Repairing a 30 year old water pressure

petcnc

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After 30 years of reliable service my water pressure washer stopped working. The motor works but the water has no pressure at all.
I have bought it from UK when I was living there and so far it worked ok for the occasional use I make.

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Compared to modern washers where plastic dominates, this is a metal body unit that was made to last (and it did last 3 decades!!).

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PART 1 Disassembly and inspection

These units are of simple construction having a pressure head consisted from 2 parts. The “motion giving unit” that is bolted directly on the motor and the “water pressurizing unit” that is bolted on the motion giving part where the water is pressurized.

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3 rods go through both units that achieve forward and backward movement from the motor through an eccentric shaft .

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The rods wok in oil bath in the first unit, exit through oil seals and enter the second unit through o-rings that are secured in bronze holders.

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To keep the high pressure water running in one direction a 6 valve system is used that are covered by bronze screw cups.

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Inside the valve chambers there are simple plastic one way valves that have seen better days as debri and o-ring parts found a way to go through them and make them inoperable.

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Those valves are secured by the bronze screw cups and sit on o-rings that have lost most of their meat.

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The chambers where the valves sit were corroded as well.

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It requires some treatment in order the new o-rings to sit and seal properly

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The main o-rings that seal the rods were in bad shape also.

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PART 2 Repairs

As the 3 rods have been replaced with stainless some 20 years ago they were ok. Just minor scratches that does not affect their operation

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So the whole unit was repairable!
A few parts later the repairs started.

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The valves received a thorough cleaning.

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To clean the chamber of each valve I have been creative and instead of fixing the unit to the mill, centering it, using the boring head and spend hours, I used a simple device made to manually clean the taps when you need to change the tap washer.

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The device bolts on the tap and by rotating it, it cleans the bottom where the seal sits

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That was exactly the way it was used in the pressure washer.

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It worked like a charm

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All chambers cleaned

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The rest was a matter of fitting the new parts and assembly the unit

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Some cleaning, new oil, a new plug and the unit is as good as new again.

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Thanks for reading
Petros
 
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