Front diffy drain plug?

[gavin]

Ok, so a couple questions.
A roller bearing pin blew a hole (almost) in my old front axle assy quite a while back
http://www.explorerforum.com/forums/showthread.php?t=217100

I'm (somewhat) in the process of re-gearing. Would it be safe to re-use this axle assy? Since I can't really be without my truck for longer than a weekend, wanting to re-gear my old axles.

and on top of that, due to the location of the hole... safe to drill and tap it for a drain plug?

 

[inh]

I think that'd be one big friggin hole, but really, I guess an allen bolt would be fine, sealed with teflon tape or something.

 

[99SportX]

It would probably work, but make sure of the thickness in that area before bothering with tapping. By the looks of it you will need a 3/4" or 1" NPT plug to cover that hole. I am not sure how many threads would be ideal to have in the material but I would say at least 3 absolute minimum.

Ideally, one would weld up that hole but tapping for a plug is the only other option short of JB weld (which it looks like you have done before).

 

[gavin]

It would probably work, but make sure of the thickness in that area before bothering with tapping. By the looks of it you will need a 3/4" or 1" NPT plug to cover that hole. I am not sure how many threads would be ideal to have in the material but I would say at least 3 absolute minimum.

Ideally, one would weld up that hole but tapping for a plug is the only other option short of JB weld (which it looks like you have done before).

it is relatively thick; if I would guess, probably the same thickness as it is where the fill plug is.

I did jb weld it, but at the time, I was still needing to drive it, so even with globs of jb weld it still leaked (hence replacing it, plus at the time not knowing exactly what happend).

it will be a pretty large bolt, and you're right with it being 3/4 or 1". I figure if I can get a fine-thread tap, it should be sufficient.
I know I'll need to check for clearance with the ring gear, as I'm pretty sure the there will be little clearance between the housing and ring gear at that spot. but if I can get a short enough bolt that doesn't even go all the way through the housing, or atleast sits flush, but that will be a very short bolt.

just trying to work with what I got, since when I do finally re-gear and it comes time to flush the lube, I don't wanna deal with pulling the whole housing again, and know that using a suction gun will probably miss a lot of the metal flakes that will probably be floating around.

 

[99SportX]

I think the stock fill plug is 1/2 NPT so it will likely have to be a larger size to cover that hole. The predrill size for a 1" NPT tap is 1-5/32 and by the looks of the pic that may work to cover the hole. 59/64 drill for a 3/4" NPT. That may work as well, you will have to measure.

http://www.engineeringtoolbox.com/npt-national-pipe-taper-threads-d_750.html

Something like this:

or this:

from www.mcmaster.com

 

[gavin]

I think the stock fill plug is 1/2 NPT so it will likely have to be a larger size to cover that hole. The predrill size for a 1" NPT tap is 1-5/32 and by the looks of the pic that may work to cover the hole. 59/64 drill for a 3/4" NPT. That may work as well, you will have to measure.

http://www.engineeringtoolbox.com/npt-national-pipe-taper-threads-d_750.html

Something like this:
[img http://www.mcmaster.com/param/images/ironsteelppf/4534k39_180x120.gif[/img]

or this:
[img http://www.mcmaster.com/param/images/ironsteelppf/44605k236_150x100.gif[/img]

from www.mcmaster.com

thanks for those links! :biggthump

 

[Cobraguy]

Make darn good and sure that if the plug goes through a tad, it won't hit the ring gear, etc.

 

[gavin]

Make darn good and sure that if the plug goes through a tad, it won't hit the ring gear, etc.

oh yeah, definitely

and of course I had remember that the hole is directly underneath the ring gear.
I'm sure I can find a drain plug somewhere that will be the perfect length... preferably a hair less than flush with the inside of the case.

 

[my pos mounty]

I don't know if I would drill and tap into the front diff in that location. I would be more inclined to drill out that hole and have a nut welded onto the outside of the diff, then thread in a plug. It is in a crappy spot and would be exposed if you hit a rock with it offroading though. Just my 2 cents and probably worth less than that.

