M37 Rear Hub Rebuild
Part numbers for the bearings and races:
Inner Bearing – Timken 28682
Outer Bearing – Timken 2984
Inner Bearing Race – Timken 28622
Outer Bearing Race – Timken 2924
Inner Seal – National 417485
Outer Seal – National 6077
Exploded view of the rear axle for reference.
I used a 2 jaw puller to get the inner seal out of the hub, it’s a lot easier than using a drift punch from the other side. It also reduces the chances of damaging the bearing or race.
NP200 Transfer Case Rebuild
Here is an outline of my rebuild with notes.
Special thanks to Damien Civiello who loaned me the spacer necessary for setting up the idler gear pre load and shared what he learned during his rebuild. His forum post can be found here.
Parts and Supplies Required:
- Power Train manual, I wouldn’t start without it (Hard copy available from Faxon Auto Literature, digital copy available from Military Manuals)
- NP200 Rebuild Kit (TCK-200 from DC Trucks, $255 shipped.)
If you want to buy parts ala cart here are the numbers: - Yoke seals - National 410308 x 4 (Double lip, double case heavy duty), Redi-Sleeve 99212 x 4
- Shift shaft seals – National 6835S x 2, Redi-Sleeve 99076 x 2
- Idler bearings – National 2793 & 2720
- Output shaft bearings – National 3720, 2793, 3780 & 2720
- Low gear roller bearing – National C1960Q
- Output shaft pilot bearing - QBR23549
- Shim Pack (McMaster-Carr, part number 3088A939, the shims included in the rebuild kit doesn’t have all the sizes needed.)
- Anaerobic Gasket Maker (Permatex)
- RTV Silicone Gasket Maker (Permatex, used on the shift shaft seals and to seal the yoke splines to prevent leakage around the shafts.)
- Thread Sealer (Permatex, used on studs that go through to the inside of the transfer case.)
- Mechanics wire, approximately 0.03" (Harbor Freight, stainless so it won't rust.)
- Glyptol (If you plan on blasting the inside this is the sealant to use, $50 from Eastwood.)
- Stainless steel shift shafts (M Series Rebuild, $100 each x 2)
- Hardened hi/low thrust washer (M Series Rebuild, $100)
Tools Required:
- 2 Jaw Puller for removing the yokes.
- Press for bearing removal and bearing/race installation.
- Bearing race and seal driver. (Harbor Freight, the kit doesn’t include a race driver for the larger race in the NP200 so I just ground down one of the old races and used that to seat them.)
- Brass drift. (Harbor Freight, used to drive out the old races.)
- Torque wrench in the 140-160 foot pounds range.
- Torque wrench in the 15-30 inch pounds range. (I bought Park Tool TW-1 $35, cheap and accurate.)
- 1 5/16” socket for removing the slotted yoke nuts.
- Spanner Pin wrench for holding the yokes when tightening the yoke nuts.
- Idler Gear Dummy Shaft (Quad 4x4 sells T2013, it’s useful for removal of the idler shaft but it’s too long to fit in the case when doing the installation, so a socket and extension will work just as well for removal.)
- Spacer for setting idler gear bearing pre load.
NP200 schematic:
| 
 | The case had 55+ years of oil and dirt stuck to it, pressure washing only got it about half way clean. A combination of a putty knife, parts washer and hot water with degreaser finished the job.
This took longer than expected, I’m not sure if there is a better way to remove the dirt and oil. |
 | 2 jaw puller removing output shaft yoke. |
 | |
 | |
 | Input shaft, shift fork and idler gear. |
 | Shift shaft spring and poppet. |
 | Shift fork, you can see the lock wire holding the set bolt in place. |
 | Input shaft. |
 | Shift fork. |
| 
| The two speed clutch gear, inner and outer teeth were fairly chewed up which explained why the shift forks had gouges as the operator would push harder and harder to get the transfer case into hi/low. |
 | Eastwood’s 2 part epoxy primer applied to the cleaned, blasted and cleaned again parts.
The primer sprayed on easily and I was pleased with the results. |
 | |
 | |
 | |
 | |
 | I used Eastwood’s 2K Chassis Black Satin for the top coat, so far it seems pretty durable. |
 | Assembly begins with installation of the idler gear, then the input shaft as shown on the left. |
 | Output shaft installed. |
 | Removing the installation lip from a Redi-Sleeve, the yoke had a groove worn in it from the original seal, the Redi-Sleeve is stainless steel and provides a perfect sealing surface.
A little anaerobic gasket maker under the sleeve fills the groove so the Redi-Sleeve won’t deform. |
 | |
 | |
 | The mostly finished product. |
M37 Number 3
Sure it’s missing a fuel pump, right front fender, headlight, batteries and windows but that’s original factory paint baby!
ETW1 Carburetor rebuild
I received my ETW1 carburetor rebuild kit today from Daytona Parts Co., the cost of the kit was $42, USPS Priority Mail shipping added another $6. Basic instructions are included, hopefully the rebuild will go smoothly this weekend.
