The 14-Bolt Bible

By Bill "BillaVista" Ansell
Copyright 2003 - Bill Ansell
(click any pic to enlarge)


This article is a compilation of information and and specs relating to the venerable GM Corporate 14 Bolt full-floating rear axle - also referred to as the 10.5" (after the size of the ring gear in inches) or just simply the "14b" for short.

There are other 14b axles out there - a 9.5" ring gear semi-float for one, and even a 11.5" ring gear full-float version. This article is not about them.

US Military CUCV Manual - 14-Bolt Excerpts

A range of US Military trucks over the years have been equipped with the 14-Bolt rear axle, including the Commercial Utility Cargo Vehicle or "CUCV".

The US Military also produces, free of copyright restrictions, manuals for these vehicles. Normally, the manuals come in large volume sets comprising hundreds of pages covering every aspect of the vehicle.

So that you do not have to wade through all this data to find information on the 14-Bolt rear axle, I extracted only the relevant information and compiled it all into a single 14-Bolt Manual in .pdf format.

Identification, Data, and Specs

The 14bolt is found in a huge number of GM 4x4 pickup trucks and vans, 3/4 and 1 ton, from the 70's right through until at least the 2000's. You can find it in:

  • 1973-1996 C20, C25
  • 1973-2000 C30, C35
  • 1973-2000 G30, G35
  • 1973-2000 K20, K25
  • 1973-2000 K30, K35
  • 1984-1988 CUCV
  • 1988-1991.5 V30

As well as a whole lot more cab and chassis trucks, delivery vans, etc.

This is what it looks like in my rock buggy.
It is most easily distinguished by its huge, uniquely shaped diff cover that is, of course, held on with 14 bolts.
It is also fairly easily distinguished from other 1 ton full-float rear axles by the removable pinion support, that can be clearly seen just behind the pinion yoke in this picture.

Being a full-float (FF) axle means it has full-floating wheel hubs and axle shafts. I simply love full-float axles, and would never go back to running anything but a FF axle, for the following very good reasons:

  • The axle shaft does not support the weight of the vehicle, but merely transmits torque.
  • Because of the above, FF axle shafts are not subject to bending loads like semi float (SF) axles are and can therefore be made of harder materials making them capable of carrying greater torque loads
  • If you should ever break a rear FF axle shaft, you will not loose the wheel too.
  • If you need to change a FF rear axle, it is extremely easy and simple to do.
  • The hubs run big, strong, common, reasonably cheap wheel bearings, races, and seals (14b, Dana 60 and Dane 70 bearings, front and rear, are all the same).
  • The wheel bearings are not pressed onto anything. If need be they can be removed and replaced with nothing more than a screwdriver and big hammer.

Before we delve deeper into the 14bolt, let's just talk about why this is such an awesome axle. It has a number of distinct features / advantages:

  • Gear strength - 10.5" ring gear, 1.750" 30 spline pinion, huge 2 piece carrier made of 8620 Heat treated alloy steel, extra pinion bearing support.
  • Shaft strength - 1.5" 30-spline full-floating shafts.
  • Housing strength - massive cast iron center section, 3.25" x 0.5" tubes (not all, varies by year and application).
  • Comes in two widths - 63" and 67" wms-wms, easily converted from one to the other (that axle shafts are common to both, it is the different hubs that account for the different widths, and these are easily interchanged).
  • Removable pinion support, unbolts from the rest of housing, makes for easier gear setup.
  • Diff housing has built-in threaded carrier preload adjusters, makes for easier gear setup.
  • Because the carrier is so large and strong, a "full" Detroit locker fits in the stock housing, and is therefore easy to install without gear setup changes, and is much cheaper than other 1 ton FF lockers.
  • Pinion yokes commonly available for 1350 and 1410 series U-joints.
  • Fairly commonly came stock with 4.10 and 4.56 gears and sometimes factory Detroit Lockers.
  • Cheap and easy to find, buy, and build.
  • Easy to convert to disc brakes.
  • Easy to "shave" for 2" inch gain in ground clearance.
  • Pinion length shorter than other 1 ton full-float rear axles (like the Dana 60 & Dana 70), for improved driveshaft length and angles.
  • Large ID spindles.
  • Shares common spindle-nut threads with Dana 60 front axle, meaning only one style of spindle nut and socket need be used / carried.

