I know this may be beaten to death, but I just wanted to add my two cents.
After reading as many of the posts on fitting the rear seal, my take-away was as follows:
They don’t make the real seals like the used to
The same white seal is supplied by the two major US suppliers
DON’T TRIM THE SEAL
Figuring I would screw up trying to refit the seal I ordered several from both US suppliers. These are my conclusions.
a. The white seals are not consistent in length. As the seals came in, I threw them in a box so I don’t know which seal to attribute to which supplier, but they were not all the same size. Some were back ordered so they did not always come at the same time. Not a big difference in length, but the difference could be one quarter of an inch.
b. There is no way on God’s green earth that the white seal, as supplied, is going to fit into that carrier. There is a substantial difference between the inside circumference of the carrier and the outside circumference of the seal.
c. I soaked the seals in oil for a week.
d. Trying to roll the seal into the carrier resulted in no joy. The ends came down a bit but still stood proud of the ends of the carrier
e. I decided to take the sizing tool, fit one oil soaked seal into the lower carrier, fitted a used seal into the upper carrier, loosely screwed the two halves together then slowly pressed the top and bottom, onto the sizing tool over the next two days, tightening the two halves together and moving the complete unit down the sizing tool Did the same for the other half. (I had some spares from another engine so I used the second carrier)
f. The seal now looks fully seated, but there is still part of the white seal standing proud which I will have to cut.
I am open to comments, chastisement, and/or admonishment regarding how I screwed the up and how I could do it differently.
george
’65 Mk2 and some other British stuff
Cincinnati OH
Old-time engine builder told me to use razor blades, with a sliding motion to cut ends of seals. AND, one pass per blade…the edge must be NEW on each cut since they go dull right away and will tear the material…those seals are tough. I believe I used 3 or 4 blades per seal end…pretty tedious.
The seals I received had to be trimmed. Mine were impregnated with graphite, which probably helped with seating in the carrier. I avoided oiling for installation in case the seal is meant to expand. The manuals that I’ve got refer to the use of graphite lube only for sizing.
If you’re using the proper sizing tool, I would be interested to know how much torque is needed to turn your crank once you’ve completed the seal installation.
Never cut the seal!. If they are to long, you have the wrong seal. They should protrude about 1/8 -1/4" on each end and will need to be compressed into the seal housing and then using the factory sizing tool, shaped to fit. Doing otherwise will result in leaks as the seal will shrink with use and form a gap if to short.
Always good to see what we are talking about , just took the old seals off a 3.8 Engine , from around 1964 , not sure if the seals have been changed in the past , but the old one looks like it is in 2 half’s, the new seal I got back some 30 years , from a main dealer part number C19654
Dick, thanks for posting this tip. I’ve seen a lot of discourse on trimming the seals and what you say makes more sense to me as I approach this job on my rebuild, especially knowing that leaks from the rear main are so common in these engines. Comments like yours based upon experience are what make this forum so valuable!
It’s not that the seal is the wrong one. I think it’s that some after market ones are too long. Some of the bones I’ve seen, would never fit without being trimmed!
At the factory,lots of us NEVER used a sizing tool to form the rear seal. We used a vice, and a small ballpein hammer. On test,I never had one leak.
Thanks for posting this Nigelplug. It’s a diversity of experiences that makes this forum so valuable. My seal appeared to be fine apart from the length, and was not going to be compressed circumferentially after being fully seated radially. Is there any reason not to cut a seal that’s too long?
Hi
Before you put the two halves of the rear seal together, gently squeeze the seals in the jaws of a vice. So they’re a slinging fit in the groove,
Apply a thin coat of silicone sealant to the bottom edge.
Then, starting from the centre, with a 4oz ball pein hammer, gently tap the seal working both ways, until the inner edge forms a slightly semi circular face., where it will be in contact with the crankshaft.You MUST do this evenly!
Once you have the seal tapped down all the way around the face, you may well find that the seal overhangs the ends far too much! If so, with a VERY sharp blade trim it back so the face is flat, leaving no more the 1/16" proud of the face.
It’s better for it to protrude slightly than be exactly flush! But certainly not below the edge!
Finally coat the face with Rocol or similar assembly lube.
This will prevent any burning of the seal on initial start up.
Do the seal half that is fitted into the block first. Then fit the crankshaft and torque up.
You need to have everything thing ready to fit the crank quickly!
Then do the other half of the seal in the same way, and fit it asap.ince the seal is fully fitted you will feel extra resistance to the crankshaft turning.
As long as you can still turn it by hand -with two head studs in the crankshaft flange, it should be hunky dory!
Good luck!
Best regards
Nigel Boycott
