New warranty replacement Guide R brakes driving me crazy...

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New warranty replacement Guide R brakes driving me crazy...
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flag TheDoctoRR
Posted: Aug 7, 2017 at 15:53 Quote
Hey everyone, got a problem here I wonder if anyone has shared.

First off I was always a Shimano guy but my latest bike came with the Guide R brakes and I have always liked them. Unfortunately they were susceptible to the expanding piston issue in the heat and so they were replaced under warranty. These new Guides have the revised piston as well as the revised Bleeding Edge bleed setup.

My problem went as follows (btw i never had this problem with the old guides):
1. Installed new brakes and with the lever adjusted fully out the brakes didn't contact the rotor until nearly hitting the bar.
2. Assumed air in the system despite them being new and bled brakes.
3. See #1.
4. Assumed I missed air and bled again (even though things weren't adding up because the eventual bite point was good and strong).
5. See #1.
6. Pulled the pads out, squeezed the lever to push the pistons out a bit, and reinstalled pads. Tedious work to get the pistons equally aligned and eliminate rotor drag since the pads are running so close but now the brakes bite at a reasonable spot.
7. Did a big ride with lots of braking that wore the pads down a bit.
8. See #1.
9. See #6.
10. See #7.
11. See #1 (Sensing the pattern here?).

Its almost like the ratio of lever pull to piston movement is way off. It also seems like the fluid reservoir isnt doing its job of supplying fluid to compensate for pad thinning. And as I mentioned earlier, this was never a problem with my old set of guides. Any thoughts on the issue?
flag ehvahn
Posted: Aug 10, 2017 at 18:02 Quote
Sounds to me like you have sticky pistons (its possible they came out of a bad batch) and they need to be warrantied. I would advise you to take them to an LBS, see what they say and go from there. Once they are fixed/ replaced, sell them and buy some XT's Wink

TheDoctoRR wrote:
Hey everyone, got a problem here I wonder if anyone has shared.

First off I was always a Shimano guy but my latest bike came with the Guide R brakes and I have always liked them. Unfortunately they were susceptible to the expanding piston issue in the heat and so they were replaced under warranty. These new Guides have the revised piston as well as the revised Bleeding Edge bleed setup.

My problem went as follows (btw i never had this problem with the old guides):
1. Installed new brakes and with the lever adjusted fully out the brakes didn't contact the rotor until nearly hitting the bar.
2. Assumed air in the system despite them being new and bled brakes.
3. See #1.
4. Assumed I missed air and bled again (even though things weren't adding up because the eventual bite point was good and strong).
5. See #1.
6. Pulled the pads out, squeezed the lever to push the pistons out a bit, and reinstalled pads. Tedious work to get the pistons equally aligned and eliminate rotor drag since the pads are running so close but now the brakes bite at a reasonable spot.
7. Did a big ride with lots of braking that wore the pads down a bit.
8. See #1.
9. See #6.
10. See #7.
11. See #1 (Sensing the pattern here?).

Its almost like the ratio of lever pull to piston movement is way off. It also seems like the fluid reservoir isnt doing its job of supplying fluid to compensate for pad thinning. And as I mentioned earlier, this was never a problem with my old set of guides. Any thoughts on the issue?
flag TheDoctoRR
Posted: Aug 11, 2017 at 0:27 Quote
I hadn't considered that though there doesn't seems to be any resistance in the lever at any point. I will take a close look st that tomorrow though...
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