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Hisforever
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1,867 Posts
Discussion Starter · #1 ·
I need some help from the experienced hope closed system bros. The ride will be much better once this problem is woked out.

I have a set of these c2's with the pro levers. 160mm rotors front and rear.

Today while riding the + - dial on the front brake seemed to fade out and do nothing, later on down the trail it seemed to pump up in lever 'feel' and actually rub and make the brakes sqeal so, what did I do? Thinking this would help I wound down on the - setting to fix it, which helps for a moment, however the reach would never change in increments only all of a sudden to the full grab position and then change to grabbing pretty close to the bar.

This brake was super finicky and I am unsure how to fix them, Does this sound like they need new fluid or a bleed? The rear works perfectly.

Any pdf manuals out there somewhere?


Thanks for the help. Just couldnt find any other posts on this...
 

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(aka SS_MB-7)
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924 Posts
SHAHEEB said:
Today while riding the + - dial on the front brake seemed to fade out and do nothing, later on down the trail it seemed to pump up in lever 'feel' and actually rub and make the brakes sqeal so, what did I do? Thinking this would help I wound down on the - setting to fix it, which helps for a moment, however the reach would never change in increments only all of a sudden to the full grab position and then change to grabbing pretty close to the bar.
My first disc brakes were C2 Pros, but that was 5-yrs ago, so it's been a while.

Inherent with the "closed" system used by the Hopes, depending on the fluid's temperature, the fluid will expand/contract which will play with the piston/pad locations relative to the rotor. That's the reason behind the +/- dial on the top of the master-cylinder...it essentially manually expands/contracts the fluid volume to adjust to the temperature. The "open" system brakes use seals to automatically account for fluid volume.

Having said this, if you've finished a really long downhill, the fluid will heat-up and could cause the pads to rub (or lock) the rotor, so you manually back them-out. Vice versa, on cold days, the fluid contracts and will suck-in the pistons into the caliper.

I'm not sure if this is the problem you are experiencing, though.

SHAHEEB said:
Any pdf manuals out there somewhere?
Ya, check-out Hope's site: www.hopetech.com for some manuals.
 

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Hisforever
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1,867 Posts
Discussion Starter · #3 ·
thats a good explanation.

that explanation seems right on.

The start of the descent was at 10,000ft, at about 8,000 they seemed weak when i tried to lock them up.

At the bottom of our ride(around 4000ft) is where the breaks were starting to lock up. they seemed to squeal of an on through the whole ride though.

The seller of my brand spankin new second hand ride was a mechanic, he told me to let some oil out of the reservoir, i havent tried it yet, but I wonder if it will work. as all this happened Sunday.

Thanks for the reply, I was hoping to hear from someone. all the other concerned c2 posters seemed to get ignored by eveyone. guess thats the case with some old gear.

cheers
 

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(aka SS_MB-7)
Joined
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924 Posts
SHAHEEB said:
The seller of my brand spankin new second hand ride was a mechanic, he told me to let some oil out of the reservoir, i havent tried it yet, but I wonder if it will work. as all this happened Sunday.
Before you go letting any fluid out, has this happened before or this a one-time thing? If you are going to be routinely hitting some wicked DHs that are going to cause your C2s to overheat, you'll definitely want to allow a drop or two out of the system to allow for more heat expansion. The simplest way to do that is to attach a clear piece of tubing to the caliper's bleed valve and then slowly loosen the bleed valve to allow just a drop or two out. Then, close the bleed valve.

SHAHEEB said:
Thanks for the reply, I was hoping to hear from someone. all the other concerned c2 posters seemed to get ignored by eveyone. guess thats the case with some old gear.
No probs. It's not that people are ignoring you, it's just that not many people had C2 Pros back then and even fewer have them now.
 
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