Cummins 6ct 8.3, how to replacement crank front seal

[Southbus]

This is the engine of my Champion 720 Motor Grader year 1988. It has been losing oil for a while from this seal and before proceeding to change it I have some doubts.
How difficult is it to remove the harmonic damper?
Will I need a special tool?
Is it necessary to remove the gear cover to change the seal?
Does this gear cover have some kind of gasket?
I appreciate your advice, maybe there is a link with a tutorial ... I already bought the seal that also comes with a guide to install it.
Thanks to all!
Cesar

 

[funwithfuel]

It appears as though the damper simply unbolts as does the seal. Doesn't look like a hard job at all...
Except that it is in a grader.
Good luck

 

[Coy Lancaster]

You will need to remove the front cover to change the crankshaft seal. The seal is installed from the inside of the gear cover with a small press, if you get the seal replacement kit there will be a plastic guide to install the seal and cover, the seal is installed dry no oil on crank or seal. The balancer bolts on to the end of the crankshaft and you don't need a special tool to remove it. As funwithfuel stated good luck.

 

[cuttin edge]

Too bad you couldn't have changed it when you had the hood and heads off. Oh well, a bit of stretching is good for ya.

 

[Southbus]

Dear, @Coy Lancaster and @cuttin edge first I want to thank you for your answers and the desire to help. I am trying to remove the damper, however the bolts are too tight and the damper turns and I have no way of locking it, I know there is an engine barrel tool but I don't have it and I can't find a place to buy in my city. Is there a technique to lock the engine without using that tool?
Can I put some metal object in the hole where the enguine barrel tool is put?

can I use this pin to lock the motor?
Although the plastic seems weak to me

Cesar

 

[cuttin edge]

Does the 720 not have a clutch like a 730? Just stop the drive shaft coming out of the bell housing.

 

[funwithfuel]

There should be a plugged hole for a speed sensor in the flywheel housing. Remove the plug, and screw a long bolt with a tapered point into the flywheel, engage between the teeth and she won't move. Do not run it in with an impact, just hand tight, move it a little and tighten some more till the flywheel doesn't turn.

 

[John C.]

The photo above shows the timing pin hole. Don't try to lock the crank up with that. As I recall on those engines there was a hole on the bell housing where you could put a turning gear to bar the engine over with. Cummins has a tool that fits in that hole and you can turn the fly wheel with a half inch drive socket wrench.

 

[Southbus]

Hi Folks! Thanks to your advice, I managed to remove the harmonic damper!!!

...the bolts were tight and with some lock, here the first question:
Should I put a bolt lock?
Any graduate recommendation?

I marked the position of the damper with respect to the crankshaft and the end counterweight, thus maintaining the balance of that axis.
Tomorrow morning, I'll remove the timing cover.
Then I will go to buy what I need at the city center:
1-Timing packing
2-Bolt Lock
Any suggestion?


I have some doubts with the process of installing the new seal, I am not sure if it is installed on the crankshaft or on the timing cover, I think the answer may be very obvious but I do not know it.
It is an old machine and I have proposed to eliminate all its leaks, after changing the front seal of the crankshaft, I intend to continue with the Transmission pump, there I will surely be consulting again in this forum that has "illuminated" my last months repairing this beauty.
Greetings from Santiago de Chile.
Cesar

 

[funwithfuel]

I would not remove the front cover unless you want to replace that gasket as well. I would carefully drill a very small hole in the seal. Then I would run a sheet metal screw in the hole and pry it out. You may have to drill and screw in 2 places opposite of one another. Good luck.
With the new seal, do not remove the plastic cone inside the teflon lip. Use no lubricant . Make sure the crank shaft is clean of any debris or oil.

 

[Bluox]

The front cover has to be removed to install the seal and the cover is sealed with ultra grey permatex sealer .
To install the seal the flange is supported and the seal is pushed in from the inside .
I use the driver tool that sets the correct depth but if you measure the old seal you could drive the new seal with a seal driver to that depth.
Good luck
Bob

 

[Southbus]

Hi everybody!
Yesterday afternoon, following all your instructions, I managed to change the crankshaft seal.

Today I will put new oil in the engine and do the pertinent tests.

What is the oil pressure at working temperature for this engine? (Cummins 6ct 8.3 year 1988)

@Bluox @funwithfuel @John C. @cuttin edge @Coy Lancaster
Thanks to all of you!
Cesar

 

[funwithfuel]

Your going to have to pull the cover back off. The nylon sleeve is there to help you slip the seal up over the crank snout without damage. It's not supposed to remain in place. My apologies, I should have been more clear in my explanation.

 

[funwithfuel]

After you reinstall the cover and let the nylon sleeve come through the seal, give it a while to let the seal relax. The teflon will want to return to its original shape. Give it a few hours at least. Good luck and once again, I apologize for not giving better direction.

 

[Southbus]

Good Morning!
@funwithfuel, The plastic cylinder came out backwards while I was pushing the gear cover and it was fixed on the tip of the crankshaft ...
Are you telling me that it shouldn't have come out completely?

Cesar

 

[funwithfuel]

In the pic, it looks like the vinyl sleeve is still in place.

 

[cuttin edge]

Hi Folks! Thanks to your advice, I managed to remove the harmonic damper!!!
View attachment 238779
...the bolts were tight and with some lock, here the first question:
Should I put a bolt lock?
Any graduate recommendation?
View attachment 238780
I marked the position of the damper with respect to the crankshaft and the end counterweight, thus maintaining the balance of that axis.
Tomorrow morning, I'll remove the timing cover.
Then I will go to buy what I need at the city center:
1-Timing packing
2-Bolt Lock
Any suggestion?

View attachment 238781
I have some doubts with the process of installing the new seal, I am not sure if it is installed on the crankshaft or on the timing cover, I think the answer may be very obvious but I do not know it.
It is an old machine and I have proposed to eliminate all its leaks, after changing the front seal of the crankshaft, I intend to continue with the Transmission pump, there I will surely be consulting again in this forum that has "illuminated" my last months repairing this beauty.
Greetings from Santiago de Chile.
Cesar
View attachment 238782

The old girl looks like she's in great shape.

 

[Bluox]

In the pic, it looks like the vinyl sleeve is still in place.

That's called a wear sleeve ,Some one has installed a metal wear sleeve .
Bob

 

[Bluox]

Good Morning!
@funwithfuel, The plastic cylinder came out backwards while I was pushing the gear cover and it was fixed on the tip of the crankshaft ...
Are you telling me that it shouldn't have come out completely?

Cesar

Did your old seal have the dust cover installed over it?
Bob

 

[funwithfuel]

I can see the wear sleeve. That's obvious. I'm talking about the white vinyl poking out. The brown teflon should be recessed.