My rear Avid Juicy Five disk brake has been giving me a bit of jip the past few months and it is now time to fix it. It all started after I left the bike on the balcony for a month or two over winter and the brake fluid either expanded, or the tubes contracted. Anyway, for whatever reason the brakes more or less clamped onto the disks. When I tried to squeeze the levers some brake fluid came through the seals of the reservoirs (on both brakes). I did a bit of Googling and found that carefully removing the top of the reservoir to release pressure would sort out this problem nicely, and it did (the front brake is still completely perfect without any further adjustment).
Unfortunately when I was doing the rear brake, my hand twitched or something and I spilt a little bit of brake fluid out of the reservoir. That’s when the problems started. As time had gone on, I’ve had to adjust the bite point of the rear lever to the point where I just can’t adjust it further. It feels like it’s biting, but it’s not gripping the disk. I thought maybe the break pads had worn out, but they haven’t. The local bike shop guy reckons I need to top up the brake fluid.
So…
I need brake fluid. I need to add this into the system. I need to make sure there’s no air in there to fark things up. Usually one would require a bleed kit for this. Avid has one, but Giant doesn’t have any in stock it seems. I’ve been told though that if I’m careful and remove the brake system and hold it vertically, so that the reservoir is at the top, I can add brake fluid without having to worry about air, since it will come to the top.
Hmmm. I’d suggest that perhaps being a bit less of a big girl’s blouse and using proper brakes would solve your problem.
Thanks, Irishstu. No problem, really. I’m GLAD to help.
i posted this in the other thread, but here it is for completeness:
bleeding the brakes may be necessary if any bubbles have gone down the tube (which is what it sounds like). these brakes are a pain to bleed as the tubing is very narrow, and the bubbles tend to stick to the tube, rather than allowing oil to run past them as in wider car brake hoses. if you can clamp the bike or the handlebars upright (or just gaffer tape it to a pole or a chair) you should be right. keep the top of the brake fluid reservoir dead flat, and lightly tap the tubing from down low to perhaps dislodge a bubble and let it flow upwards. maybe just drumming an allen key or something small will be enough. make sure you top up with the correct fluid! while some brands of disc brakes don’t actually use brake fluid, Avid Juicy brakes do. check online for an Avid manual (you know that Avid, SRAM and KMC are all the same company now, owned by Giant). also, check the Park tools webite for tips, and maybe search the web for the brakes chapter from Barnett’s manual, a shop guide.
edited for correct avid specific information… it does look like it’s best to use a bleed kit, but any pair of large syringes will do, with the correct hose and clamps (scrounge some from a saline drip kit from a hospital if you can).
the bleed kit looks like it wold be the only source for those brass screw in adaptor johnnies that seem to have taken the place of bleed nipples on ANY NORMAL kind of system. sorry.
i do find some of the Giant stores to be next to useless when it come to holding anything in stock that is not immediately of use on the latest version of the lowest end bikes…
Bleeding the brakes on that system may require a syringe as suggested, pushing the brake fluid up the system to the top and allowing it to overflow from the reservoir, but I would also try it the old fashioned way which is with a tube extended from your nipple into a container with about an inch of brake fluid in the bottom. You twist your nipple open once pressure is applied to the lever and close it off once the lever is at the bottom of its stroke. Release the lever and start again on your nipple. Remember to always keep the fluid topped off in the reservoir, and don’t let your hose pull out of the oil or else you could get air into your system again. Of course you wouldn’t have this problem if your hose was long enough in the beginning. You need DOT 4 fluid I believe.
Edit: Argh! I just had a thought. Do you have Juicy nipples at all?
If it were a car’s caliper, your setup would look like this:
Oh, well. You could always dump your disk brake system for a V brake system with Kool stop pads!
SRAM makes and sells a dedicated bleed kit that works with all it’s AVID hydro brakes…
The AVID Drip-Free Bleed Kit contains everything you need to bleed service the brake system along with instructions…
There’s one for sale here or ask your local bike shop to order you one…
Thanks for all the replies. I am more than happy to get the bleed kit. According to my LBS (he’s actually very helpful and knowledgeable), the bleed kit is under 1000nt. Problem is that he doesn’t have one and when he stuck in an order from Giant HQ, he found that it wasn’t in stock there either.
I looked into just making up my own bleed kit yesterday, but as urodacus says, there are no nipples on the system, just screws. To bleed to system, you need to remove these screws and then screw in the adapter thingies on the end of the syringe tubes (the adapters are the nipples, basically). The crap part about this (mechanically) is that once you have finished getting all the air out of the system, you have to unscrew these adapters and screw in the screws as quickly as possible, letting new air in. Genius.
