Overview
Stainless steel ball for HydraMaster by-pass valve 169-083. HydraMaster part number 000-169-204.
It is the sealing element in the by-pass valve — the part that actually holds pressure against the spring. When it wears or picks up a mark, the valve stops holding at the set point.
What it fits
- HydraMaster by-pass valve 169-083
Which puts it in:
- HydraMaster Boxxer 421
- HydraMaster Boxxer 427
- HydraMaster MAXX 450D
- HydraMaster MAXX 470D
- HydraMaster MAXX 550
Repair before replacement
A by-pass valve that will not hold pressure is usually a ball and seat problem, and the ball is the cheapest part in it. Replacing the ball — and the seals with it — is the first thing to try before condemning the valve.
Related service parts:
- 097-028 — O-ring kit (listed for by-pass valve 169-101; worth checking against your valve)
Check the seat, not just the ball
This matters more than anything else on this page. A new ball on a pitted or scored seat will leak within weeks, and you will have spent the money for nothing.
Inspect the seat with good light and a magnifier if you have one. A seat with a visible ring, a pit, or a bright scored line is finished — at that point you are replacing the valve, not the ball.
If you find debris damage, deal with the cause. Grit reaching the by-pass seat has come through the ¼ inch Y strainer, and if the screen is torn or missing it will happen again.
Fitting advice
Note the pressure setting before you start, so you have a figure to return to.
Depressurise the system before opening the valve.
Handle the new ball cleanly — a fingerprint is not a problem, but setting it down on a bench with swarf on it is.
Frequently asked questions
Will replacing the ball fix my pressure fault?
If the seat is good, usually yes. If the seat is damaged, no — and you should check it before ordering.
What size is the ball?
HydraMaster does not publish the ball diameter in the documentation we hold. We are not going to quote a figure we cannot verify — ask us and we will measure one.
Should I replace the seals at the same time?
Yes. The valve is already apart and the seals have done the same hours.
Which valve does it suit?
169-083, which is fitted to the Boxxer 421, Boxxer 427, MAXX 450D, MAXX 470D and MAXX 550.
Tell us what your pressure gauge is doing and we will help you work out whether a ball, a seal kit or a new valve is the right answer before you order.
