Spill Valve Complete 4.591-040.0

After pulling the pump off, I first tried pulling the spill valve with needle nose pliers. It was in there to tight to pull out so I reinstalled the pump without the cover on the spill valve. Hook the hoses up to the pressure washer as you normally would and turn on the water. The spill valve did not push out, so I started the engine and "pop" - slick as a whistle the valve came out. Next time I'll just leave the pump in place and take the the cover off the valve and pop out the valve as I just described. Reassemble just as the eReplacement Parts video shows. A note: The spill valve part # 4.591-040 actually is a direct replacement for 4.591-036, so fear not. It looks like they improved the upper o-ring grove so the o-ring fits better without the need for a spacer. Otherwise the dimensions are identical.

Had to remove the pump from the motor due to not enough clearance between the unloader valve and the frame above it to access the old unloader valve. This was just 4 bolts, very easy. The toughest part of this repair was extracting the old unloader valve from the pump. Long nose pliers were nowhere near enough, they would just slip off no matter how tightly they were gripped. The tool that solved this problem was a pair of long nose vise grips. They were able to firmly clamp on the top of the old valve and pull it out. Having this tool was *essential* for completing this repair. (Other brands of pressure washer may not present this difficulty in removing the old valve) Applied a little Teflon grease on the top O-ring of the new valve and reassembled the pump. Works like new now!

I followed the video on you tube. Thank you.

https://www.youtube.com/watch?v=SAhiUyk3TIk

I watched your video on pump repair several times before starting. Pulled pump, disassembled per video instruction. Found 3 stuck valves (pistons caught in the springs... unstuck them and put them back. Replaced unloader valve. Reassembled pump per video instruction. Remounted pump per video instruction. To my utter amazement, it worked like a charm!

I did all this with the instruction from the video. Could not have done it without the video, I am a scientist and not mechanically inclined

B.G. Huff
Philo, IL

1. Spent part of a day becoming an expert on karcher washer pumps (u-tube, karcher, et. al.)
2. Removed washer front cover.
3. Removed unloader cover with screwdriver.
4. Removed plastic unloader cap screws with torx driver.
5. Removed top spring & seals.
6. Removed broken unloader (spill) valve.
7. Reassembled top spring & seals & new spill valve after lubing seal surfaces with lithium grease.
8. Notes: Clean off any corrosion; no grease on spill valve lower seal surface.

Placed Karcher pressure washer on truck tailgate.
Used allen wrench to loosen 4 bolts holding pump onto the pressure washer motor.
Removed button cap holding black cap on to the pump.
Used torx screwdriver to remove 2 screws on white plastic upper portion piece that houses the unloader valve.
Removed spring, then used large needle-nose pliers to remove unloader valve.
Put grease around green band on new unloader valve.
Reinserted the new unloader valve into the pump.
Put spring and white plastic piece back in place and screwed into place.
Put black cap and button cap back into place.
Reinstalled pump back onto the pressure washer and tightened all 4 bolts.
Hooked up water hose and turned on spigot.
Started the pressure washer and all worked fine.

Tried every pair of pliers and vice grips available could not get the valve out.
I ended up having to drill and tap the valve with 10-32 threads. I put in a socket head screw and still couldn't get it out with the vice grips. I finally was able to pry it out by using two screwdrivers under the screw head. The valve cavity was very corroded so I wrapped fine sandpaper around a small drill bit and used my drill to clean it up a little. Installed the new valve and it works fine now.

Had broken internal valve which was replaced. Your repair video was very helpful. As a precaution I replaced all 6 valves instead of just the one that broke. Spill valve was also replaced. Works fine now.

Followed your tube tube video and fixed problem by replacing bent valve.