[Closed] Just fitted my new XT disc brakes and............

I'd give 'em a good bleed, mine are just not spongy at all. It took a few goes to get them there mind.
If you've looked at the other threads, you'll know whats required.

[i]but they feel a bit 'spongy'[/i]

this is how Shimano brakes are. I've Goodridge hoses on mine (old Deores, not XT )and it firms them up a bit.

put your brake fluid in the freezer over night to get the dissolved gas to 'bubble-out'

take your time, do it properly. if you don't know how - get a friend who does and give them beer, pizza, and cake.

clean your pads and discs, don't use spray lube - that stuff = death to disc brakes.

Brake levers going to the bar are not how shimano are!

Spongy too?

Air in your brakes!

You need to bl...

[i]Don't post pictures like that please. Mod[/i]

Yes, I've just changed back from XTR to Hopes, been running the Shimano brakes for about 5 months now (bled twice & used 3 different types of pads) still don't think they're a touch on the Tech Hopes.

Anyone want to buy some M975's?

my slx are in no way spongey! have you tried bleeding them?

when ever i get new brakes i tie wrap the lever to the bar over night or as long as possible to force any airbubbles to one end. seems to solve any issues for me anyway!

i'm sure someone will say it's how you set them up but i had the same opinion of them. i liked my hopes which had a "solid" lever feel as soon as they bite.

the XT's that came on a new bike lasted about a month before i ditched them. they would always stop me but just always felt soft in the lever even after bleeding and re-bleeding lots.

(i've got the old hopes back on)

no, i havent bled them. havent even got any mineral oil yet 🙂

i havent seen a thread on bleeding them, only that free stroke adjuster thing. is there a 'better than the manual' way of bleeding them? ive got a couple of syringes and pipe if that helps? manual suggests a bit of pipe into a bag.

the fact that youre saying they shouldnt be like that gives me a bit of hope. ill have to nip and get some mineral oil then. whats the best place to buy that stuff? online? LBS? halfords?

thanks

I thought shimano were supposed to be fit and forget and never go wrong? Thats what folk on here keep saying anyway

My XT's are as powerful and firm as any I have used and better than most. I have them set up so I only need to pull the lever a fraction and I can stop on a sixpence. It sounds alot like you need to re-bleed.

I've got XTR from 3 years ago and they are rock solid and very good. Not spongy at all.

You need to bleed. But bear in mind that it's a bit of a black art because bubbles can be hidden in the system. Think about where bubbles might be - move the caliper around to dislodge them, make sure the lever is the highest point (if there's a loop of hose the bubble will collect there and no amount of bleeding will shift them). Remove brake, place it all in a line (with lever level though), move the caliper around to dislodge bubbles, then let it all float to the top.. then open the top cap and wiggle the lever a bit (but not much) see if any bubbles pop out.

IIRC Shimano instructions tell you to do this rather than faff about with pumping etc. If you do the pumping the lever and operating the bleed valve thing, any bubbles in the hose will just keep floating up, no matter how much fluid you put through.

I have 975 XTRs, XT's and LX's setup myself and you have to patient if you're bleeding the shimano way-takes a while but solid.
Even bled some XTRs from users on here too as they were struggling and thats before a setting off on a trail.

I do hate using shims on shimano calipers but it could be sticky pistons causing rub. Otherwise fit and forget (except that pads need a little bed in)

I thought shimano were supposed to be fit and forget and never go wrong? Thats what folk on here keep saying anyway

I'm convinced Mr Shimano must have shagged you and dumped you at some point. Either that or you'd heard he votes Tory...

I've got a mix of Hope and Shimano brakes on my bikes (plus Julies on one of the others) and the XT and XTR's definitely have more modulation than some others (which is probably a good thing), but they definitely leave you in no doubt of their ability to lock the wheels if required. I've got Deore's on several bikes and, when set-up properly, they can be very sharp indeed. The Hopes are somewhere in between.

While I like the Hopes I have I still prefer Shimano and stick to those now. The most expensive brakes I own are Hayes Carbons and I when I took them off, replacing them with some old Deore's, I regarded that as a huge upgrade!

as said, spongeyness is a function of air in the system, not the design of the brakes themselves.

Just having a laugh steve. Second post on here in recent days with issues with shimano brakes but people still say they are faultless. Fit and forget and never need anythng doing to them.

I dislike shimano for the disposable / planned obsolescence philosophy but I fully accept that they make functional products at a very good price - there is a reason they are so big!

