Rear crossmember

I took my old crossmember to the fab shop this morning – they said “no problem, check back after lunch”. I got him to bend 3 pieces x 43″ long. I called back after lunch – $50! – but they were ready. Once I got back home, I discovered that they used a little thicker steel, so the height of the channel was about 1/8″ taller – not really a problem, so I can work with that. He went ahead and used the full width of the sheet – 49″ also.

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I began by measuring the length of the end tab and marking it with a square.

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Next, I cut the tab out on both sides.

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Then bent the tab down.

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Lastly, I measured the total length of the crossmember, marked that with a square, and added 1 7/8″ for the tab – then cut to length. I repeated the process to create the other end tab.

I test fit it in place.

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Then marked and drilled pilot holes for all of the various holes.

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I came back and used various size bits to re create the original holes. I used a step drill bit to drill the 1″ hole on the drain plug side and 7/8″ hole on the other side.

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I test fit it in place and realized that I didn’t cut the half moon out that goes around the drain plug hole. So I used my spare chassis to locate that so that I could re create it on the new crossmember (is was rusted away on the old crossmember).

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Lastly, I test fit it in place one more time and drilled the holes where the rivets originally were. I WAS just going to put bolts back in their place, but ran across some carriage bolts while looking through my bolt bin. I think they look pretty close to rivets, and definitely better than bolt heads!

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Tomorrow, the plan is to prime and paint the bottom of the tub (after I grind down those spot welds) and crossmember. Maybe if the paint dries fast enough I can get the frame welded back on the tub.

M100 frame work

I finally got around to working on the M100 again yesterday. I decided (in my mind) to use the frame off of my other M100 chassis because of how much rust was on this one. After checking out the other frame, it wasn’t worth the extra trouble – the other one was only slightly better. The rear crossmember wasn’t rusted away on it.

So…. I dragged the original frame out of the scrap pile and inspected it again. The rear crossmember needed replacing for sure. About a 1/4″ of the edges of the 2 middle crossmembers were rusted away – which I ground down when I was working on it before. So, I decided to go with it – I was going to replace the rear crossmember and leave the middle ones. I started removing the rear one.

If you’ve never looked at how the frames are assembled, they used 3/8″ rivets AND welding. The rear crossmember uses BOTH methods. There is a rivet on the bottom of each side and the edges are welded on the end and the bottom. I used the plasma cutter to cut the welds so that I could remove the crossmember so that I could get in there with my side grinder to grind down the bottom of the rivets and the rest of the welds that weren’t cut off. Once they were ground down, I was able to use my air chisel to drive out the top half of the rivets.

Then I set the frame on the tub for the first fitting:

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It fit pretty good! There are a couple of spot welds that need to be ground down a little more for it to fit flush to the tub though. Overall, it fits well. It should fit right back in the original location. I WILL have to do a little more fitting on the front angle, as it is TOO far away from the new metal that I welded in. I don’t know what is going on there yet.

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I think today I am going to scuff the bottom of the tub down (after I grind those spot welds and make sure the frame fits flush) and spray some OD on it. I might go ahead and spray the frame with primer (maybe the bottom of the tub too) and paint it too.

There is a metal fab business a few miles away that I am going to go ask if they will bend a channel for me. If so, I’ll get a FEW4′ pieces bent. The rear crossmember measures 37.5″ inside of the outside frame rails. I am guessing that the pieces of channel need to be 42″ long so I will have enough material to cut and bend the tabs on the ends. By the way, the metal is 12ga.

Here are a couple of pics of the rear crossmember after I cut it off. You can see how bad it was rusted.

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More M100 work

I got outside this morning after work since it was so nice. I cut the edges off the new floor and trimmed it up for a nice tight fit.

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I had to cut notches in the ledge for the new floor to fit flat.

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I sprayed weld thru primer on the bare edges of the new floor after I removed the paint with a flap wheel.

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After one last fitting, I drilled holes around the edge and pulled the new floor up tight with sheet metal screws.

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Then I flipped the tub over and plug welded the holes up that I drilled thru the ledge previously.

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Lastly, I dressed up the welds and plug welded the screw holes on the front panel. Then I sprayed primer over all the new work.

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The plan for tomorrow, if it doesn’t rain, is to remove the frame from my spare M100 chassis since it is useable as is with a little sanding and paint. I should also be able to get the bottom of the ub painted at the same time. So HOPEFULLY, I will be able to get the frame welded back to the tub and be ready to reassemble the running gear and tongue!


Worked on the M100 a little today

I got started on the M100 floor replacement today – the last day I am off until next week, of course. I started out by deciding on how to replace it. I (along with the advise of my brother) decided to leave a 1″ border around the edge of the tub and cut the edges of the replacement floor to fit inside the tub and spot weld (plug weld) the new floor to the ledge. The front lower edge of the tub was pretty much rusted away, so I have to leave the lip of the new floor and weld a patch panel in place in that area.

