Main Menu

Which lug studs for front drums?

Started by challenger7070, August 04, 2025, 12:20:49 PM

Previous topic Next topic

0 Members and 1 Guest are viewing this topic.

challenger7070

Hi, I'm stuck prior to placing an order for various parts, finding that there are two types of lug studs listed for front 10" drums (I can't see a way to attached a picture, so links are below).


What are Motor wheel brakes and what are Budd brakes and how can that be found out/identified? They visually look different but no idea which one is needed. I can't find anything online about what those two are supposed to be. Thanks!


challenger7070

Ok so I have some more info but a bit stuck still.

The difference between the two lugs is mainly the knurl diameter.

  • "Motor Wheel" designated stud aka DORMAN 610039 lists knurl diameter as 0.625 in (with Shoulder Length: 0.719 in, Thread Length: 1.605 in and Head Diameter:   0.775 IN
  • "Budd" designated stud aka DORMAN 610122 lists knurl diameter as 0.650 in ((with Shoulder Length: 0.625 in, Thread Length: 1.535 in and Head Diameter:    0.805 in

The replacement drum I have (Raybestos 1926R) lists the Stud/Lug Hole Diameter as 0.628 in.

So, that should mean the "Motor Wheel" style lug will pass through the drum with barely any air gap (0.625 stud through a 0.628 hole  = 3 thousandths gap). Whereas the "Budd" style stud with its larger knurl of 0.650 would not make it through the drum (or, is that the idea that the knurl is oversize and would knurl itself into the drum, fusing the drum and hub together)?

But would a 0.625 knurl on the stud be wide enough to grip into the hub. And on the other hand, would a 0.650 knurl be too wide for the hub...

Katfish

It's a press fit, stud has to be larger than opening.


challenger7070

Quote from: Katfish on August 04, 2025, 03:50:41 PMIt's a press fit, stud has to be larger than opening.

The hub or the drum? They are separate units (old hub, new drum going onto it). The drum would be larger in the case of the Motor Wheel, but if the Hub is smaller than the drum then would that be ok, as the stud would be pressed into the hub, and the drum would "float", same as the rear axle would.

challenger7070

I'm still no further on this after hours of searching :( How can it be so hard to find the right lug studs?!

Some websites say that version A fits and version B does not fit. Then another say B fits and A doesn't.

I have found old master tech scans that mention Budd brakes, but just in passing... no info on what's different and how to identify them or why there are two different types. Driving me insane.

On the front, the driver side appears to be original drum and hub, the lug stud is swagged on still. The passenger side has been replaced, maybe original hub, but aftermarket drum, has Century stamped on, but no amount of searching found any results for any of the stamped numbers on it.

What throws things even more, is even though I narrowed it down to two lugs, the one on the passenger side matches neither style!

The two I found:

  • DORMAN 610039: Smaller knurl at 0.625". Shoulder is fully knurled
  • DORMAN 610122: 0.650" knurl, shoulder is half knurled, the transition from shoulder to lug thread is 90 degrees

Then the one that appears to be on the passenger side (which has obviously been changed as no swagging), is:

  • DORMAN 610132: 0.650" knurl, shoulder is half knurled (as is 610122), but the difference is the transition from shoulder to lug thread is 45 degrees tapered

But with this DORMAN 610132, it specifically is listed as 11" drums?! But they are 100% 10" drums on there.

Who knows if the place that did the passenger side, just grabbed whatever and may have caused an issue going with the 0.650" knurl instead of the 0.625"? I want to do it right, I just don't know what to do and I can't find any info to progress the situation.

Fairly frustrating situation as these tiny things are holding up the project... quite literally as the car is stranded on jackstands for two months now... shipping overseas takes weeks, so waited a few weeks for the drum, realised it had no hub, found out the hub needs removing, found out I needed to order a swagging tool, finally received that today, then realised that lugs would be damaged so need to order new ones again from overseas, and can't even find the right lug stud to use.

What I would do is just order a single of each three and hope that test fitting would reveal something... but due to minimum shipping charges, it puts that into $50 plus the wait, then when I find which one it is, another $50 to get the set, and another few weeks. This is ridiculous, please help!

