///Plunger is scratched, cracked or broken
Intensifier: high-pressure side

Plunger is scratched, cracked or broken

Plunger damage destroys seals and can stop one side of the pump.

Safety first: Switch off the pump, release all pressure (open the on/off valve or bleed-down valve) and lock out before you open any high-pressure part. Never put a hand or tool near a running jet.
1Check the causes, most likely first 0 of 3 checked
01Debris in the water Most likely

Hard particles score the plunger surface.

How to check: Check inlet filters and water quality.

PhotoArt. no.DescriptionReplaces OEMExcl. VAT
10633 Filter element 0,5 Micron 10"
FilterKMT, BFT, Flow
Flow A-1449 € 13.08
10634 Filter element 10 Micron 20", 49834716
FilterKMT, Flow
KMT 49834716 € 19.08
10635 Filter element 10 Micron 10", 10106722
FilterKMT, Flow, CMS / Tecnocut
KMT 10106722 € 6.60
10661 Filter element 5 Micron 10"
FilterKMT, BFT, Flow, STM
BFT XF58/220 · STM HD400011 € 10.20
10714 Water Filter Housing. SS, 250 psi, 3/4" FNPT, 72118339
FilterKMT
KMT 72118339 € 286.80

02Misalignment or worn guide Possible

Side load from a worn guide or bearing scores and cracks plungers.

How to check: Inspect guide bushings and backup rings.

03End of life Possible

Plungers fatigue after many cycles.

How to check: Replace the plunger with the seal kit.

Related problems

General advice based on manufacturer manuals and service practice. Always follow the manual of your machine. Not sure? .