 

[gavin]

I don't know if I would drill and tap into the front diff in that location. I would be more inclined to drill out that hole and have a nut welded onto the outside of the diff, then thread in a plug. It is in a crappy spot and would be exposed if you hit a rock with it offroading though. Just my 2 cents and probably worth less than that.

I was thinking of something along those lines too, but a couple things.

#1, it's a street queen. Haven't been truly "off-road" in it in years, and probably won't anytime soon. Need to finish my Bronco2 for that

#2, welding... isn't the material the housing is made of, very tricky to weld on? Isn't it an aluminum-magnesium-something or other mixture? I thought I had read that somewhere, but can't remember for sure. I know it's not any kind of steel.

#3, welding... I can't, never have welded. Although I probably could find somebody.

 

[my pos mounty]

I thought it was just plain old aluminum.
Suggested it to keep the clearance in that area to the ring gear.
They couldn't charge too much to weld it up, but you would have to take it out of the truck.

 

[gavin]

it's already sitting on my garage floor :biggthump

maybe I will look into that then... would be much cheaper too.

drill bits and taps for 3/4"-1" are spendy! Atleast from McMaster

 

[Electrohacker]

it's either aluminum or cast iron and NEITHER is god to weld on, although you CAN weld on cast iron, just not well.

I bet its aluminum though

 

[my pos mounty]

You can (TIG) weld on aluminum, with very good results.
You will have to clean the area real well before hand though.

 

[MadScience]

So likesince you said your lookin to regear the thing have you given any consideration to getting one from a junker? If your rebuilding as is you could just hollow out the new(old) diff and fill it with trisodium cloride or some thing for a day or 2 then put you cvs and new parts in it.... nothing would be wrong with the junk yard part but rust if you replaced the parts inside. unless physically battered (like the one you have. what goes wroung with the casting? Other than gum and rust?

 

[gavin]

So likesince you said your lookin to regear the thing have you given any consideration to getting one from a junker? If your rebuilding as is you could just hollow out the new(old) diff and fill it with trisodium cloride or some thing for a day or 2 then put you cvs and new parts in it.... nothing would be wrong with the junk yard part but rust if you replaced the parts inside. unless physically battered (like the one you have. what goes wroung with the casting? Other than gum and rust?

the one I want to regear, was the one originally my truck that got a hole, which was replaced with a junkyard unit that is currently in my truck.

I'm wanting to re-use this "spare" one if at all possible, instead of picking up yet another housing.

 

[MadScience]

Ah I see. Makes sense now..

 

[IZwack]

It is aluminum and can be TIGed. But one of the problems with TIG welding aluminum is that, if the aluminum has already been tempered to say a T-6 state, then welding it will bring the temper back down to a much lower number (usually T-0) and thereby reducing its "strength" by about 75%. This probably wont be a problem if the vehicle sees mostly asphalt - however, we've seen a few cracked front differential housings on the forum (although all of them probably occurred off road with a high centered front differential). But as you said, its a "spare" so if the cost is low, then I would go ahead and do it.

 

[my pos mounty]

Well, given what IZwack just said, I would get the one with the hole fixed, pull the junkyard one you have under there now, put the "holey" one back in the truck, then gut the junkyard housing to regear it. You would end up with the better housing having the new gear set in it and would not have to worry about that repair too long.
Did that make sense?

 

[gavin]

Well, given what IZwack just said, I would get the one with the hole fixed, pull the junkyard one you have under there now, put the "holey" one back in the truck, then gut the junkyard housing to regear it. You would end up with the better housing having the new gear set in it and would not have to worry about that repair too long.
Did that make sense?

while that would be ideal;
both housings have different gear sets. "Spare" is 3.73, currently 4.10's under the truck.
We all know we can't mix 3.73's with 4.10s' :
I don't really want to drive around without a front driveshaft since it's AWD.

oh, not to mention I jumped the gun and already gutted the housing and removed the ring gear from the carrier

hmm... well maybe I can see how cheap the cheapest junkyard unit is, then give this one back for the core charge.

edit: scratch that, apparently nobody has any according to a search on car-part.com