[i]I dislike shimano for the disposable / planned obsolescence philosophy[/i]

Like their hubs presumably? I mean, a few ball bearings and some grease occasionally, curse them and their long lasting ways...

re brakes, just because the levers have some 'give' in them, don't mean they've got 'issues'. It's just they way they seem to come. If you want them firmer, then do something about it, they work fine, it's just an individual taste thing...IME.

just about to go buy some oil, and checking the instructions to make sure ive got all i need. 2 lengths of tubing and a syringe should be fine i reckon. but...... the instructions give 2 methods.
'adding oil and bleeding air at the reservoir tank' where it seems its just a bag and bit of tubing needed, and let oil drain into bag.
and 'adding oil and bleeding air from the caliper using a syringe' where it seems that you have to piush oil up into the system, instead of topping up in the reservoir.

which ones best? (its not recommending you to do both is it???)

people still say they are faultless. Fit and forget and never need anythng doing to them.

People are just describing their own experiences aren't they, which is what forums like this are all about.

My experience of Shimano XTs and SLX too is that they're a bit fiddly to bleed initially, but once you've done that, they're pretty much fit and forget except in sub-zero conditions when they tend to stiffen up, possibly someting to do with the seals. Am I supposed to invent faults with them just to keep you happy? 😉

[url= http://www.singletrackworld.com/forum/topic/getting-the-most-out-of-new-xt-m775-disc-brakes ]CLICK FOR HELP[/url]

TJ I dislike shimano for the disposable / planned obsolescence philosophy but I fully accept that they make functional products at a very good price - there is a reason they are so big!

Reading thread with interest....

I rode my new XT's at the weekend too. They were either almost too the bar (trapping my fingers) or too far out so I was almsot slippin goff gripping them.

When mine go spongy. I just level the levers pop the caps and give them a good pump, leave it for five, pump again, leave for five, repeat a third time and they have always firmed up.

Now I've said that I bet it all goes tits up.

Good source of tube for bleeeding is your local RC model shop. Silicone fuel line is just the right size for little Shimano bleed nipples etc. Few quid for a metre or so.
Halfords do a nice little 7mm combi spanner for them little nipples also

Think about it. Bubbles want to rise, right? So if you squirt oil into the bottom (and catch it coming out the top) you'll take all the air out with the oil.

I seem to remember it saying something abotu leaving the bubbles to rise up then putting more oil in the bottom...

Seriously follow the suggestions, it may take a few goes to get it right, but they'll come good.

which ones best? (its not recommending you to do both is it???)

I used to use the fill-up-the-reservoir method, but the last time I bled my XTs I did it from the caliper up instead, and it seemed a lot less hit-and-miss (are there any more bubbles to come out? Should I do one more "fill reservoir / squeeze lever / tighten bleed nut / release lever" cycle? When do you stop?). Just drain the current fluid out of the caliper, start pumping new fluid back in, stop when the reservoir is full, job done.

they need bleeding for sure try bottom up bleeding if you can, mine where exactly what you want from new!

http://www.gravity-slaves.co.uk/?a=427 this can be done without the kit

sadex - this sounds like your first 'bleed' - it will go wrong i promise.

but that's ok, it's all part of the fun of learning, the very first thing you need to do, when you think you're ready to go, is take the brake pads out, and put them in a different room - and close the door.

you're not allowed to open that door until you've finished.

before you start, are you sure you haven't just got oil on your pads/discs ? shimano brakes are a bit more squidgy than others - i like this, other people not so much.

one of the great things about shimano brakes is,the mineral oil, you'll end up with it all over your hands, but it's mineral oil so it's fine.

do this with dot fluid and 2 days later your skin falls off in sheets.

i use 2 syringes - a big one attached to the calliper at the bottom the push lots of fluid through, and a little one at the top to draw off the excess as it flows into the reservoir.

there's a lot more to bleeding than just pushing a bit of oil through, you need to make sure you 'access' all of the air-traps - this is not easily explained here...

When mine go spongy. I just level the levers pop the caps and give them a good pump, leave it for five, pump again, leave for five, repeat a third time and they have always firmed up.

Now I've said that I bet it all goes tits up

The pumping doesnt bring up the level of the oil to overflow?

but once you've done that, they're pretty much fit and forget

No brakes are "fit and forget", they all go wrong every so often. You might argue that shimano are better than most, but the difference is certainly not as vast as people tend to claim in brakes threads.

No brakes are "fit and forget", they all go wrong every so often. You might argue that shimano are better than most, but the difference is certainly not as vast as people tend to claim in brakes threads.

Do you actually understand what 'pretty much' means?

Yes, see your reply to TJ. "people still say they are faultless. Fit and forget and never need anythng doing to them." This is clearly not true in general. I realise that you didn't say they were absolutely fit and forget, but I assumed the context would have been sufficient that I didn't need to go to tedious lengths of quoting.

Responde se vous plait!

When mine go spongy. I just level the levers pop the caps and give them a good pump, leave it for five, pump again, leave for five, repeat a third time and they have always firmed up.
Now I've said that I bet it all goes tits up

The pumping doesnt bring up the level of the oil to overflow?

