HP LaserJet 40X0 -- Fuser Overhaul

Proceed as follows:

1) Rear Cover w/Captive Screws
- One claw at right side end.
- One claw low at centre.
- One claw at left side end.

2) Top Cover
- Two M3x4mm bright washerhead screws.
- Two tabs, one at either side. A spring hook is helpful for levering them free.
- NOTE the tab-and-slot engagement at the centre-front of the cover.

3) Exit Sensor Toggle/Flag

4) Gear Train Cover
- Two M3x4mm bright washerhead screws.

5) Dark Front Gear (33t; P/N RS5-0921)

6) Dark Middle Gear (34t; P/N RS5-0922)

7) Outermost White Gear (21t; P/N RS5-0924)

8) Lower White Tandem Gear (16/18t; P/N RS5-0923)
- NOTE that the smaller end goes inboard.

9) Inboard Upper White Gear (26t; P/N RS5-0925)

10) Diverter Lever w/Torsion Spring
- One claw.

11) Diverter
- Spread the frame a bit to free its left side end.

12) Pinch Roller Frame P/N RB1-8799
- Spread the frame a bit to free it.

13) Thermistor Connector
- One claw. There's very little slack in the cable, but enough that the connector can be taken off.

14) Fuser AC Cable
- Disconnect the white connector at the lower right.

14) Fuser Film Sleeve Assembly P/N RG5-4290
- Lift it out.

15) Pressure Roller P/N RB9-0684 (was P/N RB1-8794)
- Lift it out,
- Left Side Bearing P/N RS5-1310.
- Right Side Bearing P/N RS5-1297.

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That's typically as far as you need go.

Best practice is to replace the film sleeve assembly outright with a new OEM part. Replacement sleeves are available, though. Following is the procedure for replacing a sleeve.

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Sleeve Replacement

1) End Cap at Thermistor Connector End
- Slip it out.

2) Sleeve
- Slip it off.
- NOTE that one end of the sleeve has a dark band. That's the thermistor connector end.

3) Clean the grease from the end caps and the heater body.
- Varsol is helpful as a solvent, but you don't want to soak the assembly in it. Wipe away as much grease as you can with paper towelling. Use Varsol sparingly to get all of it. A toothbrush is helpful. The parts should all be immaculately clean before the new sleeve is installed.

4) Apply silicone grease sparingly to the end caps, and lay a film of grease down the length of the heater. Here's more-or-less how it ought to look.

Slide on the new sleeve (black band at thermistor connector end), install the end cap, give the sleeve a turn or two and wipe away any squeeze-out that appears at the ends.

Reassemble the fuser w/other new parts A/R.

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