Crank Main Oil Seal Replacement - 1st time seeking tips

[nelsonj]

Hello all,

Well as part of replacing my head, I will be replacing my front crank shaft main oil seal (and the Aux gear seal). I don't plan to take the cover off the crank area, I just want to cram a new seal in around the crank shaft. I have everything removed, including the seals, and waiting for the new parts. I have never replaced an oil seal so I am looking for a few tips before I try. I have a 1978, 1800 drive train (with a big aluminum lip) and here are a few pics so you know what I am working with



(note the old seals were still in place when I took the pics.)

and the crank gear:



Now my q's...
1) It looks like there was a sealant used on the metal surface of my old seal. Do I need to put on a sealant, and if so, what do people recommend?

2) It seems the rubber part of the crank seal can get "snagged" on the cam shaft during installation. If so, the rubber extends upwards (beyond flush with the metal part of the seal), makes contact with the cam gear, gets torn up, and starts leaking oil. How do I install it and check it to make sure the rubber is properly on the crank shaft and away from the crank gear?

3) How do I "drive" the seal all the way in so it seats? My 1 1/2 socket won't reach (the crank shaft is in the way), but it looks like I can use the crank gear as an extension. That is, I can put the seal part of the way in with my fingers, then I put on the cam gear (flush with the seal), then I put my socket on the cam gear, and then I could use a rubber hammer to hit the socket/cam gear combo to drive the seal in place. That is my current plan... Anyway, what do people recommend?

4) I plan on lubing the rubber parts of the seal in oil before the install. Should I also put oil on the cam shaft to help prevent the rubber from "binding up" and not sliding down the shaft properly?

I found this thread very helpful on what to look out for, but it didn't help on how to get the seal in place or what sort of sealant I need to use...

http://fiatspider.com/f08/viewtopic.php ... eal#p43860

Anyway, I want to make sure I get this done correctly - it is a big job for a "do-over". I tried to read everything I could find here before asking. Thanks in advance for tips/tricks or advice.

[nelsonj]

Ok - I closely compared my crankshaft, seal and crank gear with the post mentioned above. Mine is very different and it looks much more "idiot proof".

First, my seal seals on the crank gear, not the crank shaft.
Here is the seal, the gear and seal, and how they fit together.

Seal:


Crank gear and seal apart:


Seal partially on the gear:


Another view of the seal on the gear


And here is my crank shaft without the seal on it:


It looks like all I have to do is make sure my seal is fully set in. Then I put on the crank gear, it will pass through the seal (and seal), and then the gear will stop when it hits an expansion in the crankshaft. The crank gear will be very close, but will not contact the metal part of the seal. Only the rubber of the seal will contact the crank gear.

As a result, it looks like this design is much less prone to an improper seal install.

Still, if anyone knows if I need to apply a sealer/glue to my seal before installing please let me know what you recommend.

Thanks.

[RRoller123]

The seal should have an outer metal frame and press-fit snuggly into the inside of the housing. No sealant, just very clean and all surfaces lubed with fresh oil. Yours I am not sure about, looks very different from mine which I just recently replaced (?). But anyway, if the leaking old seal was left on too long (duh, it's leaking), the seal spring can wear through the rubber of the seal and carve a slight depression in the crank. Mine had this, fortunately it was quite slight. The resultant oil leaking would then cause a buildup of crystallized deposits on the shaft where the seal makes contact. I was careful to get all this off with a little solvent, but used no abrasive like sandpaper or anything. The new seal works fine now after making sure the shaft was fully cleaned up.

There was a thread here about then modifying the new seal so that the contact point would sit further in from the wear groove. I didn't do this and the seal works fine. Only a few hundred miles since replacement, but dry as a bone. As far as installing the seal, there was no room to swing a hammer on a socket to get the new seal on without rocking it or ruining it, so I remember that I used the cranknut to get it basically set as far as possible, then set it with a large socket and a few careful whacks of the hammer. A 5 lb hammer, swung cautiously, works well in the close quarters as you can get just enough force with a short swing. A large socket set from HF has all the sizes needed for thin dough. I had the radiator out for other reasons, and can't imagine trying to do any of this with the radiator in. It would get trashed in the process.

