Should Hole In Dexter Zinc-Plated Brake Actuator Fitting Be Smaller Than Old Actuator
Updated 03/31/2026 | Published 03/25/2026
Question:
Just purchased: Item T43397007K Dexter Zinc-Plated Brake Actuator - Drum - Multi-Fit Ball - Bolt On - 7,000 lbs Replacing a unit that looks identical no name on it, and I have a question. Sorry, I didnt take a picture. But, the little brakeline fitting on the rear, that comes capped, has an extremely small hole through it. Like .002 or something. However, the one that I removed has the same fitting but has about a 1/8inch hole through it. The old one looks much more reasonable. I cant imagine getting much fluid to push through that small hole. Why is the through hole so small? Am I supposed to use that, or do I need to just use the old one with the bigger diameter hole?
asked by: Denver D
Expert Reply:
Hey Denver! That small hole on the # T43397007K is actually intentional. It is a built-in orifice/restrictor in the actuator, not just a standard open fitting. This helps control how quickly fluid moves through the system so the brakes apply smoothly instead of grabbing too hard.
Even though it looks tiny the system is under pressure so it still delivers plenty of fluid to activate your brakes. I’d stick with the new fitting as-is and not swap in the old larger one since that could change how the brakes behave.
What kind of trailer do you have?
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Product Page this Question was Asked From
Dexter Zinc-Plated Brake Actuator - Drum - Multi-Fit Ball - Bolt On - 7,000 lbs
- Brake Actuator
- Surge Brake Actuator
- Farm Trailer
- Boat Trailer
- Construction Trailer
- Travel Trailer
- Utility Trailer
- Bolt-On
- 7000 lbs GTW
- 1-7/8 Inch Ball Coupler
- 2 Inch Ball Coupler
- 3 Inch Channel Tongue
- Drum Brakes
- No Lockout
- Dexter
more information >
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Denver D.
3/31/2026
I found that the old system has an inline valve about 36" after the master cylinder. I initially replaced the tiny hole fitting on the new actuator/MC with a 1/8" hole fitting. After a few days of frustration, I found that the inline valve had the tiny hole in it, which is how they were running it before. It was clogged with rust from the old system. blowing out the old line and clearing the clog several times got very frustrating. I finally drilled out the tiny hole in the valve to 1/8", bled the system through, then replaced the fitting at the master cylinder with the tiny hole fitting that came with it. After a final bleed, system is working now (no rust particles in the new master cylinder to plug the hole). NOTE: This is a flat, tilt bed trailer for hauling cars and equipment. Built 25yrs or so ago by an individual.