How To Test That Demco Hydraulic Brake Actuator DM72VR Is Working Properly
Question:
I just installed a dm72 vr on a 1998 four winns trailer. I thought it went okay but when I use a wooden bar clamp to compress the coupler back, the brakes do not tighten. But when I pull on the break away cable with the top plate off the brakes apply normally. Is there a better way to test the actuator or am I missing something? Thanks much.
asked by: Jim M
Expert Reply:
Since the break away lever on the top plate activated the trailer brakes on your 1998 Four Winns Trailer it sounds like brake fluid is at least getting sent to your brakes which means the master cylinder is working correctly.
Chances are when testing the coupler with a wooden clamp not enough force was added to the coupler to cause it to apply the brakes. This can be pretty difficult to test, so I recommend raising one wheel of the trailer while blocking the other wheels, and having a friend manually engage the coupler. A long 2 x 4 or something similar may be needed to get enough leverage to activate the master cylinder.
You should try to spin the wheel once the actuator is engaged, and it should not spin.
Another option would be hooking the trailer up to your tow vehicle, and taking it for a drive to see if you feel the trailer pushing the vehicle when stopping, or if you can feel the brakes working. You wouldn't want to go on a busy street, but would want to find an empty parking lot to test this.
I included a video of the # DM72VR for you to take a look at.
Product Page this Question was Asked From
Demco Hydraulic Brake Actuator - Drum - Zinc - 2" Ball - 7,000 lbs
- Brake Actuator
- Surge Brake Actuator
- Straight Tongue Coupler
- Bolt-On
- 7000 lbs GTW
- 2 Inch Ball Coupler
- Drum Brakes
- No Lockout
- Demco
more information >
Continue Researching
- Search Results: surge brake actuator brake actuator
- Shop: Demco Hydraulic Brake Actuator - Drum - Zinc - 2" Ball - 7,000 lbs
- Search Results: da66b
- Search Results: 8605001
- Shop: Reverse Lockout Solenoid Kit for Demco DA66B Hydraulic Brake Actuators - Non-Bypass
- Q&A: Replacement for Atwood 61101 Brake Actuator
- Video: Review of Demco Brake Actuator - Surge Brake Actuator - DM72VR
- Search Results: 1 1/16 x1 3/8 " bearing kit
- Shop: Demco Hydraulic Brake Actuator w Drop and Electric Lockout - Disc - Zinc - 2-5/16" Ball - 12.5K
- Shop: Replacement Damper for Model 20 Actuator - Qty 1
- Article: How to Tell the Weight Rating of a Trailer Axle
- Video: Kodiak Trailer Brakes 18SI-BLKIT Review
- Shop: Replacement Hub Assembly for Demco Kar Kaddy, Tow IT II, or Penske Tow Dolly - Qty 1
- Shop: Hub Bearing Kit for Lippert, Dexter, and AL-KO Axles - 3,500 lb with #84 Spindle
- Search Results: kodiak brakes
- Shop: Vehicle Tow Bar Brake System
- Video: Demco Brake Actuator - Surge Brake Actuator - DM8164311 Review
- Video: Dexter Axle Trailer Brakes - Hydraulic Drum Brakes - 23-342-343 Review
- Shop: Kodiak Hydraulic Brake Line Kit - Single Axle - 18'
- Search Results: disc brake actuator
- Video: Kodiak E-Z Lube Disc Brakes Installation
- Q&A: Dimensions of Replacement Damper for Model 20 Actuator
- Video: Review of Titan Brake Actuator - Replacement Master Cylinder for Disc Brakes - T4747100
- Video: Review of Dexter Axle Brake Actuator Parts - Replacement Damper - DX76FR
- Search Results: fulton magnum series jack
- Q&A: Bolt Hole Specs of the Demco Hydraulic Brake Actuator DM8104311
- Q&A: Comparing Demco and Titan Disc Brake Actuators with Electric Lockouts
- Q&A: How to Determine Correct Replacement Hydraulic Brake Actuator for Older Boat Trailer
- Q&A: What Exactly Does a 6 on 5-1/2 Inch Wheel Bolt Pattern Mean
- Article: How to Bleed Your Trailer Surge Brakes