Hydraulic brake install
db3266
Posts: 38
I installed some Shimano SLX M675 brakes today, complete with ice-tech RT86 rotors.
I used a bleed kit from an online shop, it does not use the funnel, but a syringe that you screw into the lever reservoir. A very good kit.
I had to route the rear hose internally through the frame and also shorten both front and rear hoses.
The method I used to bleed, was to remove the pads and install the bleed block, pass the fluid up from the calliper to the lever, lots of tapping the hoses and calliper, observed air bubbles coming out until they stopped. Once the reservoir on the lever was quite full, I removed the syringe from the calliper (nipped it up first), attached a tube and plastic bag and let the fluid drain back down into a bag (being careful not to let the reservoir empty), didn't notice and bubbles when doing this. Applied pressure to the lever and momentarily un-nipped the bleed nipple on the calliper, again, didn't notice any bubbles escaping. The instructions then directed me to apply rapid tapping pressure to the lever (squeeze, release quickly, repeat until bubbles stop). I did this to the extreme, even rotated the bike pointing skywards on the bike stand (when doing the rear brake), bubbles did come out but stopped pretty quickly. Removed the reservoir and put the screw back in.
At this stage, the brakes firmed up on immediate application, remember the bleed block is still in, so the pistons cannot move, there was no squeeze or spongy feeling, brakes felt solid.
Removed bleed block and put pads back in to the callipers.
I went through the process of aligning the callipers by putting an elastic band around the lever, then tightening the calliper frame bolts. Both wheels spin very free with no rubbing.
Brakes now have more play, there is movement, maybe about a third of the throw, then they firm up and do not compress or feel spongy past that point.
The first time I did this, I thought I had got something wrong (the brakes moving a third before firming up). So I repeated the whole process (even loosened the calliper frame bolts). But this time, I left the pads in the callipers and put the orange spacer between the pads that came with the brakes. This did not work so well. When I put the wheels on and aligned the callipers, there was quite a lot of friction and the wheels did not spin very free, there was some rubbing. I wasn't happy, so reverted to method one, which worked exactly like the first time, wheels back on, spin free, no rubbing, brake levers firm up after about a third of the lever throw.
Does this amount of lever travel sound right? I have never installed or bled hydraulic bike brakes before, so just curious on anything I may need to revisit?
I used a bleed kit from an online shop, it does not use the funnel, but a syringe that you screw into the lever reservoir. A very good kit.
I had to route the rear hose internally through the frame and also shorten both front and rear hoses.
The method I used to bleed, was to remove the pads and install the bleed block, pass the fluid up from the calliper to the lever, lots of tapping the hoses and calliper, observed air bubbles coming out until they stopped. Once the reservoir on the lever was quite full, I removed the syringe from the calliper (nipped it up first), attached a tube and plastic bag and let the fluid drain back down into a bag (being careful not to let the reservoir empty), didn't notice and bubbles when doing this. Applied pressure to the lever and momentarily un-nipped the bleed nipple on the calliper, again, didn't notice any bubbles escaping. The instructions then directed me to apply rapid tapping pressure to the lever (squeeze, release quickly, repeat until bubbles stop). I did this to the extreme, even rotated the bike pointing skywards on the bike stand (when doing the rear brake), bubbles did come out but stopped pretty quickly. Removed the reservoir and put the screw back in.
At this stage, the brakes firmed up on immediate application, remember the bleed block is still in, so the pistons cannot move, there was no squeeze or spongy feeling, brakes felt solid.
Removed bleed block and put pads back in to the callipers.
I went through the process of aligning the callipers by putting an elastic band around the lever, then tightening the calliper frame bolts. Both wheels spin very free with no rubbing.
Brakes now have more play, there is movement, maybe about a third of the throw, then they firm up and do not compress or feel spongy past that point.
The first time I did this, I thought I had got something wrong (the brakes moving a third before firming up). So I repeated the whole process (even loosened the calliper frame bolts). But this time, I left the pads in the callipers and put the orange spacer between the pads that came with the brakes. This did not work so well. When I put the wheels on and aligned the callipers, there was quite a lot of friction and the wheels did not spin very free, there was some rubbing. I wasn't happy, so reverted to method one, which worked exactly like the first time, wheels back on, spin free, no rubbing, brake levers firm up after about a third of the lever throw.
Does this amount of lever travel sound right? I have never installed or bled hydraulic bike brakes before, so just curious on anything I may need to revisit?
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Comments
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Yes, as long as once you reach the bite point, they feel firm, not spongey, then that's fine. My Deore brakes have a lot of "free stroke" too.
The advantage you have with SLX is that there should be a little screw that allows you to reduce the amount of free stroke - it's on the top of the lever, right next to the lever blade pivot - adjust it until you get the feel you want.0 -
EDIT to above - just looked for a diagram to link to and found that actually, the whilst the M675 has the threaded access port for the bite point adjuster, it doesn't have the adjuster screw itself, just a blanking bolt.
There's information here about replacing this to activate the adjustment facility:
http://forums.mtbr.com/brake-time/shima ... ost96810310
