How to make hydraulic brake levers really tight?
 

Hi

Whenever I bleed my Shimano Deore brakes, I can never get the brake levers to be really tight. They respond okay, but not tight with a fast response as I would like.

Btw, I'm following the Park Tool bleed process for Shimano.

Does anyone have any tips on how to make those levers really tight, as in very little travel?

Thanks

`Really tight` is a pretty subjective description and could mean anything. Hydraulic brakes aren`t supposed to have an abrupt ON/OFF response. Thats what good modulation is all about.

Are you saying you can`t get the same `feel` after you bleed the brakes as you had when the brakes were new and factory bled?

Yes, I would say that's a better description...

So my normal procedure is to bleed the brakes with the wheels removed to avoid any chance of contaminating the disks. The brake pads are spread using the plastic `keepers` that can with the brakes. Dimentionally those plastic `keepers` are 0.10mm thinner than the disk and using those to set up the brakes instead of the disks themselves may account for the difference in `feel` you`re talking about..

Is that any different than what you`re doing?

Pretty close. For the brakes spacers, i used wide popsicle sticks that give a diameter of 10mm to keep the calipers in place.

I`m assuming you mean 1mm. The disk is only 2mm thick and there wouldn`t be room for anything 10mm wide to be used in that orientation. If you`re actually talking about the width of the stick then measure the thickness.

If the thickness is less than 2mm and the brakes still feel mushy you probably have air in the line somewhere. Maybe you could try having it done professionally and the guy might let you watch.

The thickness of the sticks combined is exactly 10 mm or 1 cm. It works.

I don't want to piss off my LBS, so I thought I would ask here as there are many more technically advanced people than me. :)

Without meaning to be insulting - it obviously DOESN`T work otherwise you wouldn`t be posting here looking for a better result.

And I really can`t figure out what you`re doing. The total opening in most calipers is 11mm and brake pads are supposed to take up 8mm of that space. Are you removing the brake pads or forcing the pads and calipers back to accomodate your spacer - in which case you aren`t properly filling the lines and resevoir.

"It works" means that it keeps the calipers pushed out.

Would anyone else like to chime in? :)

If the problem really is air in the system, in the auto industry you can do a "full flush" - forcing a relatively large volume of fluid through through each circuit to root out any bubbles. I'm not sure what a bike system allows as I've never bled one.

You might also try changing the orientation of the bike while bleeding.

I think you're wanting free-stroke adjustment, a feature that not many Shimano levers have. You could consider getting some XT levers or a whole XT brake system, there'll be sales on the current stuff as the new XT M780 hits the market in July.

http://www.shimano.com/publish/conte...bm.512.384.gif

When bleeding hydraulic disc brakes, best practice is to remove the pads and insert the brake manufacturer's bleed block in the caliper instead, which is what you'll find in the official Shimano service instructions for your brakes. Among other things, this prevents accidentally contaminating your pads with brake fluid.

By orientation, do you mean ensuring the lever is directly above the caliper, like a top-down alignment?

No, I mean try several different orientations. Lay it over half way, then the other way. If there are bubbles stuck in the system that might help them come loose.

Got it.

I re-bled them a second with the same result; the left lever is still tighter than the right. So I came to the conclusion that I should bleed the left brake and that should make them both the same. And that's what happened!
So both levers now have the exact firmness. Not as much as I would have liked, but very functional none-the-less.