Of course, there are drawbacks too:

  • Lack of traction aiding differentials - especially spools.
  • Lack of available gearing - only down to 5.13.
  • Lack of aftermarket alloy axle shafts.
  • Carrier break. Most 1-ton FF also have a carrier break though, so it's relative.
  • Uses a crush sleeve to set pinion preload.
  • Relatively low ground clearance in stock form.
  • Heavy in stock trim.

Overall, I think they are a superb choice for a heavy duty off-road machine. The following quote from " H8Monday" (a rock crawling competitor and devout throttle-crazy maniac who runs a 14b behind a very healthy 5.0.) sums things up nicely:

"One of the best things about the 14-Bolt, other than they are dirt cheap and nearly indestructible, is the cost of building them. It is very common to find them with 4.56 gears, and often axle shops and junk yards will have used factory sets. They are very easy to set up, because they have an adjustable backlash. Spare axle shafts are nearly free, and the shafts are the same for the C&C or standard version. Not that spares are usually necessary with a 1.69" axle shaft diameter, (splines are 30). But, the best thing is, because the stock carrier is a monstrous hunk of an assembly, you do not change the carrier [when installing] a Detroit [locker],(its basically a massive lunch box locker). So a Detroit only costs about $325 (and that's if you don't shop around). My disk brake conversion didn't cost over $150 ($40 each for rotors, $40 for loaded calipers, plus about $20 for brake lines). I had about $1000 into my entire 14 build-up, including cost of the axle, gears, locker, disc brakes, and new lug nuts. Not bad for a full floater, rear axle with discs, 4.56 gears and a Detroit."

Let's have a closer look at the beast.

This pic is a closer look at the hub and wheel bearing / spindle hardware (with the brake disc or drum removed, looking at it from the back side [inside]). Note that the spindle threads are the same as for Dana 60 front and rear axles and Dana 70 rear axles. This means that all the different styles of spindle nuts (4 slot, 6 slot, hex, rounded hex) and lock washers can all be interchanged. Part numbers for the spindle hardware shown, from left to right are:

  • Spindle flat washer: Dorman 618-048.
  • Spindle nut: Dorman 615-130.
  • Spindle lock washer: Dorman 618-049.
  • Spindle nut: Dorman 615-130.

Watch out for this when you go to remove the wheel hub outer bearing and race. The bearing does not simply fall out of the end of the hub on most FF axles - its OD keeps it captive. Instead, a snap ring in the hub, accessible from the back of the hub (yellow arrows) needs to be removed so the wheel bearing can come out the back.

Blue arrows show corrosion, indicating requirement for replacement bearings and races.

The snap ring mentioned above.
Spindle OD is approximately 1.985".
Spindle ID is approximately 1.540".
Take the cover off, and you discover the massive 2-piece carrier and 10.5" ring gear.
The bearing caps have small integrated locking devices that serve to lock the carrier preload adjusters into place.
Bearing caps and adjuster locking bolts removed.

These pics are of the carrier removed. Mine is fully welded up making it a huge spool. I have read about some folks just welding the spider / side gears by filing in the valley's between the teeth and then reinstalling them. I personally have never understood this. It's not as if you need to save the carrier, since they are cheap and extremely plentiful. Also, I would think that in this manner, those welds would see quite a bit of shock loading. It's also a real bugger to reassemble the carrier and gears after you have just welded up the teeth and are trying to save the carrier.

With the carrier removed, here's a look inside the diff:

  1. Threaded carrier preload adjusters.
  2. 3/8-NC16 diff-cover bolt hole (14 in total).
  3. Extra (third) pinion support bearing.
  4. Magnet for attracting and holding metal particles / debris in the gear oil.
  5. Area where my 14b has been ground down for clearance.
  6. 3.25" x 1/2" thick axle tubes.
Close-up of pinion support bearing. The actual proper name for this is the "straddle bearing".
Threaded carrier preload adjuster and 1/2" thick axle tube.

The left- and right-hand axle shafts are different lengths.

The Left is the short side at 31-5/8".

The Right is the long side at 37-5/8".

They are a large 30 spline axle. However, the pressure angle on the splines is not the same as other manufacturers (Dana, for example).

