question regarding spring steel

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I have a question regarding the welding of spring steel. Specifically the spring plates (rear trailing arms) of an early aircooled Volkswagen bug or bus. Since these stand on edge and do not act like traditional automotive springs, how would welding affecting them? More specifically, welding exstensions on the ends of the spring plate when lowering or modifying suspension pieces. The torsions, which really act as the spring, are still inctact at the original pivot point that the plate pivots on. I know that welding spring steel can be dangerous by causing the metal to become brittle around the weld area, but in this application, where side to side movement is minimal, would it be "less dangerous"? Any thoughts or suggestions would be appreciated.ThanksJonathansome pics to help illustrate
Reply:From what you've said I think you just want to weld on the trailing arm and not on the torsion bar. You can do whatever you want to the trailing arms and not hurt the spring at all as long as you don't heat or weld the actual torsion bar itself I dont see any problem with it.
Reply:Welding regular leaf spring is a bad idea, but I think you are ok here. I am not a VW guy so I am not familair with the setup of this suspension, but I get the idea from looking at the picture. I wouldn't think that there would be much side to site motion since I can see that there will be coil springs and the torsion bars. Definitly keep the welder away from the torsion bars, they should not be altered. These are called spring plates? But has the steel been heat treated like a leaf spring?
Reply:There would be no welding on the torsions. I posed the questoin because there are many vw enthusiast that are fearful of welding on the spring plates (trailing arms) because they are spring steel and I think they have been treated as any other spring steel has. But since they are on edge and do not flex as a normal leaf spring would, i dont see how they could become weak and break.gavinpierce -  There are no coil spring on a vw suspension. The spot you are looking at is the mount for vw's version of a sway bar. The torsions are the spring just like a mopar front suspension or toyota/nissan/late chevy truck front suspension.There is some side to side movement as the axle pivots in the transaxle thus pulling the spring plate closer as the arc of the axle is higher or lower, but it is a very minimal amount of movement since its up and down movement is very little.Thanks for your inputs guys.Jonathan
Reply:what method are you going to use to do this??it may have alot to do with this......zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:It just so happens that my neighbor is a V dub guy and has a few books on them. I went over and borrowed one for a few minutes and got a pic to better illustrate the internals of the suspension and to let you know what is ok to weld and what isn't.#9 in the illustration is the torsion bar. It is spring steel and is not good to weld unless you first annealed the bar, then did your welding ,then re heat treated it and tempered it back to the original spring steel condition.#8 in the illustration is a rubber bushing. The part that the rubber bushing is attatched to is the trailing arm. The trailing arm is not spring steel and as long as you seperate the trailing arm from the torsion bar and rubber bushing you can weld away on it to your hearts content.hope this helps you out  Attached Images
Reply:Wow! Super helpful teknition. Did the manual you were looking at say that the trailing arms are not spring steel? I guess I just took the rest of the vw communities word that they were spring steel. I guess I'll be building myself some new trailing arms then! thanks for the help. I really appreciate it.
Reply:Hi SquareNo the manual didn't specify what type of steel it was. I looked at the trailing arms on his bug and they appear to be just normal mild steel stamped in a corrigated type pattern for strength so they don't bend, much like the trailing arms on the rear end of many north american made front wheel drive cars. I can see no mechanical reason for the arm to be spring steel, thats the torsion bar's job. In general it would be a bad Design to have your rear axle flopping around sideways while you are driving down the road wouldn't it?In your pics, the black piece is not the factory trailing arm. Since you are cutting most of the arm off anyway, if you want to be 100% sure its not spring steel just put it in a press and bend it OR lay both ends of it flat on a couple of cement blocks and smack the middle of it with a sledge hammer. If it bends and stays bent its deffinitely not spring steel. If it springs back to its original shape then it is spring steel.The trailing arms you have in your pics looks 10 times stouter than the factory one so I don't see any concern there. The only thoing that would concern me is if you don't have the experience or a large enough welder to do the job properly. If you are trying to do this job with one of the little 110 volt hobby welders I would say thats a dangerous idea and to get it done properly by someone thats qualified to weld it. I'd hate to have your axle comin at me down the highway without the rest of the car attached.  Happy fab'n
Reply:I've welded a torsion bar as shown in teknition's picture (item 9).  It was an emergency job and I told the guy to get it replaced asap.  Of course 50K miles later (I forget the brand (a foreign car is all I remember) - I just happened to see him again last month) and it's still in there working fine.  I used MG Super 600 electrodes in a stick welder and preheated just a little to get the moisture off.  His was cracked and I ground down to good metal and left plenty of room to fill in and kept pausing (1/2 hour each pass) to let it cool.  I have no idea how long it will last but hopefully he is knocking on wood quite often!  Of course since you are not touching that part this is just future knowledge.Have a great day
Reply:Originally Posted by toddmorrisI've welded a torsion bar as shown in teknition's picture (item 9).  It was an emergency job and I told the guy to get it replaced asap.  Of course 50K miles later (I forget the brand (a foreign car is all I remember) - I just happened to see him again last month) and it's still in there working fine.  I used MG Super 600 electrodes in a stick welder and preheated just a little to get the moisture off.  His was cracked and I ground down to good metal and left plenty of room to fill in and kept pausing (1/2 hour each pass) to let it cool.  I have no idea how long it will last but hopefully he is knocking on wood quite often!  Of course since you are not touching that part this is just future knowledge.Have a great day
Reply:teknitionthe trailing arms on the bug are different than those on my car, a vw squareback. those on the bug are also different than those on vw bus, which is what is in the pictures i used as examples since those are similar to the trailing arms used on my car. i think the vw you looked at may have been a Super Beelte with independent rear suspension. the suspension on my car is just like the photo from the manual you posted.I have decided to just make new trailing arms with a 'kick up' towards the rear to aid in lowering the car. i am going to make a template and have them water jet cut. i will have to weld in a new splined sleeve to attach it to the torsion. these are readily available new, so i dont have to cut mine out. i actually won't be doing any of the welding on this stuff, as i am not proficient enough to do a good job. i work at a hot rod shop and ill have our chassis fabricator do the welding with the tig. ill stick to the sheet metal for now, but every once in a while i jump on the tig when i get the chance to practice.i have a couple extra spring plates to abuse, so i'll try both your methods of testing to see what they are made of. and ill do a little more researsh to see if any of the long time VWers know what they are made of.thanks for the helpjw
Reply:Glad to have been of some assistance. Let us know what you find out with the hammer test.Happy fab'n
Reply:so it seems it is spring steel. but there is a spring manufacterer in town, so im going to talk to them and see if they can properly treat the trailing arms that i plan on making. ill keep this thread updated on any progress that is made with the project.thanks for averyones help.jw