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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: RS8070
- Hose: BH90
I have internal cables, so am probably going to use something like:
(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/RS8070 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?
Cleaning the pads and disc should be enough unless you have the famous leaky calliper. even then why change the hoses>?
Bh90 is a higher quality hose TJ. Less expansion from it under pressure.
ta
Sorry I forgot to mention, I've cleaned and replaced both the pads and the rotors before, rebled the system, yet the squeak keeps coming back again and again.
At this point I can only assume it's the calipers. The hose change (BH59 -> BH90) is only because the new calipers (R8070) depend on it.
E: There's also typos in the OP. RS8070 Should be R8070.
Also, look at braking technique. If you tend to hover on the brake, pulling the lever but not really applying significant braking force, you're going to glaze the pads. This manifests as a squeak because the glazed surface doesn't develop sufficient friction with the rotor.
I use sintered pads. They just have this dirt layer after a couple of times of braking - each time.
Cleaning the pads fixes the problem temporarily, so I'm assuming the calipers are faulty.
You shouldn't ever need to clean brake pads. Normal use will obliterate dirt/dust; if they're contaminated with oil then the only solution is to bin them.
Cleaning the pads fixes the problem temporarily, so I’m assuming the calipers are faulty.
What do you mean by cleaning? What do you do to them? What are you removing?
Run them on some hot water and Fairy Liquid & clean. I'm not sure if all my pads have become that contaminated that I'd need to replace them (they're sintered, so they don't suck up the oil like organic ones), but the new calipers require different ones anyway.
How are you getting oil onto the pads? It's either overspray from maintenance, in which case you have to ditch the contaminated pads (your repeated problem is evidence that that you aren't removing all the oil; it [u]is[/u] soaking into the pad material), or it's brake fluid from the caliper, ie a leak, in which case replace the caliper or replace the seals if possible. You are wasting your time cleaning brake pads, trust me.
sounds very much like the infamous shimano tiny weeny leak in the callipers
Cleaning contaminated brake pads works. I have done it many times. surface contamination only but its simple cheap and easy to do.
That Park tool is really good but on another thread someone suggested using a reverb double ended barb to pull the new hose through by attaching it to the old.
I do like the tool but it’s expensive for a bit of cable with nice ends.
@Three_Fish, Well.. that's why I'm changing the calipers, right?
I heat cleanse pads and discs with a camping gas blow torch, works well
Cleaning pads contaminated with mineral oil does work. Just needs a bit of heat. I've done it a few times, and the time after I replaced the leaking calipers they stayed fixed. How old are the RS785s? I got my RS505s warrantied after 18 months. Given how long reports of this problem have been around for, I'm very doubtful that Shimano have properly solved it, even on newer calipers.
Answering my original questions:
[quote="Det"]1) Does a BH90-SB/-SBS kit imply BH90-SS (+extra parts)?
No. A specific BH90-SS kit is needed.
[quote="Det"]2) Is there anything else I should be aware of?[quote="Det"]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
I had a pair of rs785 calipers, obvs post mount, the famous leaky ones. Never had a squeak.
Overhauled due to new frame. New calipers rs805, flat mount, new pads and disks. Horrid noises aplenty and after about 5 rides noticed black residue on rotors. Cleaned pads, disks, caliper. After one ride I'm getting squeels on hard braking. I'm keeping an eye on it but suspect the new calipers may be leaky too.
Would change to hope but am 140/140mm and the hope flat mount calipers are only 160mm.
Its driving me nuts.
That one's even with resin pads?