[1000-Oaks]

The Hope V2 caliper is made for Hope's 3mm wide vented rotor, if you run their solid floating rotor (2mm) or a Hayes rotor (1.8mm) you move a lot of the brake fluid from the reservoir into the caliper so the piston will take up the extra space.

Then you might have issues with the reservoirs running empty soon as the pads start wearing down a little, depending on how steep an angle you like your brake levers. (I have mine about 45* down, and they're starting to suck air after about twenty rides.)

Sure, it's easy enough to just open the reservoirs and top off the fluid, but then if you ever want to put new pads in the calipers on the trail you'll have too much brake fluid in the system and will have to open up the reservoirs again and let some out.

I'm thinking a simple machined aluminum spacer/tool might be handy to solve the problem, something to drop into the caliper in place of the pads while you hand-bleed the system. Instead of pushing the pistons all the way into the caliper and using the pricey Hope bleed kit, just push the pistons in all the way, insert the tool, pump the brake until the pistons bottom out against the tool (which allows each of the pistons to come out .5mm or so), then hand-bleed the brake using the old-school (& cheap) pump-n-vent method. No worries about overextending the pistons while bleeding; the tool stops them at the right place for 2mm or 1.8mm thick rotors. And the tool takes care of "lazy piston" issues when only one piston wants to move, so it would be easy to center the caliper on the rotor.

Or just say screw it and top off the reservoirs and deal with the extra fluid when the time comes for a pad change, lol.

 

[davep]

I must be missing something...


Just bleed them with the rotor you are going to run....

 

[1000-Oaks]

That would work fine, as long as you use new pads to do it. At the risk of getting brake fluid on your rotor & new pads anyway. Using a chunk of aluminum instead means no worry of pad or rotor contamination.

 

[djamgils]

shimano has blocks to put in the caliper while bleeding, maybe you could just use those.
or if you got the tools just make alu blocks.

 

[HardtailHack]

I run a Vented rotor on the front and a solid out back and don't haave the dramas you speak of. However I did change the fluid after 6 months as the rear brakes were fading on very short runs.
I have also had dramas with a rear piston sticking which caused a problem similar to yours(no air sucking noise though).

 

[Sandwich]

After dealing with bleeding issues and air in the lines and phantom problems and leaking and poor power and fading....I have one thing to say.

BUY SAINTS.

Otherwise, get a block or a deck of cards or something to put in between the pistons when bleeding, and do your best to make it work. Probably best to use the same width rotor at all times, unless you really need to swap wheels or something.

 

[HardtailHack]

If you have bleeding troubles just put the check valve type bleed nipples in.
I like my V2s so much I grabbed a set of the Tech V2's as well for my other bike.

 

[1000-Oaks]

No sucking air noise, just air getting in the lines while riding steeps (the hole in the bottom of the reservoir gets uncovered) and the lever goes to the bar. If I lift up the front tire until the reservoirs are horizontal and pump the lever a few times, the line fills back up with fluid and I have 100% brakes again. Until I start riding that is.

It's just low fluid level in the reservoirs, nothing wrong with the system.

 

[Brian HCM#1]

The brake line needs to be vertical for a manual bleed, pistons pushed all the way in and kept in place with a wedge, then when properly bleed, overfill the lever and place the cap on allowing fluid to spill over (do not remove the cap once on) Clean up the mess, reinstall brake pads, reinstall the wheel and pump the lever several time until it firms up. All done.

 

[Brian HCM#1]

No sucking air noise, just air getting in the lines while riding steeps (the hole in the bottom of the reservoir gets uncovered) and the lever goes to the bar. If I lift up the front tire until the reservoirs are horizontal and pump the lever a few times, the line fills back up with fluid and I have 100% brakes again. Until I start riding that is.

It's just low fluid level in the reservoirs, nothing wrong with the system.

You have air in the system.

 

[nowlan]

If its the rear brake your having issues with, are you bleeding the brake with the bike vertical in the stand? the caliper has to be straight up and down with the rear in order for no air to get in. Also the issue your having could be your seals.

 

[davep]

Reading comprehension 101 ????

 

[1000-Oaks]

Both front and back were drawing in air due to low fluid level in the reservoirs. (factory fill & bleed, I just bolted them on the bike)

Today I rotated the levers to horizontal, pumped until the air was replaced by fluid (air was only at the master cylinders, not the calipers) and the lever feel was solid again, dropped in new pads, pumped to make sure they were firm, topped off the reservoirs and closed them, and put the old pads back in.

Should be fine now. Basically did the same thing as I suggested doing with the tool, only I didn't bleed the brakes. I'll make the tool before I do that, super easy to do with a short piece of 1" x 0.5" aluminum flat bar and a few minutes on a vertical mill.

BTW, Motul RBF 600 (593* dry / 420* wet, ~$17 per half-liter) looks like the best brake fluid out there short of the $75 per liter Catrol SRF (590* dry / 518* wet). And you can get it at most motorcycle shops.

 

[davep]

The motul stuff is good, and comes in a nice small container so you don't have a quart of old 'wet' fluid laying around.

I have cut lines (at the lever) and essentially done exactly what you did. IMO it does help to do two things: tap the length of the hose with the handle of a screwdriver to move micro-bubbles up to the lever, and squeeze and snap-release the lever a handful of times. With the cap off, you will most likely see some very tiny bubble make their way up if you do this.

On the bleeding front, I just simply use the rotor with the pads in as you would any car or moto. A short piece of clear hose that fits the bleed nipple and a bottle (beer is prefered) will keep the fluid far away from the pads and rotors. I have not had an issue contaminating pads/rotors in the 5 or so years I have done this method.

IF you did this whole thing over again, simply keeping the MC full as you pumped the pads out to the thinner rotor would have prevented any issues and there would/will be plenty of volume displacement for pad wear.

BTW, did you know Craig?

 

[1000-Oaks]

IF you did this whole thing over again, simply keeping the MC full as you pumped the pads out to the thinner rotor would have prevented any issues and there would/will be plenty of volume displacement for pad wear.

BTW, did you know Craig?

Yep, exactly. That's basically what I did by temporarily dropping in new pads. I hesitate to bleed them with the pads in the calipers after my experiences with the $#%#@ hose poping off the squeeze bottle while bleeding Hayes calipers. (Not that I'll be using a squeeze bottle with the Hopes, but new V2 pads are pricey.)

Craig who? Can't think of anyone named Craig, but my memory is terrible.

 

[Bicyclist]

Craig who? Can't think of anyone named Craig, but my memory is terrible.

Your signature I would guess...

 

[1000-Oaks]

Ooops, I read "do you know Craig", thinking there was a guy at Hope named Craig or something.

Nope, never met Craig but I used to ride his 168cm "Screaming Tree" signature model. Great powder board, sold it to the founder/owner of Skull Candy last winter. I went back to skis after ten years of boarding, want to do more sidecountry and touring. Superfat pow sticks are so good these days and snowboards suck on long rolling traverses - had to do it.