“How do I fix my pulsing & leaking Karcher pressure washer?”

crafty_penguinI have found several complaints on-line by people who say their Karcher pressure washer pulses and leaks when the trigger is off. I have even found videos posted on YouTube demonstrating the problem, one of which is posted below.

The consensus of opinion seems to be that the problem lies in internal cracks. Some people have found hairline cracks in the plastic pump cylinder head Karcher fit to many of their power washers.

If you fancy stripping down your Karcher pressure washer to see if you can find the problem and fix it yourself the second video below should be useful. It shows a step by step guide to dismantling a Karcher washer.

Spares for pressure washers from Karcher and other manufacturers such as Nilfisk and Bosch are available by mail order from BuySpares.

Karcher Pressure Washer Pulsing and Leaking


How to Disassemble and Reassemble the Pump on a Karcher Electric Pressure Washer



  1. Excellent video -really helpful. Do all karcher electric machines have the same cylinder head. I have the AA model which has water pouring out of the unit but the cost of cylinder head plus cover part is expensive.

  2. No they don’t all use the same for the cylinder head, my k3.575 (sometimes called the jubilee) uses a different to most others and the part number is 9.001-693.0. I would suggest ordering parts for your specific model using the model number…google can be your friend!

  3. Hi. Excellent video. I have a 411A k2(1.994-972) that only leaks and pulses when I use the trigger. I have taken the pump apart, to reveal the filters and the ‘guides’. All appears well but wonder if the seal are worn. The mating surfaces of the ‘guides’ are clean. Suggestions please…… In anticipation, Thank you

      1. Volt drop occurs because of the length of the cable. However, the drop would not be substantial enough to cause major issues.

        17th Ed Amendment 3 Qualified

  4. Hi Mark I have just watched your excellent video -really helpful, will dismantle my karcher tomorrow with your hepl, thank you.
    Myra – UK

  5. Hi, I have a 3.575 jubilee, that has just started doing exactly as in the first video, pulsing and leaking while the trigger is off, what is the cause no likely repair. Any help really welcome, as I don’t want bin the unit…

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