Sill Replacement - Chapter 2

Submitted by bill on

October 02, 2009

Clamp Attack on the old original horns, getting ready to weld to the new channels. Got home from Colorado yesterday and found my sill channels from Kevin had arrived. Beautiful parts, great fit - cover to structure - even had to use a gentle screw driver to get them apart.

clamp attack

Size at this point looks good - I'll know more later. May need to grind the old internal brackets at the 5/16" radius area a bit (see photo) - or maybe just a tack weld at that point so it doesn't rub in future with vibration. Note I still think the "dimple' dim I gave Kevin is .060" too much to driver's side, but there seems to be plenty of flat for the latch.

Thinking about small drain (.065) holes inside the 18 ga cover bottom lip - hidden on bottom in the bend radius - in an attempt to keep future moisture from building up in the sill "sandwich". Might try to shoot the thing full of POR15 after re-assemby/welding.

kevin update 1

kevin update 2


I don't think the radius is a big deal - the cover/structure fit around the step is probably closer than the stock parts were. A quick grind/file on the 2 stock brackets should provide plenty of clearance.

The 2.300 dim (see attached drawing) seems a bit over (2.330-2.340) on my channels, but they seem to match up fine on the horns with a bit of clamping. You could maybe knock .020 off that dim and bring it around 2.310. Again hard to say without good original stock parts to measure.

Note the A/B dims are correct in that the top (2.030) is wider than the bottom (1.928) and both should stick out a little (my stock sill anyway) from the horn material they weld to. Stock was maybe a bit shorter - "A" matches up and spot welds to floor and my rear floor area/sill was shot - so you could knock .020 off those 2 dims. Not a big deal for me - I need to fab a piece for the floor anyway...  

Area "C" on the stock sill used a tab (part of the horn) with a 90 degrees bend to roughly fill the opening. I left it off the horn patch work on purpose. I might leave both sides open to allow more air into the sill sandwich along with the cover drain holes mentioned earlier. If I decide to close it I'll maybe use an additional small 14 ga support brace - welded inside - In which case it would really be closed.

In the process of rigging a crude fixture for welding the horns on and finishing up patch work on the horns. But I'm going to drill the channel holes before the horns get attached. Need a good source for weld nuts.






New channels with old original brackets, weld nuts and curved horns. The horns were a bit of work to patch. But everything seems straight and the measurements seem to have worked out so far. Overall seems light/springy but strong.

sill 1


sill 2


sill 3


Attached is the rough fit - things seem to line up well.


rough fit


More or less from what I can tell the horns are the same thickness but the horns seem formed with thickness variations due to the metal stretching in the tooling, etc. And they have no sharp corners with fluid radius stuff going on all over - including a slight curve on face, etc. There were fine (but distinct) welds on the top and bottom - the same area I welded. But maybe the "face" was part of the main (all one piece)? My sill was too rotten to really tell what was going on with the face area.

factory weld

More drawings relating to the rear floor and sill areas:

“A” is patch channels for the front of the bed, the area right above the rear heater. Channels are 14 GA and 16 GA and around 40 inches.

“B” are small channels that go vertical above the sill at the back door frame/end of wheel cover area.

bed kevin


Started to weld the main sill structure to my crusty old bed - still trying to save as much original as possible. Getting the outside sill cover ready - decided to go with some "drain holes" instead of sealing everything up.


crusty bed


drain holes

My floor was toast around the sill and toast around the front floor support/body mount area - not pretty everywhere else but I've decided to try to use it to keep everything original. After-market don't seem to match stock - like the stamped pattern indent with the 2 + screws on each side (rear support area), heat shield brackets bottom side, etc. etc.

My stock floor looks good from the bottom, pitted and rough on top. I cut the floor back from the sill, made a 16ga replacement patch (joined to the 14ga sill) that the 18ga sill "cover" goes over. In other pock-marked floor areas I'm filling small surface craters with a plug weld and grinding them down. The front floor support/body mount area I'll try to replace with the channels from Awl-TEQ. This 14ga support (with 16ga over the top) will need the old heat shield brackets welded to the new channel.

This hopefully will get me a solid floor that is still more or less original. Still will have a bit of corrosion in the floor-to-wheel cover seams, which I'll clean and try to seal with POR15 and seam sealer before paint. I may try to pull the rear support (the one with 4 + bolts) to clean that area up - might just leave it and try to run some POR15 in the channel from below, etc.


I've been using 3M Weld Primer - II 05917. It's the silver stuff in the attached photo. Everyone says you don't use much but it sure doesn't seem to last too long for me and still splatters a bit. On a plug weld once the two pieces are joined together I wipe/acetone the paint off the hole area, and fight through the splatter on the weld until I get a good plug. Who knows how much this will help the hidden areas but I guess it's better than nothing. The U-Pol Weld-Through Primer stuff (zinc or copper) sounds good (less splatter?) but it costly too and I can't seem to find it anywhere. The sill and sill cover (image 2) were both painted with 3M before they went together - as well as those vertical channel lap joints. Doesn't smell great when it's hot so ventilation and maybe a good mask helps. It's the silver paint in the orange circle below.

weld primer


paint 2