The Stovebolt Site Forums The Shop Area Paint and Body Shop Running Board Placement (1950 3100)

The original running boards were shot, so I got another set off another 1950. Problem is, the brackets that bolt it to the frame do not match. The brackets had been replaced at some point in time because they do not look original. I have no problem taking them off and relocating them, but here is the confusion..

Where do you relocate them to? You can't just wing it because the rear has to line up with the fenders. There is no pattern to where the holes are. Is there a precise measurement from the front of the running board to the first mounting bracket hole? If I had that, I could relocate the other two. Of course there is no sheet metal on this frame yet.

Deve, If you've got the factory assembly manual, it has frame dimensions on Sec 2, Sheet 2.00.

Front running board mounting holes on the frame bracket are 15.25 inches aft of the front of the dash, which is 13.188 inches in front of the front body mount holes. So the front bracket goes 2.062 behind the front body mount holes.

Hope that helps.

I do not take a lot of stock in the FAM because its a 1954 document and not one shred of information is actually from 1950. In this case I am sure its correct, but I am not sure how to proceed.

If I am 1/4" off in the guesswork that is measuring things that are at different heights and planes, the rear fenders will not bolt up properly. Is this something you just wait on until the rest of the sheet metal is ready THEN bolt the running boards up to the rear fender and see where to mark for the mounting holes?

How would you guys do it?

Deve, I've read your gallery story about your 1950 3100; I've been to your website; you are one brilliant guy. Sounds like you want it stock but you've made alllllll kinds of changes. So on my 1948 titled 3100 with the 1950 cab and the S10 rear main leafs and Camaro rear end and the 1987 stepside bed with reproduction steel rear fenders and 4 junk running boards that I turned into 2 good ones......don't you think that the forward edge of my rear fenders lined up with the trailing edge of my running boards? Haaaa! Who says that that junction needs to bolted up tight anyway? And wouldn't it be nice to center your rear wheels/tires in the middle of your rear fender openings? There's was so much rust and stress cracking back there that I never thought for one minute about reconnecting everything like GM did 60 years prior. I left a deliberate gap at the rear of the running boards which mimics the gap at the front. No Moisture Trap Gap I closed up all the holes in the rear fenders at that location and also closed up the holes at the back edge of the running boards. I've got a 5/16" brace going from the bottom lip of the rear fenders going to the frame. You created your own monster; and you're a really clever guy. Remember that old Nike commercial? "Just do it!" You'll figure something out. Good luck Deve.
Dave

I guess I'm not understanding why you need the locations in the first place. Did you fill the holes where the original brackets were riveted on? Or are you talking about the brackets that were welded to the bottom of the running board?

As far as measuring, I'd lay a straightedge across the body mounting holes, then with a digital level (or even a bubble level), measure back along the frame to the center point and drop a plumb bob or use a carpenters square for both horizontal and vertical positions. It might take more than your two hands, but sounds doable to me. A laser level might help out too as you don't have to hold anything along the laser beam.
As far as the FAM, why would the frame measurements be different over the years.
Hope you can get it figured out.

The FAM would be wrong as it normally is when improvements are made to the design. You just don't know when GM decided to change something that was wrong and improved a design. You can almost count on the FAM to be correct, but there are many areas where it's just flat out wrong. Bed changes, Cab changes, etc etc. I am not a FAN of the FAM for 1954 where they flat out LIED and called it a 47-54 FAM when all drawings are 53 and 54. In researching this problem further, I have heard of a fire that claimed all of the original drawings, laziness, you name it. In the end, anyone who wants accuracy for their 47-53 is just SOL.

Kevin... the problem with plumb bobs, liquid levels, etc is when you use more than one of them so you can get to a different plane is you can lose or gain an unacceptable difference. You cannot have a 1/16th inch problem when trying to bolt up the running boards directly to the rear fenders. They either bolt right up, or they don't. The running board brackets (frame) have their original holes. The running boards mounting brackets are not even close. The first one on one side is over an inch off from the first one on the other side.

It's not a hard question, but I can see it being VERY hard to correct with no sheet metal on the frame. I am looking for added intelligence in that regard...

1) Would you say that the most critical issue is the rear fenders bolting right up to the end?

2) How without sheet metal on the truck can you guarantee that junction is accurate? If there was a measurement that says.. go two inches from the front of the running board and that is where the FRONT hole would be, then since the frame is angled, 2.15 (example) for the second hole, then life would be simpler.

The 1954 frame is not EVEN the same as the 1947. The hump for the bed is lower, the trans crossmember is different. There are many other examples. Shock mounts, the list goes on and on. I THINK the issue at hand is the same so I concur with using it.

I am thinking the best idea is to just wait until the cab is on, the bed is on and the rear fenders are on, then place the running boards on and mark them for the mount brackets. I was just hoping someone knew something I do not about how to place them so I do not have to wait. But I can wait if that's what is recommended. It's not like I know everything, just enough to know you don't just start welding mounting brackets on, or bend the frame brackets to suit the whims of whoever welded them on wrong. I do not have laser measuring equipment and I don't think they did in 1950, so naturally, I was hoping someone knew from experience, bracket ONE.. goes xx inches from the front. bracket TWO.. goes XX inches from the front. bracket three goes XX inched from the front. Then, there is XX inches between bracket 1 and 3, 1 and 2, and 2 and 3 to confirm ABSOLUTELY before painting and refinishing these running boards.

