XT (M785 Icetech) brake drag issue

[Boxer]

Changed to new (genuine) pads front and rear and new RT86 rotors this week. Also fully bled the brakes for good measure.

However I now find the levers have very little travel with these new parts (previously ran generic rotors) and they brakes drag slightly front and rear reducing rolling efficiency. Neither of the rotors are perfectly true (brand new) but not what I'd call unusual amount. I cant get the caliper positioned in any spot which will totally eliminate any rubbing on the rotor on one side or the other??

Have pushed the pistons all the way back again and got a much longer lever for the first few applications, but now has again built up pressure to be quite touchy and dragging

Any adjustments I've missed?

 

[StanzaRallyMan]

rt86 are six bolt?

If so, are you sure the rotor mounting flange is square?
Are you sure the rotor is actually flat, check with a straight edge?
Most likely the rotor mounting flane is not square. You might need to put a really thin shim between the rotor and some of the mounting bolts.

 

[creaky]

Probably a bit too much oil in there boxer. I would take your pads out, push the pistons back then crack the bleed screw on the lever. Push the pistons back again to see if any fluid comes out. Tighten the bleed screw up.

Reinstall the pads etc. and see how it feels.

 

[outtacontrol]

Probably a bit too much oil in there boxer. I would take your pads out, push the pistons back then crack the bleed screw on the lever. Push the pistons back again to see if any fluid comes out. Tighten the bleed screw up.

Reinstall the pads etc. and see how it feels.

This was my thought also...

 

[Boxer]

Probably a bit too much oil in there boxer. I would take your pads out, push the pistons back then crack the bleed screw on the lever. Push the pistons back again to see if any fluid comes out. Tighten the bleed screw up.

Reinstall the pads etc. and see how it feels.

This was my thought also...

Thanks fellahs - will give it a shot and makes the most sense to me too, as I have a touchy lever.

 

[The Duckmeister]

Also check the caliper is mounted squarely over the rotor too. If it's off-centre, the top edge of one pad & the lower edge of the other, or opposing ends will drag, and also make the brake feel spongy as the first part of the stroke bends the rotor to suit.

 

[Boxer]

Probably a bit too much oil in there boxer. I would take your pads out, push the pistons back then crack the bleed screw on the lever. Push the pistons back again to see if any fluid comes out. Tighten the bleed screw up.

Reinstall the pads etc. and see how it feels.

Yeah Duck, not that - as above have played with position of the caliper to excess, it cannot be placed to not rub at all points on the rotation, also lever is not spongy, but very solid and touchy

 

[willsy01]

Is the freestroke screw all the way in?

 

[redbruce]

What, the Avid 'canners not forthcoming with advice (as an avid Avid user- 5 in the household, all good: gotta take 'em when they present themselves)?

Sorry, I didnt see you Ducky. At least that advice applies to all brake creeds.

 

[marc.r]

shimano brakes... just pick up some elixirs.. problem solved!

 

[Boxer]

^ Lol and yet even with this issue I need to sort, they are still infinitely better than the X0 world cups on my Spesh Carve

 

[redbruce]

^ Lol and yet even with this issue I need to sort, they are still infinitely better than the X0 world cups on my Spesh Carve

Light weight = light performance (if feel and modulation are important to your performance equation, as opposed to just weight).

 

[Boxer]

Thanks All,

Just thought I'd should post back up on the results as I find it frustrating when a thread doesn't have the resolution posted.

The fix was to simply throw an old set of avid transports pad spacers into the calipers and crack the bleed screws on the levers and allow excess fluid to flow out.

The spacers kept enough clearance to allow the rotors to pass through 360deg and no rubbing. Two rides down and 1500m of vert/descent and brakes are perfect