Welding Spring Seats to an axle

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I am putting a Dexter axle on a trailer.  Axle is an electric brake axle.Dexter calls for preheat of the area (500-600 degrees) before welding on the spring seats to the axle.My concern is the manufacturer pre-run electric brake wiring through the axle (comes that way from the manufacturer).  The welding alone could/will damage the insulation and the preheat of the area will certainly prevent me from keeping the heat area small and thus increase the damage risk for the electric brake wiring.Any ideas form the old heads who have done this a lot.Dexter does not address the wiring harness and the heat issue.
Reply:Does the wiring come out of the axle?
Reply:You can disconnect the electric brake solenoid wiring and completely unbolt the four or five bolts holding the brakes backing plate onto the hub. Then it's completely out of your way. Sent from my iPhone using Tapatalk
Reply:If you pull those wires out of the tube, tie a sacrificial wire onto them.Pull them out of the tube, that wire goes in.Then when you go to re-assemble, you have a wire inside to pull the brake wiring back in with!
Reply:Welded a lot of spring seats on and never preheated. But it's a good idea to pull the wires out as said. I just tied a length of welder wire to them and pull them out leaving the wire in while welding. Worst case just run the cross wire across on the trailer frame rather than inside the axle.
Reply:Originally Posted by drujininIf you pull those wires out of the tube, tie a sacrificial wire onto them.Pull them out of the tube, that wire goes in.Then when you go to re-assemble, you have a wire inside to pull the brake wiring back in with!
Reply:If you look in the right places, you can find a certain knot that is used by cablers to pull through conduit. I don't know what it is, but I've seen them do it. If memory serves, they also tape the knot to create a taper to keep it from snagging.Everlast PA160-STH... and that's about it!
Reply:I've not once preheated an axle to weld the seats on, and I've built a few hundred trailers, also never had a failure and never melted the wire. Put a wet rag at the wire if you think you're welding too close to it.  Dexter has a plastic grommet on that hole, as long as you don't burn that up your wires are fine.Last edited by toofast_28; 01-27-2014 at 11:00 AM.
Reply:Dexter states in the WPS to do the preheat is the only reason I thought I should do it.  The WPS is quite specific in many details on their axle and the spring seats.
Reply:The purpose of preheating a weld area is to slow cooling after the weld is made, it's a way to relieve stress in the area.  It usually applies to weldments on large masses where movement is restricted as the weld cools.  A large mass restricts movement, and will cause stress fractures in the weld area if not cooled slowly.  The preheat prevents the surrounding area from becoming a super heat sink, and drawing off the heat too fast.Preheat definitely applies to an axle with large cross sectional dimensions, and thick walls.  But the importance decreases as the axle diameter decreases.Also...........Don't confuse HAZ with preheating effects.  Any time you weld you create a HAZ that is brittle to some degree, the ductility decreases, and you can have fractures down the road somewhere.  Preheating doesn't eliminate the HAZ, but it does relieve some of the tied up stress near the HAZ.  At the end of the day you still have molecular change in the weld zone adjacent to the bead.A-36 is extremely weld friendly, and today's filler materials are designed to provide ductility in the actual weld bead.BUT, it doesn't hurt to preheat if you monitor the temp, and keep it at the range you have mentioned.  And a proper preheat also helps to prevent distortion.The preheat, and the weld, will change the camber angle to some degree, but it's not a big deal."Any day above ground is a good day"http://www.farmersamm.com/