Dimensions on the shafts are:

  • Spline Diameter (yellow arrow): 1.59"
  • "Neckdown" (green arrow): 1.367"
  • Operating diameter (purple arrow): 1.351"
  • Spline length (blue arrow): 2.165"
  • Spline engagement (red arrow), short side axle shaft: 1.418"
  • Spline engagement (red arrow), long side axle shaft: 1.569"
Axle diameter by the flange (yellow arrow): 1.458"
The following pics, courtesy of Benny "Bigger Valves" Langford and Clay "yotacowboy" Moulton, illustrate an alternate method of retaining the wheel bearings in the 14-Bolt. For the record, the axle shown here is from an '87 1 ton Chevy V30 (crewcab, 4x4, 350 tbi engine).

It's a very simple setup that consists of one hub nut, one key, and one clip-ring. The nut accepts the regular 6-prong 14-Bolt socket and has 6 square grooves around its inner diameter. These grooves are what you line up with the spindle groove to make the key way, as shown here.

To adjust the bearings, tighten the hub nut down until the the correct preload is achieved (see the .pdf manual at the start of this article if you are not sure how to do this), and then tighten the nut further until the next groove in the nut lines up with the spindle groove.

This pic shows the clip-ring and the small rectangular key.

Once the preload is adjusted and the grooves in the nut and spindle are lines up, simply slide the key in the key way and put on the clip ring.

The clip-ring has a curved end that fits in the spindle groove to securely block the key from backing out. The clip is very thin and flimsy which makes it easy to remove with just a screwdriver and allows it to fit snugly around the spindle in the threads.

Part numbers for this style spindle hardware are:

  • Hub nut: Dorman 615-132.
  • Key: Dorman 615-140.
  • Clip Ring: Dorman 615-141.

Dana Catalogue Page on GM 14-Bolt (10.5")

West Coast Differentials Catalogue Page on the GM 14bolt (10.5")

GM 14-Bolt Specs

(all data for single-rear-wheel (SRW) truck 14-Bolt axle - others may vary).

Pinion Bearing Preload
(Inch lbs)
25 - 35 (new bearings) 5-15 (reused bearings)
Preferred Backlash
(.001 inch)
5 - 8 thou.
Ring Gear Bolt Torque
(Foot lbs)
 Bearing Cap Torque
(Foot lbs)
Pinion Nut Torque Tighten as necessary to obtain correct preload.
Pinion Bearing Retainer Torque
(Foot lbs)
Diff Cover Bolt Torque
(Foot lbs)
Axle shaft flange Bolt Torque
(Foot lbs)
Spindle Nut Torque
(Foot lbs)
Carrier Adjuster Ring Lock Bolt Torque
(Foot lbs)
Pinion Assembly Bolt Torque
(Foot lbs)
Axle Shaft Spline Length
2.165" total
Axle Shaft Engaged Spline Length
short side 1.418"
Axle Shaft Engaged Spline Length
long side 1.569"
Axle Tube Dimensions
3-3/8" x 0.5" thick (varies depending on year and application).
Spring Perch Span and Width
(1980 1 Ton 4x4, SRW, non Cab and Chassis) 42.5" x 2.5"
Axle Shaft Length
Right 37-5/8"
Left 31-5/8"
Axle Shaft Diameter
@ splines 1.54", @ neckdown 1.367", operating diameter 1.351"
@ flange 1.458" 30 splines
Axle Flange Bolt Pattern
8 on 3.523", 1/2" holes, bolts are 1/2-NC13x1.5"
Pinion Yoke U-joint Strap Bolts
7/16 " head, 1.296" x 5/16-NF24
Diff Cover Bolts
Fourteen (14) 3/8-NC16 x 3/4"
Ring Gear Bolts
Twelve (12) 9/16-NF18
Pinion Nut Size 1.5"
Axle shaft to Hub bolts 3/4" head, 1/2-NC13, approx. 1.5" long
Ring Gear Diameter
Pinion diameter
1.750" x 30 splines
Carrier Break
4.10 / 4.56
Approximate Weight
550 with brake drums
450 without brake drums
Width - WMS-WMS
C&C DRW 63"

The Different Types of 14-Bolt

Before we get into the different types of 14-Bolt axle, a quick review of some truck terminology that will keep popping up is in order.

Truck Lingo

When talking about truck, especially with respect t rear axles, we often use the terms SRW, DRW, C&C, and WMS. Here's what they mean:

SRW stands for "Single Rear Wheel" and refers to a truck that has a single wheel on each end of its rear axle. Your average pickup truck is a SRW truck with a SRW axle.

