Incontinent Karcher K4 (and fixes)...

Jimbob76

Roof Rails Enthusiast
So, the reliability issues surrounding the Karcher K4 are pretty well documented - after a while they will wet the bed. I've counted myself lucky that mine has lasted 2.5 years before losing bladder control (others on here get through one every season - a certain @jassyo06 is probably on his 5th or 6th now - feel your pain pal, ****** annoying).

Inevitably, it was 3 months outside it's 2 year warranty, so after swearing lots, kicking it and lamenting that I might actually be tempted to throw 500 sheets at a Kranzle, I've spent an hour this evening stripping the wet-knickered b1tch down to see if I can't diagnose the problem, and fix it. Here's how I got on...

Actually pretty easy to free the guts of the thing from it's plastic housing - just a few (x8) torx screws on the back of the unit, plus a couple of plastic plugs on the base that needed teasing out with a flat head screwdriver, then you're inside. Couple of metal clips to release to get the 'engine' out, but child's play really.

Started off by fully pulling apart the plastic water pump to check for cracks - this is a common fault, especially if you don't drain the pump after each use, and very especially in winter, if the water you haven't drained from the pump pump freezes and expands, and cracks the plastic housing. Why are they made of plastic FFS? Such a stupid material for such an integral part. Anyways, that proved fruitless - no fault there, so reassembled.

Problem turned out to be a hairline crack in the plastic elbow on the rear of the unit that connects the exterior hose to the guts of the machine - this also seems to be a common fault - so much so that Karcher sell a metal replacement elbow. (uh, just fit that one as standard). £15 part, ordered, and confident this will fix the fault. Will update once I've fitted it. With hindsight I should have checked for this first before stripping down the water pump.

I was initially intending to smash the damn thing with a hammer and take it down the tip, but having taken the K4 apart, I'm actually quite impressed with how easy it is to take apart, diagnose the fault and fix it yourself. It might end up being like Trigger's broom after a few more years, but you can buy a tonne of replacement spares for it and it is very easy to work on. Still fancy a Kranzle though.

Guts of the machine removed:
Guts.jpg


Metal water pump housing removed to check the pump for cracks - there weren't any:
Water pump.jpg


Problem turned out to be the plastic elbow going into the machine here:

InkedOffending_LI.jpg


Here it is stripped out - hairline crack in the join right down the middle - caused complete loss of pressure and a fine spray p1ssing out of the rear of the machine:

InkedSplit elbow_LI.jpg


Replacement part ordered - metal elbow to replace the cheap plastic one (£15):

Part.JPG

This should fix the incontinent old girl! Will confirm once I've finished the fix. Posting in the hope that it helps someone, even if just one person. TBC...
 

AlS3BE

Registered User
My k2 did this after 7-8 years so junked it.
my k4 lasted 6 months before it died. Replaced under warranty luckily. New one seems to be holding up.
another common fault on the k4 is the pump occasionally pulsing whilst in use. Was told by the karsher folk that there were issues with certain pumps and a revised pump was the fix.
 

NevMan

Well known member
So, the reliability issues surrounding the Karcher K4 are pretty well documented - after a while they will wet the bed. I've counted myself lucky that mine has lasted 2.5 years before losing bladder control (others on here get through one every season - a certain @jassyo06 is probably on his 5th or 6th now - feel your pain pal, ****** annoying).

Inevitably, it was 3 months outside it's 2 year warranty, so after swearing lots, kicking it and lamenting that I might actually be tempted to throw 500 sheets at a Kranzle, I've spent an hour this evening stripping the wet-knickered b1tch down to see if I can't diagnose the problem, and fix it. Here's how I got on...

Actually pretty easy to free the guts of the thing from it's plastic housing - just a few (x8) torx screws on the back of the unit, plus a couple of plastic plugs on the base that needed teasing out with a flat head screwdriver, then you're inside. Couple of metal clips to release to get the 'engine' out, but child's play really.

Started off by fully pulling apart the plastic water pump to check for cracks - this is a common fault, especially if you don't drain the pump after each use, and very especially in winter, if the water you haven't drained from the pump pump freezes and expands, and cracks the plastic housing. Why are they made of plastic FFS? Such a stupid material for such an integral part. Anyways, that proved fruitless - no fault there, so reassembled.