Katfish

Are you trying to remain original?
Why not switch over to the newer single piece drum?

challenger7070

Quote from: Katfish on August 05, 2025, 08:42:48 AMAre you trying to remain original?
Why not switch over to the newer single piece drum?

I don't mind switching over to a single piece drum, I haven't found any places so far. Do know some retails/manufactures of them?
The car is quite original but I don't mind changing smaller details, especially when it makes life easier


mopar jack

reach out to Craig@mobllparts on forbbodies only. He knows these brakes and has a huge inventory of parts. He post his number on the B body site so I';; list it here. 516 485 1935

challenger7070

Ok so I have found two stamped id numbers on the factory drum. They are:

  • B53
  • 9MR9 (or could be 9M89 as the third digit is hard to make out

The second one is a little hard to make out so I may be reading incorrectly.

All I could find so far for the B53 is this page https://www.web.imperialclub.info/Yr/1972/Bodytags.htm which list some ID numbers, including brakes, but not all are identified and b53 simply has N/A.

Any ideas what these ID's could be; Budd brake system or Motor Wheel system?

I have read that supposedly Motor Wheel were stamped MW, but that was someone on a forum thinking that's what they remembered, so it would be good to have something more solid, or a picture to confirm.

Thanks

Brads70

#9
Does this help?

https://www.dormanproducts.com/gsearch.aspx?type=keyword&origin=keyword&q=wheel-studs&year=1970&make=Dodge


I used this when I was making custom hubs for another project and when I needed longer studs for custom rims. Worked great for what I needed. Note the filter options, thread size length etc....
https://www.dormanproducts.com/gsearch.aspx?type=keyword&origin=keyword&q=wheel-studs&parttype=Wheel%2520Lug%2520Stud



MoparLeo

Of course do a factory disc brake conversion solves all your problems and makes the car much safer to drive.
You are having problems because front hub mounted drums have not been used for almost 5 decades.
moparleo@hotmail.com  For professionally rebuilt door hinges...

cuda hunter

I will vouch for Craig at craigsmobileparts.
He is an awesome guy and knows his stuff. 
Had many many good interactions with Craig. Give him a call and you should find exactly what you want. 
"All riches begin as a state of mind and you have complete control of your mind"  -- B. Lee

challenger7070

Quote from: MoparLeo on August 09, 2025, 11:29:10 AMOf course do a factory disc brake conversion solves all your problems and makes the car much safer to drive.
You are having problems because front hub mounted drums have not been used for almost 5 decades.


This is an option I'd like to explore, not right now though, as currently the budget is going towards all the small things that quickly add up, to get it back up and running after sitting for 25 years. Once it's good and test driven, then I can start to look towards enhancements.

Has there been a parts list compiled for what's required on a front disc setup, and what options are out there for potential disc upgrades? For example with GM, it's fairly easy to put modern Corvette brakes on a 70's front disc car, going up to almost 14" discs (bigger wheels required no doubt). So I wonder if the same exists, perhaps something that was factory disc in the 90's, 2000's for Dodge/Chrysler that provides larger diameter discs than what was available factory from the 70's, which is somewhat straightforward to pull together.

I'm curious how all round drums are before I start to make changes. I've only ever driven disc-drum and disc-disc. The car will not be autocrossed, but it will see some mountain passes. On my daily sedan with factory disc-disc it's been fine on these roads, except on one occasion when trying to keep with a Corvette on a long downhill with many switchbacks when they needed a cool down. Part of me thinks drum-drum worked fine for the folks in Colorado in the 70's, so maybe it'll continue to be fine. Always curious to learn though.

Bullitt-

#14
Quote from: challenger7070 on August 17, 2025, 05:19:35 AMHas there been a parts list compiled for what's required on a front disc setup, and what options are out there for potential disc upgrades?

To stay more or less stock this article gives a great overview of how to
  https://www.allpar.com/d3/history/mopar/brakes/disc-main.html

  Dr Diff has a good selection of items & kits to do the disk brake conversion.
     From what I understand they are very knowledgeable & helpful
          https://www.doctordiff.com/brakes/front/

Note that E-Bodies always came with "Pin Type" front disk calipers.
  Many of the conversion kits use later model "Slider" calipers
.         Doin It Southern Style
       


Tags: