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Never enjoyed bleeding brakes. It's a faff and its getting to the point where i might just give in and take the bike to a shop - first time ever!
Anyhow -- so bleeding Guide RS, caliper end no problems. Remove caliper syringe. Time to bleed to lever body. Checked everything is tight - create vacuum - get massive amounts syringe pull and tones of bubbles. Push fluid back in - repeat. Not so much movement of syringe but bubbles just keep coming. repeat....bubbles. bubbles bubbles..i could continue all day! Anyone had this before or any ideas what the hell is going on? Its driving me mad. New syringe, new tubing - the only thing I can think of is the O ring on the bleed connector could the issue by not creating an air tight seal hence sucking in air when I create a vacuum?.
Yeah, basically sounds like the connector is leaking air. Could be the hose, too. But there's a limit to how much air you can have in a brake
Yes, I get this when the plastic tube on the bleed port on my shimanos is a bit loose. Just draws endless air in through there.
I would agree with the above having had similar with Guides.
Sucking air into the syring past the bleed screw o ring is common. Make sure the o ring is in ok condition, nipped up just so, hose connections tight.
Its a stupid bleed system, creates a load of potential problems.
You can also just use a syringe without a plunger as a master cylinder resevoir and just bleed in normally, need to keep adjusting the lever angle to get all the air out the master cylinder.
I find the cheap syringes in the bleed kits leak air at the join of the hose depending on the angle of the syringe. Wonder about getting the pro bleed kit as supposedly has better connectors and seals. Though stupid money with a lot of bits in the kit I've already got. I just want the syringe and connectors really.
Turned out to be the O-rings. New O-rings arrived today - made a massive difference!
i find DOT oil has air in it already from the get go.... i last bled my Guides using two syringes; one at the lever, one at the caliper.
push oil through from the bottom. hold the bottom syringe and then pull the top syringe to create a vacuum. you'll notice lots of little bubbles forming. let these bubbles rise to the top of the syringe and then do the same with the lower syringe.
tap the lines and squeeze/flick the lever as you go.
Guys, are there any special topics for new users?
Try to get as much air out the fluid before you start. 3/4 fill the caliper syringe. close the clamp and pull the plunger down to create a vacuum. Open the clamp and push the air out. It can take 5 or 6 cycles but will make the bleeding much easier.
Hello Sisley,
Welcome to the forum.
Worth reading this
https://singletrackmag.com/forum/topic/our-forum/
Then crack on and join in! Some specific guidance on the Classifieds forums too that is it's worth a read of you are going to sell/ buy on here.
Introduce yourself in a new thread if you like. What you ride/ where etc.... only if you want to though! 😃
<div>sisley
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Guys, are there any special topics for new users?
Only a couple.
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1. Make sure you are word perfect on the forum anthem. Essential before your next post.
2. Never say the name “Hora” three times. It’s like Beatlejuice but I can’t say more than that.
3. Posts should only relate to bikes in a very oblique and fleeting way.
4. The picolax sachets are on the way as is the Sudocreme for the cat.
I've also just taken to bleeding my guide RS and had a similiar issue where I hadnt tightened the hose on to the syringe tite enough and it was sucking air out and I ran out of plunger draw back space!
I did notice that when I bleed as per the SRAM instructions: Push fluid from lever to caliper and back a few times till no bubbles at caliper end, close caliper bleed port and then bleed lever. Once I finish bleeding the lever the lever feels solid with the lever syringe still attached, but when I remove the lever bleed syringe and replace the T10 bolt the lever feels soft. Some fluid does leak out when doing this, is this the cause or is there something I am missing?
Once I finish bleeding the lever the lever feels solid with the lever syringe still attached, but when I remove the lever bleed syringe and replace the T10 bolt the lever feels soft. Some fluid does leak out when doing this, is this the cause or is there something I am missing?
Mine do exactly the same thing. Solid as a rock with syringe attached, remove it, loose fluid and lever feels a lot softer. It feels much better now I stopped the air sucking in. I think the softer feel must be related to the fluid that is lost when removing the syringe?
Bets tip is to never pull a "vacuum" with your syringes! Pressure only, that way no air can be pulled into the system.
I usually reverse bleed, push fluid into the caliper, and then let it out at the master cyl. Shimano's "pot" system works well here, because air can bubble up out of the caliper reservoir, but not get back down in, and any small leaks, due to miss-fitting hoses etc are fluid seeping out, not air seeping in!
Mine do exactly the same thing. Solid as a rock with syringe attached, remove it, loose fluid and lever feels a lot softer. It feels much better now I stopped the air sucking in. I think the softer feel must be related to the fluid that is lost when removing the syringe?
Glad its not just me! I do wonder if maybe once the syringe is removed and just before replacing the T10 you could try add a drop or two of extra fluid in the lever just before replacing the T10, that is if this is caused by fluid loss and not air ingress when you remove the syringe and replace the T10.