Problem turned out to be a hairline crack in the plastic elbow on the rear of the unit that connects the exterior hose to the guts of the machine - this also seems to be a common fault - so much so that Karcher sell a metal replacement elbow. (uh, just fit that one as standard). £15 part, ordered, and confident this will fix the fault. Will update once I've fitted it. With hindsight I should have checked for this first before stripping down the water pump.

I was initially intending to smash the damn thing with a hammer and take it down the tip, but having taken the K4 apart, I'm actually quite impressed with how easy it is to take apart, diagnose the fault and fix it yourself. It might end up being like Trigger's broom after a few more years, but you can buy a tonne of replacement spares for it and it is very easy to work on. Still fancy a Kranzle though.

Guts of the machine removed:
View attachment 242222

Metal water pump housing removed to check the pump for cracks - there weren't any:
View attachment 242225

Problem turned out to be the plastic elbow going into the machine here:

View attachment 242228

Here it is stripped out - hairline crack in the join right down the middle - caused complete loss of pressure and a fine spray p1ssing out of the rear of the machine:

View attachment 242227

Replacement part ordered - metal elbow to replace the cheap plastic one (£15):

View attachment 242226
This should fix the incontinent old girl! Will confirm once I've finished the fix. Posting in the hope that it helps someone, even if just one person. TBC...

Great work there @Jimbob76 . Was chuckling at the incontinent old girl and wet knickers etc, I experienced that (with a Karcher) before too
 

jassyo06

T-Cut King !
So, the reliability issues surrounding the Karcher K4 are pretty well documented - after a while they will wet the bed. I've counted myself lucky that mine has lasted 2.5 years before losing bladder control (others on here get through one every season - a certain @jassyo06 is probably on his 5th or 6th now - feel your pain pal, ****** annoying).

Inevitably, it was 3 months outside it's 2 year warranty, so after swearing lots, kicking it and lamenting that I might actually be tempted to throw 500 sheets at a Kranzle, I've spent an hour this evening stripping the wet-knickered b1tch down to see if I can't diagnose the problem, and fix it. Here's how I got on...

Actually pretty easy to free the guts of the thing from it's plastic housing - just a few (x8) torx screws on the back of the unit, plus a couple of plastic plugs on the base that needed teasing out with a flat head screwdriver, then you're inside. Couple of metal clips to release to get the 'engine' out, but child's play really.

Started off by fully pulling apart the plastic water pump to check for cracks - this is a common fault, especially if you don't drain the pump after each use, and very especially in winter, if the water you haven't drained from the pump pump freezes and expands, and cracks the plastic housing. Why are they made of plastic FFS? Such a stupid material for such an integral part. Anyways, that proved fruitless - no fault there, so reassembled.

Problem turned out to be a hairline crack in the plastic elbow on the rear of the unit that connects the exterior hose to the guts of the machine - this also seems to be a common fault - so much so that Karcher sell a metal replacement elbow. (uh, just fit that one as standard). £15 part, ordered, and confident this will fix the fault. Will update once I've fitted it. With hindsight I should have checked for this first before stripping down the water pump.

I was initially intending to smash the damn thing with a hammer and take it down the tip, but having taken the K4 apart, I'm actually quite impressed with how easy it is to take apart, diagnose the fault and fix it yourself. It might end up being like Trigger's broom after a few more years, but you can buy a tonne of replacement spares for it and it is very easy to work on. Still fancy a Kranzle though.

Guts of the machine removed:
View attachment 242222

Metal water pump housing removed to check the pump for cracks - there weren't any:
View attachment 242225

Problem turned out to be the plastic elbow going into the machine here:

View attachment 242228

Here it is stripped out - hairline crack in the join right down the middle - caused complete loss of pressure and a fine spray p1ssing out of the rear of the machine:

View attachment 242227

Replacement part ordered - metal elbow to replace the cheap plastic one (£15):

