XT Hub Service
This maintenance article covers the M765 Hubs but essentially most of the modern XT hubs are similar but make sure you have the correct bearing sizes for the model of hub you are servicing. If in doubt check the Shimano tech docs for the model of hub you have here: Shimano Tech Docs.
What you need
- Spanner (to fit lock ring tool) and chain whip
- Compatible bearings - 2 x 9 x 1/4 inch steel bearings
- Compatible bearings - 2 x 11 x 3/16 inch steel bearings
- Cassette lock ring remover tool
- Flat-head screwdriver
- Grease (preferably Synthetic)
- 15 & 17mm cone spanners
- 10mm allen key
- Torque wrench (45nm setting)
Firstly remove the rear wheel and remove the quick release.
Hold a sprocket in clockwise direction with sprocket chain whip tool. Turn remover counter-clockwise, using a large adjustable or socket wrench (may require moderate force or an extension to the wrench handle) and remove the cassette.
Lock ring removed
Turn the wheel around and prise off the rubber seal.
Using both the 15 and 17mm cone spanners you need to remove the lock nut from the non-drive side. Remove any spacers and washers and remove the cone as shown below.
Remember what order the washers, lock nuts and cones are in before you take apart. Also do not allow the axle to slip through otherwise the bearings may fall out (not a problem if you are going to replace them).
Place them all in order (helps when reassembling).
Cone removed to expose mucky bearings.
Remove the axle but as the bearings are loose use a flat bladed screw driver of a pen magnet to remove them from the cups. There should be 9 bearings each side (1/4 inch) but depends on the model of hub. place again in order of disassembly.
Axle removed, bearings still present embedded in gunk!
Use a 10mm allen key to undo the internal bolt inside the freehub. This will remove the freehub.
Picture showing the freehub body and the bolt. There is also a slotted spacer between back of the freehub body and hub.
Freehub body removed showing the splined fitting on the hub.
Picture showing the slotted spacer.
Basic Freehub Body Service
You can't disassemble the freehub body but you can clean it and re-grease it (or buy a new one). Firstly remove the seal with a braddle or similar.
This exposes the bearings. Next you can drop it into a pot of solvent. If the pot has a lid then you can shake it to strip it of grease and mud and grit. Change the solvent a few times then allow to dry. Then inject grease into the bearings and keep turning and injecting until you can feel the grease getting into the ratchet mechanism inside. Clean and replace the seal.
Replace the freehub body washer.
Replace the freehub body and bolt and tighten with the 10mm allen key. Next replace the 9 1/4 inch ball bearings, preferably with new ones.
The easiest way is to place the grease in first and place each bearing into the grease, turning the wheel as you add them.
Do this both sides and then replace the axle from the drive side. I usually place a bit more grease in at this point.
Replace the cone, spacers and locknut in the right order and then tighten with the cone spanners. This takes a bit of time to get the right compression on the bearings. The axle should not rattle i.e. the cones should be tight on the bearings, but not too tight that they grind when the axle is turned (bit like doing up a headset).
Replace the dust seal making sure its seated properly behind the washer behind the locknut.
Grease the splines on the freehub body.
Replace the cassette and tighten the lockring with the tool and wrench/spanner to the correct torque (45nm usually).
Front Hub Service
This is the easiest wheel to service and usually does not need to be as frequent as the rear. Essentially is similar to the rear but both sides have a similar cup and cone config. I would remove the cone/lockring from the non-disc side as its easier to get the cone spanners in. The dust seal is first removed.
Use the cone spanners as before to remove the lock ring.
The cone is longer on the front but essentially the same.
Remove the axle and bearings, then clean the cups, regrease, reload bearings then insert axle, assemble cone, washers and lockring and tighten as before. Replace the dust seal. the front bearings on this model requires 11 3/16 diameter bearings on each side. Replace QR then your finished.