When mine go spongy. I just level the levers pop the caps and give them a good pump, leave it for five, pump again, leave for five, repeat a third time and they have always firmed up.

Now I've said that I bet it all goes tits up

The pumping doesnt bring up the level of the oil to overflow?

No its what's known as " Burping"
Combine burping with tying the levers close to the bars over night and while transporting the bike to the trail..

right, ive read the [url= http://www.singletrackworld.com/forum/topic/getting-the-most-out-of-new-xt-m775-disc-brakes ]thread linked to above[/url] and theres a few good ideas there, but also some stuff i dont quite understand.

i get the impression that the 'from the caliper up' method is best so thats what ill do.

1

Try using an elastic band or toe strap to pull the levers in to the bar and leave it, sat upright on the floor, overnight.

2

both are now tied up with the caps off over night.

3

Another thing i discovered is to gently pump the pistons out and gently push them back in, but have the lever reservoir cover off, seems to shift stubborn clingons at the lever hose union.

4

Turning the freestroke ajuster screw anticlockwise allows the cam roller attached to the end of the master cylinder to travel further into the wave slot machined into the lever. This ensures more fluid is displaced per degree of lever travel until the cam moves back across the wave slot to the power side, effectivly increasing leverage once the pads are in contact. It absolutly does work and has a marked effect thats like night and day. Trouble is, the instructions are flakey, the grafix can be percived to be backwards, and not everybody understands how to adjust them correctly.

5

Ellaccy band and burping work wonders.
Pads out/ pistons in while bleeding from calliper to lever, then top cap on while still injecting.. then as you nip up the bleed nipple a gentle push on the lever to send a little fluid out

why cant brakes just play nicely!! 🙂

if you learn to bleed car and motorbike brakes then this bike stuff is a doddle...

key tips that apply to all.. away make sure bleed points are at highest point, even it that means removing/adjusting position the caliper and lever to reorientate (shimano can't account for the calliper position on every frame design)

make sure the calliper pistons are fully back - force them back into the housings and hold them there - block of wood and card etc

force fluid through, actuate slowly so as not to froth fluid and air..

always tightened nipples whilst still forcing fuild through so when lever is half pressed tighten nipple as you finish the stroke.. this stops air getting back in.

make sure hoses are as short as they can be and avoid loops etc

if you can you syringe / vacuum pump to draw fluid through the system.

Never let the res go dry whilst bleeding and make sure you expel any air from res.

and sometimes if you are having a bad day stop, and then re bleed later / next day as things settle etc

at the moment ive just cable tied the lever to the bar. with the top cap off, but diaphragm still in place.

is this right? or does the diaphragm need to be off as well, to leave the fluid open to air?

Cap can be on while cable tied, though while it is off remove the rubber and squeeze the levers in and out gently, and watch the air come out

No brakes are "fit and forget", they all go wrong every so often. You might argue that shimano are better than most, but the difference is certainly not as vast as people tend to claim in brakes threads.

What do you find goes wrong with Shimano brakes then? Just interested, I've run about six sets over the last ten years or so from the original four-pot XTs through to the latest version and SLX, bar the occasional sticky piston they've all been extremely reliable, which is more than I can say for various mates' squealing Hope set-ups 😉

mostly it's people getting oil on their discs/pads. then attempting to 'fix' them by bleeding them. usually badly.

no offence taken i hope sadex? - i wish you well, but the chances of being able to talk you through the process of bleeding your brakes over an internet forum are very slim.

TAKE THE PADS OUT AND PUT THEM IN A DIFFERENT ROOM

1) calliper below lever - as far as possible - calliper unbolted and dangling works for me

2) attach 100mm of tubing to a 50ml syringe - fill with fluid.

3) attach the syringe to the bleed nipple

4) set your brake lever so the reservoir is horizontal

5) take off the top cap and rubber diaphragm - undo bleed nipple about 1 half turn from tight.

6) execute a well practised and considered combination of syringe pumping, lever pumping, piston resetting, calliper / hose jiggling. some air will escape towards the lever, some air will escape towards the syringe, some air will be stuck behind the pistons - letting them pump out a bit and then pushing them back in can help.

7) drain excess fluid from the reservoir as necessary.

8 ) put everything back on, and tighten.

9) clean everything, put the pads back in.

stupid double post.

my issue with shimano brakes is that the caliper seals are non replacable - this issue alone means ill not be buying another set of shimano brakes

i have 3 sets of XT (from old 4pots - non freestroke and freestroke ones) and a single saint - the non freestroke and saint brakes have all blown the piston seals and are not scrap save finding a cheap caliper in CRCs sales they have !

Hope id be looking at 10 quid tops for some seals and then some fluid and id be rolling again !

