Rear Main Seal Replacement?

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Rear Main Seal Replacement?

Postby mentorcouple » Sat May 30, 2009 8:22 pm

Hi all, can someone tell me if there is a rear main seal that can be installed without removing the crank? thanks!
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Re: Rear Main Seal Replacement?

Postby Lazy JW » Sat May 30, 2009 10:42 pm

Yup.
74 F-350 300-6, EFI manifolds into single exhaust, Carter YF, T-18B, Dana70 w/4.11, Flatbed dually w/dump bed. Great farm truck!
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Re: Rear Main Seal Replacement?

Postby mentorcouple » Sun May 31, 2009 8:04 pm

Hey JW, can you tell me what it is called so I can order the right one? Thanks!
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Re: Rear Main Seal Replacement?

Postby 300Straightsix » Sun May 31, 2009 8:32 pm

arent all 1 piece rear mains installable without removing the crank?
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Re: Rear Main Seal Replacement?

Postby Lazy JW » Sun May 31, 2009 9:41 pm

Yup.
74 F-350 300-6, EFI manifolds into single exhaust, Carter YF, T-18B, Dana70 w/4.11, Flatbed dually w/dump bed. Great farm truck!
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Re: Rear Main Seal Replacement?

Postby THE FRENCHTOWN FLYER » Sun May 31, 2009 11:04 pm

To change the seal on the engine just drill two small holes near the periphery about 180 degrees apart, screw in two sheet metal screws, and pop the seal out with vise grips. I recommend a seal for a Moduar V8.
FORD 300 INLINE SIX - THE BEST KEPT SECRET IN DRAG RACING
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Re: Rear Main Seal Replacement?

Postby Frankford6 » Fri Jun 26, 2009 11:11 am

AFTER you get the tranny/Xfer case/etc. off, it's pretty easy. No need to remove the crank, just pull & replace. It might pay to install a speedy sleeve on the crank, though, since the surface of the crank that the seal rides on is probably scored- look it over carefully.
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Re: Rear Main Seal Replacement?

Postby cdherman » Sat Jun 27, 2009 11:34 pm

The late era 4.9 takes the same seal as the 351. Interestingly, the early 351w had smaller rear main seals than the 4.9. Somewhere along the way (I researched this in detail before I replaced my rear main) Ford redesigned the seal for the 351w (and I think 302 etc as well, same block....) and used the same dimentions as the 300. (Another example of a 300 being superior to a SBF)

The material is differnt and the seal has an outer plastic dust seal. It is NOT a double lip seal as some have suggested. However, it is possible that the newer style seal does run in a little different location on the crank, which would be of advantage if there was some scorring (and you were too lazy to sleave the crank).

You don't have to ask for the modular V-8 seal -- just get one for a 95 4.9 The part numbers are the same. FWIW, My Federal Mogul / National Box has #5278 on it, and I can vouch that it drops into an early 240 block quite nicely.

I have no idea why they still make the old rubber seal with a spring in it. But if you look up the rear main for an early 300 you will get the old seal. If you look up the seal for a 95, you get the new one. Block and crank are the same......

As suggested, two sheet metal screws at 180 degrees. I used a cats paw (nail puller for nails) that I had laying around and it worked incredibly well. I also took a nice soft piece of 2x4 and whittled (I work with wood as well) a wood block that matched the curve of the new seal. Its large and tapping around the periphery of the thing often results in it just tilting in the race. Anyhow, the whittled wood tool worked real nice too, but a hammer and little block of any old soft wood works too I'd guess.....
'65 F100 240, swapped to C4, Autolite 1101, Pertronix
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Re: Rear Main Seal Replacement?

Postby 66 E100 Pickup » Sun Jun 28, 2009 2:19 am

also a short piece of 4" Schedule 40 PVC works very nicely. It needed a light touch with the file to be just right.

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