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STR9170 Hydraulic Shifter Poor Spring Return

Posted: Fri Jul 12, 2019 4:29 pm
by ymisyd
Hello,
My RH 9170 shifter has progressively been getting worse when it comes to the spring return. The left shifter "pings" back into the parked position but the RH one is very slow and doesn't have a positive spring return. This is causing the front pads to drag every time I brake. It's now got to the point where I'm manually pushing the shifter back to the parked position every time I brake.
I've cleaned and lubricated the front pistons but no difference.
Any help appreciated.

Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Fri Jul 12, 2019 4:48 pm
by Vjl
I can almost guarantee it's a lazy piston.

Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Fri Jul 12, 2019 4:48 pm
by Weenie

Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Fri Jul 12, 2019 6:18 pm
by Klaster_1
Does it return if you push the pistons in? Did you check the lever tension spring?

Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Fri Jul 12, 2019 6:20 pm
by TurboKoo
I’ve seen few cases where thin film layer of J-KIT has not been “punctured” correctly and that has created restrictions on oil flow. Check that first from the caliber end. If possible cut hose just little and put new insert and olive.

Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Fri Jul 12, 2019 11:33 pm
by ChiZ01
I got the same issue with my 8070 lever, without anything connected the lever would fail to reset 20% of the time, feels like something is causing friction to the master cylinder piston, can i put lube into the piston?

Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Sat Jul 13, 2019 12:39 pm
by ymisyd
Vjl wrote:I can almost guarantee it's a lazy piston.
Thanks for the tip. Any advice on what to do to resolve this? I'm thinking of disconnecting the hose on Monday and starting with a fresh fill and bleed. This should at least give me an opportunity to make sure the shifter spring is ok.
Any other maintenance tips while I've got it all in bits? It's a self build and all the bits are only about seven months old.

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Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Sat Jul 13, 2019 2:53 pm
by bikeguy0
I had same issue and had it warrantied. I rebled, cut hoses and new olives, and reoiled caliper piston seals and nothing worked.


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Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Sat Jul 13, 2019 3:15 pm
by TonyM
ymisyd wrote:Hello,
My RH 9170 shifter has progressively been getting worse when it comes to the spring return. The left shifter "pings" back into the parked position but the RH one is very slow and doesn't have a positive spring return. This is causing the front pads to drag every time I brake. It's now got to the point where I'm manually pushing the shifter back to the parked position every time I brake.
I've cleaned and lubricated the front pistons but no difference.
Any help appreciated.
How old are they?
And how many km/miles with them?

Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Sat Jul 13, 2019 3:25 pm
by ymisyd
TonyM wrote:
Sat Jul 13, 2019 3:15 pm
ymisyd wrote:Hello,
My RH 9170 shifter has progressively been getting worse when it comes to the spring return. The left shifter "pings" back into the parked position but the RH one is very slow and doesn't have a positive spring return. This is causing the front pads to drag every time I brake. It's now got to the point where I'm manually pushing the shifter back to the parked position every time I brake.
I've cleaned and lubricated the front pistons but no difference.
Any help appreciated.
How old are they?
And how many km/miles with them?
Seven months old
2500 miles

Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Sat Jul 13, 2019 3:26 pm
by ymisyd
bikeguy0 wrote:
Sat Jul 13, 2019 2:53 pm
I had same issue and had it warrantied. I rebled, cut hoses and new olives, and reoiled caliper piston seals and nothing worked.


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Which part was replaced under warranty? Shifter or caliper?

Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Sat Jul 13, 2019 4:45 pm
by bikeguy0
ymisyd wrote:
bikeguy0 wrote:
Sat Jul 13, 2019 2:53 pm
I had same issue and had it warrantied. I rebled, cut hoses and new olives, and reoiled caliper piston seals and nothing worked.


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Which part was replaced under warranty? Shifter or caliper?
Entire shifter.


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Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Sat Jul 13, 2019 5:05 pm
by joren
same problem over here .

Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Tue Jul 16, 2019 7:41 pm
by ymisyd
So, today I bled the brake. A couple of tiny bubbles but nothing major.
I noticed, after researching, that everybody warns against operating the brake too much without pads in because the pistons will come out of the caliper. However, no matter how many times I pumped the lever, the pistons only ever came out about 3mm - no more.
Does this give any clues to the problem? After bleeding, the brake lever still won't spring back to the parked position. Is the caliper user serviceable? I can't find any documentation.
Thanks.

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Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Tue Jul 16, 2019 10:17 pm
by Broady
Shifter warranty. Same thing happened to me, luckily was picked up before installing.

Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Tue Jul 16, 2019 10:17 pm
by Weenie

Re: STR9170 Hydraulic Shifter Poor Spring Return

Posted: Thu Jul 18, 2019 1:18 pm
by dricked
I too have this problem. I thought it was maybe some air trapped in the lever still but I guess not.