Just finished rebuilding a 2.0 SOHC Pinto for a Sports Racer S2, and I just had the worst time installing the rear seal.  The engine is a 71-74 vintage and has a one piece seal.   Push one side in, and the other pops out.  Finally drilled a 3.125" hole in a 2x6 and hammered with no luck.  Finally I clamped one side of the board down with a "C" clamp and hammered to finally seat it in.  Took a small punch to get it home all the way.  Now installing this seal shouldn't be this hard, what am I doing wrong?  Is there a special tool to seat the seal?  Should I have installed the seal prior to assembling the rear crankshaft cap?  I have a few more motors to build so any tips would be great, Thanks Allan

I just did mine in a 2.0, I just used the old seal and tapped it in with it, the new one lost some outside coating but I got it in. I hope to god it dont leak cause I dont want to tear it apart to redo it :peace:

I instal my rear main seal when I install the rear main cap.
From Pintony

You asked for tips.

The most common causes of problems installing new one piece seals of this type, are usually associated with not having cleaned out the recess for the seal well enough, or damage to the recess into which the seal has to be driven. Damage to the recess is frequently there from a prior installation or removal, but can also be from having just nicked the machined surfaces yourself while removing the seal this last time.

Sometimes with a stubborn seal, it's almost impossible to get the old one out without doing some minor damage that will have to be cleaned up afterwards. Poor technique or not have tools that can do the job cleanly can easily cause daage during seal removal.

This type of metal supported seal is such a tight interference fit, that a few thousandths of an inch of rust or some raised metal from a nick or scratch (that the new seal has to pass on the way in) can make a big difference in how easily the new seal installation goes.

Sometimes there is a build up of rust just slightly above where the edge of the old seal was installed, and if that is coupled with an insufficient larger diameter tapered relief at the outer edge of the hole and with a new, clean seal that is a thousanth of an inch larger O.D. than the old one, it may be just enough to make installation difficult.

Continuing with that thought, many people (even some well-experienced people who should know better) do not realise that by driving a new seal into a dirty or damaged recess they are likely to be compromising the seals' ability to do its job.  By starting with a dirty, damaged or distorted recess, several potential problems can arise.

With rust or any material still remaining in the recess, the seal is likely to dislodge some of the material and shove it ahead of the metal part of the seal (the shell), then trapping it between the shell and the recess. This can prevent the seal from seating fully, which may put the wiping edge onto a different, rougher surface of the shaft than the prior seal was riding, making it prone to leak from day one. Next, if the seal is driven in vigorously, or unevenly,  when the trapped material stops the seal's travel in one part of the recess with enough force, the seal's shell can be driven further in where the debris is NOT stopping it form further movement..This will distort the seals' shell, and the wiping edge as well.


Before trying to install a new seal:

CLEAN, CLEAN, CLEAN that recess. Start with solvent. Follow up with tools, then more solvent. Try to get down to clean metal everywhere.

I have a set of "dental picks" with different shaped scraping edges and ends. These sets are sold inexpensively in tool stores, and their tips are much smaller than any tool you are likely to have on hand. This will enable you to actually clean down into the tight edges of sharp bottomed holes or grooves of practically any accessible recess that yoy are liable to encounter, frequently getting out bits of rust and assorted crud that defy other methods, WITHOUT causing much or any surface damage themselves.

Inspect the metal suface of the housing carefully.

If there is a sharp edge to the outermost part of the recess that the seal has to enter, you WILL have trouble starting a new seal. This edge should have a small taper, even if it's only a few thousandth of an inch deep.  If there isn't a taper, at the very least "break" (or slightly roundover) this edge, using WET emery cloth, or a hand file. Some people use grease on the file to catch the filings, but this tends to make the file cut more slowly and to load up much more quickly. DON'T use power tools, or you will be spraying the metal you are removing around the room (along with pieces of the grinding/cutting tool bit). You can be certain that some of this power driven debris will end up in places that you don't want it to be, and result in more time cleaning or worse.

If there is a HIGH spot that the seal shell has to travel over, you should remove it at least down to the surrounding surface. If there are small LOW spots, (like the bottoms of nicks that have been smoothed down) do not worry about those.

If you have cleaned the seal recess well, and if neither it nor the seal are distorted, the seal should go in fairly easily, if you are using something suitable as a driver.  Many people use UPSIDE DOWN sockets with an extension bar inserted as a seal driver and handle. If the socket is a close match to the O.D. of the seals' shell, this should be something to check first, as most decent sockets are reasonably clean of nicks on their bottoms, as well as having wide, flat surfaces, especially in larger sized sockets. This works fairly well up to a certain size, and then people run out of sockets being large enough.



Many people also use the old seal backwards to drive in the new one, but if you don't have something the right diameter or larger to back up the OLD seal, when driving them this way it's easy for the new seal to go in at an angle, because even if you do have a big headed tool to hit the seal with, your fingers are in the way of a centered strike, so the seal is generally tapped in slowly, while moving the strike point around the diameter continuously.

If you intend to do this a lot, get a seal driver set. Saves you a lot of hassle and scrounging around.
They have stepped metal discs of many diameters, of which most usually attach to the same metal handle, and are available to cover any size that you are liable to need. Goods sets aren't cheap. Cheap sets may work for you.

For seals over about 2", if you don't have a seal driver set, try to have on hand several pieces of metal pipe as well as short sections of thick walled PVC.

For the metal pipes you can use the end of the pipe itself, or better yet, use a fitting to have
something to strike. Use schedule 80 PVC, or maybe schedule 40 as a minimum for the smaller diameters, or to drive narrow shell seals.  You'll need a striking cap for the end of the PVC pipe, and a standard fitting may not be tough enough. Measure the O.D. of each pipe and mark it with a permanent marker.

Now with your homemade pipe drivers, you can use the old seal as the leading edge for driving in a new seal.

I forgot to mention that for many installations, it is possible to use a very small amount of sealer on the seals' shell as a lubricant and to better seal any low spots in the recess.