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tjd · 06-17-2016, 04:31 AM

I just tried to have a Invisibrake installed by my RV dealership into my 2014 Diesel Jeep Grand Cherokee.

The unit is still in the Jeep just unplugged now since they could not get it to work properly. I have to revert back to my brake buddy since we are leaving town and I could not wait for them to figure it out after a week of working on it. On a job they claim would take one day.

The issue seems like a pretty simple on but they could not fix it even after hours on the phone with a tech from Roadmaster.

What is happening is that the after the breaks in the Jeep are engaged all the air is pushed out of the break pedal and then the brake pedal becomes to hard for the invisbrake to pull down so it does not work. They were originally told by Roadmaster it is a faulty system that the compressor might not be working. So they a new one shipped in and replaced that and it did not work. Then they pulled a new unit off the shelf and installed that control box and that did not work. Then they spent hours testing for leaks and so on but claim there were now and could not get it to work. That the Invisibrake was not compatible with my 2014 Diesel Jeep Grand Cherokee and they they would just unplug the unit and I would have to use my brake buddy so i can get back on the road and when I was back in town in 4 weeks they would replace it with something else.

Issue with Jeep now. When the Jeep is running everything seems fine. Brakes work and are ok but I noticed that if I pump the brakes a couple time when the car is off the brake pedal is no longer soft to push down and is hard. I know this was not the case before. Also if when the Jeep sits off for a hour and then I go try the brake it is hard and not soft. I know in the past that when I left the car overnight and would go start it and have to depress the brake it was not hard and still soft to press down. Once I turn the Jeep on I feel the brake pedal get soft again.

They claim they tested for leaks and the system was holding pressure but from what I noticed by pressing the brake with the car off it is pushing all the air out of the system and for some reason the compressor on the Invisbrake was not doing whatever it was suppose to be doing.

Any ideas?

Thanks for any help anyone can give me.

August West · 06-17-2016, 06:22 AM

I can't help you with the invisbrake problem. I would return it for an SMI Manufacturing system.

The brake pedal being soft until after a couple pushes with the engine off is normal.
The vacuum held in the booster by the check valve is exhausted after those few pushes. since the engine (vacuum pump also because diesels do not create good vacuum) is off, there is no vacuum being pulled to replenish what is lost when you pushed the pedal a couple times.
I have been in automotive parts and repair for 2 decades and every other vehicle with vacuum brakes follow that exact scenario. I would imagine before this invisibrake was installed you did not usually pump the brakes with the engine off, so this seems new.

Sorry that I can't help any more but wish you the best luck getting your invisi working.

2 Stroker · 06-17-2016, 11:35 AM

I have the invisbrake on my 98 Honda Accord and after having it come on while in tow a few times in wet weather and reading about all the problems with the system, I went with the SMI Air Force One made for air brakes on our new to us Ford Edge. All you have to do is read about all the problem with the invisbrake here on this forum. Some say it is installed wrong when they have problems but some have had them installed by Roadmaster in Vancouver, Wa and still have problems.

2 stroker