Market Insights
China Excavator Maintenance: Rainy Season Checklist 2026
One week of rain is all it takes: water is the cheapest contaminant in excavator maintenance, and at least 75 percent of hydraulic system failures start with contaminated or aging fluid. If you run China built machines through the rainy season in East Africa or Southeast Asia, this 12-step checklist tells you exactly what to check, clean and replace before the next downpour.
Here is the uncomfortable math. A set of filters costs a few dozen dollars. One day of downtime on a 20-ton excavator costs far more, and a pump or motor damaged by water-contaminated oil costs more than a whole year of preventive parts. The owners who come out of the wet season cheapest are never the ones who bought the cheapest parts — they are the ones who replaced parts on a schedule instead of on a breakdown.
This guide is built from what Chinese OEMs actually publish for their own machines in the wet season, plus what we see arrive at our warehouse for replacement. Every step below ends in a part you can order, so you can turn the checklist straight into a purchase list. Questions on your specific machine? Send the model and serial number to donald@cmpartscn.com or WhatsApp +852 60391704 and we will cross-reference it against our stock.
Why rain is a parts problem, not a paint problem
Rain itself does not break excavators. Water getting where water should not be is what breaks them, and it gets in through a short, boring list of entry points. Every single one of them ends with a specific part wearing out early.
| Water entry point | What you will notice | The part that dies first |
|---|---|---|
| Fuel or hydraulic tank cap left loose or with a perished seal | Milky or emulsified oil, higher oil temperature, sluggish controls | Hydraulic oil filter, engine oil |
| Engine oil dipstick seal worn out | Oil level creeping up, milky residue under the cap | Engine oil and oil filter |
| Air filter paper element soaked | Hard starting, black smoke, power drop, then a restricted element | Air filter element |
| Starter, alternator and sensor connectors damp | Slow cranking, charging failure, random fault codes | Connectors and wiring (dielectric spray, desiccant) |
| Mud packed into the lower gaps and chassis | Hidden corrosion, pin and bushing play, seized grease points | Undercarriage parts, grease |
Notice that four of the five entry points are sealed by a cheap consumable: a cap seal, a dipstick O-ring, a paper element, a grease film. That is the whole argument for a rainy season parts budget. The Chinese OEMs say the same thing in different words: LiuGong’s wet-season guide tells operators to check the fuel and hydraulic tank caps, watch the dipstick seal for wear, and inspect the air filter element so rain cannot soak and clog the paper. SANY Heavy Industry’s rainy-season note adds a practical hack — if a machine must sit outdoors, put a plastic bag over the oil filler as a last line of defence.
The 12-step rainy season checklist
Split into three moments: before the shift, after the shift, and after heavy rain or wading. Each step names the part or consumable involved, so you can act on it immediately. Think of it as the wet-weather half of your excavator maintenance schedule, written for crews who cannot afford to stop.
Before the shift: 4 checks that keep water out
1. Check the fuel and hydraulic tank caps and their seals. Turn each cap, feel for a loose or cracked seal ring, replace it if it is perished. This one minute is the cheapest hydraulic protection you will ever buy.
2. Pull the oil dipstick and inspect the seal ring. A worn dipstick seal is a direct channel for rain into the crankcase. Carry a spare O-ring set in the cab.
3. Service the air filter before it looks dirty. A damp paper element does not clean up — it restricts airflow and can collapse or crack. In sustained wet mud work, plan on a shorter change interval than the manual’s dry-season figure.
4. Dry the electrical connections. Wipe the distributor and wiring, then spray desiccant or dielectric grease on battery terminals, sensor plugs and high-tension leads. LiuGong’s guide names this exact fix for hard starting after rain.
After the shift: 4 steps that decide what corrodes overnight
5. Wash the machine properly, especially the lower gaps. Clay, mud and gravel packed into the underside hold moisture against the steel and is where rust starts. LiuGong is explicit: this is the spot where wetness hides and corrosion begins.
6. Wash, then grease every point on the chassis. Water washes the grease out of pins and bushings. Clean the nipple, pump fresh grease until it purges, and do it the same day — not the next service.
7. Close and seal the tanks before parking. Fuel cap, hydraulic cap, dipstick fully seated. If the machine parks outside overnight, this is the step most crews skip and the one that fills a hydraulic tank with rainwater.
8. Drain water separators and check for moisture in the oil. Water in fuel shows up as rough running and injector wear; water in hydraulic oil shows up as milky colour and worn pumps. Catching it here costs a filter change. Catching it late costs a pump.
After heavy rain or wading: 4 steps for the machine that worked wet
9. Inspect the air filter housing and intake path for water. Check the drain valve, the pre-cleaner and the ducting. A machine that took water through the intake needs the element replaced, not blown out.
10. Re-check every grease point. Mud and rain can strip a fresh grease film in a single shift. Undercarriage grease intervals should tighten in wet conditions — for muddy excavation, many crews move from a weekly cycle to every two or three days, adjusting for how abrasive the site actually is.
