Oil Leak at Ball Cap

[RecklessKelly]

I have an oil leak that lets oil out of the driveshaft ball cap. Its hard to see the oil on the cap but it is coming from there and leaking down onto the flange. Otherwise the engine is pretty much leak free. What would be the cause? Can I repair with engine in place?
I know the safety wire is missing but I did check the bolt tightness.

[CudaMan]

Situation normal. Keep the ball cap pumped full of grease to reduce the rate of oil seepage.

[RecklessKelly]

I gave it about 10 pumps but none came out, should I pump until it starts to come out?

[Humblej]

Yes, more pumps, 10 aint gonna do it.

There is a lot going on at the U-Joint ball. The front of the ball socket is the 4th main bearing. There is no seal between the transmission tail shaft and the 4th main, so it will leak, and it will leak into the U-joint ball and leak out at the ball flange where you are seeing it, and also down your driveshaft into your rear axle. There is no cure, but you can slow it down with a lot of grease in the ball.

[speedytinc]

A correct fitting 4th main (1.5-2thou) doesnt leak much. The u-joint needs to be packed full. Grease will ooze out when its close to full.
Leak multipliers include no output shaft plug & a transmission screen. The screen concentrates the left over, filtered oil right on the ball cap. One solution is to turn the ball cap either 90 or 180 degrees. (that only works if the ball cap was perfectly machined on center.)

[RecklessKelly]

Remove the four bolts and turn the cap 180?
Is the output plug shaft the visible threaded cap that allows access to the cross pin or is it internal?
If I pull the rear end and shaft, can I change the 4th main? I was reading up in the manual but without a good visual its a little hard to comprehend but Im getting there. The 4th main is babbet coated and the ID has to be bored to match its mating shaft? I have access to a lathe and mill and a long winter ahead so anything I can do I dont mind.

[RecklessKelly]

I do have a screen. Remove the four bolts and turn the cap 180?
Is the output plug shaft the visible threaded cap that allows access to the cross pin or is it internal?
If I pull the rear end and shaft, can I change the 4th main? I was reading up in the manual but without a good visual its a little hard to comprehend but Im getting there. The 4th main is babbet coated and the ID has to be bored to match its mating shaft? I have access to a lathe and mill and a long winter ahead so anything I can do I dont mind.

[Norman Kling]

One thing you might check is the gaskets between the ball joint. There should be a gasket between the 4th main and the hogs head/crankcase. But no gasket between the 4th main and the ball joint retainer ring. That will hold the ball joint closer to the 4th main. Also as pointed about above, pump much grease into the ball joint.
Norm

[RecklessKelly]

I can see displaced sealant between the 4th main flange and hogshead but I cant tell if a gasket is present. It drips there when parked but the cap leakage is only while running. No gasket behind the ball cap. Can the 4th main be pulled out enough to reseal? If so, I could cut a gasket and ultrablack it in with the slit facing up and ultrablack the ball cap flange. I'd like to get rid of any leaks if possible, I did conquer the oil pan and bolts, valve cover, trans cover and top oil tube flange leaks.

[speedytinc]

I do have a screen. Remove the four bolts and turn the cap 180? { Yes }
Is the output plug shaft the visible threaded cap that allows access to the cross pin or is it internal?
{ You would have to pull the u-joint out of the output shaft. }
{The plug is in the square just in front of the clutch spring retaining pin. Seems to me someone posted a fix on this forum. I doubt you could put the correct plug in without having the transmission out & apart. Maybe stuffing in a rubber disk?}
If I pull the rear end and shaft, can I change the 4th main?
{Yes}
I was reading up in the manual but without a good visual its a little hard to comprehend but Im getting there. The 4th main is babbet coated and the ID has to be bored to match its mating shaft?
{yes with a close tolerance. Thats best done by cleaning the shaft surface (tool post grinder) & fitting the new ball cap before final assembly }
{The ball cap is machined/centered to the small edge under the mounting flange where it centers/contacts the CC & hh hole. }
I have access to a lathe and mill and a long winter ahead so anything I can do I dont mind.

If you find the 4th main babbit is all wallered, its a sign that the output shaft is not running square. That should have been checked & perfected during final assembly.

