MB42/GPW43 Frankenweenie

[ww2DAD]

Ray,
I'm glad you sent me the information on the rims. I couldn't find the receipt from last year to check, but I remember it was an MD Juan from C&C Surplus. So I used the information you sent and it is one of theirs. Thanx for that. I will get some pictures out tonight of the oil pump rebuild. Oz posted his website here on this thread and he's got an excellent writeup with pictures of how he did it. If he ever writes a full book I'll give him all of mine to use.
Mike

[ww2DAD]

Ray,

Here's some initial pictures of the oil pump rebuild. I had already torn it down and sand blasted the castings. Tear down was relatively easy. One screw in the bottom cover and some taping with a plastic mallet and the bottom case came off. I put the upper case with impeller shaft in the vice and tapped out the cross pin. I had to use my press to press out the shaft.

The first picture shows a basic layout of all the parts and the new rebuild kit to the right. I got the rebuild kit thru Brent Mullins on ebay. The second picture is of the end of the impeller shaft. It shows the 90 degree offset of the pin hole to the distrib shaft slot. The TM says to drill 90 degrees off the slot but doesn't mention whether to drill on the fat side of the slot or the skinny side. The new gear has a starter hole for cross drilling. Oz and I had a discussion about this last night. I did look at the gear and it seems it doesn't matter as long as you drill 90 degrees off. A single gear tooth is aligned on either side of the hole.

The last two pictures are of the relief valve plunger, spring, shim (mine has one) and the washer and bolt. The last picture is of the metal disc I found on the inside of the impeller shaft. It was a good thing I looked at the TM drawing because mine was stuck to the top even after two days of soaking. I would have missed that. My pump also had just one thin gasket between the top and bottom castings.

Tomorrow I plan to put the shaft in, add the gear, and then drill the cross hole. I won't paint the two casting until that is done. More pictures to come.

Mike

[17thAirborne]

I know a few folks on the forum are against rebuilding these, but I am happy with my 40psi at idle after rebuilding. i'm sure yours will be even better

[70th Division]

I know a few folks on the forum are against rebuilding these, but I am happy with my 40psi at idle after rebuilding. i'm sure yours will be even better

Hello Oz,

Why is that ?
There are nos GPW rebuild kits available from several sources .

Best Regards,
Ray

[17thAirborne]

I know a few folks on the forum are against rebuilding these, but I am happy with my 40psi at idle after rebuilding. i'm sure yours will be even better

Hello Oz,

Why is that ?
There are nos GPW rebuild kits available from several sources .

Best Regards,
Ray

THere are a few threads where some are recommending just buying one of the new pumps. I prefer to keep things original and with the many rebuild kits available I agree with your line of reasoning and went the rebuild way also. Just have to measure all the clearances.

[ww2DAD]

So I think I have the colors that jeep was painted backwards. I was sitting out in back of my garage and the sun was shining on the inside of the hood. As I looked closer, I saw that the yellow had been painted over the khaki, the OD green over the yellow, and finally the blue over the OD green. You really couldn't see the color layers that clearly on the chassis, until looking at the inside of the hood paint with a pair of mag glasses. Strange that I missed that.

My assumption is that it was a yellow overpainted jeep before it went to Allison for reconditioning, then repainted OD by them, and then blue when given to the Air Force. Since the colors are uniform throughout the jeep, it's possible the jeep arrived at the recon fac with the MB tub. Just a guess.

Ray,

I have the pump rebuild on hold. Missing one gasket that goes on the shaft before it fits into the upper casting. Gaskets on the way, NOS.

Regards,
Mike

[ww2DAD]

Some pictures for today from the transmission and transfer case rebuilds. They are standing by for the engine block to be built. Rather straight forward rebuilds and not too difficult to do. Just took forever to get thru the grease, dried mud, and old oil. Best recommendation was my brother telling me to buy an aircraft safety wire plier. Can find them cheap on Amazon, and made easy work of the ties for the transfer case bolts.

Today's efforts were in cleaning the crankshaft bearing caps, bolts, and driving out the broken off oil drain pipe in the rear cap.

Mike

[ww2DAD]

Pictures of the steering gear box rebuild, new horn contact wiring, and final mounting. Worked on polishing the crankshaft journals today, and parts came in to finish the oil pump. Should be able to post those tomorrow.
Mike

[17thAirborne]

Nice to see those F marks on the cover. Keep up the great work.

[70th Division]

Pictures of the steering gear box rebuild, new horn contact wiring, and final mounting. Worked on polishing the crankshaft journals today, and parts came in to finish the oil pump. Should be able to post those tomorrow.
Mike

Hello Mike,
Wow you sure make good progress !!