11. Look for water in the hydraulic oil. Milky oil, foam at the sight glass, or a machine that feels soft under load: sample the reservoir, check the breather, and plan an oil and filter change rather than hoping it separates overnight.
12. Walk the undercarriage and the paint. Look for mud packed around the boom foot, the swing circle and the track frame. Rain is slightly acidic; LiuGong recommends a wax or seal coat before the long wet season if the machine will live outdoors.
Undercarriage: mud is an abrasive, not a mess
The undercarriage sits closest to the ground, and in wet conditions it is the fastest-wearing part group on the machine. LiuGong puts it plainly: the undercarriage is the lowest part of the excavator, the easiest to corrode, and wheel hubs can loosen and even perforate if neglected.
Wet mud changes the physics. Dry dust is a mild abrasive; wet clay mixed with grit is a grinding paste that works its way into pins, bushings, track rollers, idlers and carrier rollers, and then holds that abrasive against the wearing surface every hour the machine turns. The grease film that keeps a pin alive gets washed out and replaced with paste.
Three consequences you can plan for, and they all feed back into your excavator maintenance budget:
- Pin and bushing wear accelerates. Boom and arm pins develop play fast in abrasive mud, which is why the grease interval must shorten, not lengthen, in the wet season.
- Rollers and idlers corrode between shifts. Standing water in the track frame rusts the seals, and a compromised seal lets paste into the bearing.
- Corrosion turns into perforation. Mud packed against the frame hides rust until it eats through, which is why the wash-down step is not cosmetic.
Practical cadence for muddy sites: high-pressure wash the track frame and the lower gaps at the end of every wet shift, then grease the same day. If the machine works continuous clay, replace pins and bushings on measured wear rather than waiting for visible play — a new pin costs far less than a boom foot repair.
If the machine floods: the five-step recovery
Flooding is where good intentions go to die. SANY Heavy Industry’s rainy-season guidance is worth following literally, because the wrong recovery attempt converts a recoverable machine into scrap.
- Report first, then plan. Call the insurer and the manufacturer’s service team before you touch the machine, so the recovery approach is agreed.
- If you cannot leave the area, retract the cylinder rods and shut down. Pull all hydraulic cylinder piston rods in, switch the engine off, and if there is time disconnect the battery negative terminal and block the exposed air intake and exhaust pipes.
- Do not restart a machine that ingested water. Starting an engine or a hydraulic system that has taken in silt creates secondary damage far beyond the flood itself.
- Full inspection and full fluid change if silt got in. SANY’s rule is direct: if the hydraulic system or engine has taken in sand and silt, it requires a comprehensive inspection and service — not a quick fix followed by continued work.
- Replace the full filter set at the same time. Changing oil without changing filters leaves the contamination in the system, which is exactly the failure mode the 75 percent statistic is describing.
That last point is the commercial one. A flood recovery parts list is predictable: engine oil and oil filter, fuel filter, hydraulic return and pilot filters, hydraulic oil, air filter element, plus the seals and hoses you find while you are in there. Buyers who keep that list on the shelf before the rains start lose a week of production, not a month.
When your region’s rains actually start
Rainy seasons are not vague. They arrive on a calendar, and a smart buyer stocks before the calendar turns, not after the first flooded site.
| Region | Wet season window | Buyer action |
|---|---|---|
| East Africa (Kenya, southern Ethiopia, Somalia, Uganda) | Short rains, October to December | Order filters and undercarriage parts 2 to 3 weeks before October |
| Southeast Asia (Vietnam, Thailand, the Philippines, Indonesia) | Northeast monsoon from October onward | Pre-position undercarriage and seal stock now |
| India and the subcontinent | Southwest monsoon June to September, withdrawal now | Post-monsoon catch-up service: full filter set plus undercarriage inspection |
FEWS NET’s seasonal monitoring confirms the East African short rains run October to December, with above-average rainfall forecast for the current cycle and flooding risk along major river basins. In Southeast Asia the northeast monsoon takes over from October, bringing sustained rain to central Vietnam and southern Thailand. Meanwhile in China, XCMG Hydraulic’s autumn maintenance guide published on 15 October is doing the rounds — the change-of-season oil and filter service is exactly what every machine in the northern hemisphere should be getting right now, before it is shipped or before it goes into winter storage.
One more reason the wet season matters commercially: China’s excavator market keeps growing, so more of these machines are arriving on wet-season sites in their first rains. New machines are tight, but they are not sealed forever — a first rainy season is exactly when filters, seals and undercarriage consumables start their real service life.
