Old knackered Karcher K7.20MX 1.034-850 Pressure Washer

[Chris70]

Hi guys, this is really off-topic, ie, nothing whatsoever to do with woodwork. But I do value your opinions, so here goes:

About 20 years ago, I bought a Karcher 'K7.20MX 1.034-850' Pressure Washer while living in France, which gave me many years of good service. One winter I must've left it outside, charged with water, against the manufacturer's strong recommendations. It got frost-damaged. Now when you turn on the water supply to the machine, it leaks big time out of the bottom. Now, for those who don't know, I'd say the K7 series are/were the more powerful Karcher domestic washers. I recall, it cost me quite a bit at the time and it's quite a heavy beast too, so I've been really reluctant to send it off to landfill. Meanwhile,
I bought a Karcher, a 'K2 Power Control', but found it's comparatively feeble. I thought I'll fix the 7.20 beast, something I should have done in the first place!

Upending the machine, I soon saw where the leak was. This should be a doddle, I thought. After some dismantling to get to the source of the leak, the attached video suggested to me perhaps a perished O-ring. I was wrong. With a 24mm socket, I attempted to undo the white plastic threaded fitting connected to the [CuZnPb2] cylinder head. I'm not very mechanical so my terminology here is probably wrong. Shock horror, the nut part of the white plastic piece just sheared off, so I guess it was age-fatigued. It left the male plastic thread buried in the CuZnPb2 piece. Oh, I thought, I'll just replace the whole lot, so I naively undid three retaining bolts. More shock horror, loads of oil leaked out onto the bench! I them realised I should have attended the Karcher repair course :-( Evidently, I should have removed the leaky assembly without losing any oil, by employing two temporary retaining bolts.

If, by any miracle, I can obtain the part I need, and can re-assemble the Pressure Washer, commonsense tells me I will then need to fill her up with some new oil. However, the 0.4? litres of oil which leaked out was really clean. So, where can I buy a cylinder head, if that's what it is, and the right sort of oil?

Award yourself a medal for reading this far. Thanks in advance. Chris

 

[Chris70]

Err, I forgot to attach the video. Here it is.

 

[Bingy man]

Think I’d contact karcher parts department and seek advice from the experts. The parts you need could be obsolete so checking the parts are available could save you time and money..

 

[the great waldo]

I had 2 Kärchers the last one a K7 expensive and lasted about 20 hours over a couple of years. I binned it and swore never to get another Kärcher. I got a Stanley about a third of the price and it has been running for 10 years without any issues apart from the outside of the hose sheathing getting a bit crusty (they fixed the design since then)
Cheers
Andrew

 

[paulrbarnard]

Karcher are throw away.

 

[flying haggis]

Nilfisk!

 

[Spectric]

Yes the Nilfisk are the way to go, better built and last longer, Karcher are very DIY.

 

[niall Y]

There seems to be nothing quite as disheartening , as trying to get a broken pressure washer to work again.

 

[paulrbarnard]

There seems to be nothing quite as disheartening , as trying to get a broken pressure washer to work again.

I’m partial to Kranzel myself. 100% rebuildable. My 20 year old version needed a service earlier in the year along with a start capacitor replacement and all the parts were readily available.

Edit: Meant to reply to Spectric

 

[Lons]

My Karcher K5 is at least 12 years old and extensively used several time a week - every week. Still going strong and when it fails I'll fix it or buy another. You can only speak as you find.

 

[paulrbarnard]

My Karcher K5 is at least 12 years old and extensively used several time a week - every week. Still going strong and when it fails I'll fix it or buy another. You can only speak as you find.

I think regular use of this type of kit helps.

 

[Lons]

I think regular use of this type of kit helps.

Yeah it possibly does and I make certain the hose and pump are purged before putting it away. It's become a habit even in summer so doesn't get overlooked in the winter.

 

[Chris70]

Thanks for all your responses guys. I'll let you know what happens.

 

[Blister]

Re the nilfisk, My unit gave 7 years service , Then this year decided to not work , It would try and start then nothing , After buying several components that were recomended , Capacitor . Soft start device , We are now at over £40 in parts , It still did not work, Further investigation revealed a very small nylon filter , This is located behind the hose lock connector that you clip your hose pipe to , Unscrew that connecror off the body and you will see 2 white wings , I used a pair of long nosed pliers to gently remove this and it was chock solid with limescale stopping water entering the machine , Gently cleaned the filter so as not to damage the filter and we are back up and running , I advise any Nilfisk users to have a look and clean this filter as it can and will reduce the efficiency of the machine.

 

[Oldman]

Same filter position on Karcher's too.

 

[paulrbarnard]

Same filter position on Karcher's too.

And Kranzel

 

[AES]

My Karcher K5 is at least 12 years old and extensively used several time a week - every week. Still going strong and when it fails I'll fix it or buy another. You can only speak as you find.

As per Lons, you can only speak as you find.

I have just given my at least 20 year old Kaercher pressure washer away - in perfect working order. I have used it on average about twice a year in the house that we're just about to move from (into a flat, so no further need for a pressure washer - I hope)!

Always drained after every use - v easy to do - and stored in the garage - where over the last 20 years we have had overnight below zero temps some years.

The design of mine is a bit "daft" (inconvenient to store the bits when moving it around as neither the power cable nor the pressure hose + gun store properly in the compartments provided, but apart from that it's been an excellent bit of kit.

I also have a Kaercher wet/dry shop vac of similar vintage and that will go with us to the flat.

As per Lons "speak as you find", though I do recognise from this thread, and previous others, that overall Kaercher does not have a good name on here.

No idea about spares availabilty.

Anyway, HTH

 

[graduate_owner]

Several people have suggested Nilfisk. I bought a used Nilfisk commercial washer a while ago, and emailed Nilfisk to ask if they could sell a handbook / maintenance guide. No reply, not even an acknowledgement of my email. They totally ignored 3 emails altogether, so if you are thinking of Nilfisk you might want to consider their customer service.

K

 

[paulrbarnard]

As per Lons, you can only speak as you find.

I have just given my at least 20 year old Kaercher pressure washer away - in perfect working order. I have used it on average about twice a year in the house that we're just about to move from (into a flat, so no further need for a pressure washer - I hope)!

Always drained after every use - v easy to do - and stored in the garage - where over the last 20 years we have had overnight below zero temps some years.

The design of mine is a bit "daft" (inconvenient to store the bits when moving it around as neither the power cable nor the pressure hose + gun store properly in the compartments provided, but apart from that it's been an excellent bit of kit.

I also have a Kaercher wet/dry shop vac of similar vintage and that will go with us to the flat.

As per Lons "speak as you find", though I do recognise from this thread, and previous others, that overall Kaercher does not have a good name on here.

No idea about spares availabilty.

Anyway, HTH

So 40ish hours of use? Assuming it’s an hour to wash down whatever needs doing twice a year. Hardly a lot of use despite it being 20 years old.

 

[Lons]

So 40ish hours of use? Assuming it’s an hour to wash down whatever needs doing twice a year. Hardly a lot of use despite it being 20 years old.

Yebbut mine does. I wash 3 cars a couple of times a week (yeah I know ) and that includes snowfoam treatment etc with the Karcher, the motorhome gets done at least once a month to keep the pigeon carp off it and we have quite a lot of paved areas cleaned a couple of times a year which takes a good day at least.. Also used on the lawnmower and ride on occasionally and wheelbarrows and garden tools. Never let me down - touch wood.