Penetrating the Firewall

[Alan_Hepburn]

So, I'm slowly getting the JT ready for towing behind the motorhome - I'm getting ready to install the Ready Brake cables, for supplemental and breakaway braking, and so I have to drill 2 holes 5/16th inches diameter through the firewall, directly behind the brake pedal. I can easily get access behind the brake pedal, but getting access on the other side of the firewall is problematic. I see a "plug" behind the brake pedal that looks to be securing the carpet, and see something protruding through the firewall in the engine bay in approximately the correct spot but I'm not sure if it's the same item. If it is I can drill next to it with no problem but I want to make sure. I've got an image of the inside of the firewall but I couldn't get my phone and arm down into the outside firewall area so I don't have an image from the outside. Anyway, can anybody confirm for me if it's safe to drill through the firewall in that location?

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[USMC-SSGT]

So, I'm slowly getting the JT ready for towing behind the motorhome - I'm getting ready to install the Ready Brake cables, for supplemental and breakaway braking, and so I have to drill 2 holes 5/16th inches diameter through the firewall, directly behind the brake pedal. I can easily get access behind the brake pedal, but getting access on the other side of the firewall is problematic. I see a "plug" behind the brake pedal that looks to be securing the carpet, and see something protruding through the firewall in the engine bay in approximately the correct spot but I'm not sure if it's the same item. If it is I can drill next to it with no problem but I want to make sure. I've got an image of the inside of the firewall but I couldn't get my phone and arm down into the outside firewall area so I don't have an image from the outside. Anyway, can anybody confirm for me if it's safe to drill through the firewall in that location?

Why drill? There is a rubber grommet as you are on the engine side looking at the firewall. It’s about 3/4 in diameter and maybe a few inches off the fender side and maybe 12” down. Behind that is that thick rubber you are already seeing and some insulation. Use a nail (or punch) or something and go from the engine side through the middle of the grommet and through the thick rubber in the truck. Leave it sticking through. Go inside the truck and with a razor knife cut a hole in the thick rubber/plastic. I’ve used this without issue. I also have a tool for getting things through a firewall. Basically a thick screw driver that’s hollow. You could use a thick metal straw cut at an angle. Pierce through and pass the wire/cable/hose through the straw and remove the straw/tool.

 

[Alan_Hepburn]

Thanks - it's a bit more involved than just making a hole to pass some wires through. It's an aircraft steel cable, in a sheath, that has the sheath secured by a metal fitting to the firewall with a nut on each side of the firewall. The hole has to be 5/16ths inch to accommodate the fitting that secures the cable sheath to the firewall. The end of the cable is secured to the brake pedal, and the other end is secured to a lever system on the tow bar - when the motorhome brakes are applied the towed vehicle will push against the motorhome, activating the lever system to pull on the Jeep's brake pedal. A simple system that requires NO auxiliary 12V power at all - it simply works through physics.

 

[Radio Guy]

Thanks - it's a bit more involved than just making a hole to pass some wires through. It's an aircraft steel cable, in a sheath, that has the sheath secured by a metal fitting to the firewall with a nut on each side of the firewall. The hole has to be 5/16ths inch to accommodate the fitting that secures the cable sheath to the firewall. The end of the cable is secured to the brake pedal, and the other end is secured to a lever system on the tow bar - when the motorhome brakes are applied the towed vehicle will push against the motorhome, activating the lever system to pull on the Jeep's brake pedal. A simple system that requires NO auxiliary 12V power at all - it simply works through physics.

I have not tested my new Jeep but with most modern vehicles with power assisted brakes, you have to stomp on the brake pedal with everything you have when the engine is not running, otherwise it wont stop very well. How does that work with your system?

 

[Alan_Hepburn]

I have not tested my new Jeep but with most modern vehicles with power assisted brakes, you have to stomp on the brake pedal with everything you have when the engine is not running, otherwise it wont stop very well. How does that work with your system?

It actually works quite well - it has the full weight of the Jeep pushing against the lever, which in turn pulls the brake pedal. It's a lot more weight than we can put on the pedal, even if we were standing on the pedal with both feet! The Ready Brake system has been available for almost 20 years now with many happy users out there! We've been using it on my wife's JKU and it works well.

 

[smoothbronco]

It actually works quite well - it has the full weight of the Jeep pushing against the lever, which in turn pulls the brake pedal. It's a lot more weight than we can put on the pedal, even if we were standing on the pedal with both feet! The Ready Brake system has been available for almost 20 years now with many happy users out there! We've been using it on my wife's JKU and it works well.

You ever get this installed?

 

[Alan_Hepburn]

Yes, it's installed and waiting for our first trip of the year, happening in March. Installation was pretty straightforward, once I determined that the spot I needed to drill through the firewall was safe.

 

[Labswine]

<Beavis and Butthead> Heh heh...heh heh...heh heh...you said penetrating... </Beavis and Butthead>

 

[jackr]

Alan, glad you got it installed. How about a picture (cab, engine, or both) to help the rest of us. If you did it again, would you use the exact same location? Thanks

 

[Alan_Hepburn]

Okay - I managed to get a photo of the cab side of the firewall. The 2 separate brake cables went through pretty easily, directly inline with the brake pedal and then I routed them along the driver's side frame rail up to the front bumper.

 

[jackr]

Alan, thanks for the photo.

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