This is my 2007 Chevy Silverado HD2500 "SRW" truck.


© GM Company.

DRW stands for "Dual Rear Wheel" and refers to a truck that has two wheels on each end of its rear axle.

One-ton, heavy-duty pickup trucks are sometimes DRW and are often referred to as "Dually's".

This is a 2012 Chevy Silverado HD "DRW" truck.

Picture courtesy of and copyright GM Company.


© GM Company.

C&C stands for "Cab and Chassis" which refers to a truck configuration that is sold without a "box" on the back. It is, literally, just a cab and a chassis (frame), like the one shown here.

This is a Chevy C-class C&C truck (so bigger than a one-ton pickup, and it wouldn;t have a 14-Bolt rear axle but the pic clearly illustrates the "C&C" concept.

C&C trucks are sold commercially for use as work trucks to customers who need to fit their own specialized bodies such as service trucks, welding trucks, wreckers, and small dump trucks.

Picture courtesy of and copyright GM Company.


© GM Company.

As they are intended for heavy-duty work trucks, C&C trucks almost always also have dual rear wheels.

This is Chevy C3500 HD one-ton C&C truck fitted with a small dump box.

Picture courtesy of and copyright GM Company.

WMS stands for "Wheel Mounting Surface". So when we refer to the width of an axle in terms of WMS-WMS we mean the distance between the wheel mounting surfaces (on the hubs). We do this to eliminate the variables of wheel width, wheel offset, and tire width which, if not eliminated, would make for an almost infinite number of possible widths.

Back to the 14-Bolt

There are many different 14-Bolt axles available, with an almost dizzying array of possible widths, tube OD's, hub types, brakes etc. Fortunately, all are pretty similar, a huge number of parts interchange.

*CAUTION* - With this axle, as indeed with all things "axle" - there are no hard and fast laws - for every "fact" I shall present, I know there's at least one person out there, possibly many, who claim they own or know of exceptions. This is very likely true, and is due to the way in which OEM vehicle construction occurs. This variability and ambiguity is just a fact of life and unfortunately cannot be avoided or completely resolved.

What follows is what I believe to be true, or the most correct, information based on the research I have done and the letters I have received from what I judge to be the most reputable sources. Use the data with caution - "your mileage may vary" as they saying goes.

14-Bolts can be broken down into 4 broad groups. There is also at least one year break that brings minor changes, but this is in fact far less significant than the "type" of 14-Bolt axle in question.

Once again - this article is concerned only with GM 14-Bolt full-float rear drive axles. With that said, the following table attempts to capture the data.

14-Bolt Type* Width WMS-WMS Tube OD / Thickness Applications Hubs* Shafts*


67.5" 3-3/8" / 0.5" Single rear wheel trucks Type A Type 1
72" 3.5" / 0.5" Dual rear wheel trucks Type B Type 2


63.5" 3.5" / 0.5" Cab and chassis trucks Type B Type 1
Van 70" ?? G30 and G35 vans Type A Type 3

* Note that these names (or designations) are of my own invention. They are not the official designations used by the manufacturer. Unfortunately, I do not know what the official designations are, or I wold have used them. So, don't call up your local junkyard and ask if they have a 14-Bolt with "Type B" hubs and "Type 1" shafts - they will look at you funny (yes, even over the phone!) I have simply invented and used these terms to help illustrate the differences and similarities between the different axle types that are out there.


