sram guide brakes battling in the heat

NickGM's Photo NickGM 11 Jan 2017

I was wondering if anyone else has experienced this issue. I have some sram guide brakes which I've had really good service from for the last year now. However in the last few weeks I've noticed that, if I ride anywhere and the temp is in the mid 30s, the one brake lever (rear) very quickly becomes very "sticky" in that it does not return back to its original position quickly and the pistons have pushed out to the point where the pads are now grabbing the disc (braking, in other words). But if I go for a ride in cooler weather - not a problem. 

 

So my first guess is that there is a bit of air in the system. Air expands faster/more than hydraulic fluid so may push the pistons out and may contribute to the sticky feel of the lever. So I will give them a bleed just as soon as I get my hands on some Dot fluid. 

 

But....I have done a bit of digging and found this disappointingly common issue:

http://forums.mtbr.c...ty-1011229.html

 

Many of the thread's comments echo the exact same sentiment - the levers get sticky once the outside temp gets a bit warm. 

 

So if anyone has had similar experiences and solutions - please let me know. And just to pre-empt, "Buy some shimano brakes" is not really a solution yet. I've always been a shimano guy but the guides were part of a very well priced build. 

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Meezo's Photo Meezo 11 Jan 2017

check out thread with XT brakes doing the same,

 

my suggestion is probably a very good clean and rebleed and see if its the same, otherwise this might give you some kind of idea

 

http://www.bikehub.c...85-brake-lever/

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ALLMTB's Photo ALLMTB 11 Jan 2017

Yip, I know of three people who have had the exact same issue. Two of them on the same day...Guide RS and RSC. 

The brakes work flawlessly until you spend some time outside in 30 degree plus heat. 

In all cases the brakes were replaced under warranty. 

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NickGM's Photo NickGM 11 Jan 2017

check out thread with XT brakes doing the same,

 

my suggestion is probably a very good clean and rebleed and see if its the same, otherwise this might give you some kind of idea

 

http://www.bikehub.c...85-brake-lever/

Thanks! that's thorough. I'll give it a read this evening. 

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Myles Mayhew's Photo Myles Mayhew 11 Jan 2017

Yeah, agree with Meez. Sounds like it's an air problem coupled with maybe gummy pistons. 

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stefmeister's Photo stefmeister 11 Jan 2017

Mine (RS) did this as well, bleeding etc didn't fix it.

Had them replaced under warranty as it's apparently a well known issue due to the piston expanding and getting stuck.

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The_Chav's Photo The_Chav 11 Jan 2017

I've experienced this exact same thing and also only with the rear brake. I bled and cleaned the brakes only a couple months back and haven't done that much riding since to suggest they need a rebleed and clean. Nonetheless I had planned to do this and see what the outcome is.

 

But from what Stefmeister says it may be pointless...

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NickGM's Photo NickGM 11 Jan 2017

I've experienced this exact same thing and also only with the rear brake. I bled and cleaned the brakes only a couple months back and haven't done that much riding since to suggest they need a rebleed and clean. Nonetheless I had planned to do this and see what the outcome is.

 

But from what Stefmeister says it may be pointless...

OK well if you do find the issue coming up again, get in touch with Cape Cycle Systems as they deal with Sram warranties. I suspect if a bleed didn't fix it then you have the same (now well known) issue. 

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RiverInTheRoad's Photo RiverInTheRoad 11 Jan 2017

Classic SRAM....

 

:devil:

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droo's Photo droo 11 Jan 2017

Yup. Got 3 sets in the shop this week for the same issue. The tolerance between the piston and the lever bore somehow goes for a loop when the lever gets too hot and the piston jams.

 

Lever rebuild should sort it out, otherwise we've successfully modded a set by skimming about 0.1mm off the piston bushes before reinstalling.

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Meezo's Photo Meezo 11 Jan 2017

Yup. Got 3 sets in the shop this week for the same issue. The tolerance between the piston and the lever bore somehow goes for a loop when the lever gets too hot and the piston jams.

 

Lever rebuild should sort it out, otherwise we've successfully modded a set by skimming about 0.1mm off the piston bushes before reinstalling.

 

coming from a shimano brake fan, this is the nice thing about sram brakes, it can be rebuilt

 

as for shimano the McGuyver fix can/should work!

 

unrelated to this thread, droo where is the new lab? bikehub not doing a review on the new store, Nils says you closer by to us now :blush:

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Myles Mayhew's Photo Myles Mayhew 11 Jan 2017

coming from a shimano brake fan, this is the nice thing about sram brakes, it can be rebuilt

 

as for shimano the McGuyver fix can/should work!

 

unrelated to this thread, droo where is the new lab? bikehub not doing a review on the new store, Nils says you closer by to us now :blush:

Opposite Pennypinchers in woodstock. Pickwick Road


Edited by Myles Mayhew, 11 January 2017 - 12:55 .
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Meezo's Photo Meezo 11 Jan 2017

Opposite Pennypinchers in woodstock. Prestwich street. 

 

wow CSixx Stoke Suspension Woodstock CycleWorks and Pennypinchers less than a km radium from me work! WIN! :clap:

 

still think Nick and the team must do a store review thingy

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Capricorn's Photo Capricorn 11 Jan 2017

hmm, swelling plastic pistons: this old crap again. What does SRAM say about all this?

That thread on MTBR is enough to put even me off SRAM brakes...

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cpelser's Photo cpelser 11 Jan 2017

Ag nooit.

 

Paid R5k for Guide brakes about 14 months ago and I've noticed my rear brake also getting sticky.

 

What is the warranty period?

 

My wife's front Guide RSC was also rebuilt just two weeks ago.

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droo's Photo droo 11 Jan 2017

wow CSixx Stoke Suspension Woodstock CycleWorks and Pennypinchers less than a km radium from me work! WIN! :clap:

 

still think Nick and the team must do a store review thingy

 

Pickwick Rd. Coffee on your way to buy building supplies. And new and interesting ways to spend your leftover cash.

 

We're still getting a few things tidied up, but we'll be getting onto here with some promo stuff in the next month or so, don't worry...

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