M37 electronic ignition
Pertronix makes a 24 volt electronic ignition that fits the distributor of the M37. The part number is MV-161 and can be found online if you search around or you can pick one up from Charles Talbert at M Series Rebuild.
The benefit of electronic ignition means no more tune up kits, no more adjusting the points.
M37 Fuel pump rebuild
After looking around for a rebuild kit for the M37 fuel pump I got a prompt reply back from Tom at Then and Now Automotive, you can read Tom’s reply at the end of the post. My fuel pump turned out to be an AC 9804J.
You can identify the which pump model you have by looking on the pump ear where it mounts to the engine. Parts diagram included below.
The pump was in need of a rebuild and cleaning, the fuel tank had a lot of scale and that got all the way to the fuel pump as the pictures show.
The fuel pump rebuild kit includes all the parts shown below plus 3 diaphragms and a cork gasket not shown.
After several hours of soaking in hot soapy water I disassembled and cleaned the fuel pump, it always amazes me how hard it is to remove 60 years of oil and dirt.
First step in reassembly is to install the check valve gaskets and check valves. After all of the valves were in place I installed the retainers with new screws. The original screws had rusted and caused the retainers to crack so I decided to replace the screws with brand new stainless steel slotted machine screws (#6-32 x 1/4”) and purchased new retainers from Then and Now Automotive.
Next I installed the check valve gaskets, check valves and retainer in the bottom assembly.
Cover, cover gasket, cover retainer bolt and gasket installed. The parts diagram on page 60 of the Supply Manual show the screen being installed in the bottom assembly however the NOS Fuel Pump I bought didn’t have one so I left it out of my rebuild.
After assembling the upper and lower assemblies I started on the main body assembly. I installed 2 check valve gaskets and check valves plus the seal and seal retainer.
I used a mallet and socket to seat the retainer and seal without damaging it.
I assembled the arm and links next, the bearing (hollow tube included in the rebuild kit) holds it together during installation.
The installed C clip can be seen below.
I installed the upper spring spacer and spring next.
Before installing the diaphragms the priming lever, link and rod assembly need to be installed. I used an o-ring to seal the priming lever shaft and a little bit of grease as lube.
Next up in the rebuild is the most frustrating part, installing the upper and lower diaphragms. Getting the links into the key in the end of the diaphragm shaft takes a bit of work. You kind of have to do it by feel, it takes some patience. I installed the bottom diaphragm first and put my finger through the other side which allowed me to feel the diaphragm shaft. (Note picture below right is without the seal and retainer installed.)
Upper and lower diaphragms installed.
The last diaphragm goes at the very top under the cover.
The finished product is shown below, it cleaned up pretty well and looks good, had I replated the machine screws and priming lever arm it would have looked a lot closer to NOS. (NOS Fuel Pump pics included below for reference.)
Here are some pics of a NOS Fuel Pump an my rebuilt one, you can see the NOS pump machine screws are a bit shinier than the rebuilt pump.
Then and Now Automotive can be reached at:
Phone: 781-335-8860
Outside U.S.: 01-781-335-8860
Fax: 781-335-1925
Then and Now Automotive
447 Washington St.
Weymouth Ma. 02188
mailto:oldpartstom@aol.com
Dear Matt,
Thank you for your kind inquiry. We make the fuel pump kits for the M37 and all sorts of other fuel pumps, but in order to provide the right kit, we need to know the number that is stamped into the pump you want to rebuild. The pump number is on the edge of one of the ears that the bolts go through to hold the pump onto the motor.
The M-37 Power Wagon and the M-43 Ambulances tend to have AC pumps with either # 9615 or 9804 stamped in. These are pumps equipped with a priming lever, and the pumps are also equipped with fittings to run submerged (briefly).
With that number we can send the right kit- the kits contain the parts for both the fuel and vacuum sides- the gasket to block, rocker arm pin and bushing and spring; oil seal and retainer (for the vacuum side only- on the fuel side there is no seal, just the seal retainer acting as a spring seat) ; diaphragm assemblies (of die cut buna-n-nitrile rubber cloth reinforced with nylon, with upper and lower steel protector plates and the pull rod riveted through the center- watch out for crappy flea market kits which expect you to somehow take your old diaphragms apart and re-stake them!) check valves and check valve gaskets (10 check valves in this pump!) and pulsator diaphragm on fuel side, and vacuum side bowl gasket and fiber washer.
The kits are $ 69.50 because of the extra check valves and the pulsator diaphragm. Shipping and handling is $ 12.50 by UPS inside the continental US. We also offer rebuilding services on the pump at $ 145.00 for the labor and kit parts. We take the usual credit cards, and ask that you telephone or fax in your important information for an order. We cover our phones from Monday to Friday in Eastern time at 781-335-8860 from 8am to 5pm and at 781-335-1579 from 10am to 7pm> The fax is 781-335-1925 anytime.
Hope this helps, Tom