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Shimano 105 R7020 - mushy brakes?

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Shimano 105 R7020 - mushy brakes?

Old 11-23-23, 09:30 PM
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Shimano 105 R7020 - mushy brakes?

Hi folks,

I am not sure if this is how 105 hydraulic disc brakes feel but they are quite mushy? I have new pads on and bled the brakes at least twice making sure to not induce any air as much as possible yet still the brakes still feels mushy and/or spongy. When pulled, it is like half inch away from the handlebar. The front and rear are about the same with rear slightly worse.

Is there some trick that I might have missed doing these specific brakes?
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Old 11-24-23, 01:57 AM
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No they should definitely not feel like that. They sound new so I assume the pads arenít worn? When you bleed them thereís a step where you pull the lever with a block still in the calipers. How far in could you pull them at that point?
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Old 11-24-23, 07:38 AM
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Originally Posted by choddo
No they should definitely not feel like that. They sound new so I assume the pads arenít worn? When you bleed them thereís a step where you pull the lever with a block still in the calipers. How far in could you pull them at that point?
With the blocks in they felt about the same as with pads and rotor.
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Old 11-24-23, 07:52 AM
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Air in the lines is the usual reason for 'sponginess' and you do say "making sure to not induce any air as much as possible". Is there any air in the lines? Are you able to compare the 'feel' of your brakes to another bike's brakes? Do they feel the same, etc. if able to compare/contrast?
It is a fairly straightforward method to eliminate air in the lines but it may not be easy and it can be tedious.
I use the 105 12 speed version of hydro brakes on my bike and they are not spongy at all.
Hoping it is not a problem with the calipers or shifters reservoirs...good luck and keep us informed...
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Old 11-24-23, 08:00 AM
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Originally Posted by Kai Winters
Air in the lines is the usual reason for 'sponginess' and you do say "making sure to not induce any air as much as possible". Is there any air in the lines? Are you able to compare the 'feel' of your brakes to another bike's brakes? Do they feel the same, etc. if able to compare/contrast?
It is a fairly straightforward method to eliminate air in the lines but it may not be easy and it can be tedious.
I use the 105 12 speed version of hydro brakes on my bike and they are not spongy at all.
Hoping it is not a problem with the calipers or shifters reservoirs...good luck and keep us informed...
Yeah I have another bike and they are not spongy at all. I am almost tempted to push the pistons out some just to have the brakes engage earlier. I know that's probably taboo to do but it might be an interim fix.
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Old 11-24-23, 08:43 AM
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Originally Posted by Paradox77
Yeah I have another bike and they are not spongy at all. I am almost tempted to push the pistons out some just to have the brakes engage earlier. I know that's probably taboo to do but it might be an interim fix.
you can use a feeler gauge or shim or whatever that is slightly less thickness of the rotor to reduce free stroke

measure rotor thickness - use feeler gauge or shim that is slightly thinner - maybe around .020 or so (?) - remove caliper and place the feeler gauge (or shim) between the pads and squeeze the brake lever a few times - the reinstall caliper … then hopefully you don’t have brake pad rub …. if you do you can repeat the procedure - spread open pads and do again

had relatively smooth sailing bleeding brakes on two flat bar bikes with XT and XT / Ultegra brake components - but a Tiagra hydraulic brake bike was a challenge to bleed … the Tiagra levers are short reach levers (4725 as opposed to standard 4720 levers) so it was even more critical to get it right … fortunately LBS friend was (finally) able to bleed them … they are great now ***

*** of course got fluid on the pads - and eventually they began to squeal .. on one bike I was able to remove the contamination from the pads / clean rotors and it is has been fine but had to replace the pads on the Tiagra equipped bike

for reference - the bike has RT86 IceTech rotors and L05A-RF resin (finned) brake pads

Last edited by t2p; 11-24-23 at 09:08 AM.
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Old 11-24-23, 09:21 AM
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Originally Posted by Paradox77
With the blocks in they felt about the same as with pads and rotor.
Doesn't sound right at all. I could hardly pull my 105 brakes a quarter of the way with the block in.
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Old 11-24-23, 09:34 AM
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Originally Posted by choddo
Doesn't sound right at all. I could hardly pull my 105 brakes a quarter of the way with the block in.
What size blocks did you use? I am using 10mm blocks.
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Old 11-24-23, 09:38 AM
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Originally Posted by Paradox77
What size blocks did you use? I am using 10mm blocks.
The one that came with the shimano bleed kit which only just fits in with the calipers fully retracted.
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