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I forgot bleed block and popped multiple pistons in one go if that makes you feel any better
I'm I the only one that tightens the jam nuts for the compression fittings at the lever to "So tight that I'm worried that i'm going to crack the lever body"?
Turns out 8nm is pretty damn tight for that little nut so you are probably more right than wrong there. After my initial failures I checked the wrench setting a couple times just to make sure I wasn't about to strip out the damn thing as it just kept turning.
Yet to pop out a piston, but the SRAM piston massage video hints that pistons may pop out as you push others back in. They're all "don't worry just bleed the brake if this happens" as if it wouldn't totally bust someones trip or weekend.
I pop pistons out of maven's at least 70% of the time that I attempt a piston massage. I think, the a1 calipers with the larger pistons are worse in this regard, as the maven base calipers I have do not seem to be so sensitive. I love my maven brakes... but in the moment where I pop a piston out while just trying to do a piston massage, I am so... freeking... furious.
You just gave me a really bad idea about doing two brakes at the same time, man.
Been there. The worst feeling.
Even worse? I was helping a friend who was new to mountain biking work on their brakes!! I got distracted because I was talking him through the process, and didn't double/triple check my steps.
I'd forgotten that horrible memory until you reminded me. Thanks.
I have a friend who is a perpetual bolt over-tightener, and he managed to split a Maven compression nut. He had this shitty bleed that wouldn't hold air, and I checked the lever under the rubber hose/nut cover and saw oil coming out. I thought it was probably leaking because it had been under-torqued. Nope.
I'm sitting over here thinking, "Dude, I'm afraid to torque those compression nuts to the CORRECT torque spec, how did you over torque it?"
More recently, I was helping the same friend do a 50-hour service and replacing seals and wipers on his Zeb, and when I tried to take the lowers off I discovered that he had torqued the footnuts so tight that we didn't just round the 5mm allen heads of the footnuts, the footnut heads split in half. Needless to say, I was not impressed. Okay, I actually was impressed that he didn't crack his paper-thin magnesium lowers using that much torque. Had to take that one to the shop, and thank all that's holy they were able to extract the broken footnut (thanks to Jimmy at Traction Works in Lake Oswego!!).
When we got to his rear shock, the rubber o-ring that serves as the bottom out bumper in his Super Deluxe air was obliterated, floating around in chunks in the shock body. I said "I can get these chunks out and clean out all the micro-plastics, but you're on your own to replace the o-ring." It's going to need a full 200-hour service to tear down the shock to put a new bottom out o-ring on the main damper shaft. Of course he hasn't done that, and he's still riding that same shock, untouched, five months later.
I too have blasted out a piston while trying to piston massage a caliper. Late at night before a big ride wife mentions that her brakes feel spongy. Take a quick look and only one of the four pistons is moving. Brakes are long due for a bleed but I figure a quick piston advance + cleaning will do the trick. In my haste to push one piston all the way back in I shot one of the one working piston onto the floor.
The classic sram piston massage nip slip.
I have one that’s loves to sneak out really quick. The other seem to be anchored in place. Very annoying.
I wondered how many peoples brake problems are from the same thing? I would bet 95% of people don't use a torque wrench to tighten compression fittings.....
I've used a torque wrench (correctly with crowfoot) to tighten the compression fittings and then had the barb break off in the master cylinder when trying to remove the hoses. Happened more than once. I do put some of the SRAM dot (now multipurpose) grease on the threads. I'm always terrified of both not tightening them enough or overtightening them (at least I think that's whey they break off). Anyone else have similar experiences or have any advice?
Honestly I don't normally use one, I think I have lodged in my brain techinques from the original Juicy's and shimano brakes which still work...its something like tighten until its snug and you can't pull the hose out of the nut, then add 1 more turn. These days I'd finish of with the torque wrench, its not something I often do any more so might be a bit foggy.....
Not sure I've seen a broken barb, I would guess thats more like the barb wasn't fully screwed in to hose before the olive was fitted
I've seen them way overtightened in the past and didn't cause a problem - I showed a friend how to shorten hoses, and normally theres a couple of threads of the nut showing, but after he went away and did it, he managed to tighten the nuts all the way down to the lever body! Still worked fine....
For the shimano olives your smushing it down onto the barb but also making it shorter as well. Others with more meat on the olive still do this but to less of an extent so I can see breaking stuff or bottoming out the but both being possible. The exception are maguras which are absolutely terrifying because the lever body is plastic and you don't want to destroy the threads but also if it's too loose then you could have a real bad time (this happened to a friend a couple years ago).
In the spirit of this thread I need to admit to popping out a piston on a pair of mt5s that I was installing on a friends bike a couple weeks ago, only time will tell if the hose is on tight enough...
Bleeding 2 brakes at once seems like it would interfere with the beer drinking. Better to do 1 brake a time with 1 beer per brake than 2 at a time with half a beer.
Don't sell yourself short @AndehM. Your beer per brake tracks tho.
