Its a 75' JD 400 with a 340cc engine, Walbro WR carb....crank seal questions
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jake wilken
crank seal questions
I need to order a new carb kit for my sled that I cant keep running. ITs not sucking enought gas and it was suggested that I may need some new crank seals. Is this something I can do myself and how hard is it. Truthfully I dont even know where they go but am pretty mechanically inclined and imagine if its not that hard that I could figure it out....
Its a 75' JD 400 with a 340cc engine, Walbro WR carb....
Its a 75' JD 400 with a 340cc engine, Walbro WR carb....-
Matt
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crank seal questions
Start with the carb kit, and worry about seals later. In the mean time, I would reccomend getting one of the Clymer vintage service manuals that covers John Deere so you can start reading up on stuff.
Matt - JDsleds.com Administrator-
400brian
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crank seal questions
My JD service manual goes up to '74.
The '72 engines seem to require splitting the case to replace seals because of retainers in the case.
On the newer engines, the book indicates that the pto end seal can be pried out and replaced. There is no mention about the mag end, other than during crank installation.
The seals that we talk about are in the ends of the crankcase, around the crankshaft.
They are one piece, like a wheel bearing seal.
It requires the clutch to be removed at a minimum for the pto end, and complete engine disasembly for the mag end ( it appears ). There are also seals between the cylinders, but the crank has to be sent out to have them replaced.
Matt is sugesting you exhaust all other posibilities before you jump into this. Sounds smart to me.
If your seals are really bad, you should be able to tell. Either because of oily crud buildup around the seal area of the crankcase, or engine response to starter fluid sprayed at the seal while running.
These seals do go bad. On UL aircraft, Rotax recommends seal replacement every year, or every 150 hrs. This is perhaps ass covering, I doubt many folks replace them that often. On a sled that sits much of the year, and is 30 years old, it is likely that you have some corrosion of the crank at the seal area, and the seal may not last real long if you take to running it, so you need to check them every so often.
FOR ALL NEWBIES: get yourself a service manual if you are serious about messing with these sleds, it will pay!
The '72 engines seem to require splitting the case to replace seals because of retainers in the case.
On the newer engines, the book indicates that the pto end seal can be pried out and replaced. There is no mention about the mag end, other than during crank installation.
The seals that we talk about are in the ends of the crankcase, around the crankshaft.
They are one piece, like a wheel bearing seal.
It requires the clutch to be removed at a minimum for the pto end, and complete engine disasembly for the mag end ( it appears ). There are also seals between the cylinders, but the crank has to be sent out to have them replaced.
Matt is sugesting you exhaust all other posibilities before you jump into this. Sounds smart to me.
If your seals are really bad, you should be able to tell. Either because of oily crud buildup around the seal area of the crankcase, or engine response to starter fluid sprayed at the seal while running.
These seals do go bad. On UL aircraft, Rotax recommends seal replacement every year, or every 150 hrs. This is perhaps ass covering, I doubt many folks replace them that often. On a sled that sits much of the year, and is 30 years old, it is likely that you have some corrosion of the crank at the seal area, and the seal may not last real long if you take to running it, so you need to check them every so often.
FOR ALL NEWBIES: get yourself a service manual if you are serious about messing with these sleds, it will pay!
'09 Vintage Challenge Survivor, and I wasn't late for supper!
'10, '11, '12, '13,'14,'15,'16,'17, '18, 19, 20, 21, 22 Vintage Challenge Survivor !
72 400 restored, Father bought new in '71
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'74 340 green machine
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