View attachment 242226
This should fix the incontinent old girl! Will confirm once I've finished the fix. Posting in the hope that it helps someone, even if just one person. TBC...
Hi mate you've had a lucky escape with the fault being the external plastic Elbow with me its been the pumps themselves....cast elbows also have a major flaw its the circlip that holds the 5 m hose in place slips out....leaving the hose on the deck ******* out water this is what my current k4 is doing at every wash l purchased another new k4 2 weeks ago but l have'nt even seen it...no sooner was it delivered Jordan was off with it to do his plastic decking and driveway a just get used and abused lol
 

josul

Registered User
Hi mate you've had a lucky escape with the fault being the external plastic Elbow with me its been the pumps themselves....cast elbows also have a major flaw its the circlip that holds the 5 m hose in place slips out....leaving the hose on the deck ******* out water this is what my current k4 is doing at every wash l purchased another new k4 2 weeks ago but l have'nt even seen it...no sooner was it delivered Jordan was off with it to do his plastic decking and driveway a just get used and abused lol
I had this issue, added a cable tie which is holding well

20210902_114959.jpg
 

AlS3BE

Registered User
Hi mate you've had a lucky escape with the fault being the external plastic Elbow with me its been the pumps themselves....cast elbows also have a major flaw its the circlip that holds the 5 m hose in place slips out....leaving the hose on the deck ******* out water this is what my current k4 is doing at every wash l purchased another new k4 2 weeks ago but l have'nt even seen it...no sooner was it delivered Jordan was off with it to do his plastic decking and driveway a just get used and abused lol
I had this issue, added a cable tie which is holding well

View attachment 242283

another good solution to this problem is get a longer hose. I have the 10 or 12m hose so there’s less wiggling or tugging of the hose so less stress on these parts. With a longer hose my k4 is parked at edge of garage and doesn’t move as the hose is long enough to get around the car without pulling or tugging of the hose/washer.
 

Jimbob76

Roof Rails Enthusiast
Good write up @Jimbob76 this is really useful info if anyone else finds themselves with the same problem. Hopefully it will last you for a while. Hope your well? :friends:

Hey @Sandra - yes, I’m well thanks, hope you and yours are too.

Hi mate you've had a lucky escape with the fault being the external plastic Elbow with me its been the pumps themselves....cast elbows also have a major flaw its the circlip that holds the 5 m hose in place slips out....leaving the hose on the deck ******* out water this is what my current k4 is doing at every wash l purchased another new k4 2 weeks ago but l have'nt even seen it...no sooner was it delivered Jordan was off with it to do his plastic decking and driveway a just get used and abused lol

Lol - so you've now got a K4 at Jordan's house, one at your Mum's place, another 3 or 4 down the tip but 'nowt at your own gaff. Get that new 'yin back of Jordan quick sharp before he starts to consider it his! And thanks for the heads up on the circlip slipping - think I'll use @josul 's clever idea of adding a zip-tie to hold it in place. Also have an aftermarket 10m hose on mine, so as @AlS3BE says, hopefully that limits strain on the connection.
 

josul

Registered User
another good solution to this problem is get a longer hose. I have the 10 or 12m hose so there’s less wiggling or tugging of the hose so less stress on these parts. With a longer hose my k4 is parked at edge of garage and doesn’t move as the hose is long enough to get around the car without pulling or tugging of the hose/washer.
I have the K5 on a 8m hose so the unit doesn't move. The clip is just not good enough although it was a cheap fix
 

Jimbob76

Roof Rails Enthusiast
Success! New part arrived today and fitted the new cast metal ‘elbow’ going into the machine at the back. I was pretty confident, but still satisfying to bolt the whole thing back together, test it and see the fix work. Pressure restored, and no more incontinence.

Now that I’ve stripped the K4 down, and now that I’ve familiarised m’self with its innards, I’ve realised how basic the mechanics are. Very easy to work on and when it next drops a b0ll0ck (which it will) I’m hopeful I can open it up again and fix it. £15 repair. Happy. If you have a K4 don’t be shy of trying a DIY fix when it needs it, it‘s really not difficult.

One piece of general maintenance advice I would give, is purge the water pump after each use. I don’t think many people do this, but if the pump is left full of water, in winter, it can freeze and crack the cheap plastic housing. Do this before you put it away:

- Turn the electric power supply off, and turn the tap that feeds the machine off.
- Release the pressure from the machine by ‘pulling the trigger‘ on the gun/Lance
- Disconnect your hose (the ‘garden‘ hose) from your tap to the machine
- Disconnect your gun/lance from the machine
- Finally, and this is the important bit, turn the electric power supply back on, this will purge water from the pump out of the machine
 
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