Request for help. HELP! Hydraulic brake problems

Quoted message said:

How does this happen?

There could be some moisture in your system which is boiling on these
descents. Was the brake fluid from a new or otherwise sealed container?

"JohnH" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

How does this happen?

There could be some moisture in your system which is boiling on these
descents. Was the brake fluid from a new or otherwise sealed container?

That's what I figured. It was old fluid.

I guess I need to buy some new and flush the line. How rigorous do I need
to be to get the moisture out? Do I just pump a bunch of fluid through? Or
is there a product to use?

Thanks for the info.

Greg

Quoted message said:

Quoted message said:

There could be some moisture in your system which is boiling on these
descents. Was the brake fluid from a new or otherwise sealed
container?

That's what I figured. It was old fluid.

I guess I need to buy some new and flush the line. How rigorous do I
need to be to get the moisture out? Do I just pump a bunch of fluid
through? Or is there a product to use?

Pushing through would probably get most of it , but I'd probably drain all
the components (master cylinder, lines and caliper) and start anew.

"JohnH" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

Quoted message said:

There could be some moisture in your system which is boiling on these
descents. Was the brake fluid from a new or otherwise sealed
container?

That's what I figured. It was old fluid.

I guess I need to buy some new and flush the line. How rigorous do I
need to be to get the moisture out? Do I just pump a bunch of fluid
through? Or is there a product to use?

Pushing through would probably get most of it , but I'd probably drain all
the components (master cylinder, lines and caliper) and start anew.

I assume the process is similar for most hydraulic bicycle brakes so I have
a question or two about storing fluid. Saturday I used a half full bottle
along with my original syringes. There easily could have been moisture in
the syringes.

So, with regards to the bottle of fluid I know they recommend to not use it
again after it has been opened but is there anyway to keep it moisture free
after putting the cap back on?

And with the syringes should I be cleaning them with alcohol or something
before I re-use them?

If need be I'll just toss the old fluid and syringes each time since I don't
have to do this very often but I still think that is kind of wasteful.

Greg

Quoted message said:

I assume the process is similar for most hydraulic bicycle brakes so
I have a question or two about storing fluid. Saturday I used a half
full bottle along with my original syringes. There easily could have
been moisture in the syringes.

So, with regards to the bottle of fluid I know they recommend to not
use it again after it has been opened but is there anyway to keep it
moisture free after putting the cap back on?

And with the syringes should I be cleaning them with alcohol or
something before I re-use them?

If need be I'll just toss the old fluid and syringes each time since
I don't have to do this very often but I still think that is kind of
wasteful.

This http://www.brakefluidtester.com/downloads/killer.pdf is an interesting
document (intended to generate sales of their tester of course) with some
interesting stats; of interest is the 3% figure as an upper limit for
moisture.

I can't imagine you'd need to go to the extremes of alcohol cleaning and
brand new fluid each time for normal use, then again I don't know what's
normal for you.

Also, are you using dot 4 / 5.1 with these brakes?

"JohnH" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

I assume the process is similar for most hydraulic bicycle brakes so
I have a question or two about storing fluid. Saturday I used a half
full bottle along with my original syringes. There easily could have
been moisture in the syringes.

So, with regards to the bottle of fluid I know they recommend to not
use it again after it has been opened but is there anyway to keep it
moisture free after putting the cap back on?

And with the syringes should I be cleaning them with alcohol or
something before I re-use them?

If need be I'll just toss the old fluid and syringes each time since
I don't have to do this very often but I still think that is kind of
wasteful.

This http://www.brakefluidtester.com/downloads/killer.pdf is an

interesting

Quoted message said:

document (intended to generate sales of their tester of course) with some
interesting stats; of interest is the 3% figure as an upper limit for
moisture.

3% sounds reasonable, I doubt it takes much moisture to cause problems.

Quoted message said:

I can't imagine you'd need to go to the extremes of alcohol cleaning and
brand new fluid each time for normal use, then again I don't know what's
normal for you.

Well, I've had the brakes for about 15 months and now that I think back I've
always had problems with the rear. I haven't emptied and refilled the
brakes during that time. Saturday I thought it was just air in the lines so
I went through the Avid bleed process, get bubbles out of the caliper, push
fluid through the hose, and then get bubbles out of the master cylinder.
Looking at the clear bladder at the lever for the rear brake it looks funky,
like there's a couple of drops of water or something. The front looks
perfect, no bubbles, no odd textures or anything.

Saturday I used two syringes that had been sitting in a box for a year with
a small amount of fluid in them. I guess the moisture was in the syringes.

Quoted message said:

Also, are you using dot 4 / 5.1 with these brakes?

I bought a bleed kit from Avid awhile back, so it's one of the two, don't
know which.

Greg

G.T. said:

Ok, don't know how many read my last ride report but I am having
problems with my rear Avid Juicy. A couple of rides ago I went over
the bars and my rear brake hasn't been the same since. Last ride
with JD I lost my rear brake about 2/3 of the way down McGill Trail.
I get home and look at the master cylinder and I see some air
bubbles. I bleed the brakes today. I ride around and everything is
working peachy keen. I do a 1500' climb, turn around and 5 minutes
of high speed descending later my rear brake is gone again. I stop,
look at the master cylinder and there are more huge air bubbles in
there. I pump the lever a many times and it comes back and I make it
the rest of the way down without mishap. And on this descent because
of the rains this winter there is some serious exposure in places, I
can't imagine what would happen if I lost both brakes.

