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  1. Trailer Brakes
  2. Hydrastar
  3. Disc Brakes
  4. 7000 lbs Axle
  5. Hub and Rotor
  6. 16 Inch Wheel
  7. 16-1/2 Inch Wheel
  8. 17-1/2 Inch Wheel
Hydrastar Disc Brake Kit w/ Actuator for Tandem Axle Trailers - 13" Hub/Rotor - 8 on 6-1/2 - 7K
Hydrastar

Hydrastar Disc Brake Kit w/ Actuator for Tandem Axle Trailers - 13" Hub/Rotor - 8 on 6-1/2 - 7K

Part Number: HYD87VR
In Stock
$2,550.02
Trailer Brakes
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In Use/Installed

Before you hit the road, grab this all-in-one upgrade for your tandem-axle trailer. Kit includes everything you need to switch your trailer over to disc brakes for improved performance and greater stopping power. Perfect for use with boat trailers. Great Prices for the best trailer brakes from Hydrastar. Hydrastar Disc Brake Kit w/ Actuator for Tandem Axle Trailers - 13" Hub/Rotor - 8 on 6-1/2 - 7K part number HYD87VR can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
  • All Info
  • Reviews (3)
  • Q & A (0)
  • Photos

Hydrastar Trailer Brakes - HYD87VR

  • Disc Brakes
  • 7000 lbs Axle
  • Hub and Rotor
  • 16 Inch Wheel
  • 16-1/2 Inch Wheel
  • 17-1/2 Inch Wheel
  • Marine Grade
  • 8 on 6-1/2 Inch
  • Hydrastar
  • 9/16 Inch Studs

Before you hit the road, grab this all-in-one upgrade for your tandem-axle trailer. Kit includes everything you need to switch your trailer over to disc brakes for improved performance and greater stopping power. Perfect for use with boat trailers.


Highlights

  • Better Braking Feel: Electric-over-hydraulic system delivers firm, responsive stops.
  • Complete Kit: Includes actuator, calipers, hubs, rotors, bearings, seals, and lines.
  • Corrosion Resistant: Dacromet-coated parts stand up to moisture and road salt.
  • Quick Response: Pump reacts fast to your in-cab brake controller for smoother braking.
  • Wide Fit Range: Works with tandem 7K axles using 13" hub-and-rotor assemblies.
  • Proven Strength: Rated for 7,000-lb axles and tested for consistent braking under load.

Specs

Specs:

  • Axle capacity: 7,000 lbs
  • Bolt pattern: 8 on 6-1/2
  • Rotor diameter: 13"
  • Wheel stud diameter: 9/16"
  • Warranty:
    • Actuator: 2 years
    • Brakes and components: 1 year

Bearings, Race, and Seal Information:

  • Bearings:
    • Inner bearing: 25580
    • Outer bearing: 14125A
  • Races:
    • Inner race: 25520
    • Outer race: 14276
  • Oil seal: HYD27FR
    • Inner diameter: 2.250"
    • Outer diameter: 3.376"

Complete Kit Includes:

  • Hydrastar electric-over-hydraulic trailer brake actuator
  • 7K disc brake kit including hub-and-rotor assemblies with bearings, races, and seals
  • Hydraulic tandem-axle brake line kit
  • (1) 15' long brake line with 3/8"-24 inverted flare nuts
  • (1) 6' long brake line with 3/8"-24 inverted flare nuts
  • (2) 4-1/4' long brake lines with 3/8"-24 inverted flare nuts
  • (4) 18" male/male rubber flex lines
  • (1) 3/16" brass T-fitting
  • (2) 3/16" brass union fittings
  • (1) 3/16" brass X-fitting
  • 1/2" nylon hose clamps
  • 3/16" nylon hose clamps
  • Self-tapping screws


E7K-T9 Hydra Star Disc Brake Kit w/ Actuator for Tandem Axle Trailers - 13" Hub/Rotor - 8 on 6-1/2 - 7K

Installation Details HYD87VR Installation instructions


California residents: click here


Customer Satisfaction Score:

Ratings & Reviews

4.3

3 reviews
Before you hit the road, grab this all-in-one upgrade for your tandem-axle trailer. Kit includes everything you need to switch your trailer over to disc brakes for improved performance and greater stopping power. Perfect for use with boat trailers.

by:

what is the orientation of the brake caliper backing plates on the axle.

Lazer S. profile picture
Etrailer Expert

Lazer S.

3/3/2026

Hi Thomas! Most people mount them with the calipers in the 12 o'clock position, but you can also mount them in the 9 o'clock and 3 o'clock positions as well. Whichever is the easiest for you. I have had a guy mount them in the 6 o'clock position once, but that was due to him having no other choice and I don't recommend that unless you absolutely have to. What kind of trailer are you installing these on?



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3
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See what our Experts say about this Hydrastar Trailer Brakes

  • Disc Brake Conversion Kit for a 5th Wheel Trailer w/ 7,000 lbs Axles
    Hey Bill thanks for the information. The C865H-9/16 in that axle tag number means you have 8 on 6-1/2 hubs with 9/16" lug studs. The Hydrastar item # HSE7K-T1, you were looking comes with 1/2" lug studs. You'll need the Hydrastar Disc Brake Kit w/ Actuator item # HYD87VR instead. What brake controller do you have and what tow vehicle are you using? You can add this information and any other questions you have where it says Reply to Jerred H and I'll be happy to answer them.
    view full answer...
  • Disc Brake Kit for 2026 Brinkley Z3100
    Hey Michael! It looks like the 2026 Brinkley Z3100 comes with 7k axles but you will need to verify that information. Take a look at your axle tag if you aren't sure. Assuming that is correct, I recommend the Hydrastar Disc Brake Kit w/ Actuator for Tandem Axle Trailers # HSE7K-T1. This is a complete kit with the brakes, actuator, and brake lines. Hydrastar has a great system with a fast and reliable actuator. How are you liking the Curt suspension system? Any big trips coming up this spring?
    view full answer...
  • Does Hydrastar Disc Brake Kit 7k Tandem Axles Come with Breakaway Kit
    Hey Marc, no the Hydrastar disc brake kit part # HYD87VR that you referenced does not come with a breakaway kit so you would need to provide that separately like with the part # 50-85-313 which would work great with this system. A lot of trailers have breakaway setups already installed which is why this doesn't come with one. Does yours have one?
    view full answer...

Do you have a question about this Trailer Brake?


Info for this part was:

Employee Jameson C
Expert Research:
Jameson C
Employee Wilson B
Updated by:
Wilson B
Employee Michael B
Edited by:
Michael B
Employee Dawn Z
Written by:
Dawn Z

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