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Discussion Starter · #1 ·
Well I've had great service out of my Mini's for the last 10 months, but recently my front brake doesn't seem to be bitting as it used to so I'm gona try a bleed. HOPE spec's Dot 5 as what to use, but it's not really available down here, will I notice any difference between Dot 4 and 5? I know I will have to completely re-bleed the system several times to clear it so the two don't mix, but other than that??

A bonus question for the brake guru's. can I get an adapter to go to a bigger rotor upfront than the stock 160mm that the Mini's come with?
 

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Meh.
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DOT 5 is a no-no. DOT 5 is silicone based, and usually blue in color. You want DOT 5.1. DOT 5.1 is glycol based like DOT 3 and 4. Most DOT 5.1s can be mixed with DOT 3s and 4s. DOT 5.1 has a higher boiling point and is less viscuous than DOT 3. Most auto stores do not stock DOT 5.1 since it is for severe/heavy use. I had to order mine.

Yes, you can get an adapter to run larger rotors. Do you have an IS caliper? Or a post mount caliper? Is the fork IS or post mount?
 

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ballbuster
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Second that...

XSL_WiLL said:
DOT 5 is a no-no. DOT 5 is silicone based, and usually blue in color. You want DOT 5.1. DOT 5.1 is glycol based like DOT 3 and 4. Most DOT 5.1s can be mixed with DOT 3s and 4s. DOT 5.1 has a higher boiling point and is less viscuous than DOT 3. Most auto stores do not stock DOT 5.1 since it is for severe/heavy use. I had to order mine.

Yes, you can get an adapter to run larger rotors. Do you have an IS caliper? Or a post mount caliper? Is the fork IS or post mount?
DOT5 bad, DOT 5.1 good. If you;re gonna flush the system out anyway, just use DOT4. DOT 5.1 is a major PITA to find at the local auto parts shop, unless you got a line on an import tuner (you know, the little Hondas with big ass fins and purple lights and ugly stuff all over them)

that said, if you are not getting as much brake power as you used to, it may be because your pads and rotors are glazed. The fix is to sand down the pads a bit and rough up the braking surface of the rotors with medium sandpaper. Not much on the rotors, just some swirly scratches are good. Clean it all up with some rubbing alcohol and rebed the pads with a nice long stop to get them nice and hot.

A bleed probably won't do much good unless you somehow got water or air in the lines. If you did, the lever would be mushy. Remember to push the pistons all the way back in the caliper before you top off the reservoir and close the cap.
 

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Discussion Starter · #5 ·
Thanks for the advice guys and yes I meant 5.1 not just 5. I did sand the pads and clean them really good w/ alcohol and then flush them with water, but I think I might also have worn them down quite a bit. In looking at the brake fluid in the reservoir it is a bit dis-coloured and I've done about 2700 miles on the brakes so a complete system refill/bleed isn't a bad idea - they say for hard use change every year, so it's almost a year now and I ride pretty hard.

I have I.S. mounts on the fork.

Looking to order some spare pads, what's everyone using? Was thinking of trying some of the EBC pads, maybe a set of each colour and then maybe use the green on the rear and red on the front and maybe give the gold a shot front and rear and see how they feel.
 

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Discussion Starter · #6 · (Edited)
Damn!!!

Well I got the DOT4 and did the complete bleed of the system, but things still seemed not good enough. One piston seemed to have stuck out and in trying to get it back in using the tyre lever I had no results so resorted to a file handle rapped in a t-shirt, but managed to chip the piston so I think I have to get a new set of pistons. Sent off an e-mail to [email protected] mtn high and hopefully he'll be able to hook me up. Tried to find service instructions etc on the HOPE sites and all I found was an exploded GIF of the whole assembly, no instructions on servicing them etc. - very pi$$ poor IMHO.
 

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Oh bummer.... could you post a pic of the piston to see how big the damage is?

Regarding the rotor size, Hope makes both PM to IS and IS to IS adapters, so it just depends on the caliper that you have (since you said your fork is IS)
 

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Discussion Starter · #8 ·
Latest update

Well the pistons seemed to be sticking left, right and centre, but after I poped the inside one out and put it back in and then pumped them both almost all the way out and then back in I managed to re-bleed the brake again and now it's working fine. I am still going to get the pistons as they are both damaged - one inside on the face that doesn't contact the pad and on the other on the outside where it would come into contact with the seal. From having the piston out though it looks as though the seal is just a tad further back in the cylinder than the chip goes in. Didn't realize that the pistons were an alloy/composite material.

crisillo said:
Oh bummer.... could you post a pic of the piston to see how big the damage is?

Regarding the rotor size, Hope makes both PM to IS and IS to IS adapters, so it just depends on the caliper that you have (since you said your fork is IS)
 

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LyNx said:
Well the pistons seemed to be sticking left, right and centre, but after I poped the inside one out and put it back in and then pumped them both almost all the way out and then back in I managed to re-bleed the brake again and now it's working fine. I am still going to get the pistons as they are both damaged - one inside on the face that doesn't contact the pad and on the other on the outside where it would come into contact with the seal. From having the piston out though it looks as though the seal is just a tad further back in the cylinder than the chip goes in. Didn't realize that the pistons were an alloy/composite material.
Glad you manage to get them working.... no harm in getting the pistons, but just keep an eye on the brakes for now...with some luck they will do just fine as they are...
 

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LyNx said:
Well I've had great service out of my Mini's for the last 10 months, but recently my front brake doesn't seem to be bitting as it used to so I'm gona try a bleed. HOPE spec's Dot 5 as what to use, but it's not really available down here, will I notice any difference between Dot 4 and 5? I know I will have to completely re-bleed the system several times to clear it so the two don't mix, but other than that??

A bonus question for the brake guru's. can I get an adapter to go to a bigger rotor upfront than the stock 160mm that the Mini's come with?
Check out the upsizers:

http://www.universalcycles.com/shopping/index.php?category=27
 
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