Mountain Bike Reviews Forum banner
1 - 9 of 9 Posts

·
Registered
Joined
·
380 Posts
Discussion Starter · #1 · (Edited)
Tossed some DB levers and Goodridge lines on my Mono Minis... 180mm front, 160mm rear.

One thing that I noticed that carried over after the lever and line swap... seems like the rear is a bit less crisp than the front. Not sure if this is just due to the length of rear line/distance the fluid has to travel or is just a idiosyncracy of my rear caliper. Anyone else notice this? Ideas?

Cheers
 

·
Registered
Joined
·
7,006 Posts
tazdevl said:
Tossed some DB levers and Goodridge lines on my Mono Minis... 180mm front, 160mm rear.

One thing that I noticed that carried over after the lever and line swap... seems like the rear is a bit less crisp than the front. Not sure if this is just due to the length of rear line/distance the fluid has to travel or is just a idiosyncracy of my rear caliper. Anyone else notice this? Ideas?

Cheers
...most likely air in the line. Try another bleed.
 

·
Registered
Joined
·
4,040 Posts
Ditto

jncarpenter said:
...most likely air in the line. Try another bleed.
Bleed those beeyatches. For some reason my rear Hopes (non-Mono Minis and M4s) always required more attention that the front. Could be that depending on the frame the orientation of the caliper may require a little more diligence to get the air out. Tap the caliper with a wrench and/or pivot the bike in the stand to get the best angle for your dangle to get the air out.
 

·
Registered
Joined
·
380 Posts
Discussion Starter · #4 ·
Bled 3 times... if I was going to toss a number at it... let's say the front brake is at 100%, rear is at 95-97%.

Might toss the bike on a stand, use a zip tie on the lever and let it stand overnight, give it a few taps... then top off the reservoir.
 

·
Registered
Joined
·
7,006 Posts
tazdevl said:
Might toss the bike on a stand, use a zip tie on the lever and let it stand overnight, give it a few taps... then top off the reservoir.
...that old MX trick doesn't work on Hopes as when the lever is depressed, the line is closed. Try getting the rear caliper as high as you can, definitely higher than the reservoir (the closer to vertical the better). Make sure you turn the lever so the reservoir stays level. Try tapping the line & caliper. Should do it. One other thing to check, make sure both pistons are moving equally when you squeeze the lever. Sometimes you get a sticky piston & it may not feel as firm.
 

·
Registered
Joined
·
3,034 Posts
jncarpenter said:
...that old MX trick doesn't work on Hopes as when the lever is depressed, the line is closed. Try getting the rear caliper as high as you can, definitely higher than the reservoir (the closer to vertical the better). Make sure you turn the lever so the reservoir stays level. Try tapping the line & caliper. Should do it. One other thing to check, make sure both pistons are moving equally when you squeeze the lever. Sometimes you get a sticky piston & it may not feel as firm.
i've done the exact opposite on my hopes--stood the bike upright with the front wheel way up in the air...that allows any air to rise up to the master cylinder and weep out. the rear caliper should be air free, thus it should be as low as possible. after doin that the brake feel and modulation is as they should.
 

·
Registered
Joined
·
734 Posts
jncarpenter said:
...that old MX trick doesn't work on Hopes as when the lever is depressed, the line is closed. Try getting the rear caliper as high as you can, definitely higher than the reservoir (the closer to vertical the better). Make sure you turn the lever so the reservoir stays level. Try tapping the line & caliper. Should do it. One other thing to check, make sure both pistons are moving equally when you squeeze the lever. Sometimes you get a sticky piston & it may not feel as firm.
ALL hydraulic brake system are closed when the lever is pressed, otherwise they couldn't create the pressure to actuate the caliper pistons. Open systems are only open (to the res.) when the lever is not pulled. All open systems function in this manor (including virtually every mtb brake on the market.)

Your instructions would move the bubble to the caliper I can't see how that would that be a good thing.

Put the bike in a vertical position (front wheel up) in order to position the brake line nearly as vertical as possible then zip tie the lever down over night (to compress any bubbles and make it easier for them to pass up the line to the lever) In the morning release the brake and push the pads back into the caliper (remove the wheel and use a plastic tire lever) this will force some fluid (and hopefully the bubble(s)) back into the reservoir

Edit: that is for the rear caliper for the front just leave the bike level (the brake line is vertical in that case) and follow the same instructions.
 

·
Registered
Joined
·
7,006 Posts
Grumpy said:
Your instructions would move the bubble to the caliper I can't see how that would that be a good thing.
...the brakes are bled thru the caliper. Either way, I was just passing on the info that Hope tech had instructed me with. They specifically said to do it this way & specifically said that the depressed lever overnight wouldn't work.
 

·
Registered
Joined
·
734 Posts
jncarpenter said:
...the brakes are bled thru the caliper. Either way, I was just passing on the info that Hope tech had instructed me with. They specifically said to do it this way & specifically said that the depressed lever overnight wouldn't work.
You never mentioned bleeding the brakes afterward. If you are bleeding the brakes the procedure is unnecessary, the bleed will (should) flush any out. The whole point is to avoid a bleed. What would be the purpose of tying you brake lever with your bike upside down if you were just going to bleed it in the morning?

AND... only a ghetto bleed (pump and dump) is done by dumping fluid out through the caliper. The standard way to bleed brakes (much more effective) is to use a syringe or pressure bleeder on the caliper nipple and then an overflow catch on the master cylinder reservoir. The fluid is pushed into the caliper and up through the system to the lever and finally out the master cylinder reservoir. This is much more effective and really the only to effectively flush a brake system.
 
1 - 9 of 9 Posts
Top