[TRDxB2]

past discussion
https://www.mtfca.com/discus/messages/3 ... 1375394665

See other's comments about this Where there is no leaking may mean .....

[Dan McEachern]

My guess is that the plug in the driven plate output shaft is missing. That plug prevents engine oil from migrating thru the tail shaft where the u joint square fits. The driven plate must be removed to in stall one. Only way to determine this is to pull the engine or pull the rearend and look inside the output shaft.

[ABoer]

For that oil leak , I use a ]DIAPER ] see pictures .
Toon
.

[Humblej]

John,
The take-away from all the helpful advice should be that there is nothing you can do to completely stop oil dripping out of the ball joint from the 4th main. Some oil dripping there during and after running the engine is normal and should be expected. I would not recommend pulling the 4th main or even repositioning the 4th main to fix something that is not a problem. The 4th main flange and ball joint flange are the low points so that is where the oil will migrate to before it drips onto your driveway, does not mean it is leaking from the 4th main flange/transmission/oil pan connection. There are gaskets and oil seals throughout the engine and transmission but none for the 4th main and transmission shaft, therefore, it will leak oil. Consider it part of the Model T charm, like buzzing coils and gurgling radiator.

[Dan Hatch]

See Herm’s thread on how he did transmission rebuild to see how to make 4th leak as little as possible.

[RecklessKelly]

past discussion
https://www.mtfca.com/discus/messages/3 ... 1375394665

See other's comments about this Where there is no leaking may mean .....
leak nnnnn.png

Its hard to see in the photo but oil is poaring out at the white arrow.

[RecklessKelly]

I think alot of the common leak paths are just a T thing but to get in a few wins would be a good thing or at least have fun trying. I will check out Herm's rebuild thread.

[DanTreace]

As others replied, the way to subdue oil leaking is to keep the U-Joint ball smack full of grease. Ford put the largest grease cup there for that reason.

Noticed in your photo no grease oozing from the ball cap, that would IMO mean your ball joint is lacking grease.


On assembly the U-joint ball should be completely full of grease.

And when greasing the joint, fill or pump until grease flows from the gap between the cap and ball housing, that shows it's full up.

Grease at uninv joint copy.jpg (54.06 KiB) Viewed 2437 times

[RecklessKelly]

I did add some but I'll keep pumping until it comes out.

[JTT3]

If your plug in the tail shaft is the cause of the leak whether not seated or missing, simply loosen the rear axle assembly & drop the front of the drive shaft (it’s some work but not as much as removing the assembly) measure the tail shaft hole where the universal’s square head goes in. Once you have the measurement go to a Lowe’s or real hardware store and buy a oversized rubber cork and drive it into the hole deeper than the length of the square shaft of the universal joint. Reassemble and fill the bell of the driveshaft full with the highest temp grease you can. The rubber cork should not just fit the opening, it must be large enough that you have to drive it into the hole with a large flat ended punch & dead blow hammer so the cork conforms to the orifice. That should do the trick if it’s coming from the tail shaft hole. Done it, seen it done & know it works for that problem. Best John

[RecklessKelly]

How could the plug go missing, someone left it out when they were in there or it got devoured into the trans? Would I have to loosen the leaf spring or will the front if the shaft move aft? Its worth a try John, thanks.

[big2bird]

I used to do this.
Jack up rear under pumpkin, about 4-6", jack stands under rear frame rails about a foot in, pop brake rods, ball cap, and Ruxstell shifter at pin.
Unbolt rear spring clips, drop axle, and roll back.
You will appreciate the room.

[big2bird]

Sometimes the plug is forgotten.

I would NOT install ball cap upside down. When it runs dry, you will get more oil leaking.

They did make a sealed bearing 4th main. (Aftermarket).

This stops it, but to install it correctly, you have to remove oil pan and hog to dial it in spot on, or you risk snapping stuff.
Pan must be true, and you must do it engine on a stand vertically, and after if you tap a parking block, it can go south in a hurry.

[RecklessKelly]

I might just do that.

[big2bird]

If you pull it off, Mike the shaft and bearing. If worn, change it. If it's oblong, look for a bent pan. Shaft needs to be centered in opening, but with tranny sag, you really need engine nose down to tell. Fun, huh?

[RecklessKelly]

Yea for that a custom jig would be needed.