But to the op - your brakes sound wrong my free stroke adjustable ones are solid and feel great - but its just a matter of time till they blow also !

no offence taken mate. thats not the case with me tho. these are new brakes, not been used yet. and feel spongy straight from the shop. so im trying to get my head around a new bleeding system, after being used to oro's.

What do you find goes wrong with Shimano brakes then?

Beats me, I don't use them, there is the odd thread on here every so often where people have problems though.

which is more than I can say for various mates' squealing Hope set-ups

The squealing is a feature, encourages you to brake less!

update: been p*ssing about with them and ive made them better. but.....i dont think itll last :-/

why? well, i bled them as per the instructions, in fact i thought id messed it all up, because i was pulling on the syringe at the caliper, thinking i was pulling out any bubbles from that end, when i realised id taken all the fluid from the reservoir! so air had got in now!! grrrr.....

so i pushed it back hoping for the best, but resigning myself to the possibility id f*cked em up. obviously loads of little bubbles in the fluid, but once theyd calmed down i tried again. and as per instructions, the last thing i did was tube into waste bag, and opened bleed nipple and let it start draining into it, keeping reservoir topped up. ( i dont really understand that bit and why you should do it)

was expecting it to be real crap as id probably made it worse with the empty reservoir bit, but it was about the same, if not a bit better.

i did something that made more of a difference, but like i say, i dont think itll last. when id been putting that yellow spacer in between the pistons, it was loose, so kept dropping oout. which suggested to me that there was too much space between pads and rotor. and therefore too much lever travel before 'bite'.

so i took spacer out, and pumped the lever a few times to get the pistons out a bit further, so i had to force the spacer in. set it all up again, and obviously more of an instant bite. which is what i like.

am i right in thinking tho, that as the pads wear, the gap will just get bigger again tho, without compensating? and where does that free stroke screw come into this? i sort of thought that was what altered the lever travel.

sadex - you've probably read the posts froma few weeks ago when I was having similar probs with the same brakes from Ribble. Mine are now perfect 😛 I spent a good while bleeding them carefully - forcing fluid up from caliper with syringe, while reservoir horizontal, cap and rubber off and a makeshift dish tied to the bars to catch the fluid (It's new so reuseable as long as the dish is clean)I put through a load of fluid this way. I then did it reservoir down as per the Shimano instructions, which is the same as Hope (have a look on the Hope website which is very good). This sorted the spongy feeling. I then wound out the freestroke screw 2 full turns (as advised by bigyinn et al)and tweaked the nurled reach nut to get the initial bar/lever distance right. I am also running them inside my shifters, with the distances set up for 1 or 2 finger braking which also avoid lever/finger contact.

definately more of a footer than the older xt's I replaced, but much more powerful and better in just about every way. the only downside is that it is taking me a wee while to get used to not having indicator windows on rear shifter.

yellow spacer - was loose, so kept dropping oout. which suggested to me that there was too much space between pads and rotor. and therefore too much lever travel before 'bite'.

sorry, wrong (sorry).

the pistons pump out you know...?

if you pull the lever a little bit, the pistons move out a little bit, and then return to where they were when you let go.

if you pull the lever a LONG way, the pistons move out a lot more, but don't go back quite as far when you release the lever.

they automatically adjust for pad wear.

[i]when i realised id taken all the fluid from the reservoir! so air had got in now!! grrrr.....[/i]

🙄

ahwiles - you are correct, however if you bleed the system with the pistons a little further out (e.g a slightly thinner spacer) and then top up the reservoir, surely there is more fluid in the system and a quicker bite ?

no. it doesn't work like that.

(yes, you'll have a little bit more fluid in the system, but this will be represented by a higher level in the reservoir - which won't affect braking performance)

ok, I wasn't too sure about my theory anyway 😛

so theres practically nothing i can do to position the pads closer to the rotor and get a more immediate bite?

but i just DID do. it worked. or like i thought, will it just get worse as the pads wear, then back to original gap?

i wish i understood these open systems a bit more :-/

sadex - if you unscrew the freestroke screws 2 full turns this makes bite more 'instant'. It will also bring your levers in a bit, so wind them back to where you want as a starting point with the nurled nuts. Mine are now quite 'bitey' and feels better than my Hope mono mini's on the other bike, which in turn felt better than my older xt's. Shifting the whole unit in a few inches towards the stem made a big difference in the overall feel too, despite my initial scepticism !

[url] http://www.singletrackworld.com/forum/topic/who-rides-with-their-brakes-inboard-of-shifters-shimano-xt-content [/url]

iain, i use them on my singlespeed, so no shifters to consider 🙂

as far as the free stroke screw goes, i read in one of the many threads ive seen, that you had to have it screwed out to bleed them. is this right? whether it is or not, thats where they are now, so ive got no more to play with.

ta

as far as the free stroke screw goes, i read in one of the many threads ive seen, that you had to have it screwed out to bleed them. is this right?