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354-0798 CAT 988K Tilt Cylinder Aftermarket Replacement
354-0798 CAT 988K Tilt Cylinder Aftermarket Replacement
Bucket Tilt Cylinder for Caterpillar 988K Wheel Loader.
- OEM Part Number: 354-0798 / 3540798
- Replaces / alternate: 20R-7379 (Cat reman number)
- Bore × Rod: 10-1/2 in (266.7 mm) × 5-1/2 in (139.7 mm)
- Stroke: 685 mm (27 in)
- Seal kit: 248-1198
- Serial prefixes: 988K L8X, LWX, T8E, TWX
- Weight: approx. 750 kg (shipping)
- Warranty: 12 months / 2,000 hours
Product Overview
SEIGO’s aftermarket tilt cylinder, part number 354-0798, is a direct drop-in replacement for the bucket tilt cylinder on the Caterpillar 988K wheel loader. It is the current number for this position: Caterpillar’s remanufactured equivalent 20R-7379 is cross-referenced to 354-0798. The cylinder has a 10-1/2 in (266.7 mm) bore, a 5-1/2 in (139.7 mm) rod and a 685 mm (27 in) stroke, and fits 988K machines with serial prefixes L8X, LWX, T8E and TWX.
The tilt cylinder racks the bucket back to fill and dumps it into the truck. Unlike the lift cylinders, which work as a left/right pair, the 988K tilt cylinder is catalogued as a single cylinder with no hand designation, and it carries the full breakout load when the operator racks back against a quarry face or a tight stockpile. It works on the same lift/tilt circuit as the lift cylinders, with a relief setting of 32,800 kPa (4,757 psi).
The tilt cylinder sees the highest peak loads in the loader linkage: breakout against the face drives shock through the rod, and dumping at height loads the rod in tension. The usual failure pattern is rod chrome damage and scoring from face debris, rod seal leakage, and wear at the rod-eye bearing — and with a single tilt cylinder on the machine, a failure stops the loader.
SEIGO manufactures the 354-0798 to full Caterpillar dimensional specification: a 42CrMo4 induction-hardened, hard-chrome-plated piston rod at 5-1/2 in diameter, an ST52 seamless honed steel barrel machined to the 10-1/2 in bore, and a genuine NOK (Japan) or Parker (USA) seal kit matched to the 248-1198 seal layout. Every unit is pressure tested at 1.5× rated working pressure before shipment from our Guangdong factory and is backed by a 12-month or 2,000 operating-hour warranty. Standard lead time is approximately 30 days ex-works, with expedited production available for machine downtime.
Product Specifications
| Product category | Hydraulic Cylinder |
| Machine type | Large Wheel Loader |
| Machine brand* | Caterpillar |
| Compatible model* | 988K (988K XE uses the same tilt cylinder dimensions — confirm by serial number) |
| Serial prefixes* | 988K: L8X, LWX, T8E, TWX |
| Cylinder type | Bucket Tilt Cylinder |
| Quantity per machine | 1 (catalogued without left/right hand designation) |
| OEM part number* | 354-0798 (3540798) |
| Cat reman / alternate* | 20R-7379 (cross-referenced to 354-0798) |
| Related number* | 346-4440 (listed together with 354-0798 in industry cross-reference — confirm by serial number) |
| Seal kit* | 248-1198 |
| SEIGO part number | SG3540798 |
| Bore diameter | 10-1/2 in (266.7 mm) |
| Rod diameter | 5-1/2 in (139.7 mm) |
| Stroke length | 685 mm (27 in) |
| Pin-to-pin length | Confirmed against your machine serial number at quotation |
| Lift/tilt relief valve setting (machine spec) | 32,800 kPa (4,757 psi) |
| Rod material | 42CrMo4, induction hardened, hard chrome plated |
| Barrel material | ST52 seamless honed steel tube |
| Sealing system | NOK (Japan) or Parker (USA), matched to 248-1198 seal layout |
| Design option | Standard specification, or cold climate specification (−40°C / −50°C) |
| Approx. weight | 750 kg (shipping weight) |
| Testing | 100% pressure tested at 1.5× rated working pressure |
| Certification | ISO 9001:2015 certified manufacturing |
| Shipping | ISPM-15 fumigated wooden export crate |
| Manufactured in | Guangdong, China |
| Lead time | Approximately 30 days ex-works; expedited production available |
| Incoterms | FOB Shenzhen / CIF / DDP |
| Warranty | 12 months / 2,000 hours, whichever comes first |
| HS code | 841221 |
* OEM part numbers, brand names and model designations are used for identification and cross-reference purposes only. SEIGO Machinery is an independent aftermarket manufacturer and is not affiliated with Caterpillar Inc.
Cat 988K Hydraulic Cylinder Cross-Reference
The 988K uses one tilt cylinder, a pair of lift cylinders and steering cylinders. Part 354-0798 is the standard tilt cylinder.
| Function | Part Number | Bore × Rod | Stroke | Seal Kit |
|---|---|---|---|---|
| Tilt (standard) | 354-0798 / 20R-7379 | 10-1/2 in × 5-1/2 in | 685 mm | 248-1198 |
| Lift RH (standard) | 355-7377 | 210 mm × 130 mm | 1050 mm | 477-9286 |
| Lift LH (standard) | 355-7378 | 210 mm × 130 mm | 1050 mm | 477-9286 |
| Steering | 363-0218 | 100 mm × 70 mm | — | 471-0317 |
Larger-bore tilt cylinder: seal-kit catalogue data also lists a 988K tilt cylinder 381-3690 with an 11-1/2 in bore and 5-3/4 in rod. That bore matches the larger tilt cylinder specified for the 988K Millyard arrangement (291–292 mm × 671 mm). It is a different part from 354-0798 and is not interchangeable — confirm your machine arrangement and serial number before ordering.
