When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I have a 1953 Mercury M100 with a flathead engine. 255 cid. The rear main seal is leaking and I would like to change it. I'm looking for some advice and info on what type of seals are available and how to do this. I have searched forums and don't find any info on my engine. Maybe my search is wrong, still new to this site.
thanks
Welcome to the site! I assume you're in Canada? You can add that info in the UserCP (control panel), it helps in many situations.
Do you know for sure that you have a Mercury 255 in the truck? There is a misconception that Mercury trucks came with the Merc 255. As far as the rear seal goes, it really doesn't matter, it's the same block as the Ford 239. It's a rope-type seal (or "packing"). Half the seal is in the oil pan, half is in an insert in the block.
Some people replace the upper half with the crank in place, but personally I think it's not easy to do it and get a good seal. The lower half requires dropping the pan out, which isn't that hard and gives you the chance to clean it out and see what shape the bottom end is in.
Basically you roll the new rope into the groove in the pan, and cut off the excess just above the pan surface. When you put a new pan gasket on, many people put a dab of RTV where the rope meets the gasket on each side.
Best Gasket and FelPro both make good seals, Best includes a tool to help trim the rope, otherwise I've noticed no difference in performance.
I did this years ago on a '59 Ford hardtop convertible Y-block. I was a bit younger and there was no internet back then but I bought my parts from an old time parts store that was also a machine shop. The owner sold me a set of chinese fingers to install it.
Still I struggled with it for days trying to get the upper half of the seals installed. I finally asked the owner and he said that the trick is to get the seal in place ready to install in the opening with the wire over top of the crank then pull down and rotate the crank at the same time. To my relief that worked like a charm.
Thanks for the information. The chinese fingers tool looks like a good investment. Who are the suppliers that sell them? Is there a rubber or neoprene seal available for the 239, 255 engine and are they any better than the rope seal.
Thanks Ross. I plan on dropping the pan and doing an in frame replacement. Wondering if I should order a front seal also, since it will be accessible. Presently no leaks from the front end.
If you buy the FelPro oil pan set, it comes with the front. The fronts are much less likely to leak, but I guess I'd look at it when the pan is out and see if you want to mess with it.
Rock Auto had a sale on the Victor/Reinz oil pan and timing cover sets in August. I got both for about $10. I don't know if they still stock them. Thanks! for the breakdown on the contents of the Fel-Pro kit, Ross. I plan on saving that for future reference. - Bob
Bob, I've always been skeptical about those White and Black numbers. What changed on truck oil pans in '52? Nothing I can think of. I suspect the change was on cars. My parts CD shows the same truck oil pan from 48-53.
Ross, I agree. Believe I've always used the black ones at the rear because that's what I had taken out. It almost seems like the front ones were black years ago, not sure. The black seals seemed to soften up more when soaking in oil, than the white. Possibly the white material was an "improvement" and could last longer? I had a '52 car block in my pickup once, and now a '50. I've had the same pan on both engines and used the same type rear seals. - Bob
10-20-2017, 05:04 PM