  • The width of the housings and the length of the shafts used in the SRW and C&C axles are the same. The reason they are different widths WMS-WMS is because of the difference in the hubs used (see below for different hub types). The housings are actually identical except for the location of the backing plate flange (except axle tube OD and thickness may vary slightly with year and application). The brake drums & hubs are different, but the backing plates, brake shoes, and wheel cylinders are the same.
  • The SRW and Van axles use the same hubs.
  • The C&C and DRW axles use the same hubs.
  • Though different, the Type A (SRW/Van) hubs and the Type B (C&C/DRW) hubs can be interchanged. Doing so will result in a change to the axle's WMS-WMS as follows:
    • Swapping Type A hubs onto where Type B hubs used to be will cause an increase in axle width WMS-WMS.
    • Swapping Type B hubs onto where Type A hubs used to be will cause a reduction in axle width WMS-WMS.
    • See section below for pics of the different types of hubs to see why this is so.
  • SRW and C&C axle shafts are the same
  • Van, DRW, and SRW/C&C axle shafts are all different lengths as follows (long (right) side / short ( left) side):
    • Type 1 - SRW/C&C - 37-5/8" / 31-5/8"
    • Type 2 - DRW - ??
    • Type 3 - Van - 39-3/8" / 33-3/8"
  • If it helps, you can think of the C&C axle as a hybrid of the SRW and DRW axles. It uses the housing and shafts of the SRW axle fitted with the hubs of the DRW axle. This accounts for why it is the narrowest axle measured WMS-WMS (which in turn is why it is often highly sought-after for swapping into smaller 4x4s like Jeeps and buggies.
  • C&C and DRW brakes are the same.
  • In all cases one side axle-shaft is shorter than the other and pinions are centered.
  • 1350 appears to be the only available stock pinion yoke, but aftermarket 1410 yokes are available (see the XXX article for details).
  • 1-ton pickup trucks feature 40.5" leaf spring perch spacing - whether SRW or DRW.
  • C&C axles feature 36" leaf spring perch spacing.
  • 3/4-ton leaf spring perch spacing is 42.5" spacing. \
  • Wheel studs went metric for the 88-up C/K trucks, and 96-up vans
  • Front 60 and rear 14b spindles have the same bearing spacing and same bearing journal sizes. The seal journal diameter is different

Type A and Type B Hubs

The following pics, courtesy of Brawler, illustrate the differences between the Type A and Type B hubs.

Type A hub on left.

Type B hub on right.


Type A (SRW / Van) 14-Bolt hub.

The flat, machined flange you see here (through which the wheel studs are poking) is the wheel mounting surface or WMS we keep referring too.

Notice how short the central part of the hub that sticks out past the WMS is.


Type B (C&C / DRW) 14-Bolt hub.

Notice how much longer the central part of the hub that sticks out past the WMS is, compared to the Type A hub, above.


Type A hub on left.

Type B hub on right.

This picture is taken with the two hubs sitting on the bench simulating the position they would each be in when mounted on the spindle.

You can clearly see the higher height of the WMS of the Type A hub on the left that translates into the wider WMS-WMS width of an axle fitted with Type A hubs compared to one fitted with Type B hubs.

Different Years

The year split is '72-88 (so-called "first design") and 89+ (so-called "second-design). Of course, there may be variations. Differences between these years are noted below. Where the difference is known only to apply to certain "types", I shall indicate this.

  • Second design axles have more fins on the center section.
  • First design axles 1984 and earlier use a different pinion straddle bearing than 1985 and later.
  • Second design SRW axles in 1-ton pickup trucks and 3/4 ton Suburbans changed to allow for a slide-off drum (drum can be removed without pressing out the wheel studs). The backside of these hubs is not machined flat to accept a rotor, for example. The hub flange is also further inboard to allow for the thickness of the drum.

When working on a 14-Bolt axle, the biggest difference between the first and second design to be aware of is the different bearings used in the diff.

The wheel bearings, pinion seal, and front pinion bearing are common to both first- and second-design axles.

The first-design axle uses a different rear pinion bearing than the second-design axle.

And the really confusing part is that the first-design and second-design axles use the same pinion straddle bearing EXCEPT for the 1984-1985 first-design axles which use a different straddle bearing from all the rest.

Perhaps the best way to explain this is to simply list the part numbers.

The seal & bearing numbers are*:

  • Pinion Seal (1973-1999): 21955
  • Front Pinion Bearing, Cone, (1973-1999): M802048
  • Front Pinion Bearing, Cup, (1973-1999): M802011
  • Rear Pinion Bearing, Cone, (1973-1988): HM803149, (1988-1999): HM903249
  • Rear Pinion Bearing, Cup, (1973-1988): HM803110, (1988-1999): HM903210
  • Pinion Straddle Bearing, (1973-1984 & 1986-1999): R1581-TV
  • Pinion Straddle Bearing, (1984-1985): DC57524

* Cone = the roller or bearing, Cup = the race.

This picture illustrates the heavily ribbed centre section of the second design 14-Bolt housing (ignore the red arrow).

