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Discussion Starter · #1 ·
I'm new(ish) to discs, so bear with the newbie questions here. I'm running Hayes hydraulics - whatever came stock with a 2001 Specialized Enduro.

I found a new route today which involved 700m vertical of downhill on steep single trail. As the ground was loose, wet, steep, and unknown to me I was being really careful and applying a lot of brake - they worked flawlessly until the end. At the bottom, after regrouping and a ten second wait, I set off on the flat and noticed I had absolutely no brakes. A feet-assisted stop later, I noticed on closer inspection that I could pull the levers all the way to the handlebars without getting any bite from the discs - either front or rear.

I guessed the brakes were cooked, so poured some water over them. Another 30 seconds later and both were wokring fine again. Is this normal? Am I at risk of such a failure going downhill, or will this only happen once I stop?

On the way home I bought some brakes pads just in case. Is there a way of checking if the pads need replacing? And if they do, is this an easy repair?

Thanks,
 

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Gravity Rides Everything
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jesus dude, get those checked out by a dealer... Can you get them to work by pumping the levers? you might have a leak, or something... again, get it checked out by a dealer... having both brakes go like that is weird and scary. :eek:
 

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Those brakes REALLY need to be serviced by somebody knowledgable.

That should NOT happen.

Do the Hayes have a bleed-off valve in case the fluid get's too hot from the pads or something? I wouldn't think this would be the case as a very hefty friend of mine had Hayes on his Fuel and he never had this problem w/o a leak in the line ( e.g. air introduced ).
 

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Discussion Starter · #5 ·
Pads replaced...

I replaced the pads on Sunday - the rear was pretty worn out and the front had a little life in it but was changed anyway. Could this be a factor?

The only other thing I had noticed before the ride is that the bite point on the front brake had moved inwards. After pumping the lever, it moved out to the normal bite point. Strange.

I hear the message "get them checked out", but would like to learn how to service them myself. What happens when the fluid boils? How do I find out if the fluid needs replacing? How do I replace the fluid and bleed? And is it a tough job?
 

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SwissBuster said:
I hear the message "get them checked out", but would like to learn how to service them myself. What happens when the fluid boils? How do I find out if the fluid needs replacing? How do I replace the fluid and bleed? And is it a tough job?
If you're going to learn how to service them yourself (which I applaud) then you need to:

  1. Read the Disc Brake FAQ (see upper right corner of this page for a link)
  2. Read the Disc Brake FAQ (seriously, did you read it yet?)
  3. Consider taking them in to your LBS to get them done right the first time, asking them what they needed to do. (Especially considering you have absolutely no idea what you're doing. We all start there, trust me.)
  4. Don't hesitate to use the search function to get more info fast, rather than wait for people to reply to a question here
 

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phUnk said:
If you're going to learn how to service them yourself (which I applaud) then you need to:

  1. Read the Disc Brake FAQ (see upper right corner of this page for a link)
  2. Read the Disc Brake FAQ (seriously, did you read it yet?)
  3. Consider taking them in to your LBS to get them done right the first time, asking them what they needed to do. (Especially considering you have absolutely no idea what you're doing. We all start there, trust me.)
  4. Don't hesitate to use the search function to get more info fast, rather than wait for people to reply to a question here
Anyone else notice that the creator of the FAQ can't spell lose?
Also, I don't known why they don't recommend DOT5 fluid. This is the same fluid that is used in cars, and is absolutely compatible with current DOT3 & 4 fluids (just don't mix them), plus, DOT5 won't eat your paint.
 

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SwissBuster said:
I'm new(ish) to discs, so bear with the newbie questions here. I'm running Hayes hydraulics - whatever came stock with a 2001 Specialized Enduro.

I found a new route today which involved 700m vertical of downhill on steep single trail. As the ground was loose, wet, steep, and unknown to me I was being really careful and applying a lot of brake - they worked flawlessly until the end. At the bottom, after regrouping and a ten second wait, I set off on the flat and noticed I had absolutely no brakes. A feet-assisted stop later, I noticed on closer inspection that I could pull the levers all the way to the handlebars without getting any bite from the discs - either front or rear.

I guessed the brakes were cooked, so poured some water over them. Another 30 seconds later and both were wokring fine again. Is this normal? Am I at risk of such a failure going downhill, or will this only happen once I stop?

On the way home I bought some brakes pads just in case. Is there a way of checking if the pads need replacing? And if they do, is this an easy repair?

