Help - 351C Rear Seal Blown

[John Wais]

Went out to bruch with Spotterjoe and when I came back the rear crank seal was blown. Oil all over the bottom side of the car and leaking from the bottom of the clutch cover.
Can the rear seal in a 351C be replaced without completely pulling the crank or having to pull the engine??

John W

[COBRAMIKE427]

Yes it can,pull the flywheel cover,oilpan,rear main cap,rotate top half of seal out.If old seal is rope replace with neoprene unit from felpro. To reinstall apply permatex#3D to the back of the seal and rotate it back in leaving 1/8"of seal sticking out and making sure the seal is installed in the right direction. Then replace seal half in main cap leaving 1/8"of one end sticking out oppisite of the half in the block. Then apply sealer to the face of the cap only from the seal to the rear of the block then reinstall cap then torque cap bolts 95-105ft#

[Dave Wharran]

If it has the rope type seal in it and you replace it with the rubber seal, check the cap to see if the small pointy "nail" is still there. Its function was to keep the rope seal from rotating. If you use the rubber seal, remove the nail with a small punch and put a little silicon in the hole thats left to plug it.

Dave

[John Wais]

Cobramike427
Boy did you improve my disposition.
I understand all your instructions - nice detailed job - already printed out.
A couple of questions:
1. I assume that you can grab one end of the rope seal with needle nose pliers and pull on the seal and rotate the crank at the same time - correct??
2. What if its not a rope seal or did all the 351C's have the rope seal and if not, do you use the same technique and the same or different seal??

Dave Posted while I was writing this, is the nail in the cap??

John W
I see light at the end of the tunnel

[Dave Wharran]

Yes, the nail is in the cap with the point sticking into the groove the rope seal fit in. It will be obvious which you have when you get it apart. The rope is like an O ring cut in half with half in the block and half in the cap. It will be mashed flat where it rides against the crank flange and makes its seal.

The rubber type seal looks like a conventional lip type seal that is again, cut in half, with half in the cap and half in the block. The idea of rotating the split joint to not line up with the cap/block mating surface is to reduce the possibility of the seal leaking where the two ends butt.

The rubber type lip seal is probably the better (and newer) design of the two. It's lip functions just like any other conventional oil seal. It is supposed to reduce rotating friction caused by the rope type.

Don't know how easy it will be to rotate the old seal out and the new seal in the block out while the crank is still in. The cap is a no brainer. Certainly worth a try. Good luck!

Dave

[tim]

For what it's worth; I haven't ever seen a rope type rear main seal in a Ford, at least one built from the early 60's to the present. My 351C came with a rubber 2 piece seal. You may have to loosen all the main caps to allow the crank to drop down a little so that you can remove and replace the seal.
Tim

[Bill E]

Tim there is a weir in the rubber seal if you use a small wooden dal for a punch tap one end of the seal till you can get a hold of the other end. Then you should have no problems from there.

[rldunn7]

If you have a rope crank, the rubber seal will weep a little. The rope crank has small slashes(couldn't think of any other way to describe it) that help drive any seepage back into the block.....There is a rope crank seal installation kit that you can buy at NAPA....I have never replaced mine but I do know that I have a rubber seal and a rope crank...It will leak a smal amount ....enough to annoy the heck out of you but not enough to get on your back and replace it....good luck!!!

[John Wais]

Wound up with a fairly large amount of oil on a drip pan. I don't usually have a drip pan because the garage is carpeted. Drove the car about 6 miles to C & S which is a very good local shop for Cobras and put it up on the rack. Now it has only 1 small drip -- go figure. A fair amout of oil is around the rear of the pan, front bell housing cover and some splattered sideways on the frame.
Decided to replace the seal regardless and obviously the pan seal. Topside and front of the engine is dry - its not the oil pressure sensor or intake manifold.
Took Tuesday off and we will see!!!
Decided to let C & S do it instead of lying on my back trying to change it out. After all the help, I could have done it myself, just didn't feel like it. This way I will get the car back the same day.
Thanks everyone for your response, I really appreciate it.

John W.

[Jim Bee]

Nothing like dredging up an old post, but this is where I am, and it's the best post I found on the subject so far. (1973 Coupe, 351C 2V, FMX trans, sat in AZ heat for 4 years - dry upper seal?)

Engine in the car, pan is off, Rear main cap is off, all main caps are loose. Removing a rope seal, but can't actually grab it with a Sneaky Pete, but have managed to remove a lot of the seal bit by bit using it. I doubt I'll get much more out of it as it is, so I'm looking for options. This morning, because I am procrastinating dropping the crank or removing the transmission, I'm trying cooling the crank to see if the metal will "shrink" enough to loosen its grip (highly unlikely I know, and it's only 8 am, and it will be 107 today, and there are worse things than sitting in the shade under the car with ice melting nearby.)

Anyway, is it possible to now remove the rod end caps and lower the crank slightly more (letting it rest on the remaining main bearing caps) to allow the seal to come out? Or will that invite disaster, or not work at all? I suppose the alternative is to remove the FMX trans, but frankly....I'd rather not.

Thanks for any advice.

[Jim Bee]

Answer: Yes. You can, but it might not actually work.