What we supply for the wet season
We are Shanxi Yongle, a 20-plus year construction machinery wholesaler and the authorised dealer for Jingong, Jiahe, LuTong and Lonking. Machines and parts come from the same warehouse, so a parts order never has to wait on a second supplier.
| Wet season category | What we stock | Why it matters in the rain |
|---|---|---|
| Filters | Air, oil, fuel and hydraulic filters for Chinese excavators and loaders | The first and cheapest line against water and contamination |
| Seals and oil seals | Hydraulic cylinder oil seals, O-ring sets, cap and dipstick seals | Seals are what keep the water out in the first place |
| Undercarriage | Track rollers, idlers, carrier rollers, track links, pins and bushings | Wet-season wear group number one |
| Ground-engaging tools | Bucket teeth, adapters, cutting edges for excavation in wet clay | Sharp teeth cut wet clay; worn teeth push it and slip |
| Lubrication | Grease and greasing consumables for high-frequency chassis lubrication | Shorter intervals need stock on hand, not a reorder mid-season |
Two practical details. First, we cross-reference by OEM part number — send us the number off the old part and we match it, even if you do not know the machine model. Second, stock is physical: a 2,000 square metre warehouse with more than 500,000 US dollars of inventory on the shelf, which is what makes a 48-hour parts list before the rains possible instead of a promise. For SANY, XCMG, SDLG and other brands we can source parts by part number on request. Orders are contracted and invoiced through GZ BLTY CO LTD, with MOQ and lead time confirmed in writing before you commit.
Stuck on a wet site with a machine down? Send the part numbers to donald@cmpartscn.com and we will tell you today what we have on the shelf.
Frequently asked questions
How often should I change the air filter in the rainy season?
Shorten it. The manual interval is written for normal dust, not for a machine breathing damp air and running through mud that blocks the precleaner. For continuous wet mud work, inspect every shift and replace on restriction rather than on hours — roughly halve the dry-season interval and adjust for site abrasiveness. A damp paper element will not dry back to full flow.
Can I keep using hydraulic oil if water got into it?
No. Water breaks down the oil’s load-carrying capacity, causes corrosion inside pumps and motors, and emulsifies into a milky fluid that wears every precision surface it touches. Sample the reservoir, and if the oil is milky or foamy, plan an oil and filter change together. Oil is cheap compared with a pump.
Related reading: excavator hydraulic cylinder oil seal guide.
What is the right wash and grease cadence for the undercarriage in mud?
Wash at the end of every wet shift, and grease the same day. In muddy excavation many crews move from a weekly lubrication cycle to every two or three days. Treat that as a starting point and tighten it for clay-heavy or abrasive sites; the grease nipple should purge visibly clean grease before you stop.
Related reading: track roller and idler guide.
After flooding, can I just change the oil and keep working?
No. If silt entered the hydraulic system or the engine, SANY’s guidance requires a full inspection and comprehensive service, and the filter set must be replaced at the same time. Old filters re-contaminate fresh oil within hours. Skipping this is the single most expensive shortcut in wet-season ownership.
What should I do if the machine is parked unused through the rainy season?
Store it dry and indoors where possible. Start and operate the machine about once a month so the battery charges, wipe the piston rods clean and re-grease them, and add grease to all lubrication points. Check for standing water anywhere on the machine and drain it immediately. Idle storage through the rainy season is not maintenance-free storage: seals dry out, batteries sulphate, and condensation still finds the oil.
Paper air filter or oil-bath air filter on a wet-site job?
High-efficiency paper elements give better protection for the engine and are what most China built excavators ship with. In heavy wet mud and dust, keep a spare element on the machine, service the housing drain and pre-cleaner daily, and never try to blow a soaked paper element clean — replace it.
Which brands do you supply wet-season wear parts for?
We are the authorised dealer for Jingong, Jiahe, LuTong and Lonking, covering machines and parts together. For SANY, XCMG, SDLG and other Chinese brands we can source parts by part number on request. Filters, seals, undercarriage and ground-engaging tools are the bulk of our wet-season stock.
What are your MOQ, lead time and payment terms?
Most filters and seals ship in mixed cartons, so MOQ is usually per part number rather than per container. Stock items leave the warehouse within a few days; sea freight lead time depends on destination. Contracts and payment run through GZ BLTY CO LTD, and we confirm MOQ, lead time and price in writing before any order is placed.
Get your wet season parts list ready before the rain
The rainy season arrives on a calendar every year. The only variable is whether your parts are already on the shelf when it does. Send us your machine models and we will build a wet season kit for your fleet — filters, seals, undercarriage and grease — with part numbers, MOQ and lead time in one reply. Cheapest excavator maintenance is the one you scheduled before the rain, not the one you ordered during it.
Email donald@cmpartscn.com or WhatsApp +852 60391704. For the wider picture, see our excavator filter guide and undercarriage parts buyer guide.
Sources: Reducing the Effects of Contamination on Hydraulic Fluids and Systems, Machinery Lubrication; LiuGong rainy season excavator maintenance guide (18 June 2024, lmjx); SANY Heavy Industry: three rainy season rules (27 May 2021, lmjx); XCMG Hydraulic autumn maintenance guide (15 October 2026, lmjx); FEWS NET East Africa seasonal monitor.