Thread: Rear main seal
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Old 10-19-2020, 08:46 AM
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Bill Hanlon Bill Hanlon is offline
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Quote:
Originally Posted by Rocky 389 View Post
Hey Bill
Does installation require the engine to be pulled or can this seal be installed in the car??? Mine is a '57 block and crank. TIA
My info is 3rd hand. I assume installation would be the same as a 3" crank once the seal had been modified.

Below is from BOP Engineering's web site. RMS18 is the 3" seal.
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Overview:
You have purchased the most advanced rear main seal on the market for the traditional Pontiac V-8. This revolutionary design features a number of state of the art innovations including relocation of the parting line which greatly reducing the risk of leaking, a more pliable construction that will work more effectively in engines with seal groove geometry issues, and double lip design to provide twice the protection against leakage as well as supporting outstanding vacuum numbers.

Preparation:
While we do not recommend installing the one-piece seal with the crank installed because the seal will deform during installation, it has been done successfully and we provide instruction here. One of the square indents side of the seal has a small hole molded in. At this position you should cut the seal straight across (radially) using a very sharp blade. This cut will re-mate at the top of the seal groove in the block. Next liberally lubricate the groove between the seal lips is with a high temperature grease prior to assembly.

Position:
If you examine the seal closely you will see that there is a helix pattern on the oil control lip. This lip goes towards the front of the engine, not to the flywheel side. Note that the RMS18 and RMS19 have square indents on opposite sides, therefore you must look at the seal lip to get the proper direction. The radial split line should be towards the top of the engine when in the normal running position.

Installation: RMS18 (Crankshaft Out or in)
Please read installation notes on the reverse side of these instructions. If the crankshaft is out, flex the seal around the crankshaft. The radial split line should be towards the top of the engine when in the normal running position. Carefully set assembly into the engine. Care should be taken to make sure that the seal does not get mis-aligned during assembly otherwise damage may occur. If the crankshaft is still in the engine, carefully work the seal into the groove and around the crankshaft. Reinstall main cap and torque.
No sealer is required in anti-rotation holes or anywhere for RMS18 (3-inch main)

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Second page below is mostly for 3.25" cranks, but I'm including it anyway,
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Installation: RMS19 3.25-inch (Crankshaft Out)
The anti-rotation holes in both the block and cap must be filled (RMS19 3.25-inch seal only) with a quality silicone prior to installation. Fill the holes flush and install the seal while sealer is still pliable. Flex the seal around the crankshaft. The radial split line should be towards the top of the engine when in the normal running position. Carefully set assembly into the engine. Care should be taken to make sure that the seal does not get mis-aligned during assembly otherwise damage may occur.

Installation: RMS19 3.25-inch (Crank Installed)
The anti-rotation holes in both the block and cap must be filled (RMS19 3.25-inch seal only) with a quality silicone prior to installation. Squeeze silicone into the block-side seal groove between the crank and block. Lubricate seal lip sparingly with oil and use seal (or old seal) to push silicone through the groove depositing silicone in the block anti-rotation holes. Repeat this 4-5 times using the seal to force the silicone through. Repeat from the other side depositing silicone into the holes Repeat again from both sides with no additional silicone using the seal as a squeegee to remove remaining silicone from the groove, cleaning the seal with each pass through. Rotate the crank and clean seal mating area thoroughly. Feed seal around crankshaft and into seal grooves from both sides so cut ends meet at top of groove under crank. Some blocks may require loosening all of the main caps to facilitate the silicone process and/or feeding the new seal in. Fill anti-rotation holes in cap flush and install cap to complete installation.

Installation Notes: (Seal Groove)
Occasionally the seal groove may not be round, concentric with the crank sealing surface, too big, or too small due to manufacturing variations or align boring. If you are installing the seal with the crank removed, the following is a good check to perform. Position the seal in the block-cap assembly and tighten. Look through the crank hole to ensure the seal ends are mating properly and check for any circular distortion. Distortion due to buckling from too small of a groove can be eliminated by removing a small amount of material from a seal end or remove material from the backside of the seal diameter to “relax” the seal in the groove. A caliper may also be used to compare the installed seal lip diameter to the crank diameter. Approximately .020 inches of lip engagement on the diameter should be present.

Specifications:
RMS18 Sealing Diameter 3.188” +/- .003” Groove Diameter 3.812” +/- .005”
RMS19 Sealing Diameter 3.437” +/- .003” Groove Diameter 4.012” +/- .005”
Call for additional installation information

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My Pontiac is a '57 GMC with its original 347" Pontiac V8 and dual-range Hydra-Matic.