Fuel Pump difference

aforests · Post by **aforests** » Wed Oct 22, 2014 9:05 pm

I purchased a fuel pump off ebay as my pump was in shambles missing parts etc. Just got the pump today and see there is a little damage on it. this damaged area is the only part of the pump that is different than the one i have. for those of you familiar with this difference, can you tell me if this pump is viable still, or should i send it back and get my money back, or should i take the good parts and apply them to my original pump and make one good one? not sure if i do that if i can find the right rebuild kit to work... will call Now and Then with part numbers tomorrow to find out.

Post by **wesk** » Wed Oct 22, 2014 10:20 pm

Your old unit on the right is a correct M38 unit.

M38 unit. This is with the later fording/vent system. The one in your photo was used without the vent line to the bell housing.

The newer unit on the left is a M38A1 unit that had a hand priming lever on it as seen below.

M38A1 unit with Priming pump handle.

As you can see your handle is broken off and the shaft is still in the pump. It has been sealed and may have operated OK before it was removed from service and sold to you. Ask then and now if they have a primer pump lever/shaft assy available. Parts needed are:

Lever AC# 5592836, ORD# 8329704
Clip AC# 5592920, ORD# 8332080
Adapter AC# 5592921, ORD# 8329701
Gasket AC# 1537811, ORD# 7010699

You would have to build that chipped area up with a epoxy/metal filler.

aforests · Post by **aforests** » Thu Oct 23, 2014 7:28 am

Do you think I could just take the bottom or vacuum part of the newer pump and use it on my original that is missing the bottom part of the pump?

Post by **wesk** » Thu Oct 23, 2014 7:52 am

Depends on what service bulletins have been done on them. I suggest you look the info up in the two ORD 9's. The parts list for the left hand pump is in the M38A1 ORD 9 and the right pump is in the M38 ORD 9. Then just compare part numbers.

I believe Then & Now has been short on the priming arms and has been converting priming arm pumps to non-priming arm pumps when the rebuild pump has issues with the arm.

All the manuals you need are in the downloads page.

http://www.willysmjeeps.com/v2/modules. ... it&lid=109

http://www.willysmjeeps.com/v2/modules. ... tit&lid=95

http://www.willysmjeeps.com/v2/modules. ... tit&lid=87

Agill · Post by **Agill** » Thu Oct 23, 2014 5:54 pm

Id like to know when would you use the Priming pump handle ? .
Am a new at this and everyday is amazing and I just love having a M38a1

Post by **wesk** » Thu Oct 23, 2014 6:50 pm

When these jeeps are left sitting for months the bowl will often evaporate itself dry. The hand lever will draw gas from the tank and fill the bowl so it will be easier to start.

Agill · Post by **Agill** » Thu Oct 23, 2014 6:57 pm

Thank Wes That to know since winter is coming up what else should I do since it will be in the garage a few months ... winter is longue up here in Canada

Post by **wesk** » Thu Oct 23, 2014 8:22 pm

If the garage is unheated then remove the battery to a heated area and put it on a maintainer. Leave fuel system full with a mix of mogas and Avgas or mogas with a conditioner or drain the system dry and fill the fuel pump and carb with a preservative. Jack axles enough to unload tires.

G740 · Post by **G740** » Fri Oct 24, 2014 5:57 am

Midwest Military has new primer handles in stock. No need to seal off the pump, so do not let Then and Now do that.
John
MWM

Post by **wesk** » Fri Oct 24, 2014 8:30 am

There, you have it. John has the handles and I believe John also has a local Minnesota rebuilder for the pumps.

aforests · Post by **aforests** » Fri Oct 24, 2014 4:38 pm

It appears I will be able to pull the parts i'm missing on my m38 pump from the m38a1 so my original pump is usable. I ordered a rebuild kit for it, so we shall see.
If that doesn't work, then I will rebuild the m38a1 pump and use that.
Then and Now was very good to work with over the phone.

aforests · Post by **aforests** » Mon Nov 03, 2014 10:14 pm

Rebuild kit worked great and have been able to restore my m38 pump. Mike from Then and Now has been great to work with.
The bolt that holds the bottom cover on is my only issue right now. Right under the head is a hard gasket and I can't figure out if I should try to remove it or not. In order to use the gasket that came with the kit, I need to somehow remove it. Anyone have ideas on this one?

Post by **wesk** » Mon Nov 03, 2014 11:09 pm

I've been rebuilding my fuel pumps and carbs since the 60's. I first completely disassembled them, thoroughly cleaned them and their passageways and then started in on the kit and the rebuild. To kit up a dirty old carb or fuel pump is asking for trouble down the road a short ways.

Have you at least read the fuel pump TM?
http://www.willysmjeeps.com/v2/modules. ... it&lid=109

aforests · Post by **aforests** » Tue Nov 04, 2014 9:05 am

Wes,

I don't think you understood my question. I looked back at my post and I don't see where I said I'm installing a kit into a dirty old fuel pump.

This bolt after soaking it in brake fluid for 2 days has a 'rounded' type gasket that looks like it was made to be on the bolt permanently. Have never seen anything like it. Just wanting opinions on the bolt and hard gasket material. I think it needs to come off, but didn't want to ruin the bolt.

* the fuel pump has been completely disassembled and thoroughly cleaned.

Post by **wesk** » Tue Nov 04, 2014 9:14 am

I had gathered from your post that the bolt was still in the pump. Did you add that photo? I don't recall a photo in the post yesterday. I stand corrected.

Clamp the bolt head in a vise and start chipping away at the petrified remains of the old gasket and then finish up with a wire wheel.

Fuel Pump difference

Fuel Pump difference

Primer handle