Welding to Discovery Frame Precautions

[rambler5860]

I've purchase a Mighty Hauler for my Discovery 40E. I will be having a Company weld the 2 Additional Receivers to the rear frame. Obviously I'll make sure they are grounded next to the welding area, but I'm also wondering if there is anything else I should do as a precautionary method. I'm just a little concerned about all the Electrical On Board, and don't want any Electrical Problems afterwards. Any advise would be welcome.

[DegoRed]

I would not worry about the electrical, good luck!

[Gocoffeer]

This is a really great concern... I have not welded onto my frame yet but it is coming soon. The point you have brought up concerning electrical and battery is very valid. Since with all electrical welding you are really shorting out your frame with high current. Now that you have mentioned it I used to work the shop end of rally car repair for SAAB. We grounded the car chassis and disconnected the battery. This was the protection during MIG Welding on the rally type cars and I think it a good suggestion for the RV too.

Ground Frame can be a simple task...pound metal rebar stake in ground near RV ....Use auto type jumper cables from rod to a clean place on RV chassis.

[hydro45640]

Disconnect all batteries first.

[Mjay]

Originally Posted by hydro45640

Disconnect all batteries first.

Yes, disconnect all the negative battery cables. Don't just rely on the battery disconnects.

[Cbones]

Depending on whether it is a Freightliner or Spartan, call them and find out the exact procedure. I had my coach welded at Fleetwood, and they did not follow Spartan's procedure and blew out the main body computer. Of course it was on a 3 week backorder. Lucky for me it was in the middle of the winter. Just a word of caution, cause there are a lot of expensive sensitive computers that you definitely do not want to damage. And by the way, they definitely did disconnect the chassis and house batteries, so there is definitely more to it than that.

[mel s]

Originally Posted by rambler5860

I've purchase a Mighty Hauler for my Discovery 40E. I will be having a Company weld the 2 Additional Receivers to the rear frame. Obviously I'll make sure they are grounded next to the welding area, but I'm also wondering if there is anything else I should do as a precautionary method. I'm just a little concerned about all the Electrical On Board, and don't want any Electrical Problems afterwards. Any advise would be welcome.

rambler
At the very least, (in addition to making sure the welder is grounded near the welding area), I would disconnect the batteries.
The Allison and engine ECUs too, (if I could find where/how they are connected).

BTW, anyone who says, "don't worry about it" isn't going to pay for any repairs you might need if you don't take precautions.

Mel
'96 Safari

[DegoRed]

Originally Posted by Cbones

I had my coach welded at Fleetwood, and they did not follow Spartan's procedure and blew out the main body computer. Of course it was on a 3 week backorder. Lucky for me it was in the middle of the winter. Just a word of caution, cause there are a lot of expensive sensitive computers that you definitely do not want to damage. And by the way, they definitely did disconnect the chassis and house batteries, so there is definitely more to it than that.

Have welded on a bunch of vehicles over the years and never had a problem, but maybe I have just been lucky. Hearing what happen to Cbones definitely gives me pause to be worried doing so in the future.

Originally Posted by mel s

BTW, anyone who says, "don't worry about it" isn't going to pay for any repairs you might need if you don't take precautions.

True words of wisdom spoken there Mel.

[lburson]

We purchased a 2000 Discovery and in Jan., I decided to replace the four house batteries. During the install process I must have moved the cables just a bit on the engine (chassis) batteries. End result was that the previous owner/maintainance person installed the positive cable to the engine starter too close to the exhaust system, causing the protective cover to desinigrate. Long story short, I had a direct short and some smoke. Ended up replacing the cable, but the engine would not start. My worst fears were that I had fried the starter/battery relay and possibly the alternator. I could get the engine to start off of the house batteries, but not the engine/chassis batteries, so I knew that the starter relay was ok, but the alternator would only show 4/5 volt on the voltage meter, checked on a new alternator, $390.00 ouch! Made a quick call to FCC (Freightliner Custom Chassis) and the fellow that ansewered the phone suggested that I replace the engine/chassis batteries even thou my multi meter showed 12.4/12.5 volts. Replaced the two engine/chassis batteries and the engine started right up with the voltage showing 14/18 volts on the alternator gauage. $200.00 for two new batteries sure beat $400 for a new alternator!

The purpose of this story is, Disconnect your batteries before you Weld!

[planojeeper]

When welding on any vehicle you need to disconnect the battery cables and put the ground as close as possible to the area to be welded.