Disk brakes problem

[ad61]

I'm experiencing a very annoying problem with the Avid Elixir brakes of my Specialized Stumpjumper.

I own the bike since one and a half year now and my rear disk brake start to lock itself when the weather start to warm up. Early morning ride are Ok but, as soon as the sun comes out, my brakes lever start to become firm and the calliper start to pinch the disk harder and harder till complete stop. I went once to a reputable bike mechanic in Phuket and he solved the problem by releasing a bit of brake fluid at the purge knot on the calliper. I've done the same each time the problem started again and I believe that there is now too much air in the brake lines and that the atmospheric pressure changes occurring during the day are the roots of my problem. What do you think?

I would like to find an Avid bleeding kit to be able to bleed my brakes by myself as I believe it will solve the problem.

Is anybody on the forum ever experienced the same problem?

Thanks for your help.

[ad61]

Excuse me for the double post.

[ubonjoe]

I removed the other one.

[ad61]

Thank you ubonjoe!

[chiangmaiexpat]

I ride a Stumpjumper FSR, too, and I haven't had that problem yet, but it sounds like a problem with the hydraulic lines. The hydraulic fluid itself can tolerate very high temperatures without expanding. One possible cause might be that the brake fluid is hygroscopic and absorbs too much water which then expands; another cause might be that the lines contract in the heat. Just guessing, of course. I would first change the brake fluid and if that doesn't work, change the lines.

Cheers, CM-Expat

[GarryP]

I have suffered exactly the same as you (same brakes too). Releasing a bit of brake fluid is a very temporary fix. Your brakes definitely need bleeding. You have air in the line and it is expanding as it heats up which is locking your brakes on. I would suggest a total bleed and replacement of brake fluid.

As to bleeding kits I have seen them in Bangkok but this is not much use to you.

[ad61]

Thanks a lot CM expat and Garry . I will try to bleed my brakes (once I found the kit) and will keep you informed.

P.S. i have now moved from Phuket and live in Ranong; the weather here is much more humid than in Phuket (a lot more rain because of the mountains all around) and the problem has now become a daily routine . I really need to find this bloody kit ASAP.

Thanks again to both of you.

[Maeklong]

I would contact Culture Cycliste bike shop (owned by LA bicycle) via Facebook or via their website http://www.culturecycliste.com/main/

[Maeklong]

Culture Cycliste sells Jagwire brake lines and universal bleed kits.

Sent from my iPhone using Thaivisa Connect Thailand

[bobfish]

The brake seizure problem is common here. My Codes, Elixirs and XO's all suffer. [It's not air; that would have an opposite effect.]

Avid brakes use DOT 5.1 which is hydroscopic [absorbs water] which means that under certain conditions of heat and humidity the total fluid amount increases to the point where the pads contact the rotor. Bleeding a small amount is a quick fix, but the increased water content reduces the boiling point and increases the likelihood of corrosion damage. My Codes were trashed after one season..... A fresh fluid fixes the problem and you can MacGyver up a bleed kit using syringes, tubes etc. Any quality DOT 5.1 will do. Plenty of ideas on Youtube.

My Shimano's on the other hand, use mineral oil and never suffer. Guess what brakes will be on my next bike??

[GarryP]

The brake seizure problem is common here. My Codes, Elixirs and XO's all suffer. [It's not air; that would have an opposite effect.]

Avid brakes use DOT 5.1 which is hydroscopic [absorbs water] which means that under certain conditions of heat and humidity the total fluid amount increases to the point where the pads contact the rotor. Bleeding a small amount is a quick fix, but the increased water content reduces the boiling point and increases the likelihood of corrosion damage. My Codes were trashed after one season..... A fresh fluid fixes the problem and you can MacGyver up a bleed kit using syringes, tubes etc. Any quality DOT 5.1 will do. Plenty of ideas on Youtube.

My Shimano's on the other hand, use mineral oil and never suffer. Guess what brakes will be on my next bike??

It is my understanding that Avid use a closed system and as such water absorption should not be an issue regardless whether the brake fuid is hydroscopic.

One thing I have read and been told about by a number of shops is that with Avid you can up-end the bike to do repairs (stand it in its saddle and handle bars) and it will have no impact on your brakes (provided you do not squeeze the levers when the wheels are removed). However, you need to be very careful doing this with some models of shimano disc brakes as they use a resevoir system and it can result in air in the brake lines, leading to the above problem.

[bobfish]

The brake seizure problem is common here. My Codes, Elixirs and XO's all suffer. [It's not air; that would have an opposite effect.]

Avid brakes use DOT 5.1 which is hydroscopic [absorbs water] which means that under certain conditions of heat and humidity the total fluid amount increases to the point where the pads contact the rotor. Bleeding a small amount is a quick fix, but the increased water content reduces the boiling point and increases the likelihood of corrosion damage. My Codes were trashed after one season..... A fresh fluid fixes the problem and you can MacGyver up a bleed kit using syringes, tubes etc. Any quality DOT 5.1 will do. Plenty of ideas on Youtube.

