Control arm damage fix opinions

[calZ]

One of my rear control arm/transverse links had a bushing that was rusted to the tube. I tried a few different things to get it off, but eventuality had to resort to cutting it off. In doing so, I accidentally went a little deep on both sides and scored the tube that slides inside the bushing. One side is hardly more than a deep scratch, but the other side is more significant.

 

What are everyone's thoughts on dealing with this? Run a small bead of weld down the groove and grind it smooth? Or just run it as is?

 

I had assumed the bushings rotate around the tube when the suspension moves, but is that not the case? Or did this bushing just somehow rust solid in the ~2.5 years it's been sitting in my southern California garage? 

[NewZed]

The metal tube does not rotate around the end of the arm.  The rubber flexes instead.  That's why you're supposed to tighten the bolts with the weight of the car on the suspension.  

 

A picture of the end would be better.  Thread the bolt in and see if you think there's enough metal left to hold the torque.  100 ft-lbs.  That's the real concern.  If the tube splits and the bolt loosens the control arm will get loose. 

 

[walkerbk]

Depending on your welding skills. If it were me I would weld it just for peace of mind. Make sure to keep it cool so you don't warp it.

[NewZed]

The tube is a fine thread precise fit.  It's a dilemma.  Welding one side will probably warp it enough that the bolt might not fit anymore.  Put some thought in to a plan.

[AydinZ71]

If you look at the risk, it might just be easier to buy one for like $50. All the T3 and Apex junkies are throwing away their OEM LCA’s like they are bras at a Grateful Dead concert. I bet you could snag one in decent shape.

 

if it were me, I would cut off the whole end and make it a Heim/end-link, but I recognize most folks may not feel confident. 

[calZ]

I also have no interest in putting heim joints on a street car. They're noisy enough as it is. 

 

I couldn't really get a good picture to show the depth of the grooves, but I did my best to measure them. One is less than a tenth of a millimeter deep, and the other is just under 0.2mm deep at its deepest, and less for most of it. The tube is 25mm, and the bolt that goes inside it is 22mm at the max thread diameter, so 1.5mm of metal on each side. 

 

I'm going to guess there's more than a 10-15% factor of safety on the tubes, so it should be ok. I might still try to just put some tacks in and smooth it back out. If sheet metal can be welded without warping, I'd think the tube could be. 

 

Buying a new one is also an option if I see a cheap one. 

 

Thanks everyone. 

[AydinZ71]

Can’t argue with that! My Brian is in “race car” mode, and I’d probably stick to soft bushings for a street car too.

 

honestly I feel like you are probably OK to just reuse them. If I remember right, the 22mm bolt goes right into that sleeve you cut right? The bolt will keep the tube from collapsing. The plausible failure mode here is the lateral stress cracks/peels the steel back at the spot you nicked, but could it really go far enough for the bolt to come out? More likely it causes the bolt to loosen. PU bushings are more rigid, and will “hold” the OD of that tube better but they are a rougher ride of course. 
 

If you choose to run them, I’d check if the bolt may have loosened for a few days/weeks until you have some confidence it’s in there. Could also use blue locktite, but at 22mm that is a LOT of torque to break free when you do want to remove them. With that said, you can remove them without removing the 22mm bolt by unbolting the bushing shackle, then pry the 22mm bolt loose on a bench. The bolt is there to pre-load the bushing as newzed described.

 

You don’t really need my advice. I have two kids and don’t have any car friends nearby, so consider this as a technical rant from someone spending too much time on their car alone 😂. I do enjoy the “what if’s”. 

[NewZed]

You could have torqued the bolt to 100 ft-lbs by now.  Easier than all of the words, probably, and will tell you more.  Good luck.

 

p.s. cutting a groove like that is almost exactly what you would do if you were trying to remove a stuck bolt in a tube and heat didn't work.  The metal stretches at the groove and the bolt is freed.  Same concept as cutting along the length of fuel hose stuck on a barb.  It releases before you get all the way through.

 

Edited October 4, 2021 by NewZed

[JMortensen]

I would weld and grind that, personally. If you're using poly I'd suggest sanding the bushings down so that they're not way longer than the sleeve in the middle. If rubber, just remember not to torque until it's on the ground. 

[grannyknot]

4 hours ago, JMortensen said:

I would weld and grind that, personally. If you're using poly I'd suggest sanding the bushings down so that they're not way longer than the sleeve in the middle. If rubber, just remember not to torque until it's on the ground. 

This^  and if you are concerned about possible warping then you can do a couple of small spot welds, let it cool or cool it off with compressed air, then do a couple more never letting the pipe get too hot, then grind it back down.

[Mayolives]

Just a thought.....J B Weld???  I've used it for many things and the stuff really works. Part needs to be super clean before application.  When it's completely set after a few days it becomes very hard.  Then sand lightly until it's smooth.  

[fusion]

Thread the bolt in while welding so it makes it harder to lose shape

[LLave]

I would probably weld it too. Put a fastener in it. Control heat with TIG, or smaller mig tacks and cooling. Then carefully grind/sand to size. But that is me. 

 

I see you are in CA. I have a couple extra arms in my shed, if you end up needing replacement.