39 Mystery Leak

SuperDave

SuperDave

Senior Member
A good old car friend brought his 39 to me for help. A puddle appears under the transmission after the car is shut off. Looks like a mix of oil and water. After the puddle lays there over night, The water evaporates leaving oil. It looked like it was dripping from the clutch cover hole. Then I found that it was leaking from the seam where the transmission bell housing bolts to the clutch cover/oil pan. It just runs down a short distance to the lowest point, then drips from the cotter key that keeps that weep hole open. There was no water in the (low)engine oil, the transmission is a little low on lube too, but no water. I am thinking that there is either a transmission and/or engine rear seal leak and the water may be coming from a freeze plug somewhere behind the flywheel?? Is there any soft plugs in the rear of the block? I may pass on this repair!:eek:
 
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Check to see if the water is coming from the rear of the heads or from the area where the oil pan bolts to the block. The 39 block will have four core plugs in the oil pan rails and they can rust through.
 
A close inspection shows no leakage at the pan gasket or cylinder heads. I think I can see two wide places in the pan rail that are probably the plugs you mentioned. Two on each side? They are ahead of the clutch cover area and if they leak internally would leak into the oil pan. I may have to remove the pan to see if the leakage is in the rear area of the pan, if that is possible.. Other than removing the starter, can I drop the pan without unbolting the engine mounts?
 
The only question is can you get it past the wishbone? I've not worked on a 39 in years, so I can't remember how close the bones are to the back of the pan.

On earlier V8's, we have to loosen the ball-mount at the back and wedge a block of wood to hold the rear of the wishbone down - then we can get the pan off.

I don't believe the cross-steering arms will be in the way, but that is the only other thing that crosses my mind.

One question to ask him - is how is the oil pressure? If it is low, then when you're busy pulling the pan, might want to clean it out and put in a new oil pump. The one you'd use is the 49-53 pump, with the later truck pickup (you can get the pickup from Speedway). Not trying to spend your buddy's money - but sometimes when you have something all apart - a job like this is easy.
 
There are no fleeze plugs in the pre-war Ford L-head 85 HP or 95 HP V8 engines made in US or Canada. The plugs in the pan rail were core sand clean out holes left from casting process through 1940. Now I'm assuming that this is an 85 HP V8. A 60 HP V8 is a bit different in the first year of production but I'm not going to go there. The V8 engines have been known to crack just about anywhere in the block from freezing. Generally it's the pan rail that cracks but sometimes it will crack on the back side of the block inside the bell. It is more common to see this under severe freeze up where several places are cracked all at the same time but you just never know.

I would want to know if it is actually coolant seeping out or not. If the system has anti freeze, it's pretty easy to tell that. If not, not so much. Rear crank seal leaks are more common and the transmission front can leak too. If it's gear oil, you should be able to smell the EP additives. Engine oil has a different smell to it. There shouldn't be much of any sulphur in it.

Engines and transmissions can build up condensation inside depending on weather conditions and whether they are fully warmed up during operation. A vehicle that travels to the corner store and back will have a lot more than one that drives for 20 or 30 minutes at a time. 1939 Fords still had the crank open windshield too so sometimes they leak in rain or heavy dew and it will get into the car through a leaky windshield seal. It has to go somewhere and generally it goes straight down to the nearest convenient place for an exit. Cowl vents sometimes do it too but it depends on the design and whether the car has one or not.
 
I'm with Rotorwrench on this one and I would try to figure out what the problem is before tearing it apart. Can you duplicate the problem by running the car? Does it happen every time? Have you parked it in dry environment for several days to make sure the water is from the car not the environment?
 
O.K. Today I drained the ****** of the "stuff" that was in there. very light weight, at least it "appeared" to be light. The water was condensation. This car has not been driven more than a few minutes at a time for the last year or so in the Florida humid climate. been in a body shop, upholstery shop, muffler shop etc. etc. I put the heavier purple stuff in. It continued to leak the new lube, albeit a little slower. but no water. I suspect that the countershaft is leaking at the front bushing/bearing. I will pass on taking on the job of removing the ****** and repairing it. At the ripe old age of 77 and 130 LBS I am not going to attempt to manhandle that thing. There are other mechanical issues with this car too. I question the wisdom of doing all the cosmetic stuff first. make sure the mechanicals are solid before you mess with the pretty stuff. Maybe Velocity channel is a bad influence? LOL
Thanks for all the input fellas!
 
The countershaft front bore in the case can crack up to the main input bore and it will have a leak.

I agree about mechanicals first. Messing up paint finish from doing repairs is no fun.
 
SuperDave said:
O.K. Today I drained the ****** of the "stuff" that was in there. very light weight, at least it "appeared" to be light. The water was condensation. This car has not been driven more than a few minutes at a time for the last year or so in the Florida humid climate. been in a body shop, upholstery shop, muffler shop etc. etc. I put the heavier purple stuff in. It continued to leak the new lube, albeit a little slower. but no water. I suspect that the countershaft is leaking at the front bushing/bearing. I will pass on taking on the job of removing the ****** and repairing it. At the ripe old age of 77 and 130 LBS I am not going to attempt to manhandle that thing. There are other mechanical issues with this car too. I question the wisdom of doing all the cosmetic stuff first. make sure the mechanicals are solid before you mess with the pretty stuff. Maybe Velocity channel is a bad influence? LOL
Thanks for all the input fellas!
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Fancy seeing you over here Dave. old guy rich in GA
 
JSeery said:
Not totally sure what you are referring to as "purple stuff" but just be sure it is yellow metal compatible!
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Royal Purple was the only lube on the shelf that specifically stated that it was appropriate to use in mechanisms containing bronze. :)
 
SuperDave said:
Royal Purple was the only lube on the shelf that specifically stated that it was appropriate to use in mechanisms containing bronze. :)
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What weight was the lube? If it is the synthetic stuff - it is great for transmissions that are tightly sealed, but in a 39 box, you'll probably find that you'll collect all of it on the floor in a fairly short period of time.
 
It's 75-140 and seems to be a good bit heavier than the 80W I have on the shelf. Although it did drip for a while, it was a lot slower.
BUT ! OMG I just found the counter shaft sticking out of the back of the transmission about 3/4 inch! Retainer pin is missing. Of coarse the shaft doesn't just slide back in..... This box needs to be taken out and repaired properly. Sure would have been more efficient if done right the first time.
 
With the countershaft sticking out that far, the front end of that shaft must be just floating. I WOULD BE SURE NOT TO EVEN ATTEMPT TO MOVE THAT VEHICLE UNDER IT'S OWN POWER. THAT TRANS IS A GRENADE waiting to go-off. DD
 
If it is the locking pin missing at the rear you should be able to get it back togetter in the car.
BUT you have to take the shifter top off and make sure the axial shim is lined up before trying to get the shaft back in.
One guy in the car making shure the washer is in place and another gently sliding the shaft back in.
 
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