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Hynautic KS-04 Kit for K21-29 Cylinders Pre 1983

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SKU:
KS-04
Condition:
New
$95.00
In Stock - Ships Same Day M-F (Order by 5pm EST)

Description

Hynautic KS-04 - Seal Kit for K-21 to K-29 Cylinders (Pre-1983)

The Hynautic KS04 is the genuine Hynautic seal kit for older inboard steering cylinders. It services K21 to K29 cylinders manufactured prior to 1983. Typical contents include replacement O-rings to reseal one cylinder. Always verify cylinder model and production era before ordering.

Compatibility

  • Fits: Hynautic K-21 through K-29 cylinders pre-1983
  • Does not fit: K-21 to K-29 built 1983 and later - use KS-06 instead
  • How to confirm: Check the cylinder’s stamped model on the end cap or barrel and note approximate age. If unsure, contact Tech Support with photos of the end cap and the rod end.

What’s Included

  • Seal and O-ring set for one K-21 to K-29 cylinder

Note: Contents may vary slightly by cylinder revision. Reuse of hard parts is expected unless damaged.

Related Hynautic Cylinder Seal Kits

Part No. Fits Cylinder(s) Notes
KS-04 K-21 to K-29 (pre-1983) This page
KS-06 K-21 to K-29 (post 1983) Later cylinders
KS-02 K-18, K-19 Ball bracket style
KS-01 K-11, K-12 Small inboard
KS-13 K-3 (prior to 4-15-94) Older K-3
KS-14 K-51 Large inboard
KS-05 K-31 Fixed mount
KS-19 K-6 Limited availability
KS-11 K-1 Single-cylinder kit
KS-12 K-2(B) K-2 variants

Install Overview - Resealing a Hynautic Cylinder

This is a high-level overview to help you plan the job. Follow the Hynautic service manual for exact steps and specs.

  1. Prep - Clean the exterior, secure steering, and mark current hardware locations. Protect the rod from scratches.
  2. Disassemble - Depressurize the system. Remove retaining wire(s) and end cap per the manual. Withdraw rod and piston assembly.
  3. Inspect - Check the rod surface for nicks and the bore for scoring. Replace damaged hard parts before reseal.
  4. Reseal - Replace O-rings, backups, and wipers from KS-04. Lightly lubricate seals with compatible hydraulic fluid.
  5. Reassemble - Install rod assembly, seat end cap, and re-fit retaining wire(s). Verify smooth travel by hand.
  6. Bleed and test - Refill, bleed air, and verify full stroke without binding or leaks. Sea trial under safe conditions.

Tip: If the rod is pitted or the bore is scored, a reseal may not hold. Consider our Hynautic cylinder rebuild service.

Downloads and Resources

Description Link
Hynautic Steering System Manual - general reference LINK [PDF]
SeaStar Inboard Cylinder Installation and Reference LINK [PDF]
Hynautic Cylinder Rebuild Service LINK [Service]

Questions?

  • No Sales Tax on purchases outside California
  • Buy Now Pay Later with Affirm or PayPal
  • Seatech Marine Products, Inc. is an authorized dealer, service center and installer for Hynautic

International, USVI, Puerto Rican, Hawaiian and Alaskan Customers: We ship worldwide and via USPS. If shipping looks high, contact us for a quote.

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1 Review

  • 5
    Seal kit

    Posted by Charles on 28th Feb 2021

    Works as advertised

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