The Stovebolt Site Forums The Parking Lot Tons 'o Fun Lug nuts

I am not happy with what is being offered at various parts store with regards to lug nuts.

Seems like the nuts should have some sort of flange to spread the load, although none on my truck have a flange. A plain nut just doesnt seem to have the surface area I'd like to see.

I am looking at these flange nuts at McMaster-Carr. They ar 1/2-20 with a nice meaty flange, case hardened with a black oxide finish.

http://www.mcmaster.com/#hex-flange-nuts/=7xlub1

Whatcha think?

what wheels are you wanting nuts for? a flanged nut is for one style only, hub piloted, not what most of us have, which use stud centered lug nuts, the bull nose of the nut fits into the depression around the hole to center it ... see here

Bill

I have hub centered 19.5's on my 1 ton, and all the lug nuts are simple flat faced nuts that seem a bit skimpy, looking to improve.

maybe someone replaced them with whatever, like you're thinking of doing? any hub piloted lug nuts I've seen have an integral washer, like seen in Griggs tip to avoid galling the wheel - he might have some comments about it, but I'd talk to a truck parts place and make sure you're using the right thing

Bill

Not looking for "whatever", looking for the proper fastener and not having any luck finding them. Those in the pic you linked to look like they fit the bill.

see a truck shop, not NAPA, like a place that mainly sells big truck tires

Bill

What you need is a "clamp plate" like shown here in black, but obviously with 8 lugs.
http://rides.webshots.com/photo/2817686820080251109pQiKpl
They are what your truck should have had originally, and if not then they are what those wheels had in mind. I've seen plenty of them on step vans with both 16" and 19.5" wheels, and I expect on pickups too but I haven't looked close.

With the clamp plates they distribute the clamping load over a wider area than just the nut, even more still than a flanged nut. You will use tapered/beveled nuts (as if you had stud centered wheels) with the clamp plates, get the nuts from NAPA.
You can still get the clamp plates from GM, but they are ridiculously expensive, so look for used ones.

Edit: Thinking about the clamp plates again, I'm sure new ones have chamfered holes, but original ones may use flat nuts. I know this is the case with the 10 lug versions on 1.5 and 2 ton AD trucks, and I know late 8 lug ones are chamfered, guessing early ones were flat.

Grigg

Grigg, I will keep an eye out for that plate, although to be honest with you there is no trace of a plate like that ever having been on the wheels.

I will have to see how the new studs work out, the old ones {presumed original} are not long enough to allow that plate to be installed and still have the nuts fully on the studs.

I have had little luck the lug nuts {1/2-20, 3/4 wrench sized instead the normal 7/8}, but I did find 1/2-20 flange nuts 7/8 head in a Grade 8.

Been to all the truck parts places, truck tire shops, no luck om finding duplicates.

Since I found one lug nut I had randomly removed to carry along for comparison to be cracked, I figure a nice meaty flange nut of high grade would be preferable to what I have been riding with!

You really should have those plates.
As I understand it the wheels that were intended to use them rely on them for strength in that area, the wheel centers themselves are not as thick as they should be if only flanged nuts were used.

I just saw 4 of those plates on some axles I have sitting around here. If I had any extra I'd send them, but I don't right now.

What I'm trying to say is I really think you need and want the plates, and they are out there and easy to find; go find some.

Grigg

Dunno, bud!

I like the idea of the plates, but unless every stud has been replaced in the past, there is no way the plates could be mounted on the presumed original studs that are in place right now. There may be 2 threads of excess stud on the old studs.

I guess I could look for a 1/2-20 dually stud longer than the 2 7/8 studs I just installed, or see if the new studs are longer than the others and would allow the plate and full depth of the lug nuts.

The plates may not take up as much thread length as you're thinking they do
http://rides.webshots.com/photo/2776297030080251109YhSQdn
They are countersunk, so the nut seats in them pretty well.
I believe the nut in the picture takes a 1" socket.

Grigg

I just checked my '63 GM truck manual {on CD rom}, the cut-away views didnt show any rings. There are no countersunk sections on my rims. Maybe these rings are for another year/model?

Yes, the ones I have are from the 80's.
I'm not as familiar with the older 1 ton dual wheel trucks as I am the older 1.5 and 2 ton trucks.
But My thinking was that if the 1.5 and 2 ton trucks used them back then and still did until the 90's when they dropped that bolt pattern. And if the somewhat later model 8 lugs used them then the older ones probably did too, although sounds like not always....

Using the later model clamp plates seems like a good idea to me. Or using original parts is a good idea. But guessing what might be different or better is not a good idea if you don't first understand what the original solution was. Also knowing later model factory solutions to the same problem also helps make the best decision on what to do.

Sounds like you had a problem of some sort in this area recently, figure out what the right thing to do is first before moving on.

Grigg

Well...

I sheared 8 studs off the right rear at highway speed with my family on board, at night, on a bridge. So yes, you could say I had an issue!