Cat 988 Generations — Tilt Cylinder Reference
The tilt cylinder changed between 988 generations, and none of them interchange. Confirm the generation from the machine serial number before ordering.
| Generation | Tilt Cylinder Part Numbers | Rod × Bore |
|---|---|---|
| 988K | 354-0798 (reman 20R-7379) | 5-1/2 in × 10-1/2 in |
| 988K (larger-bore / Millyard) | 381-3690 | 5-3/4 in × 11-1/2 in |
| 988H | 231-1955 / 271-6441 (12-bolt head); 309-9545 (9-bolt head) | 4-1/2 in × 220 mm; 4-1/2 in × 9-1/4 in |
| 988G | 231-1955 / 152-1644 | 4-1/2 in × 220 mm |
| 988 / 988B / 988F | 9J-3632 | 3-1/4 in × 7-3/4 in |
Earlier-generation numbers are taken from published seal-kit cross-reference data and are listed for identification. SEIGO manufactures tilt, lift and steering cylinders across the 988 range — send us your machine serial number to confirm the correct part.
Why This Cylinder, Specifically
- Current number, verified. 354-0798 is the current number for the 988K tilt cylinder, and Caterpillar’s reman number 20R-7379 cross-references to it. Whichever number your records hold, we supply the current specification.
- Built for breakout load. The tilt cylinder carries the peak loads in the loader linkage when the bucket racks back against the face. We use a 5-1/2 in 42CrMo4 rod with a hard chrome finish chosen for impact and scoring resistance.
- Manufactured to Cat dimensions. 10-1/2 in bore, 5-1/2 in rod and 685 mm stroke, machined to accept the 248-1198 seal layout, so rackback, dump angle and cycle time match the original.
- Correct arrangement, verified. A larger-bore 988K tilt cylinder (381-3690) also exists and matches the Millyard arrangement. We confirm against your serial number before quoting so the right cylinder ships.
- Rebuild instead of replace. For workshops with in-house assembly, we supply the rod, honed barrel, cylinder head, piston and seal kit individually — typically 40–60% of the cost of a complete cylinder, with far lower freight than a 750 kg assembly.
- The whole 988K from one source. SEIGO also manufactures the 988K lift cylinders (355-7377 RH, 355-7378 LH) and steering cylinder (363-0218), so all front-end cylinders can ship on one order.
FAQ
Q1: What is the difference between 354-0798 and 20R-7379?
A: 20R-7379 is Caterpillar’s remanufactured part number for the 988K tilt cylinder, and it is cross-referenced to 354-0798, the current new-part number. Both identify the same cylinder position. Whichever number appears in your records, SEIGO supplies the current-specification 354-0798.
Q2: What are the bore, rod and stroke of 354-0798?
A: The cylinder has a 10-1/2 in (266.7 mm) bore and a 5-1/2 in (139.7 mm) rod, and the 988K tilt stroke is 685 mm (27 in). It is serviced with seal kit 248-1198. Pin-to-pin length is confirmed against your machine serial number at quotation.
Q3: Is there more than one tilt cylinder on the 988K?
A: The 988K uses a single tilt cylinder, catalogued without a left/right hand designation. However, two different tilt cylinders exist across 988K arrangements: 354-0798 (10-1/2 in bore) for the standard machine, and a larger-bore 381-3690 (11-1/2 in bore) that matches the Millyard arrangement. They are not interchangeable — confirm your arrangement before ordering.
Q4: Does 354-0798 fit the 988K XE?
A: Caterpillar specifications list the same tilt cylinder bore and stroke for the 988K XE as for the standard 988K. Because published seal-kit data for 354-0798 lists the standard 988K serial prefixes, send us your 988K XE serial number and we will confirm fitment before production.
Q5: Will a 988H or 988G tilt cylinder fit my 988K?
A: No. The 988G and 988H tilt cylinders have a 4-1/2 in rod and a 220 mm or 9-1/4 in bore; the 988K tilt cylinder has a 5-1/2 in rod and a 10-1/2 in bore. Confirm the generation from the machine serial number.
Q6: Can I buy the seal kit, rod or barrel separately?
A: Yes. SEIGO supplies seal kits matched to the 248-1198 layout, as well as the piston rod, honed barrel, cylinder head and piston as individual items. On tilt cylinders, rod and rod-eye bearing replacement are the most common single-item orders.
Q7: What is the lead time and how does it ship?
A: Standard production lead time is approximately 30 days ex-works Guangdong, China, with expedited production available for machine downtime. At approximately 750 kg shipping weight, each cylinder ships in an ISPM-15 fumigated wooden export crate, FOB Shenzhen, CIF or DDP.
SEIGO Machinery is an independent aftermarket manufacturer. All OEM part numbers, brand names and machine model designations are used for identification and cross-reference purposes only. These aftermarket components are not manufactured by, endorsed by, or affiliated with Caterpillar Inc.
