GRX brake lever pressure relief?
12-22-22, 05:01 PM
#1
ignominious poltroon
Thread Starter
Join Date: Jan 2022
Posts: 4,050
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 2244 Post(s)
Liked 3,444 Times
in
1,803 Posts
GRX brake lever pressure relief?
I know where this should be, but I would like cxwrench 's input.
I have some new GRX levers and when I set them up, they were a bit too squishy for my taste. So I did what any incompetent fool would do, i.e., I funnel-bled them again with worn-down pads and the spacer, rather than the yellow bleed-block. This over-did it, and I pushed the pads apart, neglecting to open the bleed port. Out popped some brake fluid from where I assume the master cylinder is located (there is a little port or hole on the side of the lever, and appears to be aspirating a tiny bit of mineral oil when I squeeze on the lever. I don't think I am losing more pressure, but this really worries me. Did I destroy the thing?
I have some new GRX levers and when I set them up, they were a bit too squishy for my taste. So I did what any incompetent fool would do, i.e., I funnel-bled them again with worn-down pads and the spacer, rather than the yellow bleed-block. This over-did it, and I pushed the pads apart, neglecting to open the bleed port. Out popped some brake fluid from where I assume the master cylinder is located (there is a little port or hole on the side of the lever, and appears to be aspirating a tiny bit of mineral oil when I squeeze on the lever. I don't think I am losing more pressure, but this really worries me. Did I destroy the thing?
12-22-22, 10:39 PM
#2
Senior Member
Join Date: Jul 2013
Location: Nor-Cal
Posts: 3,767
Bikes: lots
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 1958 Post(s)
Liked 2,932 Times
in
1,489 Posts
I'm here for ya. I have had a problem with the reservoir diaphragm leaking.
- 17 Y0C678000
Diaphragm R
It seems like they're easily damaged by too much pressure. The lever can be pumped up to feel fine, then very quickly feels mushy on the next couple of lever pulls til it pumps back up again. Here's the EV doc for the GRX levers:
Shimano ST-RX810
Sounds like the exact problem I've had before. Maybe our mods will let me play in the mechanic's section again for X-mas or New Years.
Likes For cxwrench:
12-22-22, 10:49 PM
#3
ignominious poltroon
Thread Starter
Join Date: Jan 2022
Posts: 4,050
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 2244 Post(s)
Liked 3,444 Times
in
1,803 Posts
Thanks!
12-23-22, 10:12 AM
#4
ignominious poltroon
Thread Starter
Join Date: Jan 2022
Posts: 4,050
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 2244 Post(s)
Liked 3,444 Times
in
1,803 Posts
Are these replaceable parts, or am I doomed?
12-23-22, 04:30 PM
#5
Senior Member
Join Date: Jul 2013
Location: Nor-Cal
Posts: 3,767
Bikes: lots
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 1958 Post(s)
Liked 2,932 Times
in
1,489 Posts
Likes For cxwrench:
