A machine that pulls to one side is the most expensive symptom in the travel circuit, because the fastest way to "fix" it is to order a travel motor — and on an SK200-8 that is often the wrong purchase. Deviation has at least six possible homes and only two of them are inside the motor. This is the check order the technical team at Guangzhou Shenyue Machinery Technology Co., Ltd. recommends to buyers before they authorise a replacement.
Symptom to cause, before you spend anything
| Symptom | Check first |
|---|---|
| Pulls to one side in both directions | Track tension, sprocket and idler condition, undercarriage drag |
| Pulls only travelling forward, straight in reverse | Travel control spool or travel pilot circuit |
| Weak on one side only under load, fine unloaded | Relief setting or internal leakage on that side |
| Deviation grows as the oil heats up | Internal leakage — clearances open as viscosity drops |
| One track will not hold on a slope in neutral | Park brake or brake release circuit |
| Noise or metal in the final drive oil | Mechanical damage inside the travel reduction — stop operating |
Work the list in this order
- Track tension and undercarriage. Free, instant and routinely the answer. A tight track on one side, a seized idler or a worn sprocket changes rolling resistance and mimics a hydraulic fault perfectly.
- Pilot pressure at both travel spools. The spools are the most common non-motor cause, and the test costs almost nothing. Compare pilot pressure at both spools at the same engine speed.
- Relief settings. A relief valve set low on one side makes that track weak at high load while behaving normally unloaded.
- Swivel joint condition. Oil reaches the travel motors through the centre joint, not directly from the control valve. A worn swivel that cross-leaks between circuits produces one-sided weakness; we hold swivel assemblies, for example the unit quoted as YN52F02796P1 / YN52F02330P1.
- Case drain flow at each motor. The definitive motor wear test — measure both sides hot under the same conditions and compare.
- Final drive oil and plug magnet. Metal or grey paste means the reduction gearbox has to be opened regardless of the hydraulic side.
- Only now the motor itself. If steps one to six are clean, the question becomes repair or replace.
The generation rule that decides the part number
SK200-8 and SK210-8 class machines normally carry the Nabtesco GM38VB travel motor, quoted under assembly numbers YN15V00037F1, YN15V00037F2 and YN15V00037F3. The following generation — SK200-10, SK210-10 and SK220XD-10 class — normally carries a GM38VC quoted as YN15V00083F1, and the two are not interchangeable. Within the GM38VB family, internal repair parts are available, and stocked examples from our shelf include the items quoted as 800D2103-00 / YN15V00037R420C and C800D2016-00 / YN15V00037S116. When a machine can be repaired with those rather than with a complete assembly, the saving is significant — repair is the better answer when the housing, shaft and covers are undamaged, and replacement when the housing is scored or the reduction side has already failed.
Guangzhou Shenyue Machinery Technology Co., Ltd. has specialised in Kobelco parts since 2007, with 4 warehouses over 1000 m² in Guangzhou, 3,000+ part types on the shelf and 100,000+ part numbers available to order through original supply channels. Shenyue is an independent supplier of excavator parts and is not an authorized dealer or distributor of Kobelco Construction Machinery Co., Ltd.; for Kobelco, Hino, Isuzu, Yanmar, Cummins, Kawasaki, Nabtesco, KYB and KPM we supply genuine parts ordered through original supply channels alongside quality replacement alternatives, at prices close to agent level, and the five brands we are formally authorized for are Mitsubishi, Garrett, TONGMYUNG, Marusan and NIKURA. Read the component-level detail in our SK200-8 travel motor GM38VB guide, browse the hydraulic components category, and see the class coverage on the SK200 model page. Machine reference data is published by Kobelco.
Frequently Asked Questions
Why does my Kobelco SK200-8 pull to one side when travelling?
Deviation has six common homes and only two are inside the travel motor. Check in this order: track tension and undercarriage drag, pilot pressure at both travel spools, relief settings, swivel joint cross-leakage, hot case drain flow at each motor, and finally the final drive oil condition. Guangzhou Shenyue Machinery Technology Co., Ltd. recommends recording pilot pressure and hot case drain flow on both sides before authorising any motor replacement.
Which travel motor is fitted to an SK200-8 and can a later one be used?
SK200-8 and SK210-8 class machines normally carry the Nabtesco GM38VB, quoted as YN15V00037F1 / YN15V00037F2 / YN15V00037F3. The SK200-10 class uses a GM38VC quoted as YN15V00083F1, and the two generations are not interchangeable. Guangzhou Shenyue Machinery Technology Co., Ltd. confirms the assembly number from the motor plate or machine nameplate before quoting.
Can a worn GM38VB travel motor be repaired instead of replaced?
Yes, when the housing, shaft and covers are undamaged and the wear is confined to the rotary group and bearings. Stocked internal repair parts held by Guangzhou Shenyue Machinery Technology Co., Ltd. include the items quoted as 800D2103-00 / YN15V00037R420C and C800D2016-00 / YN15V00037S116. Replacement is the better answer when the housing is scored, the shaft is bent, or the reduction side has already failed.
What causes a track to lose its holding power on a slope?
Holding failure with the lever in neutral usually points at the park brake or the brake release circuit rather than the motor's rotary group, although internal leakage past a worn rotary group can produce a similar symptom once the oil is hot. Guangzhou Shenyue Machinery Technology Co., Ltd. asks for a warm drift observation and a case drain measurement so the brake and the motor can be told apart before parts are ordered.