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Drilling of Frame Rails

I am in the process of installing an Air Force One supplemental braking system.  One step requires the mounting of the "Coach Air Connection Assembly" which consists of  valve assembly and small air tank.  This assembly is to be mounted near the rear brake valves on the coach.  There is a very obvious place to mount the assembly but would require drilling a couple of holes in the main frame rail, and then tapping the holes for mounting bolts. 

My question, "Is the frame rail mild steel or is it some kind of high tensile steel that would not be worth trying to drill?"

Thanks,

Richard
Jan & Richard Witt
1999 U-320  36ft WTFE
Build Number: 5478 Motorcade: 16599
2011 Jeep Wrangler Unlimited w/Air Force One
Jan: NO5U, Richard:KA5RIW
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Re: Drilling of Frame Rails

Reply #1 –
Check with Foretravel before drilling. Several of our fire trucks were placarded for no drilling or welding on the frame but others do it all the time. We had two trucks that developed fairly short cracks (2 or 3 inches) in the frame starting from rivets. The factory and insurance required the rigs be junked.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Drilling of Frame Rails

Reply #2 –
Post a picture of were you would like to drill etc. If it is at the end of the rectangular tubing down either side of engine it will be ok IMHO
JohnH
Coachless, now use aircraft. 2003 Ford Travelair TC280 class C. Super shape. Just for 1 yr .
1994 Ford E350 ClassC,total renovation inside and out. Now sold.
2000 U295  36' Cummins 350 c/w Banks Stinger, Resonator upgrade,Solar, LED lites.Residential fridge with slide out pantry. Build 5674. Sold
ex 92 GV 022C ored Cummins. Sold
ex 95 GV240 cat 3116. Sold
2017 Mini cooper s & 2016 land Rover LR2 HSE  LUX.
jhaygarth@aol.com    SKP #130098
treat everyone as you would like to be.

Re: Drilling of Frame Rails

Reply #3 –
Quote from: Jan & Richard –
I am in the process of installing an Air Force One supplemental braking system.  One step requires the mounting of the "Coach Air Connection Assembly" which consists of  valve assembly and small air tank.  This assembly is to be mounted near the rear brake valves on the coach.  There is a very obvious place to mount the assembly but would require drilling a couple of holes in the main frame rail, and then tapping the holes for mounting bolts. 
My question, "Is the frame rail mild steel or is it some kind of high tensile steel that would not be worth trying to drill?"
Thanks,
Richard
I had my Air Force One system installed in Quartzsite. When I was leaving the other day I went to plug in the air line and the bolt holding the bracket snapped off. I had to drill a new hole next to it using titanium bits I bought for drilling some stainless steel. I started with a small hole and worked my way up. I love these titanium bits. In the rush to leave I did not think about tapping the hole but now that it was brought up it would have been better to tap it.
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Drilling of Frame Rails

Reply #4 –
The holes I want to drill would be in the rectangular tubing beside the transmission, not in the end of the tubing. 

I will e-mail Foretravel tomorrow. 
Jan & Richard Witt
1999 U-320  36ft WTFE
Build Number: 5478 Motorcade: 16599
2011 Jeep Wrangler Unlimited w/Air Force One
Jan: NO5U, Richard:KA5RIW
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Re: Drilling of Frame Rails

Reply #5 –
Quote from: Jan & Richard –
The holes I want to drill would be in the rectangular tubing beside the transmission, not in the end of the tubing. 

I will e-mail Foretravel tomorrow. 

I installed mine right behind the passenger rear tire mudflap where I access my starting batteries.  I just used normal drill bits and tapped whatever size I needed.  Haven't had any issues in the 3+ years its been on there.
Robert
Build # 5304
1998 34' U270 Cummins 6CTA8.3

Re: Drilling of Frame Rails

Reply #6 –
The air-relay (aka Coach Air Connection Assembly or CaCa) unit can be installed anywhere.  Many install it near engine rear access door.  No reason to crawl under coach to maintain the unit.  Run nylon air hose to air supply, brake can and to coach's rear air disconnect.  I have no idea why they specify a particular installation location.  I would not drill or mount to frame.

Re: Drilling of Frame Rails

Reply #7 –
Thanks Robert and Barry.  Tomorrow I will check out alternate mounting locations. 
Jan & Richard Witt
1999 U-320  36ft WTFE
Build Number: 5478 Motorcade: 16599
2011 Jeep Wrangler Unlimited w/Air Force One
Jan: NO5U, Richard:KA5RIW
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Re: Drilling of Frame Rails

Reply #8 –
After fifty years in the metal working industry I learned a new trick from an installer I had come in to fabricate stainless steel coolant guards on one of my machines.

His "trick"? Pulsate your drill so you vary the rotations per minute. This lessons the chance of the material work hardening in front of your drill bit. I have used that trick ever since and not had any work hardening issues since.  ^.^d  ^.^d
Nitehawk,  Demolition Lady, & our NEW master, Zippy the speeding BB cat.
1989 Grand Villa 36' ORED
Oshkosh chassis, 8.2 DD V8
2006 Saturn Vue AWD

Re: Drilling of Frame Rails

Reply #9 –
Jan and Richard, I mounted mine in the eng compartment just in front of the air intake pipe on that ledge that's about 8 inches wide. Easy access. Will take a picture of it tomorrow.
Richard & Betty Bark & Keiko our Golden Doodle
2003 U320T 3820 PBDS
Build # 6215
MC # 16926
2016 Chevrolet Colorado 4X4 diesel
 

Re: Drilling of Frame Rails

Reply #10 –
To follow up on my Air Force One install, I mounted the Coach Air Connection Assembly to the angle iron hangers for the chassis battery tray on the passenger side of the coach. 

The entire installation on both the coach and toad went very smoothly.  A test drive proved everything is operating as it should.  It took me a good portion of two days, mostly reading and rereading instructions and figuring how best to make a clean install.  Thankfully my coach documents included a good schematic drawing of the air system; without it I would not have had nerve to cut into the coach's air brake lines. 

Thanks for all the responses.  And Nitehawk, thanks for passing along your "trick" for metal drilling.  I will try to remember and use it. 
Jan & Richard Witt
1999 U-320  36ft WTFE
Build Number: 5478 Motorcade: 16599
2011 Jeep Wrangler Unlimited w/Air Force One
Jan: NO5U, Richard:KA5RIW
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