Rear Main Seal Issues

Hey all, I just had a quick question about the rear main seals in a 1865 Mustang with a 200 Cubic Inch Engine. First off, I am having trouble finding a rubber split type seal. The Felpro Part Number is BS30135, but its not available anywhere. Another part number is National 5116, but that's not available either. I have a rope seal but the problem with using that is the pin in the bearing cap looks to be cut, or damaged and I'm not sure that would hold the seal. So is there anyplace to get a new pin, or is there any part number that would work as a rubber rear main seal. Finally would it be possible to cut a rear main seal from another engine type to make it fit mine? Thanks for all the help!


Supporter 2021
Supporter 2018
Hi, I think the two piece seal comes with a Felpro full gasket set.The number on the Napa website is FPG KS2300. If you are switching to the two piece seal you must drive the pin out of the bearing cap and fill the hole with silicone. Then follow a Ford or Chiltons manual for assembly instructions. Good luck


Top Poster
Staff member
Supporter 2021
Supporter 2019
Hi A1aman, and welcome to the Ford Six site B Ron Co has you covered on going with a newer neoprene rear main seal. If however you find that you would want to go back with the orginal Rope type seal you can drive out that old cut off pin with a small punch. Then you can make a new replacement pin with a small Finish Nail of the right diameter and cut the head off to the correct length this is Aprox. about 3/16 of inch or more sticking of the pointed end up into the seal area to hold onto the seal from turning. This new pin should not stick up high enough were it would go through the rope seal and come into contact with the crankshaft seal surface. I think a 3 or 4 Penny Finish Nail should be about the right diameter but check it out against the old pin that you drive out. Best of luck
I wanted to thank both of you for replying so quickly. I did end up ordering the kit, and it ended up coming with the rope rear main seal. I will follow bubbas idea of using a nail. Thank you again!