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Hydrastar 7K Axles, 8 Lug Integral Tandem Axle Trailer Disc Brake Kit (5/8")

Hydrastar® 7K/8K Hybrid, Axles, 8 Lug Integral Tandem Axle Trailer Disc Brake Kit (5/8") - "Kaufman" {#E8KK-T5}

SKU #E8KK-T5
by Hydrastar
Save 16% Save 16%
$2,499.00
$2,499.00 - $2,499.00
$2,499.00
$2,099.00
$2,099.00 - $2,099.00
$2,099.00

Complete tandem axle disc brake conversion kit for 7K and 8K axles with 8-lug hubs. Includes the Hydrastar EOH actuator, disc brake assemblies, brake lines, and all hardware needed for a full conversion.

Limited Warranty Included
2 YEAREOH Actuator
3 YEARDisc Brakes
LIFETIMEBrake Lines
7K-8K
Axle Rating
TANDEM
Axle
DISC
Brakes
DOT
Compliant
What You Get

In The Box & Sold Separately

Included
✓
(1) 381-7067 — Hydrastar® Electric Over Hydraulic (EOH) Trailer-Mounted Brake Actuator (1600 PSI)
✓
(1) 496-252 — Hydrastar® Hydraulic Tandem Axle Brake Line Kit – 25 ft., 3/16 in., 3000psi hydraulic brake pressure
✓
(4) 25580 — Hydrastar® 6K/7K/8K Rated Inner Bearing
✓
(4) 02475 — Hydrastar® 7K/8K Rated Outer Bearing (5/8 in., 9/16 in.)
✓
(4) MAT-10-225-15 — Hydrastar® 6K/7K/8K Rated Rubberized Grease Seal or Oil Bath
✓
(4) 303-E78DOALC — Threaded Sealed Oil / Grease Cap - Aluminum Cast
✓
(2) E303-8KK5-A — Hydrastar® 7K/8K Rated, Dacromet Coated Integral Single Axle Brake Kit (5/8 in. ) - NOTE: Specialized Wheel Offset intended for use on "Kaufman" Car Trailers using industry unique 17.5" wheel with a -.50" wheel offset.
✓
(2) 303-E7/8RK5 7K/8K Axle Rated Integral Dacromet Coated RotorKB
✓
(2) 303-E78C 7K/8K Axle Rated Dacromet Coated Integral
✓
(1) 303-E7BL 7K/8K Hybrid Axle Rated Dacromet Coated Bracket
✓
(1) 303-E7BR 7K/8K Hybrid Axle Rated Dacroment Coated Bracket
Sold Separately
–
DOT 3 or DOT 4 Brake Fluid
–
Tools for installation
–
Hubs & Drums (use existing)
Questions about fitment?

Feel free to reach out to us or start a live chat in the bottom right corner for assistance.

Additional Details

Specifications & Compliance

•
We have redesigned this brake kit specifically catering to Kaufman's unique 8k axles that use a 02475 Outer Bearing along with a 17.5" offset wheel for proper fit and alignment with these types of axles. No wheel spacer is needed.
•
Durable, sealed, fully enclosed extruded anodized aluminum housing case to easily withstand the environmental and road demands (not cast or plastic).
•
2 YEAR LIMITED WARRANTY from date of purchase.
•
Complies with CFR-393 Federal Braking Requirements and meets all Department of Transportation (D.O.T.) regulations.
•
Designed for Drum and Disc Brakes with reliable 12 V DC operation and solid-state electronics.
•
Color-coded, heavy duty 12 Gauge wire for easy and quick install. (Black/Constant power, Blue/Brake controller, White/Ground, Yellow/Break-away)
•
4 ft. Wire, Enough Length to Customize Any Job.
•
Required use of D.O.T. 3 or 4 Brake Fluid. (Not included.)
•
Compatible with any trailer configuration with 1-3 axles.
•
Corrosion-resistant Dacromet Coated Rotor and Bracket for Industry Standard trusted performance.
•
Premium, corrosion-resistant Stainless Steel Caliper construction for reliable performance.
•
5/8" in. wheel studs
•
5-Bolt Brake Flange
•
The Hydrastar® Brake Line Kit includes: – Brake Lines – Fittings – Required Hardware
•
Corrosion resistant, high-performance alloy tubing backed by a Lifetime Guarantee.
•
Triple annealed and eddy-current tested, Hydrastar® brake lines are walled 40% thicker preventing kinking and allows simple routing and smooth bends without bending tools required.
•
Meets SAE J1650 Standards (0.028 in.)
•
Made in USA
Common Questions

Before You Buy

What PSI actuator is included?+
The 1,600 PSI GEN 8 actuator is included. This is the correct pressure for both disc and drum brake applications.
Do I need anything else to complete the install?+
You will need DOT 3 brake fluid (not included). Basic hand tools and a way to mount the actuator to your trailer tongue.
What is the difference between integral and slip over?+
Integral kits replace your entire hub and rotor as one piece. Slip over kits mount the rotor over your existing hub — faster install, no hub removal needed.
2024–2026 GM Truck & SUV Owners

Dashboard showing “Service Trailer Brakes”? Brakes disabled?

Affects Silverado, Sierra, Tahoe, Suburban, Yukon, Escalade, Colorado, Canyon & Hummer EV with integrated trailer brake controller.

That’s a known GM compatibility issue across the 2024–2026 lineup. Hydrastar has the fix — the GM Diode Module (#381-7074) is a plug-and-play inline solution.

New Ford Truck Owners

Connectivity issues before or after the dealer flash? Brakes dropping in and out?

Affects new Ford trucks when switching from electric mode to EOH mode.

Our Hydrastar Controller Adapter Module (#381-7073) has been very successful resolving this for Ford owners. Note: this is not a Hydrastar issue — just a Hydrastar part that helps.

Need Help Choosing?
Our team has helped thousands of trailer owners find the right setup.
Fastest response? Use the chat bubble in the bottom-right corner ↘
or call (812) 655-4544 · Mon–Fri, 8am–4:30pm ET