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Welding Precautions

1K views 6 replies 3 participants last post by  bobterry99 
#1 ·
Hi Guys

I've booked my SL into a local body shop next week to have the rusty front bumper (fender) support brackets replaced. I know the guy has never worked on an SL before so I was just wonder if there are any precautions he has to take like disconnecting the battery, alternator or anything else maybe?

Russ
 
#2 ·
Disconnect or place shunt across battery terminals. Best to disconnect.

You've got the EZL module on the front wheel arch, which you might want to disconnect as a precaution.

Fuel charcoal canister in nearby on L/H behind headlight.

Brackets are close to U/S of headlamps and headlamp washer pumps, so would obviously pay to weld in short lengths to keep heat down.

Garage should repair paint finishes locally on top and to u/s of wheel arch.

Hang on. I guess you are talking about the bumper end brackets next to the wings (fenders).

If these are corroded, I would expect the central bolts and anchors in the plastic bumper are corroded as well. If you find the latter, you can rebond new bolts with large washers into the bumper to avoid the expense of a new bumper.

Rob
 
#3 ·
This is going to show my ignorance...... but what do you mean by a 'shunt' and what is the 'EZL module'?

The bumper end brackets should be spot welded on so I'm hoping there wont be too much heat coming thru the inner wing into the engine compartment.

The 'L' shaped support brackets and bolts are all rusty so are going to be replaced. I might fab some steel plates with captive nuts to replace the rusty ones on the bumper or just use large washers.

These are the new brackets I'm having fitted.

Russ
 

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#4 · (Edited)
This is going to show my ignorance...... but what do you mean by a 'shunt' and what is the 'EZL module'?
An EZL is an ignition controller used prior to '94 in 6-cylinder cars and prior to '96 in others.

A shunt is a low resistance path between two points in an electrical circuit. In this case you would disconnect the leads from the battery and connect them electrically with a jumper cable or other means. I do not see how this is necessary, but I would do it.
 
#5 ·
Old scool is remove battery negative to protect battery and alternator from spikes. New school is leave battery connected as the battery helps to protect ECU, modules etc by cushioning the spikes.

The shunt is as Bobterry says. (Grateful to you Bob). :)

If you leave the battery connected, put a spike protector on the battery.

Least risky in my view is to disconnect both battery terminals altogether and shunt across the disconnected battery leads. This avoids the current finding a path to the welding clamp return line via electronic control modules and potentially damaging them. Also, for this reason, make sure there isn't an electronic component between the weld and and the return. Best to keep return clamp as close as practicable to the area of weld.
 
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