14-Bolt Wheel Studs

One of the most popular modifications to any 14-Bolt axle used in an offroad truck is to remove the huge, heavy drum brakes and swap to disc brakes. I wrote a compete article on this process which you can read for detailed info.

One thing though, is that when you swap from drums to discs, the wheel studs are usually no longer long enough because they have to pass through the disc and the hub (that's how the disc is held to the hub).

Over the years there has been much discussion and experimentation with using different wheel studs, with different folks reporting different levels of satisfaction with different options. As far as I know there has never been a universally accepted one perfect solution, but the following data I consider quite reliable and should at least allow you to narrow down some choices with which to experiment to achieve a level of satisfaction you are comfortable with.

How to Cure the 14-Bolt of it's Achilles Heel weak link!

The mighty 14-Bolt does have 1 terrible weak link - an Achilles Heel.  It's the crappy, lousy design, weak, expensive and hard to find straps for holding the U-joint in the pinion yoke.

The proper straps are a pain to find.

No parts store I have ever tried, from NAPA to Car Quest ever has them.

That leaves only the GM dealership, where the strap (GM p/n: 3920486) will set you back $3 EACH! and the bolts (GM p/n: 458300 or 14018700) another $2 EACH.


As for all the local and big chain parts stores - they will all gladly sell you a "strap kit" for a "1-ton GM rear axle" or "GM 10.5" rear end" or a "14-Bolt full floater" or a "1980 Chevy K30 1 ton 4x4 " or whatever else you have to say to them to get one - but, in my experience (NAPA, Car Quest, Canadian Tire, and a couple of local independents) they are all WRONG, and it won't fit at all.

The top strap is the one the parts stores will sell you, the bottom the GM part.

In any case - the stock straps are weak and badly designed - very soon they end up looking like this.
Complete junk!!

Fortunately - there is a solution - and a very cool one at that - read all about it  - the High Angle Driveline 1410 Pinion Yoke kit

Shaving the 14-Bolt

The only real disadvantage to the 14b is the huge size of the differential, and subsequent scarcity of ground clearance. I must admit, in stock form, they do tend to hang a little low and get hung up on stuff. Most users will "shave" them. This can range from simply smoothing out the bottom with a hand grinder, to cutting a big chunk out of the bottom of the diff housing and machining down the diameter of the ring gear.

The following pics illustrate the nicest case of the later, more extreme, shaving job that I have come across. It is the work of Phil Jensen, from Ottawa, Canada.

The diff before the shave.
The piece cut from the diff housing. Phil used an abrasive wheel/blade in a circular saw to start, and finished with a reciprocating saw. Starett blades are reportedly good for this.
After the cut of the housing, this is the carrier back in place, before it was machined down. It was then removed and approx. 1/4" machined from the OD of the ring gear. This did not effect the performance or durability of the gear set at all.
The 1/2" thick mild steel plate that was TIG welded to the housing.
The plate welded in place

The gears machined and re-installed

Just over 2" of clearance was gained. That's the same (at the diff) as going from 35" to 39" tires!!

Originally, Phil made a quick cover by altering a stock cover. It didn't last well enough for his liking, so in the end he constructed a complete custom cover from 3/8" plate steel, which has reportedly held up very well. Unfortunately, I have no pictures of the later cover, but here are some of the original.

From the research I have done (I have no personal practical experience) the methods that have been used successfully for trimming the OD of a ring gear for a radical shave job are:

  • Abrasive grinder
  • Diamond-tip on lathe
  • Ceramic inserts on lathe
  • Wire EDM

I believe the preferred method is the wire EDM. Here's what has to say about EDM.

EDM is one of the most accurate manufacturing processes available for creating complex or simple shapes and geometries. EDM works by eroding material in the path of electrical discharges that form an arc between an electrode tool and the work piece.  EDM manufacturing is quite affordable and a very desirable manufacturing process when low counts or high accuracy is required.  Turn around time can be fast and depends on manufacturer back log.

