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Discussion Starter · #1 ·
I can't seem to get my Shimano SLX brakes properly bled.
I've tried top down, bottom up and leaving the levers pulled on over night with elastic bands.

Anybody got any tips?

Mine are the model with the servowave levers and the two pot callipers.
 

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Discussion Starter · #3 ·
Goran_injo said:
Don't understand.
I don't think servowave are any different to bleed than your non servo shimano brakes.
Well yes that's what I thought too. I've not had a problem bleeding Shimano brakes before really, but these SLX just won't play ball...

Basically my problem is that although they feel reasonably solid as the pads contact, you can then squeeze the levers quite a bit more. There is also literally no power in the brakes unless they're really hot, but once they're up to temp they're really really powerful. I'm so confused with them. :madman: :madman: :madman:
All I can think now is that there is some stubborn air trapped in the callipers or hoses...
 

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I bled a 2008 XT with servo few weeks ago w/o problems.

What i did:

-Open the resorvoar and keep it opened and add oil as required so it is hihg all the time

-press the lever.

-while lever pressed, open the bleed nipple for a 1/8 turn

-close the nipple, lever stil pressed

-slowly release the lever. Watch that the air does not get in - oil should be full in the reserovir

-repeat until it is firm.

I used the bleed hose from local store.
 

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Discussion Starter · #5 ·
Goran_injo said:
I bled a 2008 XT with servo few weeks ago w/o problems.

What i did:

-Open the resorvoar and keep it opened and add oil as required so it is hihg all the time

-press the lever.

-while lever pressed, open the bleed nipple for a 1/8 turn

-close the nipple, lever stil pressed

-slowly release the lever. Watch that the air does not get in - oil should be full in the reserovir

-repeat until it is firm.

I used the bleed hose from local store.
Thanks, this is what I referred to as bleeding from the top down. Trouble is that I don't think it would help if there was air trapped in the calliper.

I've ordered a new set of pads in case the old ones got contaminated somehow (doubt it).

How much flex should there be in the levers? If these are anything like my LX, it should be practically none. :madmax:
 

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retro83 said:
I've ordered a new set of pads in case the old ones got contaminated somehow (doubt it).

How much flex should there be in the levers? If these are anything like my LX, it should be practically none. :madmax:
If you've got a few bike shops nearby then go find a bike that comes with XT or SLX brakes to experience what they should feel like first hand. Engagement should feel positive but it should have more movement after that than brakes from Hayes, Hope etcetera, that's part of the new design for these brakes.

If you have the organic pads then they're very easily contaminated, these new brakes feel like crap in cold weather, no brake feels quite as good in cold weather but these new ones from Shimano feel particularly bad and though many people may claim that the new XT's and SLX are a breeze to bleed that's not exactly true, I had no end of trouble trying to bleed mine properly and in the end I gave up when Shimano themselves had a go and failed, a lot of the early reviews for the XT brakes mentioned that and I know someone else with the same problem. Lastly the XT's are not as powerful as Hayes Stroker's or Formula Oro's in the first place so I can only imagine that SLX's would be the same or less powerful.
 

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I don't see a connection between brake pad and sponginess due to air in the system.

What I can tell you, as the only shortcoming of the brake, is that they are stiff (brake without any play in the lever) in the cold weather (manifested my reduced retraction of the caliper pistons). The issue was discussed on this forum also, and I have experienced it first hand, that is why I changed the oil and bled the breke, to see if that is the cause, wasn't, it is the seals in XT calipers.

Flex in the levers? Not sure what you mean by that.
 

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Goran_injo said:
Flex in the levers? Not sure what you mean by that.
Again, if he was comparing to harder feeling brakes like Hayes or Hope then the SLX's should feel softer after the initial engagement, that's something Shimano designed into the new Servo Wave brakes to improve modulation, if that's what the OP means…
 

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EGF168 said:
If you've got a few bike shops nearby then go find a bike that comes with XT or SLX brakes to experience what they should feel like first hand. Engagement should feel positive but it should have more movement after that than brakes from Hayes, Hope etcetera, that's part of the new design for these brakes.

