Mercury MerCruiser Quicksilver Port Power Trim Hose 864959 | 32-864959 Alpha One R MR
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Mercury / Quicksilver OEM Port Power Trim Hose — Part No. 864959 / 32-864959
| Part Number | 864959 / 32-864959 |
|---|---|
| Brand | Mercury Marine / Quicksilver |
| Product Type | Hydraulic Power Trim Hose |
| Side | Port (left) |
| Hydraulic Circuit | Down-pressure |
| Connection | Trim cylinder to connector block |
| Length | Approx. 11-1/2 in. / 292 mm |
| Sold As | Individually |
| UPC / GTIN | 745061565944 |
| Supersedes | 32-999031 / 32-99903-1 (earlier Mercury reference) |
About This Part
The 864959 / 32-864959 is a genuine Mercury Marine / Quicksilver OEM hydraulic hose that carries fluid between the trim cylinder and connector block on the port (left) side of MerCruiser R, MR, Alpha One, and Alpha One Gen II sterndrive trim systems. It operates in the down-pressure circuit — the side of the hydraulic loop that pushes the drive down when trimming in. Any leak or failure in this hose will result in loss of trim pressure and prevent proper drive operation.
Critical distinction: This is the port-side hose only. The matching starboard-side hose is 864960 / 32-864960. Although the two hoses are nearly identical in appearance and length, they are position-specific and should not be swapped.
Compatible Applications
Confirm the drive model, transom assembly, trim-cylinder configuration, and hose position before ordering.
- R Drive
- MR Drive
- Alpha One (Gen I) — 1983–1990
- Alpha One Gen II — 1991 and later
Earlier part number 32-999031 was used across R, MR, Alpha One, and Alpha One Gen II applications and is fully superseded by 864959.
When to Replace
- Hydraulic fluid leaking from the hose body, fittings, or crimped ends
- Cracked, hardened, or deteriorated hose material
- Corroded or damaged fittings
- Visible abrasion, chafing, or kinking
- Deformed or collapsed hose
- Loss of trim-down pressure traced to the port hose
- Damage discovered during trim-cylinder or transom assembly service
Any hydraulic leak in the trim system should be corrected before continued use — operating the drive with low hydraulic fluid can cause pump and cylinder damage.
Installation Notes
- Relieve trim-system hydraulic pressure before disconnecting any hose, per the MerCruiser service procedure
- Confirm the replacement hose is installed on the port side in the down-pressure position
- Inspect the starboard hose 864960 at the same time — if one hose is deteriorated, the other likely is too
- Check trim-cylinder fittings and the connector block for wear, corrosion, or thread damage
- Route the hose exactly as the original to prevent chafing against the drive housing or pinching during trim movement
- Refill the trim reservoir and bleed the hydraulic system per the service manual
- Operate the drive through its full trim range and inspect all connections for leaks before returning to service
Cross-Reference / Alternate Part Numbers
- 864959 — primary SKU (this item)
- 32-864959 — Mercury-prefixed number
- 32-999031 / 32-99903-1 — earlier Mercury number, superseded by 864959
- Sierra 18-2115 — aftermarket cross-reference
- GLM 26240 — aftermarket cross-reference
Related Products
- 864960 / 32-864960 — starboard-side down-pressure trim hose (companion to this part)
- Mercury MerCruiser Trim Cylinder O-Ring Kit 87400A2 — trim cylinder seal kit for Alpha One and R/MR drive trim systems
Parts Desk Insights
The most common ordering issue on trim hoses is not knowing which side is needed. 864959 is the port (left) side — standing at the stern looking forward, port is the left. If both hoses are being replaced at the same time (which we recommend whenever the trim system is open), you’ll need 864960 for the starboard side as well. We also frequently see customers replace only the leaking hose without inspecting the trim cylinder seals — if the hose has failed from age or heat, the cylinder o-rings are worth checking at the same time to avoid pulling the system apart twice.
Shipping information
In-stock and OEM parts: ship same or next business day.
Supplier-stock items are usually ready for pickup or shipping within 24 hours of ordering.
Special-order timing may vary.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.