Looking great !

Best Regards,
Ray

[ww2DAD]

Ray,

Trying like he%*. It's been a long 8 months. While I was waiting for the engine block to come back from the machine shop, I rebuilt the generator, starter, and distrib, and other ancillary things. I'm in the middle of the oil pump right now since the gaskets came in and had posted some pictures earlier. I will post the remaining pictures hopefully tonight.

Block is back and painted. Getting ready to polish the crankshaft. Watched a good video on the internet last night on how someone did it. Hadn't thought of his idea but he simply wrapped 800 then 1000 and finished with 1500 grit sandpaper around the journals with oil on each different one, and then wrapped a 3 ft long piece of old cloth around the sandpaper. He just looped the cloth around the sandpaper and pulled it back and forth like sawing a log. I was going to do it the hard way. His results were beautiful. Simple but effective. Wish I had thought of that.

Strange but you may be right that the engine was rebuilt in Europe. I say that because today I went and tried to buy some oil gallery plugs. I thought they were 3/8ths but the ones that were in the block turned out to be 10mm. I have found a couple of other metric threads on other things. So, it's a good possibility that it was rebuilt over there after the war.

Mike

[ww2DAD]

Ray,

Here's some updates on the oil pump I promised. Include having to use a small file to clean up the inside of the new impeller (1st pic) because of extra material from the machining, a picture of the gasket that fits inside the housing and then on the shaft (same gasket), and then lining up the 90 degree drill hole. I was able to knock the gear onto the shaft without having to use my press. Just a small brass hammer.

Second set shows the gear in place (90 degrees to slot - you can see the pilot hole on the side of the gear), checking the distance between the gear and casting (.0312 inch), checking the gap between the impeller and casting edge (.015 inch) and drilling the cross hole with a 5/32 drill as Oz recommended. Drilling was fairly easy since the material was softer than I thought.

Tomorrow will be painting and then final assembly.

Mike

[70th Division]

Ray,

Trying like he%*. It's been a long 8 months. While I was waiting for the engine block to come back from the machine shop, I rebuilt the generator, starter, and distrib, and other ancillary things. I'm in the middle of the oil pump right now since the gaskets came in and had posted some pictures earlier. I will post the remaining pictures hopefully tonight.

Block is back and painted. Getting ready to polish the crankshaft. Watched a good video on the internet last night on how someone did it. Hadn't thought of his idea but he simply wrapped 800 then 1000 and finished with 1500 grit sandpaper around the journals with oil on each different one, and then wrapped a 3 ft long piece of old cloth around the sandpaper. He just looped the cloth around the sandpaper and pulled it back and forth like sawing a log. I was going to do it the hard way. His results were beautiful. Simple but effective. Wish I had thought of that.

Strange but you may be right that the engine was rebuilt in Europe. I say that because today I went and tried to buy some oil gallery plugs. I thought they were 3/8ths but the ones that were in the block turned out to be 10mm. I have found a couple of other metric threads on other things. So, it's a good possibility that it was rebuilt over there after the war.

Mike

Hello Mike,

That is great information there, you certainly have great skills master getting these items rebuilt, and polishing the crank .

It is interesting that you found metric threaded oil gallery plugs, another clue added to the collection of those mysterious blocks, and metric was certainly not in use in the US factories back then !

Best Regards,
Ray

[70th Division]

Ray,

Here's some updates on the oil pump I promised. Include having to use a small file to clean up the inside of the new impeller (1st pic) because of extra material from the machining, a picture of the gasket that fits inside the housing and then on the shaft (same gasket), and then lining up the 90 degree drill hole. I was able to knock the gear onto the shaft without having to use my press. Just a small brass hammer.

Second set shows the gear in place (90 degrees to slot - you can see the pilot hole on the side of the gear), checking the distance between the gear and casting (.0312 inch), checking the gap between the impeller and casting edge (.015 inch) and drilling the cross hole with a 5/32 drill as Oz recommended. Drilling was fairly easy since the material was softer than I thought.

Tomorrow will be painting and then final assembly.

Mike

Hello Mike,

Thanks for the pictures and tolerances, I will be getting to my oil pump soon, and see what I have.
Looking forward to getting it completed !

Best Regards,
Ray

[ww2DAD]

Ray your welcome.

Here's today's progress. Painted the oil pump housings and made my 2nd set of oil pump studs. Can't find them here in 2 3/4 inch length, and I'm too cheap to order some. Was bored anyway. Made two sets - this is the 2nd iteration.

Mike