Rear Trailing Arm Issues

[MackZ24]

The Background;

Upon removal of my passenger side rear trailing arm I ran into a bit of a problem. The Lower Shock Mount bolt snapped. This wasn't such a big deal, there were still a few threads showing, so I welded a nut to the end and tried to break it loose again. Well, no dice. It just broke again and this time flush with the rear trailing arm. So the drill was brought out, drilled a pilot hole and then a larger hole inside the bolt. There was only about 2mm or so of bolt left on each side. Took a 5/16" EZ-Out and went to work. Well, this bolt was persistant and the hardened steel EZ-Out snapped. After this I was getting pretty frustrated. Didn't have any cobalt bits, so grabbed a Titanium tipped one and tried to get through the EZ-Out but that just isn't happening.​

So here's where my problem sits now. This EZ-Out is stuck, it's not coming out, and I'm not sure what my options are. I live out in the country (in Canada) and there aren't really any parts cars around me to get another rear trailing arm from. I could attempt to find one a few hours away and have it shipped to me. My current trailing arms are all ABS, is it going to matter if I put a non-ABS arm on only one corner of my car? I don't think the ring on the ABS hub that isn't present on the Non-ABS will make a difference but I just had to make sure first.

The other option is where it gets really tricky. I basically have full access to a large fabrication company. What I was thinking about doing was just completely cutting off the mount that the shock bolt goes into. It shouldn't be very hard for me to find another piece of steel tubing with the same inner and outer diameter. I thought that if I could do this, I could weld it on where the previous one was, then just re-tap for the correct thread size and use that. However, I'm not sure if this is completely safe. For the most part, the welding should hold up, but it is a rather stressed part of the car and I didn't want to take any chances if there is anyone that is sure it wouldn't hold up.

I apologize for the lengthy post, but any help in this matter is greatly appreciated.

-Mack

 

[ahaidet]

The local fabrication shop may have a machine called an EDM (electronic Discharge Machining) Machine. EDM machining uses controlled electronic pulses to carry away the old metal, it would have to be a newer probe style EDM machine as the old style wire EDM machine would not work to remove the bolt. It is one of the few ways to remove hardened metal with precision. It can be rather pricey to have done it would be cheaper for you to get a new trailing arm, hopefully the fab shop and you are on good terms and they will give you a good discount. Check into it. If you cant have it done I recommend going through the classifieds on this website or DSM trader, I got two used trailing arms in good shape for $50 bucks on here.. local junkyard wanted $110 for one. As for welding a new shock attachment on there, I see a few problems:
1) the weld quality strength issue
2) it would have to be machined on a lathe, just welding a random piece of metal the approximate right dimensions wont work as the mount has a slight taper to it. When you tighten the bolt up the shock gets "pressed" onto this taper which helps to hold it on.
3) the alignment of the mount is critical or it will put angular loads on the shock and possibly bend or fatigue the shock itself, welding this piece on at the right angle could be tricky

EDM prices are high, lathe machining prices are lower, used trailing arm should be the cheapest option (even with shipping). Unless you get a discount at the shop. Wish there was a cheaper easier solution..

 

[MackZ24]

Thank you for the reply ahaidet. I didn't think anyone had any input on this. I did in fact find a used trailing arm, as like you mentioned I noticed the slight pitch that the mount is on, and figured it would be difficult to replicate this without the right equipment. The trailing arm should be in the mail to me right now, but has been a little while. If for any reason it doesn't come I will keep you in mind and drop you a PM. Thanks again for all the advice.