I had a 2′ piece of 1/8″ x 3/4″ piece of scrap steel that I used for a straight edge. This, added to 1/2 the diameter of my plasma cutter’s tip came out to right at 1″ – perfect for the ledge I wanted to leave! Man, am I glad I bought that plasma cutter years ago! It only took about 10 minutes to cut the floor out – with PERFECTLY straight lines! It took me about 15 minutes more to decide on how to cut the rusted front out of the tub and to cut it.

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After that, I went around and straightened all of the edges and ledges and used a flap wheel to take the red oxide off of the ledges.

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Lastly, I cut some sheet metal I bought from Tractor Supply ($10 for a 12″ x 24″ piece, and it wasn’t even 18ga!). Again, I sure am glad I had the plasma cutter! I tacked them in place, then filled in with more tacks. I will have to do more work on this after I get the floor in place and it is more sturdy to work on. I didn’t do anything with the seam on the inside yet – it WILL show, so I will have to use filler or something to make it look good.

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I cut the new metal a little wide, so I will have to grind it down to match the height of the floor once it is in also. The original front and rear panels have a 1/2″ bead in them, but I didn’t have anything to make this bead – so a flat piece is what it got on the replacement. It probably won’t be noticeable.

The last thing I did was to spray all the bare metal down with a zinc weld through cold galvanizing coating. This will keep it from rusting until I can get back on it and get the floor in next week. Plus, it will let me plug weld the floor in without having to grind it back to bare metal, so these areas shouldn’t rust years from now.

The plan is to grind the lips off of the side and one end of the new floor panel so that it fits tightly between the tub walls. Then I will drill holes and install sheet metal screws all along the 1″ ledge of the tub to pull the floor tight to the ledge. Then I will remove them one by one and plug weld the floor to the ledge. Then I can come back and grind away the welds. Hopefully the gap between the new floor and tub walls will be so minute that I won’t have to do anything else, but if I have to, I will use seam sealer to cover it up.

New trailer floor


Bought this from D&L Bensinger in PA. My father in law picked it up for me on business, so he saved me $100 shipping (thanks Mike!). Overall, I am happy with it – appearance wise. I won’t know about the fit until I start to install it – it IS a foreign made repro, but $200 less than the US made ones (if I bought all US made parts, I would quickly have more in the trailer than it is worth – even with what these trailers bring today!).

Now, with that said, here are a couple of things that I have noticed so far:
– drain cover pieces are squared instead of rounded.


– pan is cut and welded back at all of the ribs ( I guess because the panel twisted when stamped?)

– didn’t include drain plug retainers even though they were supposed to be included (according to MD Juan)

– pretty heavy piece. It looks like .062″, or 1/16″. I don’t have a metal thickness gauge, but a conversion is about 16ga?

wpid-wp-1434045884047.jpg– has the center cross member spot welded on.

– side edges are turned down and ends are turned up.

Frame off of the trailer tub

As you recall, my next project was to remove the frame from the M100 tub so that I can replace the tub floor.

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I finally got around to doing that a couple of weeks ago. I used my plasma cutter to quickly cut the remaining spot welds loose. I am glad that I had it, because there were A LOT more welds than I thought! Also, some of the welds that I cut loose with the cutoff tool weren’t completely loose either. I basically just cut, then pried to find the next weld – and so on, and so on until the frame came loose.

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You can see in the picture above that some of the frame rails will have to be replaced because of rust. There is a metal shop a few miles down the road that might be able to make those for me.

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You can see the rust through where the front lip of the frame overlapped the tub. Over the years, water and debris packed in behind this lip and held water, resulting in the holes. There are holes in both front corners where someone drilled 1/2″ holes for drainage and didn’t seal the holes (I guess) – then the rust started and ate metal away from there. The floor on the inside is pitted and the metal is thin with a few pinholes. I am starting to think that repairing these places is the way to go. I have heard that the floor and side edges were rolled together for a water tight seal. Looking at mine, you can tell that they are separate instead of rolled. I thought about trying to find the spot welds and cut them out to remove the floor, but I couldn’t identify them – that might be a problem!

I cleaned the rest of the undercoating from the floor. You can see all of the spots that I had to cut to remove the frame – I think I counted 50 of them! If I repair the floor, I will have to weld up all of those holes in it.


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You can see in the last pic that the floor is bent down between the frame cross members – that would be another reason to replace the floor I guess – if I can come up with an easier way to do it. Maybe cut the original floor out and leave a 1/4″ lip around the edge, then cut the new floor lip off so that it will just fit inside the sides of the tub. Then I could use epoxy panel adhesive to bond it to the 1/4″ lip. I will still have to replace the rusted metal on the front panel lip.