Every lug nut on the machine, with one exception, is a 1/2-20X3/4 head nut, with slots cut into the top {not castellated}which were bent in to make a locking nut. The slot is where the crack occurred. Truthfully, I'm not interested in the OE nut, the slots left d****** little metal holding the tires on.

These nuts seem to no longer exist, fine by me. Catalogs show a 7/8 head nut, which simply doesnt put enough metal on the mating surface.

Something tells me a grade 8 with more than triple the surface of what appears to be the OE nut, along with a drop of the proper thread sealant will be at least as secure at the OE when new, if not more.

sounds like some good ol boys fix for the last time he lost the nuts, that slotting to make a lock nut, GM never did that and I certainly wouldn't have taken it on the highway like that

as I said above, the thing to do is check with a truck tire shop and see if they can get you the right size of the hub piloted nuts - or check this place out that crenweige linked on a big bolt thread, might find something there, the black one bottom right looks useful

Bill

The slots arent handmade, perfectly symmetrical, and "he" would have had to lose 31 lug nuts, only 1 is different. I kind of doubt that they were a home-made fix. If so, "he" went to a lot of trouble to get an oversized head nut cut with the proper threads and then added the lock slots. It was hours of store visits today just to find a 1/2-20 nut in a 3/4 wrench size.

Been to the truck mechanical shops, been to the fleet supply houses, been to the truck tire shops...trucks dont run 1/2-20 wheel studs.

Considering that grade 8 hardware is rated to 150K psi, I dont see a huge problem. One will lift the truck, 8 should hold the wheel on.

I will check on that link, they have no online shop, but look to have some 1st rate fasteners.

The nuts you had are called "Marsden" nuts http://www.lok-mor.com/mar-loc.html
I think NAPA does list them as I saw pictures in the catalog a month and a half ago. And I've seen them on original Chevy trucks. I've got some wheel adapters that were installed early on if not when new, and they used Marsden nuts for lug nuts and not very likely they ever came off or were replaced.

Have you looked in a 60's parts manual to see what was used when the truck was new?
We've both/all been guessing at it so far.

I looked in the 29-54 parts manual (I don't have a newer one for small trucks)
Page 371, section 5.820
"Ring, Rear wheel hub clamp"
Part number 3680931 (fits 1 ton)

I did not look for the nuts, but can later this evening. Did notice a nice chart of studs with dimensions and part numbers.

Part of what you may run into is you have 1/2" studs, and later stuff has 9/16" studs.
Did you investigate upsizing to 9/16" or would the hubs need to be bored larger to fit the available studs (which is an option)?

Grigg

You hit the mark with those nuts, exact match. Thing is, having found one cracked at the slot, I have no interest in using them.

There has been a lot of guessing as to why my right side duallies departed; loose lugs, tight lugs, and now I find this cracked lug after randomly selecting it to take along as a sample.

My guess as of today is that I will find more cracked nuts, and that they caused the problem, or where a significant part of it. There is no way a cracked lug nut can hold the specified torque, unless that torque is less that the energy required to open the crack.

As far as checking as to what was stock, I dont have a parts manual for the vehicle. I do have the GM shop manual covering all trucks for '63.

The side cut-away view of the hub/wheel attachment {dually and the single front} clearly shows no hub ring, and a simple flat faced lug nut. Wish I could copy the picture, but I guess it is copy protected.

Switching to a 9/16 stud would require modifying the hub and brake rotors, and probably the wheels as well.

Seems like the grade 8's I have ordered, and a drop of Locktite blue should do the trick without reinventing the wheel!

{pun intended!}

Here are some pictures of a '56 GMC 1-ton that I came across recently.

19.5" tubless wheel mounted without a pressure plate using 1/2 Marsden lock nuts.


Center of wheel closeup


Closeup of 1/2" lug nut (Marsden lock nut)

These are 16" wheels for later trucks. I'm not sure of the exact years on the rim on the left but the holes are 9/16"+ while the ones on the right are 5/8"+ dia. 19.5" versions of the wheel on the right were found on 3500HD flatbeds and P30 vans (bread trucks, tool vans etc.)

Mid 60's (?) 16" dual and mid 80's 16" dual

16" wheels side by side


Mid 80's wheel with tapered lugnuts and pressure plate mounting on 9/16" studs.

Mid 80's up 8-lug mounting

Pressure plate and 5/8"+ wheel holes

This last picture is the 1-ton hub and drum. The 16" wheels are not even close to slipping over the brake drum.

56 1-ton hub and brake drum.


There is a picture of a 2nd series 1-ton GMC on oldGMCtrucks.com. It has the 18" tube tires on it and a pressure plate is clearly visible on the front wheel. This is on a 15,000 mile original truck.

When I bought the 16" wheels with the taper flange plates, there was another wheel available that used the flanged lug nut. The rim was a completely different part number. I bought the rims at 6-Roblees in Seattle and they have on online catalog.

That 1st picture is my set up, spot on.

Got my new lug nuts in today, happily they are the deformed oval type lockers. On brand new studs, should be bulletproof, no loctite required.

Next step, ordering the various drums, studs, cylinders and shoes to complete the 100% stud and brake revamping!