Editors note: This may be the root cause of a LOT of my dumb bike problems.
My newest dumb problem is that I got one of the new tr11 frames and they put the screws for the frame cable guides underneath the cables and it’s pretty delicate plastic. So you need a buddy to pull the cable out of the way super hard while he also holds the guide in place and you fight to get the tiny screw in with my fat fingers. Why they removed external routing ill never know.
I’ve broken an MT5 lever body by over tightening, that sucked. I think the trick, without using a crow foot torque head, is only tighten until it starts spinning the hose. All the threads are usually just disappeared into the body at that point. Thoughts?
Here’s another dumb one, possibly already mentioned above. While installing a front brake caliper with an adapter, to go from 160 to 180 rotor, I screwed in the longer bolt where the shorter bolt was supposed to go and sheared the post mount right off the fork leg. Expensive.
Ouch.
add me to the list again, I always thought I had just a noisy EP8 motor.
turns out it was my fidlock bottle just rattling this whole time after replacing it with a traditional bottle cage. 4 years it took me to figure this out lol
what a dumbass.
I have 4 years on mine as well and the Fidlocks are so dang loud! Im about done with it and going to a normal cage too haha
What I've experienced is that when taking a rear break off a bike and disconnecting the hose from the MC (because people even dumber than me decided we should put brake hoses inside the frame), the barb breaks off flush with the end of the hose and leaves the olive in the MC. Then you have to disassemble the MC and use a punch to delicately tap out the olive from inside the MC.
Interesting that you think I could not be tightening either the barb into the hose or the olive onto the barb tightly enough. I'd love to be doing something stupid I could correct.
OK, the following tricks apply to you DWM, but others may benefit as well.
1. When tightening a hose to a MC/Caliper, Insure you hold the hose into the bore firmly while doing so. Reason for a hose to pop off is improper install. Holding it deep in the bore while you tighten the comp nut insures the bushing starts compressing around all the hose it needs to. This is easier to do with the cal or MC mounted.
2. When tightening the comp nut I see if I can twist the hose in the bore easily or not. It should require a good amount of force to get it to spin in the bore. More often than not that correlates to the torque spec. Magura is the only one I avoid this and just trust the torque spec and that the insert is driven home and the comp bushing is set right. I am wary of plastics, yes.
3. If the comp bushing pulls off the end of the line (I.E is stuck in the bore), use a sharpened spoke to pop it out. Really handy on the Hayes 1 piece compression fitting but works with Shimano and Avid/Sram as well. The insert end will break off, and that's fine. Just insert the spoke/sharpened pointy thing in the remaining insert/bushing, and cock it sideways a couple times. Comp bushings rely on a straight-line mechanical fit, cocking them off center breaks the mechanical fitment and they can be pulled out without having to disassemble anything. May require a little wiggling, but I've yet to have any issue requiring tearing anything apart once I figured this out.
There's simply nothing like watching a brake line pop out of a fitment and squirt fluid all over the place. It's also why I no longer wear khakis period. Trying to get old DOT or any age mineral oil outta the crotch of your pants is an A+ effort in Futility.
I really wish they did external routing on that thing! If it wouldn't void the warranty I would just about add nutserts to the top of the downtube and some cable clamps just for the rear brake line. I really like that frame and it will probably be my next downhill bike but damn! I would have really liked external routing.
Yeah after reading it again - if this is a sram brake I definitely think it wasn't tightened enough. The olive should be crimped on to the hose so they are pretty much impossible to separate. And because the barb threads in to the olive, thats why it snaps off. I guess its tight enough to press against the housing, but hasn't squashed down on to the hose properly. Older brakes (and I guess shimano) could pop the line out completely if the hose wasn't clamped enough, like @HexonJuan described but the more recent threaded inserts prevent that (I say recent but I think they've been around over 10 years now.....)
It is sick, exactly like my spire but with longer chainstays which is what I wanted. Great at jumping, way more nimble than the trek I came off. But yea the routing is just so annoying.
This is amazing. Thank you for taking the time to write all that out.
Glad to help others learn from my follies.
OK this thread is getting WAY off topic with helpful advice and success👎
Some basic rules from my time as a customer facing shop mechanic:
Hey, I did mention how a hose popping off squirted my khakis in the right spot to make the rest of the day a gag for everybody I worked with. Maybe not that full part, but yeah. Just consider the bonus material a helping hand for anyone else who still thinks wrenching in khakis is a good idea. Which begs the Q: Is there a correlation between folx wrenching in khakis and those experiencing dumb bike problems on the regular?
Had a real dumb one today. Had some noise somewhere on the front of the bike. Kept stopping trying to find it but couldn’t feel anything wrong and couldn’t get the sound to go off the bike.
Turns out the cap for the air valve on the fork was a half turn loose. Boy did I feel stupid once I figured it out. And of course proceeded to destroy my derailleur next run so I actually had a problem then.
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