Well Chuck (chmurt) hears the answers to your questions.
First I’m going to start out with a picture. There are two different side mounted spare tire mounts used on the step side pickups. One is for the long bed step side and ones is for the short bed step side. The brackets and fenders are different and cannot be interchanged with each other. See the below pictures to see the differences. You said that your truck is a short bed and I hope you have the correct bracket and fender, you cannot make a long bed bracket and fender work on your truck.
Question 1. Do you have any pics of the bottom support bracket under the bedwood and how it fits up and attaches to the vertical supports? (A fitup dimension and hole drilling location headache!)
I did not have or use the bottom support assembly on my truck. You can see it in the above picture for the short bed installation. I figure that you’re trying to fit your bracket to a bed side that did not have the mount holes already drilled. There is one hole in your bed side that exists and all the rest of the holes that are needed can be measured off that hole. I marked up the above picture to show this hole and retyped the dimensions on the factory drawing because they were hard to read. Personally I would remove the fender and assemble the bracket, attach the bracket using the one hole and mark all the need holes off the bracket. The dimensions on the drawing should be close but may not match your bracket exactly.
I didn’t like how the aft short leg fit between the top of the fender and top of the bed side plus the legs looked flimsy to me. That’s why I went into a redesign mode and made mine a one peace aft leg passing thru the fender. If you look at my posts you will see in the first post #79 thru #82 that I started with a factory mount (two part aft leg), but in my last post #84 I showed my redesigned legs. (hears a link back to the page)
http://67-72chevytrucks.com/vboard/s...=318544&page=4 You didn’t say whether your using 6 lug rims or 5 lug rims, you should probably check your mount out to see what lug pattern it has and see if it matches what rims your using, you can print out the lug nut patter In post #79 to check it. I had to modify my mount from 6 lugs to 5 lugs.
Question 2. How much clearance do you have between the tire and bedrail and the side of the fender cutout, or are you butting the tire tightly against those areas?
As you can see in the above picture I ended up with 3/16 inch clearance between the tire and fender lip. I was shooting for a 1/8 inch gap, didn’t want the tire riding on the rail or cutout in the fender. If it had been riding I would have shimmed the rim out from the mount to get some clearance. The rim size and backspacing plus tire size that you’re using are all going to play into what clearance you end up with. I’m using ARE-625873 American Racing, Outlaw II Wheels 15 in. x 8 in., 5 x 5 in. bolt circle, 3.75 in. backspace, -19.00mm offset and P255/60R15 BFGoodrich Radial T/A tires.
Question 3. The fender Grommet through which the rear bottom leg of the side mount bracket passes: I finally found one through internet search which is close to original - suitable but flimsy. The one on your installation looks much more substantial and, although it doesn't apply to my installation, I see it also handles the antenna cable. Can you recommend a source and part number?
The above pictures are the best ones that I have that show the grommet in question on the finished installation. I don’t have any part numbers for you, I made it from stock material. If I remember right the hole in the fender is approximately 1-3/4 inch DIA. I used a standard grommet for the hole size and then glued a peace of 1/8 inch thick rubber on top of it, then drilled/cut the holes in the rubber peace where they were needed.
Question 4. Do you see a need to coat the bedsides in the fender wells with Herculiner or some other product similar to what the fender insides are coated with? Seems as though there used to be undercoating there.
Your right, this area is normally undercoated, I don’t have any plans to undercoat this area on my truck. I did the undercoating of the fenders off the bed as can be seen in the above picture, much easier to get it in all the nooks and crannies and I hope that the inside bed panel does not need the added protection. Back in the 60’S I worked in an undercoating shop for a few months (not a job that I wanted to pursue – smile). We would normally spray this area, but as I’ve taken off a few fenders from older step sides that had been undercoated. I found that some of them had rusted areas on the flange of the fender. Some of this rust was caused because the undercoating had sealed the fender flange to the bed side and created a water pocket that trapped water in the area, I hope that leaving it unsealed will let any water that might get in there a way to drain out and not cause any rust in the future.
Question 5. You mention on Page 15 of the thread that you applied Seam Sealer where needed before the painting process at the shop. I will need something like that in areas on the bed and tailgate when readying for paint. Can you recommend a product?
As far as recommending a specific product (NO), but as to a type of product (YES). I would recommend using a two part seam sealer. It’s like an epoxy compound that mixes the two parts in the applicator/mixing tube. In using this type of product there is a problem and that is that each manufacture might have their own stile gun and it does require a special gun to apply it. The gun generally looks like two caulking guns put together and is very expensive to buy and own for a onetime use. I used the body and paint shops gun and the two part seam sealer that they used. You can see my seam sealing of the upper drip rail in (Post #411)
http://67-72chevytrucks.com/vboard/s...318544&page=17
Just as a side note, don’t over seal things, it can cause problems down the road. If I remember right there’s only two areas on the step side bed that were called out on the factory drawings for sealing. One is the tail gate lip top and bottom on the back of the tail gate and the other area was on the inside of the spare tire cutout on the fender. I welded my cutout in instead of using it with the factory spot welds that where there. You can see the welded in panel in (post #65)
http://67-72chevytrucks.com/vboard/s...=318544&page=3
Question 6. I've not mentioned that the front fenders, hood & cowl have been painted but are not fully assembled, although the cab exterior, interior and doors are complete painted and installed. Are the inner fenders installed prior to or after installing the outer fenders? I didn't see that mentioned in your build thread and couldn't tell from the pics.
(After the outer fenders are installed) The front inner fender wells where the last items installed, everything was complete prior to the fender wells going in. I think it is very important to test fit them before painting because some of the holes in the inner fender may need to be slotted a little to line up the holes. You can see the installation on (post #613)
http://67-72chevytrucks.com/vboard/s...318544&page=25
Hope this helps you out in your project/build. There’s probably more information than you wanted hear but I thought that it possibly could be of help.
Enjoy Your Build
Bruce