oxy acetylene + control arm (need advice)

Therian

The Highlander
Founding Member
Apr 21, 2002
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Waterloo, Ontario
So after breaking (3) 21mm sockets on both of the front lower control arm bolts, and after going through several sawsall blades, it looks as though my only option is to cut these suckers off.

I've never used an oxy acetylene torch (or any cutting/welding torch) for that matter. I'd like to learn however. The problem is, I don't have anyone to show me how. I have pieces of scrap I can practice on

What is the technique here? I don't want to mess up the k-member while cutting off these bolts.

Thanks guys
 
Do you have a cutting tip on the torch? It's kinda tricky when you are first getting used to it, but you basicly want to get a nice balanced flame. To do this I turn up the acetylene just until the black smoke goes away. Then I slowly turn up the oxygen valve until the flame goes a nice blue and til JUST after the "feathers" leave the end of the blue cones. Using that technique should get you a good neutral flame to cut with....From there on out, getting a nice clean cut is all about practice...
 
I haven't decided if I will be buying a unit or renting one. As far as the cutting tips go, are there different gauges? the one area I have to cut is pretty thin (in between the k-member and the control arm) so I would imagine I would need a relatively thin flame. I don't really care if I mangle the control arm, as it is being replaced...the k-member on the other hand, I'm not too interested in replacing at the time being
 
If you're going to rent a torch but already have an air compressor, rent a plasma cutter instead. a 220 unit will rip through 1/2" steel and a 110 unit will handle 3/8". They are much easier to use and will cut through almost anything metal as well. An Oxy-Acetylene torch will only cut steel. it won't touch stainless or cast iron.
 
IF you need the tools get an electric cutoff wheel.. cheap ones are $40.... I bought a $90 one and about 6 blades to cut the control arm then cut the bolts out...

my 4.5" grinder wouldn't reach bolt without cutting off the arm too...
 
If you're going to rent a torch but already have an air compressor, rent a plasma cutter instead. a 220 unit will rip through 1/2" steel and a 110 unit will handle 3/8". They are much easier to use and will cut through almost anything metal as well. An Oxy-Acetylene torch will only cut steel. it won't touch stainless or cast iron.

a plasma torch would be nice, however although I have the air compressor, I do not have the outlet required for the power on a good unit. the sleeve plus bolt is probably around an inch thick.

IF you need the tools get an electric cutoff wheel.. cheap ones are $40.... I bought a $90 one and about 6 blades to cut the control arm then cut the bolts out...

my 4.5" grinder wouldn't reach bolt without cutting off the arm too...

How big were the wheels that you used? Did you use a dremel type unit? Seems like a slow, painful process
 
I bought this one: Dewalt D28402K at home depot for $89

Then I went through like 5 blades at less than $2 each....

Each bolt took me 15 minutes max once i figured out what to cut... BAsically cut the arm so you can get it off the bushing sheel, then cut the bushing shell (this stinks due to the rubber) then remove the rubber and then cut the bolt...

Now if I had a 6" cutoff it may have been able to just cut the bolts directly.... kinda wish I did that in the first place.

But you can get these things for under $30 for the actual tool...
 
I bought this one: Dewalt D28402K at home depot for $89

Then I went through like 5 blades at less than $2 each....

Each bolt took me 15 minutes max once i figured out what to cut... BAsically cut the arm so you can get it off the bushing sheel, then cut the bushing shell (this stinks due to the rubber) then remove the rubber and then cut the bolt...

Now if I had a 6" cutoff it may have been able to just cut the bolts directly.... kinda wish I did that in the first place.

But you can get these things for under $30 for the actual tool...

talked to my mechanic, and he said a reciprocating saw should have worked. Maybe I have the wrong blades. Nevertheless, I believe I do have an angle grinder at home, so I'll see if I can have some luck with that
 
A reciprocating saw will work, just make sure you spend the extra $$$ on good blades that are rated for stainless or hardened steel. You'll hill 2 or 3 standard steel blades per bolt if you don't.
 
A reciprocating saw will work, just make sure you spend the extra $$$ on good blades that are rated for stainless or hardened steel. You'll hill 2 or 3 standard steel blades per bolt if you don't.

When I initially tried (I didn't have time to get to the car today) I was using dewalt T14 blades. on the little tag at home depot it said aluminum, copper and zinc. I didn't see any other blades made by dewalt that specified other metals.

Maybe I should be looking at other blades from other companies.
 
First control arm off, with a combination of 5 reciprocating saw blades, and one angle grinder disc. Took about 3 hours to figure out the right method...I assume the other control arm should come off in no longer than half an hour.

I don't wish this upon anyone else
 
You want Lenox 614R 14T Bi-Metal blades. Thats what we use on the Rescue to cut cars apart. All you really have to do to them bolts is sit there with a propane torch and get them super super hot and use a breaker bar. Its a bitch but can be done. Good luck
 
Ahh.. thats actually not a bad idea, I never tried it but maybe if I'm ever in this sort of scenario I'd give it a try. If you heat at least part of the bolt till its glowing bright red for a couple of minutes, then remove the flame and IMMEDIATELY douce the hot metal in lots of cold water, you cause a localized martensitic transformation, which should make the metal brittle enough to just snap the bolt in half with a breaker bar. Good call.