If you have the organic pads then they're very easily contaminated, these new brakes feel like crap in cold weather, no brake feels quite as good in cold weather but these new ones from Shimano feel particularly bad and though many people may claim that the new XT's and SLX are a breeze to bleed that's not exactly true, I had no end of trouble trying to bleed mine properly and in the end I gave up when Shimano themselves had a go and failed, a lot of the early reviews for the XT brakes mentioned that and I know someone else with the same problem. Lastly the XT's are not as powerful as Hayes Stroker's or Formula Oro's in the first place so I can only imagine that SLX's would be the same or less powerful.
I have both the new xt and slx and they have been perfect...although I did pull them off for the winter to go with my bb7 to aviod the cold weather issues...
Bleeding had been a breeze,I have bleeded them as the method with my hopes,fast and easy.
Thet have earned my rave reviews.....:but if you got a bad set,that blows....thumbsup:
 

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According to Shimano my set was fine so perhaps you can answer the question I asked them, why could they not bleed them to a satisfactorily working state if there was nothing found to be wrong with them? Why do I hear other people having the same problems, though clearly very few on Mtbr? Why have I So far felt quite a few of these brakes and only found the factory bled OEM ones to be up to scratch.? Once again I’d like to point out that this was mentioned in several professional reviews.

Shimano’s UK distributor obviously knew they were hard to bleed because they’ve decided to do it for Shimano…
 

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“While some sets have felt superb, we’ve had all sorts of inconsistencies with others. They’re a real fight to bleed properly, which makes their DIY kit format irritating

Even if you like your levers close in, multiple bleeding is required before the separately supplied pieces feel consistent. Pricing is undoubtedly very impressive if you’ve got the patience to get it sorted, though.

…but we’re still not totally convinced”

That’s what What Mountain Bike said, they said similar things in their sister mag MBUK in an earlier and separate test. They’re some of the most experienced and thorough testers there are.

"As well as the similar appearance, the SLX brakes also share a somewhat finicky bleed procedure with their more expensive brethren. The current generation of Shimano brakes seem to be a little prone to getting pockets of air trapped in the calipers."

Oh my! Not another one...from bike magic and I know of at least two other tests saying the same thing.
 

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Weird stuff, I just installed SLX two months ago and had to shorten the lines which meant a bleed for both ends and I had no trouble at all, they're the first hydros I've owned and it couldn't have been any easier, the rear squeels occaisionally but they work very well, the modulation is excellent, maybe theres an internal defect in some but not others, feeling rather lucky now, by the way I did nothing special except to make sure the bike sat so the nipple was fairly vertical (just common sense stuff).
 

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stumpy pilot said:
Weird stuff, I just installed SLX two months ago and had to shorten the lines which meant a bleed for both ends and I had no trouble at all, they're the first hydros I've owned and it couldn't have been any easier, the rear squeels occaisionally but they work very well, the modulation is excellent, maybe theres an internal defect in some but not others, feeling rather lucky now, by the way I did nothing special except to make sure the bike sat so the nipple was fairly vertical (just common sense stuff).
Im with ya.........:thumbsup:
 

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29ERCAT said:
Im with ya.........:thumbsup:
Hopefully you now understand that just because yours have been easy to bleed it doesn't mean other peoples will and that mine is far from an isolated incident, in fact there's another thread on this forum today that mentions it…:thumbsup:

Edit: Make that 2 other threads today on this site that mention having bleed problems!
 

