[volvo4fun]

A 1988 318 Deere jumped in my trailer today (so the story goes) and would not get out.

790 hours and major oil leakage on the front crankshaft seal. The previous owner was fed up with dealing with the oil problem. Lost as much of a quart of oil every time he cut grass.

I am concluding that this has been going on for a while, judging by the liberal coating of oil that everything underneath has.
My question is if there is a reasonable chance of just replacing the bearing and seal is all that it needs, or can I expect to see a worn crankshaft?

P218G engine

 

[boomers_influence]

robert
are you talking about the seal behind the
elect clutch?
in onan speak that is a REAR seal.
the fan/flywheel is always the FRONT of
the onan engine.
please advise.
thank you. boomer ( the used onan engine parts guy )

 

[volvo4fun]

The PTO side.

 

[pa88316]

I just did this same job on a 650 hr p218g in my 88 316. It was pretty simple, boomer helped out a ton with parts and insider info/tricks. I also replaced the oil pan and oil filter gaskets at the same time, as well as the plastic thrust washer which you also probably have (boomer pointed this out to me, i take no credit) all in all it took me several evenings working very slowly, and i doubt if i had 100$ in all the gaskets and what not

 

[Hammerdown-7]

Hello Robert
Replacing the PTO side of the engine seal is pretty straight forward and can be done with leaving the engine in the Tractor frame. An Onan-Cummin's dealer will have the new seal and be sure to get the Bearing Plate Gasket that goes between the block and bearing Plate as it does effect Crank shaft bearing pre-load some. You will have to remove the entire electric PTO assembly to get the engine down to the bearing plate. Remove the bearing Plate bolt's then what I used was a Plastic mallet to Tap the Bearing Plate off of the engine. It is a Machines fit so they do fit snug, do not pry on it as the crankshaft bearing is inside the bearing Plate assembly, and you don't want to Maul the back side of the bearing Plate or surface of the block where the gasket has to seal fully. There may or may Not be a shim behind it depending on how much Crankshaft end play was there when they built the engine, Mine did Not have a shim just the Gasket there. The gasket can be scraped off with a safety razor blade but be careful as to Not scar the Plate or block area where the two Pieces mate. Make sure the front section of the block is clean where the bearing Plate sit's against when it is bolted down as well as the bearing Plate surface as well and don't use any gasket material such as silicone or Gasket maker as it will effect the Crankshaft Pre-load or may fill The Oil Galley hole that supplies engine oil to the Crankshaft bearing the Bearing Plate and block surface are meant to have a clean Gasket only seal.




The PTO seal can be removed once the bearing Plate is off the engine I Placed mine in my vice and drove out the old seal Lightly with a Punch. When I installed the new seal I coated it with never seize Internally on the rubber Portion of the seal where it meet's the crankshaft so that it sealed well and Taped it into Place using a Piece of PVC Plastic Pipe until it fit flush into my Bearing plate. Make sure when you Put the Bearing Plate back on the engine that the Bearing Oil Galley lines up it is the raised round Portion of the Bearing Plate and there will be a Hole in the block where it allows oil to travel to The Main crankshaft bearing. Hand Thread the bearing Plate bolt's then Torque them down slowly and evenly In sequence per the Onan service manual's suggested torque. The Onan manual say's to use a piece of cardboard between the seal and crankshaft when Placing the bearing plate back on the crankshaft putting it back into Position on the block, But I used plenty of never Seize on the seal and it Glided right over the crankshaft ride without any issues & The Never Seize will allow Plenty of Lubrication when starting the engine back up for the seal to seat good to the crankshaft surface and not leak any More. I hope this helps here is a Link to the Onan service manul if you do not have one in hand Refer to section 10-14 of the Manual, Kurt


http://www.cumminsonan.com/www/pdf/manuals/965-0762.pdf

 

[volvo4fun]

Got the engine running this morning, and it looks like the bearing has plenty of play. I could hear it but also see the bolt move all over the place.

@Sam & Kurt : did you also replace the bearing?

 

[pa88316]

Nope, i only replaced the thrust washer(which was plastic, and apparently prone to self destruction) and the gasket. Mine did have the .005 shim against the thrust washer, and after i did all the math on how thick my new gasket was versus my old one(boomer told me they make 3 different thicknesses of gasket, so this is important or you will have too much/not enough crankshaft end play) i put everything back together and ended up with way too much end play, and had to re assemble everything, this time with the thrust washer shim. I believe i ended up with .008 of crankshaft end play, which is ideal. I couldnt imagine the bearing itself really wearing out, its a pretty hefty piece of high grade steel, but i suppose it could end up "wallowed out" if you had some other issue that threw the crankshaft out of balance. Boomer is the true expert here, and i highly recomend you email him, he ll set you straight, and supply the parts. Its a one stop onan shop with him.

 

[charms]

I have seen 2 or 3 Onans, out of maybe 30 or so, that had worn enough main bearings that you could rock the flywheel an easily noticeable amount. I didn't need a dial indicator to see that was way past spec. So yes the bearings can wear.

 

[volvo4fun]

Allright, I will report back when I got it pulled apart.

 

[volvo4fun]

Compression test showed 125 psig on both cylinders.
Pulled the PTO off and to my great surprise I see one of the bolts that holds the bearing support plate in place was completely unscrewed. The others were less than hand tight.
Pulled the plate and everything looks fine, no unusual wear on the crankshaft. Bearing was kind of rough.
After consulting with Boomer we decided to replace the bearing, seal and the plastic washer.
The plastic (spring) washer was replaced with a metal one.
Two days later I have the parts in my hand and one hour later the engine is running again.

If there ever is a price for creative and secure packaging I will nominate Boomer, nice job.

On to the next problem: high speed surge / runaway. Will post separate thread on that.

Thanks all for your suggestions

 

[boomers_influence]

robert
THANK YOU for the kind words.
your next problem may be the broken
flyball spacer.
thanks again. boomer