Karcher K4 leak

[newbie69]

I have my K4 for almost 2 years now, probably used it 20 to 25 time s max but recently, I got a big leak right where the 6m hose connects to the water outlet. As a result of that the water is escaping in the form of a high pressure sprey right where the two connect and the "gun" has no power to pressure wash as shown in the photo below (the handle/bracket that goes above has been removed to show it clearer, but the spray is the same with that on too).





Upon disassembly of the connection, I noticed the o-ring at the water outlet pipe where it connects to the hose elbow, was slightly damaged (a small bit was missing) so I figured that would be the cause. In the photo, the o-ring has been removed but it goes right over the groove pointed by the red arrow:




Now I measured that o-ring and it seems to be a custom size: 11.6mm inner dia / 14.6mm outter dia / 1.5mm thickness. I tried a few o-rings from generic o-ring sets available to me, the closest one being a 10mm inner, 13mm outter, 1.5mm thick  but it still leaks as in the picture above. 

I'm wondering whether it has to be absolutely the exact same size for it to work, didn't think it mattered so much at the beginning as the new o-ring is the same thickness as the old one and is being slightly stretched around the groove providing a similar outter diameter to the stock one once installed, but it doesn't work.


Anyone had a similar issue before and is it only the genuine Karcher ones that would do it? Can't think of another cause as the rest of the connection's parts are solid and seem fine. I have to order a full set of replacement o-rings and rubber stops which I don't need (around 17eur) just to get the one I need...
 

Edited 1 May, 2020 by newbie69

[NJRJ]

1 hour ago, newbie69 said:

I have my K4 for almost 2 years now, probably used it 20 to 25 time s max but recently, I got a big leak right where the 6m hose connects to the water outlet. As a result of that the water is escaping in the form of a high pressure sprey right where the two connect and the "gun" has no power to pressure wash as shown in the photo below (the handle/bracket that goes above has been removed to show it clearer, but the spray is the same with that on too).





Upon disassembly of the connection, I noticed the o-ring at the water outlet pipe where it connects to the hose elbow, was slightly damaged (a small bit was missing) so I figured that would be the cause. In the photo, the o-ring has been removed but it goes right over the groove pointed by the red arrow:

Now I measured that o-ring and it seems to be a custom size: 11.6mm inner dia / 14.6mm outter dia / 1.5mm thickness. I tried a few o-rings from generic o-ring sets available to me, the closest one being a 10mm inner, 13mm outter, 1.5mm thick  but it still leaks as in the picture above. 

I'm wondering whether it has to be absolutely the exact same size for it to work, didn't think it mattered so much at the beginning as the new o-ring is the same thickness as the old one and is being slightly stretched around the groove providing a similar outter diameter to the stock one once installed, but it doesn't work.

Anyone had a similar issue before and is it only the genuine Karcher ones that would do it? Can't think of another cause as the rest of the connection's parts are solid and seem fine. I have to order a full set of replacement o-rings and rubber stops which I don't need (around 17eur) just to get the one I need...
 

Not on a Karcher but when I've replaced O-rings with a smaller one I allow for stretching, so I use a slightly thicker O-ring  ~1.8mm thickness, good nitrile(?) O-rings don't distort as well as butyl ones do.

[BoxerBoy]

I recently lost the small O ring out of one of my nozzles, so bought a kit from the Amazonian Palace.

 

I reckon one of these will fill your gap.

 

Edited 1 May, 2020 by BoxerBoy

[newbie69]

1 hour ago, NJRJ said:

Not on a Karcher but when I've replaced O-rings with a smaller one I allow for stretching, so I use a slightly thicker O-ring  ~1.8mm thickness, good nitrile(?) O-rings don't distort as well as butyl ones do.

So I tried a 2mm one also but apparently the groove is less than 2mm wide so the thicker o-ring cannot compress/sit fully inside and ends up being too big...

[newbie69]

51 minutes ago, BoxerBoy said:

I recently lost the small O ring out of one of my nozzles, so bought a kit from the Amazonian Palace.

 

I reckon one of these will fill your gap.

 

Aha! Could you do me a favor and check if the one supposed to be on the top left picture is indeed a 11.6 inner /14.6mm outter o-ring? Or whether any other o-ring in that pack meets those dimensions? From the pics it doesn't seem any of those is supposed to fill that... gap!

[J.R.]

A man can never have enough O rings, I keep buying the boxed sets in Lidldidaldi forgetting that I already have several (keep thinking they are in the other country) have also bought some assortments in a Jiffy bag for next to nothing on E-bay, I also have a kit with O section cord that you splice to the required size in a jig with superglue, thats been waiting 20 years to break its duck.

 

By the time I have searched through them all it would be quicker to buy the right size on E-bay!

[newbie69]

9 minutes ago, J.R. said:

A man can never have enough O rings, I keep buying the boxed sets in Lidldidaldi forgetting that I already have several (keep thinking they are in the other country) have also bought some assortments in a Jiffy bag for next to nothing on E-bay, I also have a kit with O section cord that you splice to the required size in a jig with superglue, thats been waiting 20 years to break its duck.

 

By the time I have searched through them all it would be quicker to buy the right size on E-bay!

Lol, what are you using them for so frequently?? I haven't needed one all these years before getting the pressure washer!

[BoxerBoy]

It’s 11pm and my wife thinks I’m a lunatic for venturing out to the garage and rummaging for a packet of O rings.

 

But hey-ho it’s beer time on a Lock Down night.

 

The largest O ring in my kit is 14mm OD. It is 2mm thick. So 10mm ID.

 

Don’t know where all your numbers come from, but I’d bet that it would fit your hose.

 

Remember that if you stretch a small O ring onto a hose, then the effective O ring thickness has been reduced. So it won’t seal.

 

Go on - splash out on some OEM spares.

 

 

[SuperbTWM]

26 minutes ago, J.R. said:

A man can never have enough O rings, I keep buying the boxed sets in Lidldidaldi forgetting that I already have several (keep thinking they are in the other country) have also bought some assortments in a Jiffy bag for next to nothing on E-bay, I also have a kit with O section cord that you splice to the required size in a jig with superglue, thats been waiting 20 years to break its duck.

 

By the time I have searched through them all it would be quicker to buy the right size on E-bay!

 

Those 'make your own' 'O' ring kits have got me out of bother quite a few times at work.

[newbie69]

9 minutes ago, BoxerBoy said:

It’s 11pm and my wife thinks I’m a lunatic for venturing out to the garage and rummaging for a packet of O rings.

 

But hey-ho it’s beer time on a Lock Down night.

 

The largest O ring in my kit is 14mm OD. It is 2mm thick. So 10mm ID.

 

Don’t know where all your numbers come from, but I’d bet that it would fit your hose.

 

Remember that if you stretch a small O ring onto a hose, then the effective O ring thickness has been reduced. So it won’t seal.

 

Go on - splash out on some OEM spares.

 

 

That's sounds pretty exiting given the circumstances...  Well I measured it with a caliper, couldn't be so off I think, and I believe the 2mm is too thick, will check again though and thanks for the reply!

[J.R.]

35 minutes ago, newbie69 said:

Lol, what are you using them for so frequently?? I haven't needed one all these years before getting the pressure washer!

 

Infrequently but you need to be autonomous where I live, also when I am in the UK doing repairs its usually short periods & there just isn't time to wait for things to be delivered, have repaired trolley jacks, kitchen & bathroom taps, washing machines, cavity wall injection machine (frequently), sprayguns, air tools, weedkiller sprayers, all manner of repairs.