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Discussion Starter · #15 ·
EGF168 said:
Hopefully you now understand that just because yours have been easy to bleed it doesn't mean other peoples will and that mine is far from an isolated incident, in fact there's another thread on this forum today that mentions it…
Thanks, that's just it. I've bled Avids and Shimanos many times before with no problems (once I'd done it a couple of times). These are very frustrating.

stumpy pilot said:
Weird stuff, I just installed SLX two months ago and had to shorten the lines which meant a bleed for both ends
You can shorten the hoses without a bleed at all if you're careful, and you certainly shouldn't have gotten air trapped in the callipers doing so (which seems to be the problem I'm having).

Goran_injo said:
Flex in the levers? Not sure what you mean by that.
Well I'm not sure how else to explain it, other than my brakes feel like the levers are made from plastic. There is a definite bite point, but you can carry on squeezing the levers (with some resistance) further than you'd expect. I was clutching at straws as to where the problem was, I think at this point I'm fairly certain that air in the system is the problem.
 

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I bled them until I saw the air bubbles come out in the bleed line and continued until only fluid was coming out, it doesn't matter whether air is in the line, caliper or lever it will still compress and give a spongy feel.
Take the pads out and remove the wheel so the rotor is out of the way, sit the bike so the nipple and line are straight to the top (easy for the front, harder on the rear) fit the 10mm plastic block that comes with them for bleeding or failing that a 10mm allen key will do, pump and bleed like normal and tap the caliper with a screwdriver handle sometimes to un-seat any air pockets, this is all I can think of except that if you have air up in the top end somewhere it would take quite a while to bleed out.
It's a shame your having so much trouble with yours, I hope you get it sorted as they are really nice brakes.
 

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Discussion Starter · #17 ·
OK. Tonight I tried for about 4 hours to get my front brake bled. It just will not play ball.

Starting from scratch (completely empty system) has anybody got any fool proof instructions (or even better, a video) of how to fill and bleed these mutha-flipping brakes?
 

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Or try this very similar Park Tool Link

Personally, I use a different method where I inject in the fluid at the caliper, using the small Shimano bottle and tube, up to the lever. This pushes the air up to the lever/master cylinder. I squeeze the lever a few times (watch for bubbles) and then take off some of the fluid in the master cylinder using a syringe so it doens't spill all over the place. Then I inject some more fluid in from the caliper to top up the reservoir level and push the last of the bubbles out to the lever. Again, I squeeze the lever a few times, bang on the tubing up to the lever and repeat as necessary until the bubbles are gone.

I just did this yesterday as I recently broke the cast handlebar clamp (in 2 places!) on the XT 775 lever and had to replace the whole lever and, while doing that, I decided to change the fluid in the line in the process.
 

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Discussion Starter · #20 ·
DGB said:
Personally, I use a different method where I inject in the fluid at the caliper, using the small Shimano bottle and tube, up to the lever. This pushes the air up to the lever/master cylinder. I squeeze the lever a few times (watch for bubbles) and then take off some of the fluid in the master cylinder using a syringe so it doens't spill all over the place. Then I inject some more fluid in from the caliper to top up the reservoir level and push the last of the bubbles out to the lever. Again, I squeeze the lever a few times, bang on the tubing up to the lever and repeat as necessary until the bubbles are gone.
Thanks, this is similar to the method I normally use on my LX brakes with no problems.
Just to confirm, you close the bleed nipple before squeezing the lever don't you?

Another thing I tried last night is this:
  • Fill system from bottom up with a syringe (with no air bubbles!) whilst tapping the calliper and hose with a spanner to dislodge any air - note: I never ever see any bubbles in the master cylinder doing this-just pure mineral oil
  • Close bleed nipple
  • Close master cylinder by pulling the lever to the bars and hold tight with a couple of 'laccy bands (in theory creating a closed system?)
  • Open bleed nipple, and pull outwards on the syringe plunger. Extract lots of air bubbles!
  • Close nipple, release brake lever and ensure res does not empty

I did this for ages, and got nowhere. It was still spongey afterwards. I just can't understand what is going on. The air seems limitless inside the callipers. :madman: :skep: :confused: :confused:
 
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