What Is The Needed PSI For Roadmaster InvisiBrake Supplemental Braking System & Jeep Wrangler

Updated 07/09/2021 | Published 07/06/2021

Question:

I dont know where to place the knob for the vacuum pressure on the invisi brake and my 2011 Jeep Wrangler two door I have it now set about 20 were going away and my wife is afraid thats going to be either too much too little so I dont know what to do

asked by: Steven L

Expert Reply:

The Roadmaster InvisiBrake Supplemental Braking System, # RM-8700 has been pre-set at the factory at a level appropriate for "most" towed vehicles; there may be no adjustment necessary but this must be evaluated.

The correct pressure is dependent upon whether the brake pedal clamp is positioned as low as possible on the brake pedal arm; and the number of curves in the cable between the cable anchor bracket and the air cylinder. The higher the clamp is positioned on the brake pedal arm, and the more curves in the cable, the higher the braking pressure must be set. Test-drive the motorhome and towed vehicle for a short distance, making six to eight stops. The degree to which the brake pressure setting will affect the motorhome will vary, depending on the size and weight of the motorhome in comparison to the size and weight of your Jeep.

Roadmaster has posted a resource guide stating that 05-21 model year Jeep Wrangler's (InvsiBrake mounted under seat) have a suggested starting braking pressure setting of 60psi. I suggest starting here, (most vehicles listed in this guide are in the 50 to 60 psi range) then in a safe low traffic area test drive and evaluate for reaction, adjust as needed.

Happy Travels!

expert reply by: Michael R