lower unit leak 45hp Chrysler

[skizawa]

You can see from the pic that the leak isn't from the fill screw, but it's leaking from the bolt above it. Do you know what seal in the lower unit would cause this leak?? Maybe the shift rod seal??
Your input is certainly appreciated! Thanks!!

 

[Jeffe74]

That's gear oil for sure?

I have the lower off of my 55 right now, in that area you would have the drive shaft seal and the shift rod seal.

 

[skizawa]

Looks like my next task replacing those two seals. Thanks for the reply!

 

[Jeffe74]

I asked if it's gear oil because it seems like an odd place for that to be leaking from.. if its the same as my 55 it would run down from the seals and come out of the two drain holes.

I pressure tested mine. You can check with soap and water to find a leaking seal.

 

[jerryjerry05]

If the waters getting in the oil leaks from the weakest point.
It can suck water in from one seal and leak oil from another.
IF? that's gear oil it's coming from the shift shaft or the drive shaft.

 

[skizawa]

Yes it's gear oil. I put in two new driveshaft seals....ran the engine in gear for 10 mins and later saw a stream of gear oil streaming down same place. I called the dealer, explained that the seals were leaking and seemed they weren't real tight on the drive shaft. They sent two more "quicksilver" seals, I tapped them in gently with small block of wood, and damn leak started again same place. I'm lost with this one!

 

[Nordin]

You have to pressure test the LU.
It can be the shift rod seal that leak.
It can be the drtive shaft seal too, even if you replace it.
The lips at the seals makes a grove in the shaft and you need to go down in the diameter for the shaft at the seal or replace the drive shaft.
Pressure test is the first thing to do to know where it leak..

 

[jerryjerry05]

You inspect the shaft before installing the seals?

A 45 Chrysler 1968-1984 minimum of 35 years old.
The shaft over time can wear grooves in the shafts and the seals can leak.

Putting the seals on upside down or adding a shim under them can make the seal work.


Remove the drive, drain the oil.
A little compressed air and a spray bottle of 50-50 Dawn soap and water.
Spray the leak points with the soap mix and see where the bubbles show up.

 

[skizawa]

Thanks for your advice!!! Good idea about the pressure test. I couldn't feel any worn out spots on the driveshaft, but I should of used calipers to see if it is worn. Thanks again!

 

[skizawa]

I gave the lower foot a air pressure test with soapy water and did not see any leaks. I used calipers on the driveshaft and could not tell any difference. I pounded the new seals a hair deeper, plus rubbed some brake fluid on them, supposedly it helps to expand the seal, but damn lower unit leaked fluid again after a 10 min run. Thanks for your comments!

 

[kbh121956]

If the drive shaft is worn, you can see the small groove where the seal rides. When I pressure test, I use a foot bicycle pump, it has a gauge on it. I pump it up to 12 psi and leave it for an hour. After an hour has passed and if the gauge is still at 12 psi, I figure it's good. (you can also check it for leaks with soapy water in a spray bottle.) Then I use a vacuum brake tester and pull vacuum on the gear box. You need to "push, pull" the seals when checking them.

 

[Nordin]

When pressure test turn the drive shaft clockwise, pull and push the shift rod up and down and turn the drive shaft while the shift shaft is in gear to make the prop shaft to turn.

The leak can be in drive shaft seal, shift shaft seal, prop shaft seal and the o-ring in the outer diameter of the prop shaft bearring cage.

 

[jerryjerry05]

Next try adding a shim "under" the seal, raising it up.
Did you put it in upside down?

A "new" seal can be bad.
It can be 30 years old setting on a shelf waiting for YOU!!

 

[skizawa]

I just stuck an air nozzle in the fill hole, the drive shaft wanted to pop up so I had to hold it in. I started the engine again, this time let run in reverse for almost ten mins, then put it in forward. Came back an hour later and didn't see any leaks. Crossing my fingers on this one. I appreciate your time gents!!!

 

[skizawa]

I used digital calipers on the driveshaft. Between the worn area and good area, the difference was 045 thousandths. Do you think that is enough wear on the shaft to make seals leak? I also put in a new shift rod seal, and am waiting for o-ring for foot. Thanks!

 

[jerryjerry05]

.045 is enough to let it leak.
Like I suggested add shims under the seal and lift the seal to an area that hasn't been worn down.

 

[skizawa]

I can't do like you said because I would have to order the third set of seals that cost too much. Can't take the old seals out without ruining them. Thanks!