Interesting! My left RSC lever just started to develop the same. Sometimes after leaving the (cold) bike in direct sunlight for a few minutes the lever gets stuck or will only return very slowly. It usually gets better after a few minutes, so seems to be a weather/temperature related issue

 

It's an O ring issue in the lever they are aware of. Had mine replaced under warranty without question. Temperature does seem to exacerbate the issue, pouring ice cold water on mine would momentarily fix it.

 

maybe Sram is gonna supply me with a thermosbottle to carry ice cold water with me

 

my Juicy 3s did this when it was hot outside. ill never use Sram brakes again. theyld lock up when it was hot outside, and wouldnt release until it cooled down at night

lame

 

The same thing is happening to me. Sounds very common after reading up on it. I have a few questions...

How long did the warranty process take?
Did they warranty both brakes or just the one?
Did they also upgrade the rotors to fit the new brakes?

Thanks for the post!

 

Incase anyone else is having the same problem.

Mine was definitely caused by heat. When the bike was stored in the AC there was no problem at all. In the bike shop the brake would act perfect. However, by the time I would get to the trail the rear brake is back to being stuck closed with no spring back from the lever. Sometimes leaving the brake locked in place. Fun! Especially when it happens halfway on a there and back trail!

Just dropped mine off at a LBS for a warranty claim. Hope they can handle mine too!

 

Has anyone been able to have this problem resolved without going through a LBS? My new, (400 miles), Guide R's will stick if left out in the sun. Pouring cool water on the lever fixes it every time. I would rather not be without my bike while going through the warranty process, plus I got my bike from Bikes Direct, so I am sure that the LBS won't put me on their priority list! What is the actual problem/fix? Is it just O rings, or is the piston/housing faulty? I did properly bleed it with no change in it's symptoms.

 

Yes I do carry two bottles now. One for me, the other for my Guide. Like me, she is very thirsty when it's hot outside

 

Interesting I found this thread -- I just had an issue yesterday. Brakes Guide R's pretty much completely failed in a dangerous defect kind of way. Modulation was way off, front lever stuck to bars, and the adjuster rotated to lock it in -- I went over the bars and smashed into the crunchy sagebrush -- which thank God it was there, it broke my fall and I only have scrapes, bruises and a little whiplash.

This is a design defect! If all Avid has to do is replace, they are getting out ahead -- some people may get more injured and sue. NEVER had an issue like this with Shimanos, been mountainbiking for 25 years.

If you look at the photo, you'll see the adjuster has rotated to lock the lever in place -- It's locked in place, I can't get it out without prying it, and the brake is hydrolocked.

 

Interesting I found this thread -- I just had an issue yesterday. Brakes Guide R's pretty much completely failed in a dangerous defect kind of way. Modulation was way off, front lever stuck to bars, and the adjuster rotated to lock it in -- I went over the bars and smashed into the crunchy sagebrush -- which thank God it was there, it broke my fall and I only have scrapes, bruises and a little whiplash.

This is a design defect! If all Avid has to do is replace, they are getting out ahead -- some people may get more injured and sue. NEVER had an issue like this with Shimanos, been mountainbiking for 25 years.

If you look at the photo, you'll see the adjuster has rotated to lock the lever in place -- It's locked in place, I can't get it out without prying it, and the brake is hydrolocked.
View attachment 1073502

I've just received my RSC replacement and they redesigned the levers, now it's theoretically possible for the above to happen if you're unlucky. The original levers were better in this regard...

 

I'm so glad I found this thread! I am having the same issue with my Guide RS brakes on my one-year-old YT Capra. I started to notice it last fall (when it was still warm in TX), but assumed that I just needed to rebleed and clean the caliper. I did just that this winter (completely replaced the fluid and followed the service manual), and it seemed to be a bit better, though never as good as new. As the season has progressed, I've noticed it more and more, and, of course, it is strongly correlated to the increasing temperatures. Particularly after a ride on the roof rack, in the sun.

I'm in Austin, TX and just had my first 90+ degree ride of the season, and the levers were super slow on the return. Much worse on the rear brake than the front, but noticeable on both. After seeing this thread, I took my bike inside to the air conditioning. Checked this morning, and the levers felt perfectly normal. So strange. I don't think I ever would have diagnosed it as heat related until I found this thread. I'm certain no LBS around here would have figured that out either. I have a long, hot summer ahead of me and am not happy about this defect!

I've written to YT tech support and hope they help me out. I've already had two other SRAM products replaced under warranty: Reverb with blown seal and Pike with premature stanchion wear due to insufficient oil from the factory.

 

Same thing here, 20 C slow return 25C et + very slow return and the levers get stuck. Send it to Sram got it back 10 days later, change parts in the front lever, now it worst, slow return at every temperatures and rear lever no change. Very disapointed, think about trow them in fire and dance around it for conjuring the bad luck...

 

Very disapointed, think about trow them in fire and dance around it for conjuring the bad luck...

you wouldn't be the first...

 

Just when I'm considering switching from Shimano, something like this comes up. Sorry SRAM.

