|   XT brake fluid | johnnyeastside
Mar 30, 2003 7:06 AM | | I just had an interesting thought. I run XT disc brakes and about once a season they need to be bled. The way to bleed them seems to be standard issue for typical motorcycle brake which are pretty much enlarged replicas of the XT's. It seems that it just doesn't work like it should, I never get the lever I really want. I'm a Harley-Davidson mechanic, so while pondering my braks, I realized that the Motor Co. uses DOT 5 brake fluid which is silicon based, I wonder if it would be compatible in my Mtn bike? If anyone has any bleed tips for XT's, or if any scientists can shed some light on fluid physics, the world would be a better place. |
| What difference would the fluid make, assuming it works? | Monte
Mar 30, 2003 9:53 AM | | Do you think using dot 5 will allow you to go longer between bleeds? I have an idea that the fluid isn't compatible anyway.
You will never get a hard lever with the XT's. They are just a little soft, you'll have to get used to it, or get different brakes. You could try different hoses though. I've heard of using the Deore lines with success.
Monte |
| re: XT brake fluid - DON'T USE DOT !!!! | Sigmund
Mar 30, 2003 10:58 AM | | NEVER use DOT brake fluid on systems designed for Mineral Oil & vice versa.
Doing so will destroy the rubber fittings & co.
Shimano XT is Mineral Oil based, as is Magura
(allbeit not the same variety of oil and should not be interchanged)
Hayes / Grimeca / Hope are DOT based. |
| re: XT brake fluid | iceaxe
Mar 30, 2003 11:06 PM | | DOT fluid has a higher boiling point than mineral oil. I believe it's some where around 500 degrees F. As you pointed out, DOT 5 is silicon based and doesn't absorb water as readily as DOT 3 and 4. Even a small amount of water absorption is very detrimental to the performance of the fluid. Mineral oil has a much lower boiling point, but won't absorb water and lacks the paint thinning effects of DOT. In most cases, mt bike brakes won't generate the kind of temps that you would encounter on your harley, so it really isn't neccesary to use DOT. If you use DOT in your xt's it will ruin the seals. Remember that all liquids are incompressible and therefore will not effect on the firmness of your lever.
I have XT brakes and I had a similar issue with mine. I switched cables to the Deore cuttable ones. The shimano braided cables just suck suck suck! They've been on my ride for 3 years and I only bled them when I first got them. Don't worry, you'll get used to it, they really don't require a whole lot of force at the lever to slow you down.
Hope this helps,
-Amadeo |
| paging Amadeo - XT brake shake, rattle & squeal | Sigmund
Mar 31, 2003 9:43 AM | | Amadeo, just a question for an "old" xt user from an xt newbie :)
Mine seem to rattle a lot on "interesing" tracks, I've been able to track this back to the brake pads dancing around. Any way you can recommend to silence this?
Also, what to do about the horrendous brake squeal, which appears when braking hard and you almost come to a stop? Any ideas?
I guess I need to retighten the spokes, as I presume they're the ones vibrating like mad, but I would appreciate some wisdom :)
I'm kinda ticked off, since my old Grimeca 8 didn't have any of these problems, although the XT brakes a *lot* better and more reliably. |
| paging Amadeo - XT brake shake, rattle & squeal | iceaxe
Apr 1, 2003 5:33 PM | | I'm assuming yours are quite new. Take out the return spring and bend the prongs further out, that should keep the pads better in place. It will go away completely when your pads wear in a little more. As far as the squealing is concerned, make sure all your hard wear is tight. Then sand your pads down and repeat the burn in process. That took care of it for me, there must have been some contamination or something. If all that doesn't work, it's probably your wheels. Let me know how it proceeds. As a last resort, you can put some disc brake quiet on the back of the pads.
-Amadeo |
| paging Amadeo - XT brake shake, rattle & squeal | Sigmund
Apr 3, 2003 9:36 AM | | Thanx. Yup, my xts are brand new, replacing my grimeca 8's. (The difference is huuuge, despite the similar design).
What surprised me is that I've ridden them for hard about 50 miles (reducing burn-in time :) ) before they started squealing. I used my old Grimeca rotors, which I had thorougly cleaned up beforehand.
Due to the pitch of the squeal I'm betting my money on loose spokes in the front wheel. I'll tighten them it tomorrow and I'll post back as soon as the weather clears up and I can take them out for a ride. |
| paging Amadeo - XT brake shake, rattle & squeal | iceaxe
Apr 3, 2003 11:22 AM | | I know that the Grimmeca rotors aren't identical to the shimanos. That might also contribute to the problem. As there seems to be a bit more material on the shimano rotor.
-Amadeo |
| paging Amadeo - XT brake shake, rattle & squeal | Sigmund
Apr 4, 2003 1:55 PM | | Nah, the Grimeca System 8 rotors (at least the 160mm one) are exactly like the new Shimano rotors, only visible difference being that the Shimano one is labeled to rotate in the other direction.
Rgds & thanks for all the info, Sigmund. |
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