How does this happen?

By removing reliable V-brakes for those complicated contraptions.

:-D

Bill "my version of the SSnipes" S.

On 2005-07-11, G.T. penned:

Quoted message said:

I guess I need to buy some new and flush the line. How rigorous do
I need to be to get the moisture out? Do I just pump a bunch of
fluid through? Or is there a product to use?

Thanks for the info.

See, this is why I'm glad my disc brakes aren't hydraulic. It just
seems so complicated ... and hard to jury-rig on the trail.

--
monique

"Get a bicycle. You will not regret it, if you live."
-- Mark Twain

Quoted message said:

Well, I've had the brakes for about 15 months and now that I think back I've
always had problems with the rear. I haven't emptied and refilled the
brakes during that time. Saturday I thought it was just air in the lines so
I went through the Avid bleed process, get bubbles out of the caliper, push
fluid through the hose, and then get bubbles out of the master cylinder.
Looking at the clear bladder at the lever for the rear brake it looks funky,
like there's a couple of drops of water or something. The front looks
perfect, no bubbles, no odd textures or anything.

Saturday I used two syringes that had been sitting in a box for a year with
a small amount of fluid in them. I guess the moisture was in the syringes.

Quoted message said:

Also, are you using dot 4 / 5.1 with these brakes?

I bought a bleed kit from Avid awhile back, so it's one of the two, don't
know which.

Greg

The rear brake is notorious for being a little harder to bleed due to
the extra length. I've gone thru the same thing you are with my Hayes
and it ca be very frustrating.

Some tips that may or may not be useful for you:

1. Always, always use brand new fluid. I know, it pisses me me off too,
but its worth taking the extra precaution.
2. Make sure to follow your bleed procedure; don't take short cuts. Pump
the rear (if possible - with Hayes you can) while filling.
3. Run some fresh fluid thru the syringe to rinse/prime it. Dump that
portion and refill for the bleed job.
4. Use as high a boiling point fluid as possible. Not all brake fluid is
created equal, some of the brands have higher boiling points than
others. I've actually switched over to
http://www.pbase.com/slack/image/46088984 Yeah, its expensive, but the
stuff works great.
--
Slack

"Slack" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

Well, I've had the brakes for about 15 months and now that I think back

I've

Quoted message said:

Quoted message said:

always had problems with the rear. I haven't emptied and refilled the
brakes during that time. Saturday I thought it was just air in the

lines so

Quoted message said:

Quoted message said:

I went through the Avid bleed process, get bubbles out of the caliper,

push

Quoted message said:

Quoted message said:

fluid through the hose, and then get bubbles out of the master cylinder.
Looking at the clear bladder at the lever for the rear brake it looks

funky,

Quoted message said:

Quoted message said:

like there's a couple of drops of water or something. The front looks
perfect, no bubbles, no odd textures or anything.

Saturday I used two syringes that had been sitting in a box for a year

with

Quoted message said:

Quoted message said:

a small amount of fluid in them. I guess the moisture was in the

syringes.

Quoted message said:

Quoted message said:

Quoted message said:

Also, are you using dot 4 / 5.1 with these brakes?

I bought a bleed kit from Avid awhile back, so it's one of the two,

don't

Quoted message said:

Quoted message said:

know which.

Greg

The rear brake is notorious for being a little harder to bleed due to
the extra length. I've gone thru the same thing you are with my Hayes
and it ca be very frustrating.

Some tips that may or may not be useful for you:

1. Always, always use brand new fluid. I know, it pisses me me off too,
but its worth taking the extra precaution.
2. Make sure to follow your bleed procedure; don't take short cuts. Pump
the rear (if possible - with Hayes you can) while filling.
3. Run some fresh fluid thru the syringe to rinse/prime it. Dump that
portion and refill for the bleed job.
4. Use as high a boiling point fluid as possible. Not all brake fluid is
created equal, some of the brands have higher boiling points than
others. I've actually switched over to
http://www.pbase.com/slack/image/46088984 Yeah, its expensive, but the
stuff works great.

Thanks for the tips. I'm going to follow all 4.

Greg

5. Use a mech on the rear. I went over to this and can't tell the diff.
Tried a mech on the front and missed the modulation...but the rear doesn't get
used very much and when it is, it's more a supplement to the front than anything
else.

--
PeteCresswell

"(PeteCresswell)" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

5. Use a mech on the rear. I went over to this and can't tell the diff.
Tried a mech on the front and missed the modulation...but the rear doesn't

get

Quoted message said:

used very much and when it is, it's more a supplement to the front than

anything

Quoted message said:

else.

Very good suggestion. I'll keep it in mind if I continue to have problems.

Greg

Per G.T.:

Quoted message said:

Very good suggestion. I'll keep it in mind if I continue to have problems.

I also tried a v-brake on the rear but my calf kept bumping part of it on every
pedal stroke.

A marginal consideration against the v-brake is the rim as a consumable.... but
I'd call that *really* marginal bc one can refrain from using the rear brake in
muddy conditions.

If it weren't for the calf thing, I think I'd be running v's on the rear of both
my bikes.
--
PeteCresswell

"(PeteCresswell)" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Per G.T.:

Quoted message said:

Very good suggestion. I'll keep it in mind if I continue to have

problems.

Quoted message said:

I also tried a v-brake on the rear but my calf kept bumping part of it on

every

Quoted message said:

pedal stroke.

No rear mounts here so that's not an option. I actually considered it when
I bought the frame.

Greg