Short answer: repair a pneumatic rock drill when the fault is bounded, the correct parts and competent labor are available, the restored configuration can pass a controlled service-release test, and the total recovery cost is justified against a verified replacement. Overhaul when several wear systems must be restored together. Replace when identity, structural integrity, parts support, repeat-failure history, downtime or test confidence makes recovery uneconomic or unsafe.
This guide is for mines, quarries, tunnelling contractors, rental fleets and distributors deciding what to do with an owned hand-held or air-leg pneumatic rock drill. It covers the repair, overhaul, replace or hold decision. It does not diagnose an individual fault, set universal wear limits, approve a welded or cracked housing, or replace the exact model manual and site engineering controls.
Freeze the decision inputs before asking for a price
A repair quote is not comparable with a replacement quote until both describe the same operating requirement. Record the asset, the failed function, the evidence quality and the cost of keeping the drill unavailable.
| Input | Evidence to record | Why it changes the decision |
|---|---|---|
| Asset identity | Exact model, suffix or revision, serial or fleet ID, air-leg model and controlling manual | Controls parts, interfaces, limits and the permitted repair method. |
| Required duty | Hole range, direction, rock condition, steel and bit, shift pattern and required fleet availability | A repair can restore the old specification without meeting the current job. |
| Fault boundary | Observed symptom, inspection findings, affected assemblies and evidence preserved before dismantling | An unbounded fault makes price and return-to-service confidence weak. |
| Repair history | Dates, parts, labor, repeat symptoms, post-repair tests and time in service | Recurring repairs can signal a missed root cause or worn mating system. |
| Supportability | Parts list, revision match, availability, lead time, tools and competent workshop access | A technically repairable drill may remain commercially unavailable. |
| Recovery cost | Inspection, parts, labor, freight, testing, downtime and repeat-failure allowance | The bench invoice alone understates the business cost. |
| Replacement baseline | Verified new configuration, delivered cost, lead time, accessories, spares, training and acceptance evidence | A bare drill price is not a complete alternative. |
Repair, overhaul, replace or hold: decision matrix
| Evidence pattern | Preferred path | Release condition |
|---|---|---|
| One bounded serviceable fault; identity is confirmed; mating parts remain within the exact limits; parts and method are controlled | REPAIR | Complete the defined repair and pass the applicable post-repair inspection and operating test. |
| Several wear systems have reached intervention condition; the core structure is acceptable; a complete parts and measurement plan exists | OVERHAUL | Document the teardown scope, measured condition, replaced parts, assembly controls and full service-release test. |
| Structural crack or prohibited modification; uncertain identity; incompatible mixed configuration; unavailable critical parts; repeated unresolved failure; or recovery cannot meet required duty | REPLACE | Specify and accept the new complete drilling system, not only a nominal model. |
| Diagnosis, manual, wear limit, parts revision, quotation scope, downtime input or replacement baseline is missing | HOLD FOR EVIDENCE | Obtain the missing controlled information before authorizing work or purchase. |
| The drill can support non-critical learning or parts recovery but cannot be proved fit for service | QUARANTINE / CONTROLLED SALVAGE | Prevent return to the operating fleet; identify which parts may be assessed under the approved procedure. |
Do not create one universal percentage rule such as “repair below half the new price.” The correct boundary depends on downtime, failure consequence, fleet redundancy, replacement lead time, confidence in the repair and the value of standardizing the fleet. Use a site-approved threshold only after all costs and risks have been placed on the same basis.
Calculate total recovery cost on one time horizon
Use a common planning period for every option. A practical comparison is:
Total recovery cost = inspection + parts + labor + freight + verification + downtime consequence + risk allowance
Compare that with:
Total replacement cost = delivered equipment + required accessories and spares + commissioning + training or changeover + downtime until release − controlled residual value
Keep cash cost separate from uncertainty. The risk allowance should be approved by the buyer and based on evidence such as repeat-failure frequency, missing history, repairer warranty and strength of the final test—not a convenient invented percentage.
Illustrative worksheet
| Cost or risk line | Repair / overhaul input | Replacement input |
|---|---|---|
| Equipment or parts | Quoted parts with exact references and quantities | Quoted complete drill and required package |
| Workshop | Diagnosis, teardown, measurements, assembly and test | Incoming inspection and commissioning |
| Logistics | Two-way freight, customs and handling | Inbound freight, customs and site delivery |
| Unavailable time | Days to diagnose, quote, source, repair and retest | Days to supply, configure and accept |
| Operating change | Usually low if configuration is preserved | Possible steel, hose, air-leg, spares or training change |
| Confidence | Fault boundary, parts traceability, warranty and test strength | Supplier evidence, configuration match, warranty and acceptance plan |
Convert unavailable time into the measure your operation actually manages: lost drilling hours, hired replacement cost, delayed heading or blast, crew standby, or reduced fleet redundancy. Do not claim lost production twice in two different cost lines.
Seven-step decision workflow
- Make the drill safe and preserve evidence. Isolate air and water, release stored energy, tag the asset and record the as-found condition. A longer test run can destroy the evidence or create secondary damage.
- Confirm identity and duty. Match the nameplate, suffix, parts list, air leg, steel interface and manual. Confirm that the present application still suits the drill.