My Shimano's on the other hand, use mineral oil and never suffer. Guess what brakes will be on my next bike??

It is my understanding that Avid use a closed system and as such water absorption should not be an issue regardless whether the brake fuid is hydroscopic.

One thing I have read and been told about by a number of shops is that with Avid you can up-end the bike to do repairs (stand it in its saddle and handle bars) and it will have no impact on your brakes (provided you do not squeeze the levers when the wheels are removed). However, you need to be very careful doing this with some models of shimano disc brakes as they use a resevoir system and it can result in air in the brake lines, leading to the above problem.

Yeah, I like the Avid's theory, but it doesn't seem to work in the real world. I bled a little out of my Codes each time, but as noted, they dissolved. My Elixir and XO's are holding up, but I change the fluid when they seize.

I do notice that I can't store my Shimano equipped bike vertically [by hanging the front wheel on a hook], because air gets in the system. Your explanation makes sense. Thanks!

[Spacer]

Ad61, Have you found a bleed kit?

Amazon has bleed kits. Mine took a little over a week to arrive.

[ad61]

Ad61, Have you found a bleed kit?

Amazon has bleed kits. Mine took a little over a week to arrive.

Hi Spacer,

I found several bleeding kits on Ebay.

Could unfortunately not yet order one as most of the sellers are working with PayPal account which I didn't have and had to apply for; still waiting for my personal code number to be able doing the transaction.

Thanks for your help.

[ad61]

Finally, my bleed kit has arrived (yesterday) and the bleeding of my Avid brakes has been done successfully; they are now working again like (even better) than when the bike was brand new :-).

Life is beautiful again ;-)

[T_Dog]

Finally, my bleed kit has arrived (yesterday) and the bleeding of my Avid brakes has been done successfully; they are now working again like (even better) than when the bike was brand new :-).

Life is beautiful again ;-)

Glad you got it working. It takes only a few small bubbles of air to cause the problems so glad you got it sorted.

[aarn]

I mucked around with hydraulic disks for sometime.

IMHO, you are better off going with mech disk brakes.

Still plenty of things to waste time attempting to repair/refurbish with bicycles. AA

[bobfish]

I mucked around with hydraulic disks for sometime.

IMHO, you are better off going with mech disk brakes.

Still plenty of things to waste time attempting to repair/refurbish with bicycles. AA

AA: You may have a point for just pottering around, but for power and modulation you can't beat a well set up hydraulic system when the going gets raucus.

[T_Dog]

I mucked around with hydraulic disks for sometime.

IMHO, you are better off going with mech disk brakes.

Still plenty of things to waste time attempting to repair/refurbish with bicycles. AA

AA: You may have a point for just pottering around, but for power and modulation you can't beat a well set up hydraulic system when the going gets raucus.

Hydraulics are really the only way to go as there is zero maintenance except for replacing the brake pads if they are set up correctly. My Hope XC twin piston units have been flawless for nine years now, never bled or fluid replaced. Just ride and use until the pads are thin. With mechanical pull brakes, you will always get corrosion in the pull cable.

[bobfish]

T Dog,

yeah, Hopes are good brakes.

Any thought of giving them a bleed before the decade's out? or committing to a long downhill run?

I mucked around with hydraulic disks for sometime.

IMHO, you are better off going with mech disk brakes.

Still plenty of things to waste time attempting to repair/refurbish with bicycles. AA

AA: You may have a point for just pottering around, but for power and modulation you can't beat a well set up hydraulic system when the going gets raucus.

Hydraulics are really the only way to go as there is zero maintenance except for replacing the brake pads if they are set up correctly. My Hope XC twin piston units have been flawless for nine years now, never bled or fluid replaced. Just ride and use until the pads are thin. With mechanical pull brakes, you will always get corrosion in the pull cable.

[T_Dog]

T Dog,

yeah, Hopes are good brakes.

Any thought of giving them a bleed before the decade's out? or committing to a long downhill run?

I mucked around with hydraulic disks for sometime.

IMHO, you are better off going with mech disk brakes.

Still plenty of things to waste time attempting to repair/refurbish with bicycles. AA

AA: You may have a point for just pottering around, but for power and modulation you can't beat a well set up hydraulic system when the going gets raucus.

Hydraulics are really the only way to go as there is zero maintenance except for replacing the brake pads if they are set up correctly. My Hope XC twin piston units have been flawless for nine years now, never bled or fluid replaced. Just ride and use until the pads are thin. With mechanical pull brakes, you will always get corrosion in the pull cable.

Guess I just think of the old adage "If it ain't broke, don't fix it." Should probably replace the fluid after all these years but they are still so strong with just a single finger needed that I don't want to take the risk of adding air bubbles. Remembered that I have had to replace the mounting screws as they corroded from all the hand sweat in that area. I wonder how the current Shimano hydraulics measure up against the Hopes?