Bloody SRAM bleeding?

[Semmelrocc]

I had my first bike brake bleeding adventure the other day. After what I'd read about SRAM brakes being very difficult to maintain, I was very skeptical whether it really was a good idea to do it on my own. Especially as the bleeding became necessary after my LBS had replaced the rear brake pads and apparently didn't do it right.
So I ordered a bleed kit for my Guide RE, watched a few explanatory YouTube clips, and with a pair of helping hands it worked like a charm at the first attempt.
My personal conclusion: SRAM brakes are better than their reputation. So far I've never experienced a lack of power or modulation with them and servicing them is tricky, but not impossible. What are your experiences? What do other manufacturers do better?

 

[militantmandy]

My experience with Codes is that the bleed process is extremely easy and clean, but the results can be unexpectedly variable. By that I mean, they feel good after the initial bleed, but then after one ride, or maybe a week, or even two or three, the lever will start pulling to the bar again and the feel will go spongey. I assume this is due to some bit of trapped air inside, but that's just my guess. FWIW, RSCs appear to be slightly less prone to this that Rs. Don't know if I've been unlucky, but every set of Code Rs I've had have had this issue and that includes where I've given up and taken them to professionals to bleed. Across my riding friends it's probably 50/50 between those who have the same issues and those who never seem to have any problems at all!

Magura can be a bit the same, especially with rear brakes, but my last effort went well. They can also be tricky to align. On the plus side, if well bled then they seem to last months before they need done again.

TRPs have been the easiest and most consistent brakes I've bled. Simple process that seems to be fairly idiot proof and they appear to go a long time between bleeds.

Hope....can't believe spilling dot fluid is a specified part of the process. Not for me thanks!

 

[Semmelrocc]

I'd say the trickiest part is that you really need four hands to make sure both ends are kept upright during the whole process to prevent any air from traveling back into the system. But then I can't imagine this problem to be SRAM exclusive.

 

[iXi]

My latest bleed of G2's has been the best yet. I really took my time getting as much micro air bubbles out as I could. I just got a new Levo with codes and instantly they feel mushy and lever pull is shite. Going to try bleeding them tomorrow, I'm not sure bike shops know how to bleed brakes correctly or just don't care.

 

[The EMF]

It’s like all things that have moving parts exposed to the elements ie calliper pistons it’s worth taking a little bit of time to make sure they extend and retreat with as little resistance as possible and all at the same rate. A stuck or sluggish piston will require more effort at the lever to operate and can result in a spongy feel. Thera loads of maintenance hacks on YouTube to improve brake performance before heading for the bleed kit. I’ve had Avid and Sram brakes in various forms and touch wood they’ve been good. I’ve Code R’s on my Whyte and the only real inconsistency is type of brake pad manf claims. Always migrate back to Uber race matrix pads……not tried Trickstuff pads though

 

[Kingerz]

I've left them behind because Shimano is so easy and effective.
Even the fluid is better.
The size of the brake is so small and the ease of gravity bleeding is madly easy.

 

[RustyIron]

My personal conclusion: SRAM brakes are better than their reputation. So far I've never experienced a lack of power or modulation with them and servicing them is tricky, but not impossible. What are your experiences? What do other manufacturers do better?

No brake I've used is perfect. If they work well for you, then that's all that matters. I think SRAM's Bleeding Edge system is brilliant, and they have good modulation. The stopping power isn't the best, and the tightness of the seal inhibits extension of the pistons, resulting in varying engagement as the pads wear.

The Hayes Dominion A4 offers excellent braking power, good modulation, and their set-screw alignment feature is pretty handy.

My favorite is the Magura MT7. The piston/seal interface allows easier movement and more consistent extension of the piston... or maybe it's because of the mineral oil. Whatever the reason is, it results in consistent operation and ease of caliper alignment. MT7's offer excellent stopping power along with exceptional modulation. Their drawbacks are that they make a slight amount of noise, and the reach adjuster screws are just plain floppy, to the point of needing a drop of Loctite. There's also a little nub of aluminum that acts as a lever stop, which always gets sheared off pretty quickly.

Nothing's perfect, we all have our favorites, but we can all agree that almost all top-shelf brakes are vastly superior to whatever we were running only a few short years ago.

 

[Bontee]

There is a very simple and cheaper way,get a disposable plastic 50 mls syringe ,which cost way less than a quid.Remove the caliper bleed screw and push the syringe filled with fluid into the hole ,screw in carefully to get a good seal.then remove the reservoir screw and depress the syringe plunger the fluid travels up the hose and comes out of the reservoir hole,just make sure you wrap things up well in rags when no bubbles come out of the top screw replace the screw this forms vacuum ,then replace the bottom screw,I have bled countless sram brakes this way and have had perfect results.I agree if you have the kit it will do the job beautifully but this method does it just as well and you don’t need to buy the kit which you won’t use for ages .You will get some leakage but as long as you pay attention to the usual things ,like protect or remove brake pads ,put spacers in between the pistons,it is quick and dead easy.