Don't know if any of this helps, but best of luck!

[bobplyler]

A question. Why wouldn't you just remove the front crankcase seal holder? It makes changing the seal easier.

[RRoller123]

Nearly impossible to get it off from the oil pan. I tried when changing my front crank oil seal. The crankcase seal holder is integral to the pan and pan gasket for some reason. The old gaskets are like concrete and we know what it takes to get the oil pan off and change that gasket.... If it doesn't leak, don't mess with it for sure.

[bobplyler]

That makes sense. I'm getting ready to change my oil pump and the front seals. The oil pump and seals have 140000 miles on them.

[RRoller123]

My take is don't even think of trying to take the front oil seal casing off unless the engine is pulled. Mine has about 68K on it and the seal to the case and oil pan gasket was absolutely nuclear. LOL. I went at it with a rigid razor knife briefly to try to separate the gasket from the casing and realized the futility immediately and decided to let the sleeping dog lie. <{:^)

[nelsonj]

Update:
I finished installing both seals (Aux and Crank) today.

Aux Seal: After cleaning the location, I used my 1 1/2 socket to "tap" the seal in to place. It was pretty direct - hopefully I did not pound it in too hard.



The crank seal was a bit harder. I could not get my 1 1/2 socket on it because the crankshaft was in the way. At first I tried to use the old crank gear, big part first, as a tool to install it. I put the seal in, then the crank gear, then I used my socket to hammer on the crank gear. This sort of worked, but I was afraid I might get the gear stuck on the crank shaft so I stopped and removed the gear. Instead, I took an old bolt and put the head of the bolt on the seal. I then tapped the exposed side of the bolt with a hammer and worked my way around the seal until it seemed fully set in. This seemed to work.

Hear is the crank seal from the top:


And the seal from the bottom:



I then put on the new crank gear. They originally shipped the wrong gear (the one with the small lip) and the correct gear did not arrive until late yesterday. I used my 1 1/2 socket and a hammer to help move the gear down the crank shaft, through the seal, and then to the fully installed position on the crank shaft. Since my gear has a long "lip", the seal seals on the gear, rather than on the crank shaft. This picture shows that once the gear is fully in place, the teeth of the gear do not contact the outer metal part of the seal, rather the gear is spaced back about 1/16 inch away from the metal of the seal.



Then I installed the Aux gear. Hear is a picture with everything in place.



Ok - hopefully once I get the car running these will properly seal and no oil will leak from the crank or Aux shafts.

[djchan]

First, my seal seals on the crank gear, not the crank shaft.

This to me doesn't make sense, because then there is nothing to keep oil from slipping out from the space between the outer diameter of the crankshaft and the inner diameter of the slide on crank gear.

[FiatMac]

First, my seal seals on the crank gear, not the crank shaft.

This to me doesn't make sense, because then there is nothing to keep oil from slipping out from the space between the outer diameter of the crankshaft and the inner diameter of the slide on crank gear.

I was thinking the same thing!

[majicwrench]

A lot of engines are like this. And yes, it is possible for oil to make it tween the crank OD and the pulley ID. But realisticly it aint gonna happen. Pulley is pushed up hard to crank, and their aint much clearance OD to ID either. If you are really worried bout it, you can put a tad bit of any kind of sealer tween crank and pulley. There is no pressure here, just splash and spray. No worries.

[pastaroni34]

There's an o-ring that goes between the timing drive gear and the crankshaft pulley. This is only on the early engines, 1438, 1592, 1608, and early 1756. The timing drive gear has a pocket cutout for the o-ring to fit into. See installation guides below:

Early Style: Fiat Early Crank Pulley Installation Guide

Late Style: Fiat Late Crank Pulley Installation Guide

[LucN]

Hi,

Maybe a stupid one,... but how do you remove the crankgear?


LucN