A new ball doesn't always mean a good seal.
When repairing Bosch CRI and CRIN injectors, replacing a worn ball may not be enough. Repeated contact can damage or deform the conical seat, allowing fuel to leak into the return circuit.
So how can you restore the seal without compromising the durability of the repair?
Two MARBED tools offer different approaches.
9700-CR — Grinding and lapping
The 9700-CR toolset allows the technician to rework the conical seat by removing material.
This can restore sealing, but there's a trade-off: removing material may also reduce the hardened surface layer designed to resist wear.
8210 — Reseating without removing material
The MARBED 8210 compact pneumatic press uses a specially hardened, precision-calibrated ball to create a new circular sealing contact on the seat.
No grinding. No material removal.
The aim is to restore sealing while preserving the surface properties that contribute to a longer-lasting repair.
The machine is supplied with 10 special working balls, each designed to process approximately 1,000 seats. These are precision tooling components, not replacement injector balls.
What about scratched seats?
Experienced repairers know that not every seat can be recovered with reseating alone.
When scratches cross the circular sealing contact, careful preliminary lapping may help reduce their depth before using the 8210 to establish a new sealing ring.
Deep damage, however, may make replacement unavoidable. Every repair should be followed by proper testing.
The goal isn't simply to make the valve seal again. It's to restore sealing while preserving what makes the seat durable.
How do you deal with worn or scratched ball valve seats in your workshop?
Share your experience or contact InjectionPower to discuss the most suitable tooling for your application.