 

[nosuchuser]

My codes have been good as gold since changing to trickstuff power po pads and following this bleed procedure: Brakes problem.. (Code R, RSC and lever throw) - EMTB Forums

 

[Hammick]

I bought a bottle of SRAM 5.1 brake fluid from Planet Cyclery. It has the color of hangover piss. Before I bleed my Elixir 5 brakes is this fluid supposed to be yellow? The bottle is dated the 10th week of 2021 and the seal seems to be intact. Thanks.

 

[sdcoffeeroaster]

No brake I've used is perfect. If they work well for you, then that's all that matters. I think SRAM's Bleeding Edge system is brilliant, and they have good modulation. The stopping power isn't the best, and the tightness of the seal inhibits extension of the pistons, resulting in varying engagement as the pads wear.

The Hayes Dominion A4 offers excellent braking power, good modulation, and their set-screw alignment feature is pretty handy.

My favorite is the Magura MT7. The piston/seal interface allows easier movement and more consistent extension of the piston... or maybe it's because of the mineral oil. Whatever the reason is, it results in consistent operation and ease of caliper alignment. MT7's offer excellent stopping power along with exceptional modulation. Their drawbacks are that they make a slight amount of noise, and the reach adjuster screws are just plain floppy, to the point of needing a drop of Loctite. There's also a little nub of aluminum that acts as a lever stop, which always gets sheared off pretty quickly.

Nothing's perfect, we all have our favorites, but we can all agree that almost all top-shelf brakes are vastly superior to whatever we were running only a few short years ago.

I never considered seal tightness before and do agree that could be an issue with piston movement leading you to think you have a stuck piston. I've bleed my code rsc brakes a few times now and learned several tricks along the way so the results are pretty good. SRAMs choice of DOT fluid I think is one source of issues. It can hold so much dissolved air in it that that step of degassing can take forever. I ended up making a tube to hold the vacuum while the bubble migrate up the syringe. It's just a 3 3/4" pvc pipe cut with a slot to clear the syringe shaft and take the load off my hand to allow multiple degassing pulls easily (just takes forever).

But seems like no matter how many times you pull a vacuum you still get bubbles. And I now degass the initial fluid fill of the syringes. So this process can take hours if you really try to get most of the dissolved air out. I am not sure it's worth the effort to because you never can get all of them. The other thing I suspect is an issue is the centerline rotor design. It just wants to sing out like a tuning fork so easily (just cleaning for instance) so if anything is slightly out, uneven piston movement, etc. they will squeal out. Sometimes it's just when they are cold and suddenly needed. But it's sort of unpredictable except that they will never be completely silent on a ride. I've tried metallic, resin and ceramic pads so far with the same results. My latest set up is with 203mm Shimano rotors which don't seem to have this resonant issue (but need the right mounts or 1.5mm washer shims). Otherwise I do like the feel of the code rsc brakes (new set given to me to upgrade my code r's). The bite adjustment actually does something unlike my old Shimano mt520 brakes I had on my Focus.

 

[RustyIron]

SRAMs choice of DOT fluid I think is one source of issues. It can hold so much dissolved air in it that that step of degassing can take forever.

I’ve thought it would be fun to get a vacuum chamber made for stabilizing wood. It could double as a degassing chamber for brake fluid. But like you suggested, it might not be worth the effort.

 

[sdcoffeeroaster]

I’ve thought it would be fun to get a vacuum chamber made for stabilizing wood. It could double as a degassing chamber for brake fluid. But like you suggested, it might not be worth the effort.

Yes I used a small chamber to degas epoxy years ago. The epoxy needed to be free of air for better transmission of sound from a piezo slab that was bonded to another surface with the epoxy. I think it was an oven as well.

Here's a DIY version without the heater:

 

[sdcoffeeroaster]

OK I finally had a quiet ride with zero squeals from my SRAM Code RSC brakes. And as I suspected the centerline rotors were the cause of all the noise. They are just not stiff enough at their 6 bolt attachment points causing a lot of resonance. The least expensive Shimano 203mm rotors (SLX, RT66 I think) produced zero noise and performed great. I love my SRAM brake now, lol.

 

[sdcoffeeroaster]

Here is another update on switch to shimano rotors. The one I used on the front came with the retail box. I only found the 2nd online at Commencal and it was an obvious OEM that came without the std packing and much less money but looked genuine. However it is not wearing the same as the std one I have on the front. The punched features look to be much more distorted and not making as much contact with the pads as the more expensive boxed version. I only bought the one from Commencal, still only $28. because I could not find them in stock anywhere else and they still are not in stock anywhere else. But they must be 2nds or knock offs based on this. Not noisy but this probably affect braking and cooling a bit. Seems to be a quality issue with the Commencal part and I've written them to question this.