Once those measurements are taken by a few Bolters, we can PUBLISH with complete accuracy EXACTLY where those aftermarket running board mounting brackets are placed for a successful install.

The way it works is, people go out and measure where each bolt is (both forward and outward holes) for all three positions. We then argue the little dimensional differences, then we conclude with absolute accuracy where they should be placed and KNOW that if you place them there and they do not fit, there is something ELSE wrong.

I hope I get it figured out too! But we could sure use a couple volunteers with tape measures!

OK, I think I've got it now. You're trying to locate the channel type mounting brackets that go on the running board itself.

You're right about most of the drawings in the FAM being '54. I flipped thru my copy and saw only a few with a '53 date on them.

I agree that the critical thing is to get the joint at the rear fenders correct, but I'd think you just need to get within 1/8" overall. The reason I say that is the rear fenders are bolted to the bed, which is bolted to the frame and there's definitely some fore-aft slop available at both places.

I may be out at my truck this weekend, which still has the running boards mounted on it, and get some measurements for you. But even then that may not get you what you need as the mounts on the bottom have rusted away or collapsed over the years. The front driver's side has bolt heads sticking thru the running board and the right front fender has taken a pretty good hit. But if those measurements will help you, I'm happy to do it for you.

You may be right about the best approach being waiting till you get at least the bed and rear fenders in place to locate the brackets on the running boards.

Kevin

Thanks Kevin! Yeah, you understand perfectly. In doing a frame up resto, it is not ideal to leave the running boards off all the way until last since it's a good way to mess up your legs! BUT.. maybe it makes sense because even with the slop you mention and adjustment room, you do not want ANOTHER factor in setting the bed on straight.

I just wonder how the running board manufacturer places those three brackets under the running boards.

Deve

You make a good point about leaving the running boards in place to protect your shins. I was just thinking about getting mine off, and maybe put some foam insulation around the brackets sticking out.

I'm sure there was some kind of jig for putting the mounting brackets on the running board at the factory. It's a shame there isn't a set of dimensions for doing that. I'm wondering if the repro running boards come with brackets already welded in place or if they expect you to to it yourself. Maybe a call to Jim Carter would lend some light on that. Or they might have an original running board they'd be willing to measure for you.

I'll see what I can do this weekend. My running boards are in good enough shape to restore, so the bolt locations might be close enough.

Running board mounting brackets/arms do not come with the 47-55 3100 reproduction running boards.

It is expected that the original mounting brackets are still riveted to the frame.

We are not talking about those brackets. They are part of the frame. We are talking about the brackets that are tack welded to the bottom of the running boards. They are the first thing to go bad so they sell replacements. We are just trying to figure out WHERE to put them other than "in the same place you took them out of" since in this case that isn't an option.

Deve

Here's a dimension for you. I measured from the forward face of the inboard fender bolt hole (the lower one) forward to the centerline of the inboard bolt hole of the middle running board mounting bracket. Dimension was 29 5/8". Measured it on the best side and checked against the other side as well. Got pretty much the same dimension there as well.

You should be able to go from that and locate the front and rear mounting brackets using the dims from the FAM.

Hope that helps.

Thanks again Kevin. I got a few measurements from another forum that will also help... here:

http://talk.classicparts.com/threads/1950-running-board-placement.22385/

I think with this information, we can get exact numbers which I will post here once I do a little measuring myself. Thanks to all who got out the tape measure and helped out.

Mine are still in place, so I didn't realize that the brackets aren't perpendicular to the centerline of the truck. Makes sense, though after looking at the photos on the classic parts forum. The support needs to be out at the corners.

My left rear bracket took a pretty good hit, so will either need to be straightened or replaced also.

Another thing that would be good is to get dimensions to the holes from a front to back reference line on the running board. Looking forward to the info you can post up, as my running boards will need new brackets that I'm just ordering up.

After getting input from several people and also measuring 3 sets of my own running boards and 4 truck frames, I averaged out the numbers for each dimension. If you measure on your truck you can be about 1/8" off of these numbers since that seems to be the tolerance GM used... plus or minus 1/8".

Please look this over carefully and then critique it. I want people to argue these numbers because if they are not right, I would want to know sooner than later.

http://devestechnet.com/Images/Projects/RunningBoards/RunningBoards0038lg.jpg

I am perplexed that we do not have this information available anywhere. Those frame brackets get bent, running board brackets deteriorate. Who knows why they didn't put it in the FAM. Is there anything else concerning running boards we need? I also have a bunch of pictures concerning running boards here:

http://devestechnet.com/Home/MorePix#runningboardpics

Deve

Is the bolt spacing from the outer edge the same for all the brackets?
Looks like that measurement I gave you is within 1/8 of what you have on your picture.

They were within an 8th like yours, but some were closer, some were further away. Using the frame mounts to correlate, I came up with those numbers representing the average give or take 1/8".