rear main leak on 1955 Merc 292

[arcticbuicks]

I have a rear main leak on my Merc ,engine is fairly new rebuild,everything is excellent and it has over 60 lbs oil pressure idle,but has nasty rear main leak ,i heard that many do ,and heard there are some new style seals to solve this ? and i heard of some drilling a hole in rear main cap,steel pin to wedge rubber seal tight etc

i am not too familiar with these engines as far as this problem.

anybody know of a sure solution for this common problem on a 292

[Lahti35]

On 10/21/2023 at 12:28 PM, arcticbuicks said:

I have a rear main leak on my Merc ,engine is fairly new rebuild,everything is excellent and it has over 60 lbs oil pressure idle,but has nasty rear main leak ,i heard that many do ,and heard there are some new style seals to solve this ? and i heard of some drilling a hole in rear main cap,steel pin to wedge rubber seal tight etc

i am not too familiar with these engines as far as this problem.

anybody know of a sure solution for this common problem on a 292

This type of seal should not leak if installed correctly. The original rope type seal can be upgraded to a modern lip type seal. If the rear bearing retainer block was not sealed when installed it can leak there also, the rubber side gaskets and pins have to be installed 100% correctly for it all to work. You could replace the crank seal but if the bearing retainer seals are not right it will still leak. 

 

A sneaky pete tool can removed a rope seal, sometimes they don't work on old dry rope seals but if yours is new it may work. This is a fairly intense job as you have to remove the oil pan and rear main bearing cap to get to it. Pressing the new lip seal in is usually not too bad as they are stiff and have some give at the lip.

 

I have reduced oil leaks at rear rope seals by gaining access, using a blunt piece of wood to pound the upper seal up into it's canal thereby tightening it against the crank. A new bottom rope seal needs to be cut to protrude above the bearing cap to make up for the compressed upper seal. It did not stop the leak but reduced it 90%. If it's your rear bearing cap side seals leaking though this will do nothing to stop the leak other than giving you the opportunity to install new side seals which could help if they are the issue. 

 

Why ford came up with this system I don't know, I guess it does make for a stronger block but what a pain to deal with!

[arcticbuicks]

thanks very much for the great description ......these engines are notorious for rear main leaking i have seen and just never saw one with zero dripping.......plus have such high oil pressure at idle too and even higher starting on cold days ....-13 in a few days here...........i have seen 3 different style seal kits and just wondered the best also......i do prefer the rubber i think,but if you think the rope style........i have done this on several over the years......and yes a little bit of fun to do the top rope i did find......thanks again

[1957Birdman]

Check out the following link: Neoprene Rear Oil Seal Installation (Plus other key points to consider) - Classic Thunderbird Club International (ctci.org)

This is something that is encountered quite frequently in the early T-Birds.

Lew Bachman

1957 Thunderbird

[Lahti35]

On 10/23/2023 at 8:11 PM, arcticbuicks said:

I do prefer the rubber i think,but if you think the rope style........i have done this on several over the years......and yes a little bit of fun to do the top rope i did find......thanks again

If I have to pull a rope seal I'll replace with rubber if avaliable, if I can't pull the rope seal I'll try the "mash it up there" trick. Some of those old rope seals don't want to come out with the sneaky pete. Worse yet some manufactures put a pin or spike in the upper block half to keep the rope from rotating which also makes sliding a new rubber seal in impossible. Oh the fun we have!