The EDM system consists of a shaped tool, an electrode, and the part. The part is connected to a power supply. To create a potential difference between the work piece and tool, the work piece is immersed in a dielectric (electrically nonconducting) fluid which is circulated to flush away debris. The cutting pattern is usually CNC controlled.  Many EDM machine electrodes can rotate about two-three axis allowing for cutting of internal cavities. This makes EDM a highly capable manufacturing process. EDM comes in two basic types: wire and probe (sinker). Wire EDM is used primarily for shapes cut out of a flat sheet or plate. With a wire EDM machine, if a hole needs to be created, an initial hole must first be drilled in the material. Then the wire can be fed through the hole to complete the machining. Sinker (probe) EDMs are generally used for complex geometries where "line of sight" is not thru/straight or very small pieces where conventional milling is not practical or very difficult due to the hardness of the material-such as cast and heat treated tooling. Probe EDM can cut a hole into the part without having a hole pre-drilled for the electrode. Design Considerations

  • Relax the surface-finish for the part, if feasible. This allows the manufacturer to produce the part with fewer passes, at a higher current level and a higher metal-removal rate. Design the part such that the amount of stock removed by EDM is relatively small. Use traditional machining techniques to remove the bulk of the stock with the finishing operations performed by EDM. This significantly reduces the amount of time and cost for each part. The EDM manufacturer should consider fixturing such that several parts can be stacked and machined simultaneously or a single part can have several EDM operations performed simultaneously.
  • When existing holes are to be enlarged or reshaped by EDM, through holes are preferred to blind holes as they permit easier flow of dielectric fluid past the area being machined

Dimensional Accuracy (+/- 0.0005 inches per inch)
Feature Profile accuracy of .0003 is obtainable with cutting path
Features to feature true position of .002 is reasonable and down to .001 is possible when geometry requires removal and reattachment of wire.

Surface Finish (micro inches) Features created by EDM have an "orange peal" appearance.
32 RMS is achievable, 64 or higher RMS is typical. Wall Thickness
Min Wall Thickness (inches): 0.01 (over a 5" inch span)

Significant depths can be obtained with wire EDM, probe EDM does have depth and access limitations dependant on machine capabilities.  Consult with EDM manufacturer for specifics.


More Great 14-Bolt Articles

The Following are additional BillaVista technical articles related to the 14-Bolt axle:

14-Bolt Disc Brakes V2. A new and more complete look at converting a 14-Bolt to disc brakes, including weld-on and bolt-on brackets, a larger calliper option, and a detailed look at wheel stud and wheel nut options.
14-Bolt Gear Setup. Detailed, step-by-step instruction for setting up gears in a GM 10.5" Full-Float 14-Bolt rear axle. Contains theory and tech of interest and use in setting up gears in other axles too.
ARB RD114 14-Bolt Air Locker Install. A mini-bible on ARB air lockers, including installation tips and techniques and a large FAQ section.
Yukon 14-Bolt Gears and Install Kit Review.
Jethro-Bilt 14-Bolt HD Diff Cover Review.
14-Bolt Disc Brake Conversion. Detailed look at how I added disc brakes to the GM Corp. 14-Bolt rear axle in the Wolf. Procedure can be used for other rear axles too (D60, D70, etc). Contains hints and tips on other axles. Includes detailed part numbers. Also contains excerpts from Military 14-Bolt maintenance manual on axle shaft R&R and wheel bearing R&R and adjustment.
14-Bolt 1410 Yoke Install. How to cure the 14-Bolt of it's Achilles Heel weak link!