My LBS guy recommended going to the Giant shop on Nanjing E Rd, more or less opposite the Brothel (sorry, I mean “Brother”) Hotel. It’s the flagship store apparently. I’ll do that after work today.
Sulavaca, you don’t have any Avid bleed kits in stock at Alan’s at the moment, do you?
I’m unable to use that yahoo auction site, due to my Chinese being non-existent, but thanks for that suggestion, plasmatron.
Sorry, I’m not working there these days since our move to Shilin prevents me from having the time to go there. I’m sorry really, as I loved hanging out there fixing bikes. I doubt they have the bleed kit, but you can always give them a call.
Hey guys, thanks for all the advice. I managed to pick up the bleed kit at the Giant shop on the corner of Da-An park last night, 1000nt for a couple of syringes and some brake fluid (ouch), but it was supposed to be 1200nt$ so I suppose I can’t complain.
either that, or your wife finally installed a smell-detector on your computer keyboard. (like one of those alcolocks in cars, you know…)
good luck.
when you unscrew the little brass jobbies once you’ve done the deed, there should be less risk of getting air back into they system if you ensure that the channel in the brass device is full of fluid. perhaps add a drop of brake fluid into the screw hole once you’ve removed the niple device, and before you insert the closing screws. then, once it’s all tightly screwd closed again, WASH the bike with lots of water to get rid of the paintstripper, i mean, glycol.
Ok so reading this stuff confirms what I just went thru. Ive had my hybrid MTB for bout 3 years now and i think i the three years i went bout 500 miles . And low and behold and discovering the joys (NOT) of hydraulic disk brakes and all the problems it brings. Simply put my front brakes went no workey well for me and the rear failed completely. Did some reading and read that hydraulic disc brakes may need bleeding once or twice a year and the pads need replacing bout 500 to 1500 miles or so?? ? IN comparison the ol rim brake pads can last upwards of 15,000 miles. And there is no bleeding of fluids and all one has to do is adjust the cable if it gets loose or stretched. And why why did we abandon this and go hydraulic disc brake? With all its complexity and mess? Well apparently most bikes 800 and up now have hydraulic disk brakes. Some lesser ones have a disc brake but operated by a cable. I honestly didnt find my brakes to be really any good. And now they are shot.
i bought a bleeding kit and tried to bleed it and made a mess. And i think my pads are worn down . So decided to have my bro pick up the bike and figure it out.
Well turns out pads are worn down and theres some issue with the brake itself (the rear) so he decided to upgrade my bike with a better hydraulic disc brake system. My problem still not solve. I actually wanted to go watch him fix it so i can learn but have been busy at work.
bro is like a car dealership, you go in to fix a flat on one tire and they end up replacing the whole set and replaced your pads and rotors too all at a convenient cost of 6000 dollars !! USD too.
Bro replaced front and rear pads and brake and of course refilled with new brake fluid.
I only have experience of car systems, and only extensive rebuild experience of a Daihatsu Skywing. They SHOULD be basically the same, but bicycle manufacturers seem to have an addiction to special tools that makes Citroen look like makers of Soviet military equipment, so I dunno.
On a car, a cheap enema syringe, (usually 50-60ml) widely available in Taiwan, does the job very well. You can suck or blow fluid, and you can cycle it bi-directionally to dislodge especially stubborn bubbles. On a bicycle I suppose a smaller syringe would do.
Americans seem very keen on “power-bleeder” kits that AFAICT offer no advantage except costing a lot more, which seems to confer some kind of consumerist vertue.
I prefer DOT3 brake fluid, since, although harder to find, it is less hygroscopic, about half the price of DOT4, and the theoretically higher temperature tolerance of fresh DOT4 is unlikely to ever be relevent outside of a racetrack.
IF you’ve never changed your brake fluid, it’ll get wet by absorbing atmospheric moisture, have a tendency to boil, causing total brake failure in use, and will corrode your brake system, causing it to jam, all of which happened to my car. You cant fix or clear the corrosion by flushing and will need to strip and clean the system. This was successful on the Skywing but I understand most people just replace.
Maybe have your brother replace them with cable actuated “mechanical” disk brakes. From what I can tell they are still quite popular within a certain sect (set?) of cyclists. The old Avid BB5 or BB7, TRP Spyre, or even boutique Paul or Growtac.
If I ever build up the old cannondale 29er frame that was gifted me, and I’d like to this year, that’s the route I will go.
