Protecting The Underside of a Series
After a couple of rough weekends at Uwharrie, the Lightweight needed a bit of a fix. The main cross member (the one that is welded to the frame) was in very poor shape. In fact it had a 4 inch gaping hole on one side. During the rebuild over the winter, we did not have time to fix this but now something needs to be done. While doing this, why not add a skid plate to protect the xfer box and tranny brake?
At 9am, I met over at Bill's shop. He is lucky enough to have all the metal working equipment one would need when doing this kind of work (we just made a set of bumpers for Ric and Bill's son Wil). Once there, Bill had to wrap up some work on a pair of jetskis and then made room for my truck.
We lifted it up on jack stands and when Bill saw my cross member, I took a ribbing all day about my driving habits. Yea, it was a little banged up - just a tiny bit. It could not be saved so after analyzing how it was installed, we cut it out and started work.
We left the ends of the cross member intact on the truck. They were in excellent shape and could be used as attachments for the new cross member. One we cut out the damaged piece, the ends were ground smooth and square. We saw no need to weld directly to the frame if we did not have to. We thoroughly inspected the welds to the frame. This meant scraping and sanding the black goo that protects the metal. We determined they would be a solid mount.
The new cross member was built out of 1.5"x4" U tubing. It is 1/2" thick. They were welded together to form a huge 3"x4" rectangle. Once that was together, we needed to cut to fit in the space provided. After getting a good fit for the lenght, we needed to cut a divot out of the top to allow clearance for both the front drive shaft and the bell housing. This was trial and error. The first cut was very close but still needed a bit more clearance. We marked off some more until we got a good dry fit.
Now we have a perfect recatangle with a huge chunk cut out of the top. It needs to be sealed up. We found some 1/4" flat stock and welded it to one side. Using the torch, we heated up a section and began bending it to fit the curve of the metal. Once all bent to shape, we welded all the seams and ground everything flush. We did another dry fit. It is really a close fit to the bell housing but it looked pretty good.
The next step is to create dog ears on the ends which will be used to attach to the ends left on the frame. Using 3/8" flat stock, we marked, cut, welded and ground them in place. We also drilled holes in the dog ears so we could bolt it in place. Another dy fit. It seems we are just about 1/16" to high and bell housing rubs it. No problem. We mark the area where the bell housing sits and took it over the bench. We heated up the area and using a hammer, made a nice smooth divot where the bell housing would fit. Once cooled, we fit the piece again. Perfect fit.
Initially we thought that we would drill holes and bolt the cross member into place. In the end, we opted to NOT drill and attache with bolts. We had the dog ears ready but getting a drill in there would very cumbersome and time consuming. We also saw no real advantage to having the piece removeable.. Instead, we plug welded the cross member in place. The nice thing is if you ever need to bolt it in, you can. Just drill out the weld (the holes are already there for the drill bit to line up). Once welded, we tested it for strength. It is VERY solid. I will have a hard time bending it now.
Wtth the new cross member inplace, we looked at how to protect the under belly. The oil pan has taken one small hit but the cross member, xfer case, and tranny brake seem to have taken most of the damage (I had to replace the xfer case gasket from the last time I was out as it got damaged). We decided to make a plate that would cover all these areas to give it more protectoin. Using 1/8" diamond plate, we cut one piece to cover it all. We made 3 holes in the bottom of the new cross member for bolts and one in the other cross member for one bolt. We also bent up the front endge of the plate and the rear corners so it would be less likely to snag/hang up on anything. We tapped the new holes for 5/16" bolts. Once we fit it, we ground it all smooth and put it in place.
The last thing to do is mount the back edges of the plate otherwise they would contstanly flap. We created two new brackets for each rear corner. These were welded to the frame and then bolted on the rear corners of the new plate. Once all attached, we started up the truck to test for rattles. Nothing.
We were running out of time so we cleaned up, loaded the truck on the trailer, and drove home. All that is left is painting the new cross member and skid plate and replacing the bolts with button head bolts. Oh, and I also have to fix the tranny brake backing plate. Seems to rub a bit from the last time it got hit. The result of the days work is a lot more protection to the underside of the truck. At least now I do not have to worry so much about damaging those areas.