Here is my write up on Cleaning the Capping Station OUT of the machine to verify complete, 100% operation. This is NOT a manual for replacement, you can find that in the Repair Manual at 2manuals.com
Removing and cleaning Pump Assembly
I would recommend a straight up replacement IF you are committing to taking this unit out of the printer, for $50 you can replace this unit, it will make life a whole lot easier, cleaner and ensure a fully functioning Pump Assembly, eliminating that as an option for issues down the road.
BUT, for those of you/us who like making things work without replacement (being this world has become such a disposable culture), I will humor you all with a solution for cleaning your Pump Assembly while REMOVED from the printer, there is NO way of doing this while in the printer, unless you want to make a BIG HUGE mess of your printers!
Now, for that wiper blade, you really need to make sure it’s in good working order, otherwise, this whole process would be in folly. There are no promise this is going to work, but like I said, if your anything like me, it might be worth a try to save throwing away an entire Pump Assembly!
With Capping station removed, place over a sink to minimize the mess, wear you gloves and an apron too! MESSSSSSYYYYY jobs call for preparations! Disconnect the waste ink lines leaving the capping station and going to the junction where the line goes into to the pump, leave these lines dangling into the sink. Now, squirt flush fluid through the capping station and watch to see the fluid go through the lines freely. Now, do the same through the pump, Reconnect the lines going from the capping station into the pump, not an easy task, pinch the hose together and push the smaller one into it. You will need to use a syringe with a blunt tip needle and make a seal with your fingers the best you can and squirt the flush through until it runs through easily.
OK, now the FUN part!. No seriously, if you are anything like me, you will LOVE this part! Insert the end of your syringe luer slip into the end of the waste ink line on the end where it connects into the waste pad lines, now poor some flush into the syringe with the plunger OUT, once you have a 1/4 of the syringe filled with flush, install the plunger. Now, push the flush gently until the flush comes out the capping station, this is a reverse motion then before. Once you see the flush bubble up into the capping station, pull the plunger back out and keep working the flush in and out making it bubble up out over the top, you will see quit a bit of inky pigment draining out into the sink. You can leave it sitting for a bit to help break it up. Then, once your done playing with that, suck all the fluid out through the syringe and put it all back together. VOILA! The capping station is free and clear of clogs and “should” work to full function.
NOTE- Just because your Capping station is back to full operating status, does NOT mean you print head (if out of specs) is going to be miraculously cured. Keep this in mind before you spend the $ and the time in this endeavor, I am not that hopeful the capping station is a fix all for these machines.