RubeRad

My MTB has Elixir 7 hydraulic disc brakes, and the rear one got real bad, I can hold the lever to the bar and not lock the brakes rolling down not much hill.

So I ordered an avid bleed kit from bleedbicycles, watched this video , and this video , took a lot of notes, and set to it. 3 tries later, I'm in exactly the same situation.

First try, since I don't have a thick brake block, I stuffed the handle of a bamboo spatula that was about the right size. When I was done, brakes were squishy.

Second try, I left the pads in, along with a brake spreader (that came with the brakes). I forgot to take the bottom syringe off and put the bottom bleed screw back in, so when I got up top to squeeze the lever 10 times, the bottom syringe hose flew off its barb.

Third try, I thought I really had it. Up top, I was getting no more bubbles in the vacuum, and the lever squeeze was very firm. But then after replacing the upper bleed nipple, the lever was totally squishy. And one of my nitrile gloves is torn to shreds, so I can't try again until I make time to go buy some more.

Is it always this hard? Or do brakes that were as bad as mine always need a lot of bleeds to get the job done? Any tips or tricks would be appreciated.

jimc101

With all the self inflicted issues, & using a model of brakes which is known to be hard to bleed, then yes it will be 'this hard'

For all the issues you have had, would just replace with a Shimano equivalent, current Deore brakes are generally seen as very good value for money, easy to work on and last well.

Cyclist0108

Are your pads and/or rotors worn ?

Dan Burkhart 

+1. Sram hydraulics have a complex fill and bleed procedure which must be followed precisely, and even then, failure rate can be high.
Shimano systems are simple and straight forward, far less time consuming, and use mineral oil which is not nearly as nasty as DOT fluid.
Plus, they just plain work.

RubeRad

No the bike is only a couple months old, less than 100mi. It's from BD, so I'm dealing with it myself.

At this point I'm not about to junk the brakes and buy shimano (although I am very attracted to mineral oil instead of toxic, and simpler bleeding is also looking really good...)

Any particular reason the lever would seem firm until I pull the top syringe and put the top bleed screw back in, then be mushy?

Darth_Firebolt

>avid
Yup. It's gonna suck.

Cyclist0108

An air bubble that dissolves in the fluid when you apply pressure. (Anther reason why I too favor mineral oil.)

After 8 or 9 years with Avid Juicy brakes on a mountain bike, I finally broke down and replaced them with Shimano XT brakes, rotors and pads. These, admittedly, are two extremes, but I wish I could have those 8 or 9 years back a lot more than I miss $300.

RubeRad

Where was the air bubble when I was squeezing the lever 10x with the syringe on? Did it get in when I swapped the syringe for the bleed screw?

When that port is open, what keeps the hydraulic system in stasis, just the fact that it's not pressurized, so it will tend to stay in its current state? I don't get fluid leaking out the port, so I guess (hope) I'm not getting air going in

Cyclist0108

What happens when you turn the bike upside-down? If the brakes get even more squishy, it is most likely air. If your syringe can make an air-tight seal (vacuum grease in the leur lock can help), you can purge the system with negative pressure. But I had so little success with Avid that I don't want to pretend to be able to advise.

gsa103

Some simple tricks that may help.

1) Allen wrenches can substitute for bleed blocks.

2) Remove the caliper from the bike. This way you can move it around to try to dislodge any stuck air pockets.

corrado33

If you splashed brake fluid all over everywhere, your pads are likely ruined. Just FYI.

Brake fluid isn't really that bad for you seriously. You'll be fine not using a glove. People are just safety sallies now-a-day.

I don't get it, most brakes are the same for bleeding... Attach reservoir/syringes to both sides, push fluid through (either one way or both, usually bottom to top) then cap both sides (bottom first), then squeeze lever...

I've had good luck pushing fluid through in BOTH directions. On a few bleed jobs I did we pushed fluid through one way, then the other, then the other. Bubbles came out of both sides every time, and the brakes turned out great. Probably wasn't the "specified" way of doing it, but it worked.

RubeRad

Those are great tips, I'll definitely try #1, maybe #2 if all else fails

RubeRad

OK if I ever get to the point where my brakes can meaningfully push the pads against the rotors, I'll watch for still poor braking. But I think it splashed only straight out/horizontal, I don't think it got into the pad area.

I've seen a drop corrode new bike paint in a very short time (minute?), so I didn't want to take any chances.

Not avid, you should watch either of those videos, it's not just pushing fluid up/through the system, it's drawing air out of the fluid with vacuum pressure first in the syringes before attaching them, then at the caliper, then at the lever.

RubeRad

Is this for real? A full shimano hydraulic brake set for $44 from Thailand, or $56 from Los Angeles?

wschruba

Unless the paint wasn't properly cured/was poorly bonded, this is not the norm. It takes legitimate paint stripper at least minutes to begin lifting paint (and usually more, on a good paint job). You shouldn't let it sit, of course, but you don't need to treat it like acid on skin, for example.

A spray bottle of water will saturate the DOT fluid, and 90% rubbing alcohol (aka IPA) will remove it handily.

RubeRad

All my IPAs are for drinkin! I'm not gonna waste any to wash my hands!

GeneO 

You drink IPA you die!

Darth Lefty 

355 is Altus level. I'm not sure if Shimano makes anything cheaper. I can't tell you if those listings are legit but the prices seem plausible. They both look like established sellers with ok feedback, and the parts are likely not boxed. I don't think you'll find anyone strongly advocating you buy them.

dksix

I'm curious for a comparison.

I watched the first video and it seems like a lot a aggravation. I've never had to bleed a hydraulic bicycle brake system, any brand. I have installed every component of hydraulic brake systems on cars, motorcycles and ATV's and had to bleed out those systems that I consider to be straight forward and though aggravating not complicated. From someone who has worked on other hydraulic brake systems, how does having to maintain a bicycle's system compare?

Cyclist0108

As a chemist, I would not recommend touching DOT brake fluid.

Mineral oil, however, is safe enough to drink (possibly apart from the red dye Shimano puts in it).

RubeRad

I'm surprised at the Altus level the disc brakes are hydraulic instead of mechanical -- or even that they exist instead of V-brakes. Does Shimano even make mechanical discs at all?

RubeRad

I'm curious too, but I've got no car/moto experience. Hopefully somebody else can chime in.

But once I've got the two syringes screwed in, I suppose I could push the fluid back and forth between them until I see no more bubbles on either end.

Canker

They all have different quirks. I've only worked with Avid/Sram HUGE PITA, Tektro minor PITA, and Shimano easy as pie. With Shimano you can just gravity bleed them if you want and they work fine.

RubeRad

OK, so a few weeks went buy before I finally picked up a box of nitrile gloves, and got some time to try it again, but on a whim I tried the brakes out first, and they're fine!

I think what happened is, I finished the bleed, put the wheel in, so between the pads was the rotor instead of the spreader, and the first couple pumps is all that I checked, those were soft because they were self-adjusting to the rotor width (less than the spreader).

I mean they're not great, but at least I can stop the bike without the lever touching the bar, unlike before I could bottom out the lever and barely slow down.

Gonna leave well enough alone...

fietsbob

Magura does put thought into the bleeding, & service .. Mineral oil.

(I got their rim brakes, they are a improvement over V brakes..)