Troubleshooting A Roadmaster Invisibrake That Isnt Building Air Pressure

Updated 04/11/2023 | Published 04/10/2023

Question:

I had the invisibrake for about four years with no issues of any kind. The other day I got the dingy ford fiesta 2013 all hooked up and ready to go and when I tested the brake system....nothing. I had to disconnect the dingy from the RV and took off without it. I am not sure what is wrong. I checked all the connections and every thing looks good. When am I supposed to see pressure on the invisibrake pressure dial? Is it when the RV to dingy cable is hooked up? I noticed that with everything hooked up like I usually do, there was zero pressure showing on the dial. I asked my wife to press on the RV brakes and nothing. Did the fuse blow up on the invisibrake, maybe? Please advice,

asked by: Gerry P

Expert Reply:

If your Roadmaster InvisiBrake Supplemental Braking System # RM-8700 isn't building pressure there could be a few different causes. The controller will only build up pressure when connected to the motorhome. The 20 amp fuse would be a great place to start with, and would be located on the red power wire running from the controller to the battery.

From there you would need to look at the vacuum line running and each of its fittings to see if there's a leak. After that you could be looking at a failed air cylinder. There is also a tech note about the dial spinning completely around to zero when at max power so you can also check rotate the dial counterclockwise to see if this is the case.

expert reply by: Kevin C