Welding Toyota 8" Rear Axle 4 Link Mounts

phansigar0614

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When welding link mounts and gussets on a stock axle, do I need to make a jig to keep the axle from warping or is this even a problem?
 

partybarge_pilot

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Depending on how you weld them on it can be a large problem. A jig can help but design and welding technique can go a long way.
 

phansigar0614

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Thanks, I'll probably make a jig as well as take my time and not let it get too hot. I was thinking I should put extra tack welds on all the link mounts and supports before laying the larger beads. Maybe weld a couple of braces on the cut them off later.
 

Giant Geoff

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You do not need a jig to weld on the link mounts; you don’t even need to take anything apart. If you are welding a truss that has a lot of surface, a jig will not help, you need to preload a housing the opposite direction that the truss is on to counter balance the weld pulling. People will say weld an inch at a time to keep it from toeing out if the truss is on the back side but it may not help.

I build over 50 housings a year and found the best way is still the simplest, use a long chain and bottle jack.
 

partybarge_pilot

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If you design your truss so that the warping from welding cancels itself out, you don't need to pre-load the housing. A little design will go a long way, A lot farther than a bottle jack and chain guestimation bend.
 

Giant Geoff

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People that have not done it before will have to guess how much to preload them, but after building housings for 15 years I’ve paid attention to how mush is needed. I have a preload measurement for junkyard housing and a measurement for an after market, some after market housings will already have a carve in them that I take into account.

The bottle jack and chain is just a great tip that I picked up from an old school metal genius.

I have learned how to keep thing straight that have equal amount to weld surface on both sides, how do you design a part to not wrap if it has a long weld surface on one side with out having to preload?
 

partybarge_pilot

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how do you design a part to not wrap if it has a long weld surface on one side with out having to preload?

Design it with the majority of the welds opposing each other. This means making the brace tall enough to fit over the tubes so that the welds are on the top and bottom....... 180* apart. Since most of the warp takes place in the tubes, this pretty much eliminates it. Weld the tubes first and weld the back of the housing in small sections without putting to much heat in it. No preload necessary.........
 

Giant Geoff

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Cool thanks, I don’t have I high level of education just tons of practical experience. How does that look having a tall truss like that? I can foresee it get in the way when trying to mount leaf springs.

So, less work and less concern about warping?
 

partybarge_pilot

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I'll try to take a pic of an installed one tomorrow. Haven't seen one installed on a leaf sprung axle yet. The spring pads should be tall enough to clear everything though you would have to notch the brace around it. Could be a pain if the truck was running a lot of pinion angle (Bronco). Way less work, way less worries.
 

partybarge_pilot

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OK, here is a 9" leaf sprung rear end with the truss welded on. It just barley clears the leafs at full droop, will probably rub under use. New Currie housing that was strait to start with and is still strait after the truss was installed. No jig or pre-loading was used.

 
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