Sram brakes locking, is there a fix?

[teK--]

Ye

Osmosis, and water vapour molecles are really small.

Although sealed against the the flow of large-volume liquid, the action of the pistons through the seals leaves a small film of fluid on the sides of the pistons, enough to attract water vapour molecules out of the air and suck them in. DOT 5.1 has a particularly voracious appetite for water vapour.

Thanks for sharing, Duckman!

Although dot 5.1 has a higher boiling point, it is never reached in a MTB. For that reason and because 5.1 goes stale more quickly than dot 4, is why I choose to use the latter.

 

[Dozer]

That description is 100% not the piston problem, no way at all. As @The Duckmeister said; you can have some fluid expansion. The easy way and I guarantee the quickest trail side fix is to use the torx key to loosen the bleed port on the lever body and let the excess fluid seep out around the bleed screw. Wipe the fluid off before it drips on your caliper or rotor, tighten the bleed port screw then pump your levers. Your pistons will retract and you'll have lever feel again and be able to ride care free. This fix takes less than a minute and costs you $0.
Don't buy into the "SRAM brakes are shit 'cause they seize up" bullshit. Anyone with some intellect at setting SRAM brakes up will tell you that they're a good brake. I've run Avid's oand SRAM as a preference for 105 years. I've had every kind of Shimano, Tektro, Hayes, Hope etc etc and none of them offer the lever feel and modulation a well tuned Avid or SRAM brake does. I prefer them across all of my bikes (hardtail, enduro, downhill, even roadie) and have great confidence in them. Each to their own of course but anyone who trusts any brake to be the best brake out there straight out of the box without doing any sort of work to them to fine tune it isn't really trying hard enough.

 

[fatboyonabike]

Sram/Avid brakes would be great if they ran mineral oil rather than paint stripper in the lines..
no doubt that they do have some good products, just the con's outweigh the pro's
its not like the're Hayes brakes, now they are really shite!

 

[Zaf]

Removed by user

 

[Dozer]

We've been waiting so long for you to say this. It's okay though, you're with friends now!
DOT fluid using, lever slow returning, expensive zone-locked costing, caliper locking, feature up-sale having, useless brakes.

Shit, I walked into that one.

 

[Binaural]

@Dozer you seem to be saying that it's possible to overfill an open brake system? If letting a tiny amount of fluid out of the lever works, then the brakes are not well designed. Should be easy to tell the difference between this and sticky cylinders - if it's overfill, the locking should be noticeably worse after dragging them downhill for a few minutes to heat them up.

In my case, the levers feel like a handbrake - you pull them in, they stop and release a little bit.

 

[Dozer]

@Dozer you seem to be saying that it's possible to overfill an open brake system?

Nah, the fluid expands and the only place it can find to shift that excess is by pushing the pistons out a little; hence the tighter clamping of the brakes. I'm not suggesting this is a neat feature by any stretch but my method to cure it instantly works a treat and you have great lever feel straight up.
I like my brakes to be on when I touch the lever, I'm not one of these crazy kids that pulls it all the way to the bars before it works, those kids are nutters.

 

[Binaural]

Two issues at play: One is that they're early Guides, with known problems as dicussed above. The second is that any brakes which use DOT fluid, especially 5.1 will absorb moisture over time, which increases the volume of fluid in the system, which pushes the pistons out & binds the brakes on..... Additionally, SRAM brakes tend to run with tighter pad clearance than others, so they're more prone to jamming on when the fluid goes off.

Which is why all brakes that run on DOT fluid need to be bled periodically to flush out the old shitty fluid.

One point on this. MTB brakes are all open systems, every time you release the brakes the piston allows the pressure in the brake line to equalize with an air pocket in the lever body (hence "open"). Provided this air space is large enough to not act as a spring , that means that the brake pads won't actually push in over time, but the fluid will be more prone to local boiling at the caliper due to the water content.

Fun fact: this was not always the case. A mate of mine used to race DH in the very early days on some cheap early Formula brakes that heated and closed up over a run! They were closed systems, which are cheaper to build and design if you aren't too worried about expansion.

 

[Dales Cannon]

Early Hopes could be had in a closed system too.

 

[Cardy George]

@DozerIn my case, the levers feel like a handbrake - you pull them in, they stop and release a little bit.

I doubt your levers are old enough, but I resurrected some 1998-ish Avid Juicy 7s with sticky levers by clamping the piston in a drill and carefully turning it down until it stopped sticking.

After sitting around for years the nylon had swollen and was binding in the barrel

 

[pink poodle]

Ha ha! @Dozer has owned tektro brakes.

 

[ualf]

Well I still use Avid Codes.... flame away.

No wonder you have had some spectacular crashes ;-)

 

[link1896]

Ha ha! @Dozer has owned tektro brakes.

Ha ha at least he has time to ride his

 

[Dozer]

Well I still use Avid Codes.... flame away.

Possibly the greatest component ever bolted to a bike. Hang on to them forever!

 

[Dozer]

Ha ha! @Dozer has owned tektro brakes.

Nowadays they are known as TRP and I can't say they are kicking any more goal than they did "back in the day". I'm part way through a review on a 2019 bike with TRP equipped and while they aren't the best brake ever, they certainly appeal to some.

 

[Zaf]

Removed by user

 

[Dozer]

I'm taking the bait!
Saint's have gone six years without an update (or need for one), and counting. I guess the Code's to bow your head when they gaze upon a Saint.

Shimano guys racing world cups were putting Codes on their bikes and covering the logo's. SRAM guys now are still running the older Codes, doesn't say much for the current generation of brakes but the Codes kick arse.

 

[Rossm]

ahh nice, they are guides, yes.

I'll visit the LBS tomorrow and see what they can do for me.

Stupid question i know, with the replacement parts from SRAM the issue should not reoccur? I don't have a trust issue yet but they are brakes after all....

If you go to the LBS, push them to have the SRAM distributor fix this under warranty. There is NO statute of limitation for warranty in Australian consumer law (where the fault is an original defect in manufacture or design). I had same issue recently on 2yr old brakes - it was fixed at no cost under warranty. SRAM are well aware of this issue, as they had to re-design the master cylinder piston. My front brakes were fixed with a one week turn-around. (Rear brakes still running fine).

If you want to do it yourself, order a "Guide RSC Ultimate Internal Kit - Gen-2" Part # 11.5018.005.010

 

[Oddjob]

Shimano guys racing world cups were putting Codes on their bikes and covering the logo's. SRAM guys now are still running the older Codes, doesn't say much for the current generation of brakes but the Codes kick arse.

It's a good thing those pros have team mechanics. Having to work on those SRAM brakes yourself is a freaking pain.

Sent from my SM-G900I using Tapatalk

 

[Flow-Rider]

One point on this. MTB brakes are all open systems, every time you release the brakes the piston allows the pressure in the brake line to equalize with an air pocket in the lever body (hence "open"). Provided this air space is large enough to not act as a spring , that means that the brake pads won't actually push in over time, but the fluid will be more prone to local boiling at the caliper due to the water content.

Fun fact: this was not always the case. A mate of mine used to race DH in the very early days on some cheap early Formula brakes that heated and closed up over a run! They were closed systems, which are cheaper to build and design if you aren't too worried about expansion.

Where's the air pocket, most avids are a sealed unit some of them had bladders. If you leave any air in the hand piece it will result in spongy brakes.