14-Bolt Part Numbers from the On-line Listing at DTS

Product Name Description Manufacturer
GM 3920486GM 10.5 YOKE STRAPS  
GM26004800GM 10.5 PINION SUPPORT 91 & NEWER  
DTS327721-GGM 10.5 3.73 RATIO (O.E.M)  
DTS26026100-GGM 10.5 4.56 RATIO (O.E.M)  
DTS26016819-GGM 10.5 4.88 RATIO (O.E.M)  
AAM 26055283GM 10.5 5.13 RATIO (O.E.M)  
AAM 26055280GM 10.5 3.42 RATIO (O.E.M)  
AAM 26054996GM 10.5 3.73 RATIO (O.E.M)  
AAM 26054993GM 10.5 4.10 RATIO (O.E.M)  
AAM 26054990GM 10.5 4.56 RATIO (O.E.M)  
DTS471871GM 10.50 3.73 RATIO DTS
DTS471872GM 10.50 4.10 RATIO DTS
DTS14012704GM 10.50 3.42 RATIO-GENIUNE GM DTS
SPGM-14-105-373GM 10.50 3.73 RATIO SPICER
DTS327721-GGM 10.50 3.73 RATIO O.E.M STYLE DTS
MGGM10.5-373GM 10.50 3.73 RATIO MOTIVE GEAR
GM26020811GM 10.50 YOKE GM
DTS1551438-GGM 10.50 5.13 RATIO O.E.M STYLE DTS
DTS6258340-GGM 10.50 CASE 4.56 & UP EMPTY MUST USE (GM 331421) RING BOLT DTS
GM26067040GM 10.50 COVER GM
GM15994582GM 10.50 PINION NUT GM
DTS471873GM 10.50 4.56 RATIO DTS
MGGM10.5-410GM 10.50 4.10 RATIO MOTIVE GEAR
SPGM-14-105-410GM 10.50 4.10 RATIO SPICER
DTS26029468-GGM 10.50 4.10 RATIO O.E.M STYLE DTS
DTS26026100-GGM 10.50 4.56 RATIO O.E.M STYLE DTS
MGGM10.5-488XGM 10.50 4.88 THICK MOTIVE GEAR
MGGM10.5-456GM 10.50 4.56 RATIO MOTIVE GEAR
SPGM-14-105-456GM 10.50 4.56 RATIO SPICER
DTS26016819-GGM 10.50 4.88 RATIO O.E.M STYLE DTS
GM331421GM 10.50 RING GEAR BOLTS 4.56 GM
GM331422GM 10.50 RING GEAR BOLTS '4.10 & DOWN GM

14-Bolt Wheel bearings and Seals

Hub Seal
Interchange Number Mfr
14116 FELTPR
15527652 GM
2081 ABI
2081 DELCO
2081 L&S
211587937 GARLOK
2620286 DELCO
28426 C-R
29112 DELCO
3680994 GM
3686563 GM
37222 SPICER
3742583 GM
3743202 GM
3828916 GM
3883386 GM
3909063 STEMCO
3929063 STEMCO
3974847 GM
41X10836A DEERE
455511 NATION
46203 TROSTL
469694 GM
48287 DANA
49552 VICTOR
51X7937 GARLOK
60964 VICTOR
63X7937 GARLOK
84503 FITZGE
A215F964 R-S
A56401S L&S
BH1290E1 NOK
Inner cup
Interchange Number Mfr
0009813580KZ M-BENZ
0009814581KZ M-BENZ
053146 RIV
105497H IHC
10578 A-C
107845A WHITE
10A7292 WHITE
111E050032 AM
111E0500321 AM
1331442400 ARAMCO
142223 GM
149505 MACK
150805 JEFREY
167717C1 IHC
195521M1 MASSEY
195525M1 MASSEY
196068M1 MASSEY
20641 EATON
207234H1 IHC
212037 A-C
2150007 GOODMN
2150007 WABCO
3010578 A-C
30105787 A-C
313037 AUSTIN
382A NTN
384350R1 IHC
388533R1 IHC
392689R1 IHC
3950457 GOODMN
45733 HYSTER
471489 WABCO
49029 NEWHOL
4T382A NTN
516149E WHITE
520013 GEHL
545905 EATON
Inner Cone
Interchange Number Mfr
10X15157 WHITE
1331445600 ARAMCO
181267 WABCO
206087M1 MASSEY
218285 A-C
2182855 A-C
243146 RIV
319014 AUSTIN
327195R91 IHC
49030 NEWHOL
49X50209A DEERE
565906 SPICER
613862C91 IHC
826926C91 IHC
9436882 GM
9500172 JOY
95X387AS JOY
A629826 GERLIN
Outer Cup
Interchange Number Mfr
1331928200 ARAMCO
287066 NEWHOL
2953549 CHRYSL
2955374 CHRYSL
364462C1 IHC
431667C1 IHC
4TLM104911A NTN
565918 SPICER
7451813 GM
8128842 AMC
9428539 GM
LM104911 NTN
Outer cone
Interchange Number


1331928500 ARAMCO
2825729 CHRYSL
2852729 CHRYSL
2852729 GM
2953550 CHRYSL
364463C91 IHC
431668C91 IHC
4TLM104949 NTN
5357401 AMC
565905 SPICER
591651C91 IHC
7451814 GM
8128841 AMC
929742 A-C
9428909 GM
FLM104949 SEAL-P
J5357401 CHRYSL
LM104949 NTN
LM104949JX2 NTN


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