[wintermute]

Apologies for this one, it's probably really simple.
Under front braking my RD04 seems really snatchy at low speeds, possibly its just not as noticeable at higher speeds. It's sorta intermittent, and if stopped, when I pump the lever there seems to be varying amounts of resistance.
I'm a bit clueless when it comes to brakes, so any theories are appreciated, the disks don't look warped BTW. I'm thinking maybe the brake fluid needs replacing, as I'm pretty sure it was a fairly cursory service it received when it was sold to me by the dealer.
Would heavier Fork oil help with the braking? I also feel like it's a bit twitchy on the front end, particularly on tram-line style tracks. Is there a desirable aftermarket setup to improve the front suspension?
Answers on a stamped, self addressed postcard to the usual address.

Thanking you in advance for your time and trouble.

 

[robelst]

Good chance it is the slider pins on one- or both of the calipers (not the pins where the pads slide on, but the pins between the caliper and mount). This prevents the calipers from floating freely, pushing the pad on the piston-side much firmer against the disc than the other side, giving eaxctly this very feedback. At higher speeds it is (far) less noticable because brake-forces are higher, pushing harder on those unwilling pins but I know from experience you will start feeling it there as well as pins detoriate. One of the pins on my AT's right caliper looked like an archeological find :shock:

If this is indeed the case you will probably see uneven pad-wear (piston-side worn down more than the other side), and potentially deep(er) scratches on the outer disc-surface. Pins are not expensive, but act quickly otherwise you will need new pads and disc(s) as well
If discs are already effected by it, you may be left with still a bit of "pumping" after the fix, but if you are lucky it is only caused by surface-scratches and may wear off during use.

Also check if the rubber "boots" on the pins are not damaged, and fit them with a bit of cupper-paste or silicon-based grease otherwise the new ones will start corroding too.

Good luck!

 

[anton88]

sticky brakes

I would guess at the least you would need to do a caliper strip down/clean and re-build plus new brake fluid to be safe. As a starting point.