Can I Convert a Demco Drum Brake Actuator to Work With Disc Brakes?  

Question:

Expert Reply:

Hello Zach,

Thanks for writing in!

No need to apologize at all, this is actually a really good question. Since you have the Demco Hydraulic Brake Actuator # DM8759522, it is important to know that this particular actuator comes set up for hydraulic drum brakes, so you do not want to use it as-is with the hydraulic disc brakes on your new 7,000 lb axle.

Disc brakes require higher hydraulic pressure than drum brakes. A drum brake master cylinder will not provide enough pressure to properly operate disc brakes. On the flip side, a disc brake master cylinder produces too much pressure for drum brakes, so the master cylinder really does need to match the type of brakes you are running.

Since you have already purchased the # DM8759522, I would first see if you are able to return or exchange it where you bought it for the disc brake version (I do not see an order with us). If you are not able to return it, no worries, you can convert the one you have. You will need to replace the drum brake master cylinder with the Replacement Master Cylinder for Demco Actuators - Disc Brakes # 5672.

You will also want to add the Reverse Lockout Solenoid Kit for Demco Hydraulic Brake Actuators - Non-Bypass # DM5837. This will keep the disc brakes from applying when the actuator compresses while you are backing up.

So, since you already have the actuator, you definitely have options. If you can't return it, swap out the master cylinder and add the reverse lockout solenoid, and you will be set up for the hydraulic disc brakes on your axle.

How big of a water tank are you putting on this trailer? And if you have any other questions, please ask away =)

expert reply by: Kate F

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