Chassis Alignment (welded wrong)

tpinthepack · Post by **tpinthepack** » Sat Mar 10, 2007 2:58 am

Well, My really nice chassis that was shortened late last year has a problem. I am fitting new floor pans, and noticed the chassis is shortened about 3/8 inch more on the drivers side than on the passengers side! At first I figured I should just adjust the rear axle in the spring plate, but I just had the tunnell shortened and I am doing the pans still so maybe I should cut it apart, or at least cut the longer side and get the alignement better?? Anyone have thoughts on this? Thanks In Advance

newmanx59 · Post by **newmanx59** » Sat Mar 10, 2007 1:53 pm

I would cut it apart and start over. Use the body to determine how long the pan has to be then square it from there. If you don't weld you can hire a mobile welding service to come to your house to weld it. This way you can have it set and ready to weld when he gets there.

Oil_Eater · Post by **Oil_Eater** » Sat Mar 10, 2007 3:52 pm

What could have happened? Did the pan get shortened to the body? On my own Minivolks, the body is not 100% where it bolts to the pan. I can see where it would be easy to get out of alignment if the pan was shortened to fit the body, rather than by measurement. I would cut it and re-work it myself. Jay

fubar · Post by **fubar** » Sat Mar 10, 2007 5:38 pm

I would think that the front and rear beam need to be parallel and square within 1/16"(diagonal with a tape). Having the body fit would be a bonus. Did the choppers measure spindle centers? Or just made a math error? Seems like quite a bit to be off.

CairoManx · Post by **CairoManx** » Sat Mar 10, 2007 7:42 pm

First you should absolutely confirm its not straight. You said you noticed it when you're replacing floor pans. The floor pan area isn't the place to measure. You should measure from each top front corner of the frame head to the centers of the body mount bolt holes on the top of the rear torsion tube. I had a pan shortened by a "dune buggy shop" back in the 60s and it was crooked and too long. I tried to straighten it by putting a pair of caster shims under both torsion tubes on one side of the frame head. It still went down the road like a crab. You need to redo it or get a new pan and start over and get it straight. I've done a couple pans myself since, even though I'm not an expert welder. I do all the measuring, cutting, trimming and aligning. Then I use a small wire feed welder to tack weld everything straight. That's really 90% of the hard work. Then I take it to a professional welder and he runs the beautiful bead on all the seams. If you do it yourself, definitely lay the body on the pan and mark exactly how long the pan should be and where it should be cut. Also remember, there are three axes to check: straight, flat and no lateral twist.

tpinthepack · Post by **tpinthepack** » Sun Mar 11, 2007 1:23 pm

The spindle to rear axle is almost perfect on the buggy. However, the spindle could be bent, or the rear plates may have been adjusted. I measured from the inside of the beam, to the inside of the rear torsion. It was 3/8 longer on the passenger side. I then measured from the front cross member to the bolts on the torsion, and the passenger side was 3/8 longer. I measured from the lower shock studs on the front, to the torsion center and the passenger side was 3/8 longer. What really got me measuring was the pan contour on the drivers side does not match the tunnell contour. As if the passenger side is longer. I have not fitted the passenger side pans yet, but I am guessing it will not match either, but in the other direction. I think I should cut both welds apart on the sides, and most of the bottom and top leaving an inch or so of weld to hold it together. Then use a long bar clamp or cumalong to pull the passengers side square. Then tack weld the sides and fit the pans. Then test the body fit. And finally have it welded back. That way it never gets cut totally apart. Any thoughts on my measurements, or plan?

CairoManx · Post by **CairoManx** » Sun Mar 11, 2007 3:27 pm

I think the way you describe would open a gap on the longer (driver's) side which would be very difficult to close. Any weld where the parent metal didn't meet would be very poor. I think you'd probably have to cut through all the way around. On the longer side you'll have to use a grinder or large cut-off wheel until the frame is straight and you have a straight face to face seam.

fubar · Post by **fubar** » Sun Mar 11, 2007 6:21 pm

Even if you are not filling a gap, where ever possible on the opposite side of the weld back it with a piece of copper or aluminum. (chill bar) This makes a pretty effective weld and cuts down on warpage. And remember welds can make things shrink, so alternate side to side even when tacking it together.

tpinthepack · Post by **tpinthepack** » Wed Mar 14, 2007 1:52 am

http://www.meyersmanx.com/gallery/showg ... hp?cat=554 I am for sure cutting it apart. I need this perfect. Thanks for all the advice.

markmark · Post by **markmark** » Wed Mar 14, 2007 3:35 am

[QUOTE="manxter10"]Here is a link to a method of pan cutting that I have used and have seen used numerous times. Never had a problem. The secret is to make a lot of measurements and then measure it again, before cutting and then rewelding. http://www.meyersmanx.com/garage/garage_shorten_p1.htm Joe[/QUOTE] I used that link to the letter when I was doing my pan and it turned out perfect. You are so right Manxter10 when you say about measuring and then measuring again and again. I think I must have measured mine about ten times while it was being welded.

CairoManx · Post by **CairoManx** » Wed Mar 14, 2007 4:36 am

Weld some metal reinforcement over the two slots for the heater control on each side of the parking brake. Many, many dune buggy frames have cracked through there.

Manx Club

Chassis Alignment (welded wrong)

Chassis Alignment (welded wrong)

Measurements

Pictures of the Damage