UFP by Dexter XR-84 Complete Disc Brake Actuator – 8,400 lb (K99-184-24 / 445-K9918424)
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UFP by Dexter XR-84 Complete Disc Brake Actuator – 8,400 lb
The UFP by Dexter XR-84 is a heavy-duty surge brake actuator engineered for hydraulic disc brake trailer systems rated up to 8,400 lb. It combines a self-latching 2" ball coupler with a corrosion-resistant aluminum master cylinder and a removable inner-member design that keeps servicing straightforward. The coupler automatically opens and closes around the hitch ball as the trailer is lowered onto the tow vehicle — no manual latch required.
Key Features
- Rated for trailers up to 8,400 lb GVW
- Designed for hydraulic disc brake systems
- Self-latching 2" ball coupler — opens and closes automatically
- Corrosion-resistant aluminum master cylinder
- Removable inner member — all primary working components can be extracted for service or replacement without disturbing the outer housing
- Zinc-finished, bolt-on actuator configuration
- Mounting holes spaced 3" apart and 3/4" below the mounting surface
- Smooth, surge-actuated braking operation
Compatible Applications
- Boat and utility trailers with hydraulic disc brake systems
- Straight-tongue trailer configurations rated to 8,400 lb
- Trailers with a 2" hitch ball and compatible mounting-hole pattern
- Replacement for worn or damaged XR-84 disc-brake actuator assemblies
Fitment Notice
Before ordering, confirm the following on your trailer:
- Gross trailer weight does not exceed 8,400 lb
- Brake system is hydraulic disc (not drum) — hydraulic pressure requirements differ between brake types
- Hitch ball is 2"
- Tongue dimensions and mounting-hole pattern match the XR-84 bolt pattern (3" spacing, 3/4" below mounting surface)
- Brake-line connection and reverse-lockout arrangement are compatible
Alternate & Cross-Reference Part Numbers
- 445-K9918424 — Catalog SKU
- K99-184-24 — UFP / Dexter manufacturer part number
- K9918424 — Common condensed reference
- 38-2003 — Alternate cross-reference
- K99-184-20 / K9918420 — Related XR-84 disc-brake inner member assembly
Parts Desk Insights
The two specs to confirm before ordering are the 8,400 lb capacity and disc-brake configuration. The XR-84 looks similar to other UFP actuator families, but the brake type, mounting pattern, and original K99-184-24 part number must all match — substituting a drum-brake actuator in a disc-brake system will result in incorrect hydraulic pressure and unsafe braking. If the outer housing is still in good condition, the inner member can often be replaced independently rather than purchasing the complete assembly. For related Dexter actuator options, see Dexter Model 80 Disc Brake Actuator (K99-Z85-20) or Dexter Model 66 Drum Brake Actuator (K99-066-00).
Related Products
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
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.