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Overhauling Squeaky Hydraulics

by Det
Sun, Apr 29, 2018 10:27
4

Hello guys, I'm wondering if you could help me.

I am in the process of overhauling my permanently squealing hydraulic brakes, apart from the levers (RS505). That includes the rotors, pads, the calipers and even the hose.

Old setup:
- Caliper: RS785
- Hose: BH59

New system:
- Caliper: R8070
- Hose: BH90

I have internal cables, so am probably going to use something like: https://www.youtube.com/watch?v=QZaGL83RMFI (with e.g.: https://www.parktool.com/product/internal-cable-routing-kit-ir-1-2)

According to the Shimano Compatibility Chart: http://productinfo.shimano.com/#/com/2.4?acid=C-499  and this thread: http://weightweenies.starbike.com/forum/viewtopic.php?t=147493, ST-RS505/R8070 should work just fine using a BH90 straight-straight kit.

My questions:
1) Does a BH90-SB/-SBS kit imply BH90-SS (+extra parts)?
2) Is there anything else I should be aware of?

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

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4 comments

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Leeroy_Silk | 6 years ago
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What pads are you using? Sintered pads are known for squeaking, organic pads are generally much quieter. 

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kevvjj | 6 years ago
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I would be keen to hear how this turns out... in my experience doing what you are doing will have no effect on the squealing brakes. It's all down to the pad and rotor interface. Disc brakes nearly always squeal when wet and most will at some time squeal in the dry too. Take yourself off to a cyclocross race and you'll hear brakes sqealing for the duration of the race. When disc brakes are allowed in all UCI races this will be the sound of the peloton as it bears downhill.

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Det replied to kevvjj | 6 years ago
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Answering my original questions:

Det wrote:

1) Does a BH90-SB/-SBS kit imply BH90-SS (+extra parts)?

No. A specific BH90-SS kit is needed.

Det wrote:

2) Is there anything else I should be aware of?

Det wrote:

Old setup:
- Caliper: RS785

New system:
- Caliper: R8070

This won't be possible (flat-mount calipers on a post-mount frame/fork).

Anyways, unimaginably, a quick test of 1/5th the price resin pads instead of finned sintered ones completely muted the brakes (exact same method of bedding in - brake firmly from good speed without locking wheels about 10-15 times).

However, one of the pistons in the other caliper doesn't move at even speeds even after cleaning, which keeps bending the rotor. They don't sell those separately, so gonna have to replace the whole caliper.

Otherwise, everything's nice apart from few things nothing to do with brakes. Completely fixable as well tho.

smiley

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Det | 6 years ago
0 likes

Forgot to mention, I've replaced both the pads and rotors before, rebled the system a couple of times, and the squeak keeps coming back again and again (dirt layer on top of pads), so I can only assume it's the calipers.

The hose change (BH59 -> BH90) is only because the new calipers (R8070) depend on it.

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