Rear Main Seal And Sleeve

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Mr. Recovery
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Re: Rear Main Seal And Sleeve

Unread post by Mr. Recovery » February 13th, 2011, 4:54 pm

I agree with rickf, the only oil plug in that area of the motor is the camshaft rear bearing expansion plug, the one on the lower right in the photo.

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Re: Rear Main Seal And Sleeve

Unread post by Westech » February 13th, 2011, 10:47 pm

FLMV.NET has sleeve and TNJMURRY has the correct seal.
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Re: Rear Main Seal And Sleeve

Unread post by Grasshopper » April 9th, 2017, 1:56 am

Is it possible to change the rear main seal without removing the crankshaft? I pulled the pack so I can change the transmission seals , and found the rear main leaks badly when the motor is tilted. I should add that the issue is likely due to lack of use and age of seal.

Thanks in advance

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Re: Rear Main Seal And Sleeve

Unread post by svramselaar » April 9th, 2017, 4:11 am

hi

normally there is no pressure at the seal
there is a hole at the block so the oil from the bearing can go to the sump
is this hole maybe clocked ??
the seal must sit with the spring to the block and straight


george

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Rear Main Seal And Sleeve

Unread post by Horst » April 9th, 2017, 7:58 am

Yes, it can be replaced without issues with everything else in place. Insert a few self tapping screws to have something to pull it out with.
Horst

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Re: Rear Main Seal And Sleeve

Unread post by Grasshopper » April 9th, 2017, 1:32 pm

Thanks for the good advice. It leaks with the engine out and tilted on the hoist. Didn't take much of a tilt, so anytime it goes up a hill it would be leaking.

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Re: Rear Main Seal And Sleeve

Unread post by m3a1 » April 9th, 2017, 4:03 pm

I'm just gonna jump in here for a minute and say something I think is important...because in my experience, anytime there is a total rebuild involved, particularly when you've paid someone else to perform the rebuild, catastrophic problems such as you are discussing are most likely the fault of the rebuilder.

So if you've paid a reputable party to perform a rebuild on your engine, STOP what you are doing and contact the rebuilder and have them make good on it. You paid for a rebuilt engine. What you got is a high speed oil distribution system.

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Re: Rear Main Seal And Sleeve

Unread post by Grasshopper » April 10th, 2017, 8:46 am

I've known the truck a long time, as I assisted with some of the restoration. The bottom end of the motor wasn't touched (the then owner was at the time an impoverished student) but the head did come off for a check of the bores and installation of hardened valve inserts. He purchased it as a non-runner, but it didn't take much for us to get her running.

The history of the truck is unknown, except for being released from a USAF base here in the UK and the discovery of some Arabic or Hebrew markings on it. I'm under no illusion that one day I might need to rebuild the motor, but for now she doesn't smoke, has good oil pressure and runs at a good temperature so I'll leave alone. Given that the oil seals in the transmission, which was purchased from a dealer at a show as NOS overhauled have gone hard and leaked (likely due to poor quality seals or age hardening), I suspect that the rear crank seal has suffered similarly, or has an issue from days in service. If there is any suspicion of bottom end issues, I will investigate and attend to them.

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Re: Rear Main Seal And Sleeve

Unread post by rickf » April 10th, 2017, 11:47 am

In order to tilt the engine far enough for the oil level to reach that main seal you would have to be on a hill it is unlikely you would be able to climb. I have seen a lot of leaky rear main seals and even one that someone forgot to put in but not as bad as what you are describing, not even the missing seal. It was just a steady drip. Albeit a fast drip. :roll: Crankshafts are hardened steel so unless there was a steady supply of sand in there, unlikely due to the closed area, then there is probably no groove and just a dried out seal. Unless you have money to burn I would just get the seal first and then if you need a sleeve get that, it would only be a couple day wait.
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Re: Rear Main Seal And Sleeve

Unread post by Grasshopper » May 2nd, 2017, 3:48 am

Having stripped the clutch and flywheel off, I didn't realise that the holes in the crank for the flywheel bolts went straight through. The flywheel bolts didn't seem particularly tight either, so this may have been the cause of my leak. The flywheel bolt holes also seem slightly oval, but I've no time to do anything about that for now but should further issues manifest, I'll either have have the flywheel machined back to spec or install a new one. The flywheel didn't seem to move and located positively when installed; what did surprise me is the lack of a drive dowel on the crank/flywheel interface but I guess being an industrial motor this wasn't considered necessary. Most motors I've worked on have them. The old oil crank seal looked ok, but seemed to be installed slightly askew. I renewed it, dressed the crank shaft and flywheel mating faces, re-assembled it all and tipped the engine up and it now no longer leaks so I'm happy. To be fair it only seemed to leak out when I tilted the motor to about 30 degrees, which its unlikely to do with normal driving but I don't like the idea of oil leaks as they normally indicate a problem.

Having renewed the transmission seals, the pack now just needs re-assembling and installing. The output seal for the rear drive shaft on the transmission turned out to be covered with "silicone snot" on the inside and outside, so I am now suspicious of this transmission (which was purchased from a dealer by a previous owner as NOS army reconditioned). It seems to drive ok, doesn't jump gears and has no excessive play so I'll just have to see how it goes. I swapped out the sliding flanges from my spare transmission and they have far less play on the splines than the ones that were installed, so hopefully this cures the rather worrying oil loss from this area.

Somebody pointed out in a picture of my MUTT on another thread that my temperature gauge was the incorrect one, and as it doesn't seem to work I've taken the opportunity to fit a new sender and obtain (hopefully!) the correct gauge too. My intention is to be on the road for a local event in 2 weeks.

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