Improving GRX 820 brake lever feel?

Rear brake lever touches the bars (well, tape) when fully compressed, I’ve bled the system, I’ve adjusted the reach and free stroke as far as I dare, but yet it doesn’t feel as firm as the front brake (which doesn’t touch bars). Any pointers?

Assuming you’ve tried it with new pads, then it sounds like you still have air in the system

I’ve lost count of how many times I’ve pushed and pulled fluid through the system, apparently not enough 😫

Rear brake lever touches the bars (well, tape) when fully compressed, I’ve bled the system

My GRX600 levers are the same, but without the benefit of any adjustment. The rear needs bleeding bi-annually and an overnight rest with the lever pulled on and front wheel off the ground. Front brake never needs attention

My GRX810 levers are still only coming half way back on the shop set up and original pads 14 months in.. brake feel is excellent across both sets of wheels I have despite my best efforts to contaminate the discs and pads with wayward GT85 . Replacement pads turned up in the office today…

Not sure this helps…

Not tried it myself, but I saw a video suggesting that by lightly squeezing a syringe of brake fluid in at the caliper as you close the nut, you will reduce the freestroke. Like pressurising the system.

They benefit from a gravity bleed to get air out of the calipers, and then burp the levers at various angles to get air out of the master cylinder. Should be a short stroke and a firm bite.

Another vote for burping the levers at different angles, also removing the caliper from the mount and changing it’s position, rotate it horizontal both ways, etc.

Was on my third bleed, and almost out of patience, after shortening hoses before trying the caliper hanging free which released a load of trapped air. HTH

I can only empathise with it being a massive ⚽️🤕

I need to put a Sunday aside to mess around it.

The Park Tool site has a really thorough explanation of the angles you need to have the levers at for a lever bleed. Mine need to be done first tilted right forward – levers almost parallel to floor – then in normal position. You can stand the bike on its front wheel Endo-style to do it, or simply loosen the stem faceplate bolts to rotate the bars forward.

Makes a surprising difference ime. Different levers use different angles, but Park is comprehensive on sequences for various Shimano drop bar levers.

Getting the rear line closer to vert on a drop bar bike means undoing the lever, means untaping the bars, means CBA mate. I think this is the main reason why rear is always a harder bleed. Whereas the front line just sits vertically without needing to do anything.

Once you’ve got it sussed, they’re easy – certainly eay easier than the MTB 4 pot Shimanos.

Mine you barely need to touch and they engage. That’s one that the hose was shortened without a bleed and one where the lever was empty so full bleed. Took 2 attempts but they feel great now. I did all the repositioning and had obvious air coming out as I did it. Persevere as once right they feel great.

Getting the rear line closer to vert on a drop bar bike means undoing the lever, means untaping the bars, means CBA mate. I think this is the main reason why rear is always a harder bleed. Whereas the front line just sits vertically without needing to do anything.

Surely just rotate the bike on a work stand (with the calliper ‘hanging’ if required)?

This is the Park Tool article. As above, my experience is that you can take a lot of softness out of the system just by pumping the lever with the bars rotated to the suggested positions even without cracking things open, though I guess it depends on how much air you have in the system to begin with, but a little air goes quite a long way.

https://www.parktool.com/en-int/blog/repair-help/brake-bleeding-for-shimano-drop-bar-hydraulic-brakes-using-the-bkm-1

Surely just rotate the bike on a work stand (with the calliper ‘hanging’ if required)?

Cant with a road / gravel lever and a funnel, oil all over the floor. Need to undo the lever.

Flat bar brake lever is way easier as you just rotate it round the axis of the bars and there is no tape hassle.

Can you fit a syringe to the lever bleed port and create a vacuum to remove the air? Would also allow rotation without spillage

I always leave the rear dangling and move around by hand to ensure bubbles go through the system. Also a lever clamped and suction bleed of the caliper. Then do the 35-/35+/0 bar angle lever bleed.

Make sure you have any adjustment fully out

Cheers for the pointers. I’ll have another go at bleeding some point this weekend, if no joy then I’ll book it in, for £30-ish quid to sort it’s worth paying for my sanity.

Need to undo the lever.

Need to undo the bar you mean.

Flat bar brake lever is way easier as you just rotate it round the axis of the bars and there is no tape hassle.

Slightly loosen bar in stem, or is this another reason why all-in-one bar/stems are crap?

That plus hidden hoses, routed via the headset, often don’t allow sufficient play.

I had this issue until I realised the flare on the bars tilted the brifters at an angle. I leant the bike so brifter was vertical and one top bleed later, firm lever.

Cant with a road / gravel lever and a funnel, oil all over the floor. Need to undo the lever.

Tilt bike, undo stem plate, rotate bar to vertical, bleed then return to original position.