Tested this out on a handful of demo bikes on display at a shop. Almost all of them had the sticky lever.

 

I've encountered the issue too but it doesn't seem a widespread problem like the bite point glitch of the M8000 XT brakes.

 

I'm having the same issue with a set of DB5s. Took them apart to find the master cylinder was rubbing on the lever body and wearing down. Had to push the cylinder out with fluid, it wouldn't just pull out like it should.

 

interesting but not sure what you mean,
how can the cylinder rub against the lever body?
please elaborate

 

I ordered and installed the Sram lever internal parts kit; 100% cured the problem! I found that rubber from the piston seal was rubbing off inside the bore. I guess the rubber they used would swell from the brake fluid, and the tolerances were so close that the slight expansion from heat would cause too much friction and binding. Cheap DIY fix, ($17), but the snap ring is a pain in the butt to get out, (in one piece, anyway!).

 

pictures or it didn't happen

 

I will be doing the exact same thing when my replacement internals get here tomorrow and will post some pics.

 

As promised here are pics from the old master cylinder. The rub marks can clearly be seen. It seemed to have 100% fixed the problem when I replaced it, but time will tell. I also gave the internals of the lever a good cleaning. As mentioned above the snap ring was a b!tch to get off.

 

Is it the rubber or the plastic that is making it stick? Looks like a lot of rubbing on the plastic.

Mine has the same issues described. I decided to go with the rebuild kit. Can never find the time to go the bike shop and anticipating the hassle of dealing with a SRAM dealer where I didn't purchase the bike (no confidence in my LBS either).

So I disassembled mine today. The snap ring was removed with moderate aggravation. However the piston (not sure of the proper name) was completely seized. Usually it would work just fine at room temp, but this time it was stuck. I think dirt/sand got in there (it is somewhat exposed).

Anyway, I decided to remove the piston with a shot of compressed air. Well this worked really well. Too well. The piston shot across the room and, I think into another dimension, because I have not been able to find it. I did find the spring. I was hoping to be able to take a look at my piston to see why it was sticking, well maybe it will show up in a couple of years, when I've forgot about it.

Will report back when I get the new parts assembled.

 

My piston was also seized, pushed it out with an Allen key from the other side. I think it's a combination of the plastic and seals. I did the other one today and the rub marks were much worse.

 

My piston was also seized, pushed it out with an Allen key from the other side. I think it's a combination of the plastic and seals. I did the other one today and the rub marks were much worse.
View attachment 1079780

An Allen key?? How anticlimactic! :idea: I think I'll try packing the next one with gunpowder!:ihih:

 

Thanks a lot for the pictures.

Kudos to these few brave who take matters into their own hands!

 

UPDATE: The Dog found the lost piston. She had it in her mouth. Not sure how the dog found it. We searched for hours for that thing.

Anyway, it looks just like the others with lots of rub marks etc.

I clean it off really good and tried inserting it back into the lever. It was still stuck tight (yes, this time I removed it with an allen key, no drama ).

So my question is, should this piston move freely with just the spring tension, or does it need fluid in there?

Still waiting for my parts to arrive.

 

The new piston I put in moves very freely with only spring tension. Soaking it in brake fluid as recommended loosened it up even more.

 

Are we talking about some isolated issues here or will a larger number of Guide brakes develop this sticky lever syndrome over time?

If the ruber seal inside "swells" from the brake fluid that sounds very much like another faulty design/inferior materials in the first place

 

If the ruber seal inside "swells" from the brake fluid that sounds very much like another faulty design/inferior materials in the first place

nice troll and guess, but not.

 

Holy crap balls this is old news. I've worked on a bunch of old sram/avid brakes that have this problem and they used the same (similar) white piston. What happens is that the brake fluid combined with heat causes that white piston to expand which causes the brake lever to stop working. What we did at the shop was remove all the rubber rings, put the skinny end into a power drill, find some fine sandpaper and sand down the fatter part of the cylinder until it goes back into the housing without any friction.

The good news is that once you've done this a couple times it only takes about a half hour, including a bleed, to restore the brake to be fully functional and it lasts for a long time.

I can't believe SRAM is still using that plastic piston after all these years...

 

If you want to get this white part, it is necessary to lower the lever into the cold water. It freed, if it sufficiently cooled .

If you want to fix the lever. It is enough to gently whittle away some fiber with small projections in this white part

 

If you want to get this white part, it is necessary to lower the lever into the cold water. It freed, if it sufficiently cooled .

If you want to fix the lever. It is enough to gently whittle away some fiber with small projections in this white part

excellent fix. glad to see folks not just give in to the 'ahh hell it's broke throw it away and buy new' mentality as there's much satisfaction in improvising when successful.

Glad to see the ignore list function work it's magic :thumbsup:

 

Are these the correct instructions?https://www.canyon.com/download/manuals/Manual_Guide_Brakes.pdf

My levers are getting sticky, the back's the worst and I wonder if it's necessary to get the lever parts kit or if I can just clean, trim the piston and reinstall? Nearly new bike from Bikes Direct, so I'll be doing any work myself.....