Magnesium 915 Weld

[jmcn3rd]

Does anyone know what type of filler rod to use for welding a magnesium 915 trans case? I will get some pictures hopefully tonight of the crack, which is definitely a crack on one of the mounting holes. Our welder has tried to weld it with magnesium rods but was unsuccessful in getting it to stick. Perhaps there is a specific rod material that someone knows of? Or possibly does someone know a good welder in NJ that could handle this?

[Flieger]

Did they try AZ91 Magnesum Alloy?

[jmcn3rd]

I'll check tonight. Is that one that you have had success with on a 915?

[Flieger]

I've never done it but that is a common alloy- the Magnesium cases and other engine bits are made of it so I would expect the transmission to be made of it as well.

[Steve@Rennsport]

AZ92 rod works on that using TIG.

[jmcn3rd]

Thanks, just sent the info down to my mechanic to check.

[jmcn3rd]

Here are two zoomed pics of my transmission crack. Think it looks like a weld will save it?

[john walker's workshop]

piece-o-cake!

[jmcn3rd]

Thanks, that is what we suspected but apparently they have been having issues with the material used. Will keep trying though.

[jmcn3rd]

Does anyone think this is not a magnesium case? It has a mech speedo for sure. I wish I had a pic of the part #.

[tobluforu]

JB weld that thing. If it's an org. 72 tranny then its mag, whats the number on the bottom?My 72 after I sprayed the hell out of it with Gibbs is much, much darker then that.

[jmcn3rd]

I suspect there is silver paint on it. There is very little original on my car so can't say that it def a 72. I will grab the number and look it up tonight though.

[tobluforu]

Snap a pic of the inside of the tranny as the 72 was one of the only years with a seal that can only be replaced from the inside. Is that why it's covered in oil as mine was leaking, but not as bad as that. Or, is that from the RMS?

[jmcn3rd]

Yea I am pretty sure this is leaking from inside. There is a chance it is from the main seal on the engine but we kind of doubt it. Though, my car, either engine or trans, barely ever left anything on the floor, just a tiny spot after a couple of days so it is not a gush. We have been debating whether or not to open it and replace the seal.

[tobluforu]

That sure looks like the inside of my 72. With the tranny on the bell housing, wrag under it, I could get tranny oil to come right out of the seal in no time. Clean it up, fill it and do the same, if it comes out a lot, it's up to you to slide down that slope if you want. If it leaks just a tad, look up Grady's dam seal trick.

[tadd]

Your going to have to disassemble it to get it clean enough. ALL the oils got to go and older mag is somewhat porous. You'll also need proper pre and post heat to do it right and have a forever fix.

Unless it's an uber rare part, get another. Think about all the money you can save on engine mods by building a short box !

Just my 2¥.

t

[70S Targa Guy]

Originally Posted by john walker's workshop

piece-o-cake!

Damn, I love JW and his professionalism & willingness to constantly contribute to this forum! Hey John, time to expand....Ya wanna open up a satellite shop in beautiful Bucks County, PA?