it bites too close to the bars no matter what I do with the reach and bite point screws.
Suggests residual air in the system.
I'd purge the whole thing again with a full syringe.
Remove wheel, pull brake, advances pistons.
Rebleed again.
Job done
I guess I’ll have another go - got plenty of mineral oil. Hate bleeding these brakes with the stupid funnel thing - give me sram bleeding edge and 2 stringers anyway. But I like di2 and don’t want AXS because of little batteries that need more frequent charging.
Funnily enough I struggled with the rear rx4 too. Yet everytime I’ve done a front it’s been fine. Must be the longer run to the rear brake hose and angles I guess.
Pull the wheel out, pump the brake. Push the pads back in a tiny bit, reinstall the wheel and pump the brake. It should work.
3 positions for the lever to be bled to chase the bubbles out
This. You need to pull the lever on and off with it at various angles in the correct sequence, which varies according to the lever. You can do it with the levers unbolted or simply adjust the angle of the whole bike, which is ungainly but does work. The Park Tool instructions are pretty straightforward and, ime with GRX, lever bleeding like this does the job, though you may have to repeat the sequence a few times.
Yes, that too, but once I've got the bar angle right, I can't be bothered to mess around with it.
If it's an old caliper the pistons might be sticking and not advancing. Take the wheel and pads out, use a tyre lever to hold one piston still and carefully pump the lever to advance the piston, but not so far that it falls out. Push it back in, repeat, then do the other one.
Otherwise, I've found that doing some sharp rather than smooth pushes with the caliper syringe can dislodge stubborn bubbles. You can push and push the same fluid back and forth repeatedly, if it's clean. Pull gently, then push firmly.
Do the bleed with the reach all the way out, although as long as it doesn't hit the bar when you pull it doesn't make much difference.
I’ve got brand new calipers so shouldn’t be any sticky pistons. Wonder if I’m getting air stuck behind either of the pistons - might follow the Hope technique of advancing the pistons and pushing back in.
Will also try being less smooth with the syringe - although I think the syringe from epic bleed solutions is a bit cheap and crap.
Could just be a knackered lever?
I have 11spd Ultegra and the rear brake stopped working on a trip to Lanza, got it to work just enough while I was there but no good when I got back.
Apparently there's a known issue with the m/cyl, seals I think. Of course they're not replaceable!
Cost me a new Di2 lever....
(If anyone ever needs a rear lever to try and re use the electrical gubbins....)
If it’s the rear I put my bike vertically in a stand and turned the bars. Worked fine, you could always marke the original bar position or take a photo.
I’m hoping the lever isn’t knackered - it’s not had loads and loads of usage and it’s not the latest 11 speed lever with the button on the top of the hood so might be difficult to replace like with like.
Thats a good idea on putting in the stand vertical and rotating the bars - I’ll give that a go - thanks!
@joe mine was the same, very little use, never out in the rain, proper Sunday spec bike...
Fingers crossed you find a decent bleed solution though
– give me sram bleeding edge and 2 stringers anyway
I do prefer their system, but I don't like using DOT, much prefer mineral oil. SRAM with mineral oil would be my perfect system.
You need to pull the lever on and off with it at various angles in the correct sequence, which varies according to the lever.
I didn't bother the other day, refitted some Ultegra shifters to a new bike, they'd been lying around dry for a few months. The first purge was interesting, fluid went in pink, came out grey. Did wonder if the new hydraulic hose had some mold release agent in it etc. 2nd syringe full came out pink. Didn't bother with the pumping at various angles and it seems fine.
"I’ve got the caliper filled etc and the lever is firm"
If the lever feel is firm, it might just be a case of advancing the pistons further. If the lever feel is spongey then that would hint that the bleed is the issue.
Ffs - didn’t realise the bleed block had fallen out when doing the front brake and This is the result:
Didnt seem to be cracked so pushed it back in and isn’t currently leaking. See if it’s still dry in the morning. If not I’ve just cocked uk a brand new caliper ffs. I hate the brakes on this bike.
Ffs - didn’t realise the bleed block had fallen out when doing the front brake and This is the result:
Didnt seem to be cracked so pushed it back in and isn’t currently leaking. See if it’s still dry in the morning. If not I’ve just cocked uk a brand new caliper ffs. I hate the brakes on this bike.