The bad news is that the plastic these parts are made of seem to be a Teflon hybrid and even the best epoxy doesn't last real well.
The even worse news is that DeskJets are disposable, just like Bic lighters.
HP will NOT sell you any internal parts.
They will not sell them to your dealer.
They will not even sell then to a so called HP service center.
All DeskJet service takes place in Corvallis, Oregon. A second possible location is Mississauga, Ontario but I think they just forward printers to Corvallis.
Here's the deal as I've been told; you pack up your printer and courier it to Mississauga, ($40 Cdn.), pay $175 Cdn. for a refurbished version of your Deskjet, and then pay another $40 Cdn. to ship the refurb back to you. That's $255 Cdn for a used printer when there are any number of new printers that can be had for a comparable price (and would also have a warranty).
That, to me, means DeskJets must be disposable because nobody in their right mind would pay that much for a three or four year old printer. It's bad enough when you consider 540's, which back then had a 3 year warranty, think about all the poor suckers buying newer HP's with only a 1 year warranty...
That's got to be enough harping on my part, the short of it would be that if you've got it working and your cartridge parks okay, it might be best to leave it alone. You won't get any worthwhile out-of-warranty help from HP. Check on parts availability on any future new printers you might ever buy. You can't assume that they won't forget you the day your warranty expires.