Bleeding deore brakes

t0pc4t

Question no less dumb than my usual. I have to replace the lever on my deore brakes and as Shimano don't sell the blades alone, it has to be the full assembly and so I will need to bleed the system.

Online I have seen vids where a syringe is attached to the bleed nipple and used to push fluid into the caliper to bleed it by forcing bubbles up to the resevoir at the top.

My question is, why is this necessary and why can't I just bleed brakes like I would have on a motorbike? By this I mean attach a pipe to the bleed nipple on the caliper, put new fluid into the resevoir at the top and then pull the lever with the nipple open, close the nipple, release the lever rinse and repeat until there are no bubbles in the resevoir and none in what comes out via the pipe attached to the caliper nipple.

Am I missing somehting?

cooldad

You can, just get the brake line as level as possible.

nicklouse

which Deore brakes?

mister p

You can do it that way but it is much easier and quicker to force fluid in from the calliper end. As the fluid is under pressure it forces any air out with it and you should be able to get a solid lever feel first time every time. I have bled quite a few Shimano brakes this summer at various downhill and gravity enduro events and this method has saved me loads of time and bother.

andyk19

I have to agree with mister p. I've had a few sets of shimano hydros and have tried both methods of bleeding. The method of putting fluid into the reservoir with the bleed nipple on the caliper open whilst actuating the lever took hours; particularly as I'd emptied the system of fluid. On the other hand using the syringe and bottle method with a bleed kit takes minutes, is much cleaner and results in a better bleed (in my case anyway).

I was also able to find a copy of the shimano bleed kit on eBay which only cost £25 as opposed to a little over £50, it seems to work fine - afterall its only a syringe, a bottle and a clamp.

The Rookie

Agreed again, I can bleed my XT's in 2 minutes with a syringe and hose on the caliper.

t0pc4t

thanks everyone for an understandable and logical set of responses. Really appreciate that, bought a bleed kit from Dr Coopers, unfortunately can't use the strangely shaped funnel thing as my Shimano pre-dates that

Nick - it's a replacement for an M486 (no longer made) M445 I think.

nicklouse

t0pc4t wrote:

thanks everyone for an understandable and logical set of responses. Really appreciate that, bought a bleed kit from Dr Coopers, unfortunately can't use the strangely shaped funnel thing as my Shimano pre-dates that

Nick - it's a replacement for an M486 (no longer made) M445 I think.

hence the question as the funnel is only for certain models.

this lever?



basically the reservoir is so small you would be topping up all the time of forgetting and having to start again.

t0pc4t

thanks the kiddie and thanks matey.

would be nice if the lever blades were user serviceable though, then I wouldn't have to be bleeding anything

nicklouse

the blades are removable and repacable.

t0pc4t

That's odd, I was told by 2 bike shops that the lever blades were not removable and replaceable and I am not entirely sure how it would be done.

Do you know how to get them off? Would save me doing the bleeding then at least. I can see how one would disconnect them from the piston but not how to remove the main pivot.

nicklouse

which lever? M486 ?

just about to finish work but will be on later.

nicklouse

nicklouse wrote:

which lever? M486 ?

just about to finish work but will be on later.

Mmmm just had a thought. those ones have the pivot as a "rivit" IE it aint replaceable. so more effort to change. new bolts etc and then drilling out the pivot.....

t0pc4t

Ah ok thought as much from looking at the replacement, oh well bleeding it is, thanks for the input everyone, at least I know I'm not going off half cocked.