Thanks,
You might have a leak and lost line pressure. After repumping your brakes fluid from the reservoir is pumped back into the line and they feel normal again. Eventually you could end up running out of fluid. What most likely happened is the fluid boiled or you got vapor lock. This is when the fluid gets so hot any moisture that has slowly worked its way into the system turns to steam and creats an air bubble. I'm not sure if this happens to DOT fluid which absorbs moisture and just ends up with a lower bioling point.I know this is more dangerous on mineral oil setups which don't mix with this moisture creating water bubbles. Either way, if your bike is a 2001 model and you've been riding it with no service since then you are overdue for a rebleed, particularly if yo ride in wet conditions frequently. Bleeding the brakes is actually not very complicated and you can do it yourself. You can buy a bleed kit from most shops and get the hayes instructions. There's also plenty of guides for working on those brakes.
 

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Kill that $hit!
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That same thing happed to me!

Hecubus said:
You might have a leak and lost line pressure. After repumping your brakes fluid from the reservoir is pumped back into the line and they feel normal again. Eventually you could end up running out of fluid. What most likely happened is the fluid boiled or you got vapor lock. This is when the fluid gets so hot any moisture that has slowly worked its way into the system turns to steam and creats an air bubble. I'm not sure if this happens to DOT fluid which absorbs moisture and just ends up with a lower bioling point.I know this is more dangerous on mineral oil setups which don't mix with this moisture creating water bubbles. Either way, if your bike is a 2001 model and you've been riding it with no service since then you are overdue for a rebleed, particularly if yo ride in wet conditions frequently. Bleeding the brakes is actually not very complicated and you can do it yourself. You can buy a bleed kit from most shops and get the hayes instructions. There's also plenty of guides for working on those brakes.
...A while ago and nobody had any answers for me. Your answer makes complete sence. Thanks. Btw, I did do a rebleed and cable change and that worked too. I just didn' t know how the problem happend. Not to mention getting to the bottom of Downieville w/ a back break! Cheers,

-C
 

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SwissBuster said:
...for the pointers, especially the one to the FAQ. :eek: I'm about to embark on another adventures in home mechanics.

Hubcap - from dictionary.com:
loose: Not fastened, restrained, or contained
Not taut, fixed, or rigid, etc.
lose: To be unsuccessful in retaining possession of; mislay, etc.
wow! I'm an idiot. LOL (maybe I've been working too hard?) hahaha. My appologies.
 

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AgentHubcap said:
Anyone else notice that the creator of the FAQ can't spell lose?
Also, I don't known why they don't recommend DOT5 fluid. This is the same fluid that is used in cars, and is absolutely compatible with current DOT3 & 4 fluids (just don't mix them), plus, DOT5 won't eat your paint.
As the editor and one of the writers of the FAQ, could you show me where you found the word "lose" spelled wrong? Then I can get it changed. I'll add that I certainly do know the difference between lose and loose but typos do occur even though that FAQ was edited 100x.

As for the DOT5 question. Rather than me quoting from brake manuals or brake fluid tech pages I'll refer you to the Google search engine for your info. The FAQ's exact sources for its brake fluid info are now long forgotten, especially seeing as the sources of the info were not listed in the FAQ.

Mike T. (mcm # 717)
 

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Mike T. said:
As the editor and one of the writers of the FAQ, could you show me where you found the word "lose" spelled wrong? Then I can get it changed. I'll add that I certainly do know the difference between lose and loose but typos do occur even though that FAQ was edited 100x.

As for the DOT5 question. Rather than me quoting from brake manuals or brake fluid tech pages I'll refer you to the Google search engine for your info. The FAQ's exact sources for its brake fluid info are now long forgotten, especially seeing as the sources of the info were not listed in the FAQ.

Mike T. (mcm # 717)
Actually, I had just read through it pretty quick, and mistook "loose" with "lose". After re-reading it, I admit that I was an idiot, and it is actually spelled correctly.

As for the DOT5 fluid, logic tells me that it should work just fine. I've been running it in my car just fine, and it calls for DOT3/4 fluid. The reason why I switched to DOT5 is because it doesn't absorb water, and doesn't peel paint (I'd die if I ruined my paint!!!).

I just did a google search for DOT5 and apparently, because DOT5 won't absorb the water, and is actually less dense than water, any moisture that collects in the system will pool at the lowest point (caliper in the case of a bike), which will boil at a much lower temperature, which leads to brake fade. I suppose it is possible that there is a vent (in the master cylinder, maybe?) that could allow moisture to be introduced into the lines. If that is the case, then DOT5 is definitely a bad idea.
 

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AgentHubcap said:
Actually, I had just read through it pretty quick, and mistook "loose" with "lose". After re-reading it, I admit that I was an idiot, and it is actually spelled correctly.
Ahhh thanks. I didn't think I was loosing it by being lose with with my contexts.

As for the DOT5 fluid, logic tells me that it should work just fine.
I don't remember the reasons but I do remember there were some and as I'm not about to mess around with warranties I don't mess around with manufacturers suggestions.

Mike T. (mcm # 717, a looser who's lost it)
 
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