I decided to convert my new bike to a drop bar MTB. An affectation which cost considerably more than I thought possible.
Anyway, I'm using DOT 5.1 in the system but they are spongy as hell. I've gone through the process several times. I'm wondering if my fluid has gone off. Is that even a thing?
Anyway any tips or pointers gratefully taken onboard.
I don't know about SRAM brakes but whenever I've bled my shimano drop bar brakes I've found that doing the levers at a few different angles can sort spongy problems.
wondering if my fluid has gone off. Is that even a thing?
Yes, it's a thing.
dot fluid absorbs water which reduces ots boiling point. Its still not compressible. Spongy brakes is either air in the system or occasionally sticky pistons / misaligned callipers
It's got to be me, by that I mean it has to be air in the system that I'm not getting out.
I find my Shimano hydraulic system with the screw in reservoir for bleeding a much more efficient way of doing it.
You just seem to push the fluid back and forth with Sram in the vain hope that all the air is expunged from the line.
Are you closing the caliper bleed port and then doing to vacuum pull with the lever syringe - that seems to work w flat bar SRAM bleeds
Are you preparing the syringes before you use them - i.e. removing as much air as possible from the fluid in the syringes by clamping off the hose and pull back on the plunger a bit until you don't get any (or very few) bubbles released
The levers also need to be set to around 75-80mm from the bars (according to the SRAM bleed instructions).
I'm wondering if my fluid has gone off. Is that even a thing?
Not in the sense of creating a spongy lever when the brakes are cold.
Spongy brakes means air in the system. They need to be properly bled.
Degas the fluid on the syringes as described above.
Make sure caliper bleed nipple is lowest point and lever nipple is highest point, so air has easiest travel. May require adjusting lever position.
Connect syringes and open both up.and give the lower one a push until about half full. Clamp top hose and then draw back lower syringe plunger to pull any air out the caliper.
Clamp lower hose, unclamp upper hose and pull back upp syringe plunger to pulll any air out the lever. Whilst doing this, gently flick the brake lever as that should help pull any air in hose out.
Once happy all air is out, remove lower syringe and seal caliper bleed nipple, give the lever a few flicks , once last draw up of upper syringe plunger and then give the plunger a wee push down to get as much fluid as you can in the lever, remove syringe and replace bleed nipple.
Should feel better.
Degas the fluid on the syringes as described above.
Make sure caliper bleed nipple is lowest point and lever nipple is highest point, so air has easiest travel. May require adjusting lever position.
Connect syringes and open both up.and give the lower one a push until about half full. Clamp top hose and then draw back lower syringe plunger to pull any air out the caliper.
Clamp lower hose, unclamp upper hose and pull back upp syringe plunger to pulll any air out the lever. Whilst doing this, gently flick the brake lever as that should help pull any air in hose out.
Once happy all air is out, remove lower syringe and seal caliper bleed nipple, give the lever a few flicks , once last draw up of upper syringe plunger and then give the plunger a wee push down to get as much fluid as you can in the lever, remove syringe and replace bleed nipple.
Should feel better.
Are you using the bleed-a-majig port at the caliper? If so, de-gas the fluid as above then do a normal bleed remembering to open the reach adjuster (is there is one) fully.... last bit is close the m/cyl port and slightly pressurise from the caliper end, close the bleed-a-majig port and then remove the syringe....
Of course, none of this will apply if your SRAM kit is different...
Ah yes, I got my last bit mixed up - close the lever end, then give a wee final squeeze of the lower plunger then tighten up the bleed nipple - assuming you have the quick bleed port thing.
Clear as mud! Thanks all, will give it another go. (Again)
I don't do any of that in general but if i do use the kits i will often do this. Bleed it like a car. Make sure rhe reservoir is always full though as holds tiny amounts of fluid.
Pump up the lever and hold tight. Release the nipple and the lever will go to the bars. Lock the nipple. Repeat several times and keep reservoir topped up.
No air will be in the system.
This helps.... don't know if your drop bar levers are much different
There’s plenty of how-to guides on YT. Repeating the process of pulling air out the lever at least 3 times - tapping the lever body with a spanner, as well as flicking the lever to release any air bubbles.
I have a last resort for systems that don't bleed. Take them off the bike and rig it so the hose rises constantly and steeply from caliper to lever, then bleed. A faff, but has never failed for me.
Yeah Im wondering if this is the issue particularly for the rear. All good points thanks.
I don't have a bleeding edge tool right enough although Im not sure that's the issue. I think I need a a more aggressive angle for gravity to work with me.
Seriously it's why bike shops exist.
I'm not doubting your ability to find a way around a bike but the likely hood is your probably using a 5 year old used 10 times yellow branded plastic bleed kit bought in 2021 from amazon which has the sealing capacity of a rich tea, dot fluid small bottle costs less than a pint so not starting with a fresh bottle when your questioning the quality of your current bottle is also another idea why home mechanic,s struggle .
It's genuinely one of the easiest jobs to do with the proper equipment and knowledge.
There is also 100,s of official sram videos documents available as I find asking a vicar a baker and a candle stick maker on the Internet how to bleed brakes just further muddies the water .
Its the reason I like this place. There's always someone who has a different technique or approach to a task. Its a rich vein of support and information for bike and life stuff and has been for many years.
See all the genuinely helpful posts above, which I'm going to use when I re bleed. If at first you don't succeed...see what I did there.
My bleed kit is a relatively new Superstar item and my fluid is in fact in date, so its all me.
Thanks though.
a last resort for systems that don't bleed. Take them off the bike and rig it so the hose rises constantly and steeply from caliper to lever, then bleed. A faff, but has never failed for me.
Unless you've got internal cable routing.......
In which case it's a matter of bike stand gymnastics to get your brake lines as vertical as possible to get the air moving
I often look at this forum and wonder why people ask questions on subjects such as, say car maintenance, when it is fundamentally a mountain bikers forum. But in this case it's an on topic question.
I haven't taken a bike to a shop for work in my life - the only thing I've sent off is shocks, and am doing more and more of that myself also. The next thing I send off will be a Fox Transfer as it is nitrogen charged and I don't have the kit.
often look at this forum and wonder why people ask questions on subjects such as, say car maintenance, when it is fundamentally a mountain bikers forum
You new here? 😉
often look at this forum and wonder why people ask questions on subjects such as, say car maintenance, when it is fundamentally a mountain bikers forum
You new here? 😉
Nope, been here from just about the start!