- Bound the fault. Use the applicable diagnostic guide, measurement method and wear limits. Separate a hose, oiler, water, steel or air-leg fault from a drill-body fault.
- Inspect the load path and mating system. A failed component may be the result, not the cause. Check the connected parts that control alignment, clamping, impact transfer, rotation and retention.
- Obtain comparable scopes. The repair quotation should state parts, labor, measurements, exclusions, warranty and final test. The replacement quotation should state the complete configured supply and delivery basis.
- Compare cost, time, risk and fleet effect. Apply the same horizon and site-approved assumptions. Include whether the choice simplifies or fragments spares, manuals and training.
- Authorize one disposition and one release plan. Name the decision owner, acceptance evidence, stop triggers and record location. No repaired or replacement drill is ready only because an invoice is closed.
Repair confidence gate
Approve repair or overhaul only when all applicable gates are satisfied:
- The exact configuration and controlling manual are known.
- The workshop can inspect the relevant internal and mating parts with suitable tools and limits.
- Structural cracks, prohibited welds, severe deformation and unsafe control modifications are rejected or handled by an authorized engineering route.
- Replacement parts match the correct revision and source requirements.
- The repair scope addresses the root cause, not only the visibly failed part.
- The final test reproduces the required functions under a controlled, supported setup.
- The record identifies measured condition, parts fitted, assembler, test configuration, results and approver.
The published YT28 troubleshooting guide covers model-level symptom diagnosis, while the chuck-bushing wear guide covers front-end wear and mating-part checks. Use the performance-test report guide to specify measurable supplier evidence. This page begins after those findings are available and turns them into an asset decision.
When fleet standardization changes the answer
A repair may look cheapest for one drill while increasing fleet cost. Record whether it preserves a supported model family or keeps an isolated revision that needs unique spares, tools and training. Conversely, replacing one drill with an incompatible new model can create a second hose, steel, air-leg or parts system. Treat standardization as a named decision factor, not an automatic reason to discard serviceable equipment.
For a hand-held or air-leg fleet, verify connector and restraint systems, line-oiler requirements, drill-steel shank, air-leg attachment, water connection, operating documentation and critical spares before approving substitution.
RFQ block for a repair or replacement comparison
- Asset model, suffix, serial or fleet ID and air-leg identity
- Application, hole diameter and depth, drilling direction and rock condition
- Steel shank, length, bit connection and bit diameter
- Air and water supply configuration, hose and connector standard
- Observed fault, diagnostic record, inspection photos and repair history
- Required workshop measurements and controlling limits
- Parts list with exact references, quantities, availability and lead time
- Repair or overhaul scope, exclusions, warranty and post-work test
- Replacement configuration, included air leg or accessories, spares and documents
- Delivery basis, destination and required acceptance evidence
asset decision record
Asset / fleet ID: Exact model, suffix and serial: Air-leg / steel / bit / connection configuration: Required application and availability date: Observed fault and evidence references: Controlling manual / drawing / limits: Repair history and repeat-failure pattern: Repair scope / parts / labor / warranty: Overhaul scope / measurements / final test: Replacement specification / delivered package: Repair or overhaul unavailable days: Replacement unavailable days: Downtime consequence method: Recovery-cost total and assumptions: Replacement-cost total and assumptions: Fleet standardization effect: Unresolved evidence: Decision: REPAIR / OVERHAUL / REPLACE / HOLD / SALVAGE Required service-release or acceptance test: Decision owner / date / approver:
Frequently asked questions
Is an expensive repair automatically uneconomic?
No. Compare the complete recovery and replacement options, including time, accessories, changeover, risk and required duty. A high repair invoice may still restore service faster; a low one may leave the root cause unresolved.
When does a repair become an overhaul?
Use the workshop’s controlled definition. In practice, an overhaul addresses multiple wear systems through planned teardown, inspection, measurement, replacement and full release testing rather than one bounded fault.
Can repeat failure justify replacement?
Yes, when records show the fault recurs despite correct root-cause work and release testing, or when the remaining uncertainty and downtime exceed the approved business threshold. First confirm that the supporting air, water, lubrication, steel and operating setup are not recreating the failure.
Should a cracked housing be included in a normal repair quote?
No. Isolate and quarantine it. Structural damage needs the exact manufacturer or authorized engineering disposition; do not normalize welding, grinding or reuse from a price comparison.
Who should approve the final decision?
The site should name accountable maintenance, operations, safety and procurement roles appropriate to the consequence. The person approving cost should see the same technical evidence as the person approving return to service.
Safety, maintenance and commercial route
HSE maintenance guidance requires work equipment to be maintained in efficient order and emphasizes safe maintenance arrangements. ISO 55001 asset-management information frames lifecycle decisions around balancing cost, risk and performance. Neither source supplies a model-specific wear limit, repair method or economic threshold for a PerfoMax drill.
Review the Rock Drills collection, including the YT28 air-leg drill and Y19A hand-held drill. To compare a repair scope with a replacement configuration, send PerfoMax an RFQ with the asset record, application, interfaces, evidence gaps, quantity and destination.
Bottom line: authorize repair from a bounded technical scope, overhaul from a complete restoration plan, and replacement from a comparable lifecycle decision—not from the workshop invoice or purchase price alone.