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UFP Hydraulic Surge Actuator for Disc Brakes 8400 lb Capacity fits 2 inch Ball with Solenoid (former Model XR-84)

UFP Hydraulic Surge Actuator for Disc Brakes 8400 lb Capacity fits 2 inch Ball with Solenoid (former Model XR-84)

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Part Number: 26827
by UFP - Unique Functional Products: 099-184-24
UFP 8400 lb Capacity Hydraulic Disc Brake Actuator with Solenoid (Former Model XR-84)
Feature: WARNING: Cancer and Reproductive Harm -

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Quantity Price
1 $447.33
2 - 3 $325.34
4 - 7 $308.52
8+ $298.23
Price $447.33
In Stock
As a perfect complement to your UFP (Unique Functional Products) Brake System, we offer UFP Surge Actuators as the chief authority in the business. This is a UFP Disc Brake Actuator (former Model XR-84) that features a self-latching robust cast front end rated to 8,400lb of towing capacity that uses a 2" towing ballWhen considering carrying capacity and the usage of this model, consider you current carrying capacity. Typically this surge actuator outfits either a single axle or tandem axle trailer with one or two 3,500lb capacity trailer axles. This would mean that the maximum capacity of the trailer itself would be 7,000lbs. This makes this model ideal for trailers utilizing UFP 3500lb Capacity Disc Brake Kits, as the capacity of the kits matches what this actuator would be rated for. 

As far as outfitting this item to your trailer, typically you will be using (3) 1/2 inch Diameter by 4 1/2 inch Long Stainless Steel Bolt  to mount to your trailers 3 inch wide tongue. You must have a straight, 3 inch wide tongue to mount this Model XR-84 actuator. It is not uncommon to need to drill new holes, as different manufacturers use different bolt spaces when the tongue actuators are produced. 

A UFP Surge Disc Brake Actuator works by using the force of the towing vehicle stopping to engage the master cylinder, applying pressure on the brake fluid to flow through the brake lines. 
This particular listing is for the UFP XR-84 with the Reverse Lockout Solenoid. The job of the reverse lockout is to allow you to go in reverse with your trailer without locking the brakes out. Two wires run from it, one as a ground, and the other connects to your wiring harnesses 5th wire (for 5 Flat connectors). This wire is commonly blue. Under normal operation while driving forward and braking the Reverse Solenoid Valve does nothing, however, once you need to reverse or back into the ramp, this is where the Solenoid Valve becomes crucial. When you put your truck in reverse, a signal is sent to the reverse lockout solenoid (through the 5th wire, which on the truck side connects to your vehicles reverse light) and the device blocks the flow of hydraulic fluid, this allows you to reverse without the surging of the coupler stopping you as you lounge backwards down the ramp. Keep in mind this means as you reverse, your truck is your only source of braking. 

When installing a new disc brake system on single or tandem axle disc brakes it is not uncommon to spend a good amount of time priming the lines, and using a good amount of brake fluid. It is important to begin at the furthest away caliper when trying to get the fluid through the lines and out the caliper bleeder.


  • The XR-84 inner housing is interchangeable with any UFP actuator 8,400 lbs and below.
  • Top Mount (slides over your 3" wide tongue)
  • Housing: 14.5" Long, Zinc Finish. 4 mounting holes - 3/4" down, 3" centers/ top mount for 3" & 4" tongues
  • Mounting hole configuration interchangeable with Atwood 6k, Titan Model 60 & Tie Down Model 66
  • Former XR-84 Model # (#40220)
  • 840 lb max tongue weight
  • Uses DOT 3 Brake Fluid

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