Rear Main Seal Problem..Yes, SEAL!!!

M

Marshall V. Daut

Well-known member
I'm helping a friend sort out a 1930 Coupe he bought and I've run into a new one on me in regards to the rear main. Look at the accompanying photos of the rear main cap, rope "seals" and crankshaft modification. When I was adjusting the mains, I saw one of these oily rope seals crammed into the main bearing cap, which partially blocked off oil flow through the tube. Blowing through the tube resulted in very little pressure going back into the cap until I dug out the rope seal. I thought, "That was dumb. No wonder this thing leaks like a struck pig. I'll remove it and all will be well." But then I noticed something odd about the crankshaft in this area: the rear slinger has been machined off! And inside the aluminum slinger "seal" in the block, I saw another oily rope. Obviously someone had tried to modify the rear main oiling design by machining off the rear slinger and cramming rope seals in the block and in the cap. They are longer and thinner than the typical rope seals found in the front of the oil pan and timing gear cover. So if these must be re-used, I'll have to blot out as much oil from them as I can.
My question is, if I must put these &^$#*& rope "seals" back in, this engine is going to leak again because there's no way for the oil to effectively drain through the oil tube - the bottom rope partially covers the hole in the slinger area. Can I just leave these ropes out and re-assemble the rear main cap, trusting the original gravity drain design to do its job? Or because the rear slinger has been machined off the crank, do these ropes have to be re-installed? The crux of the matter is, then - does the lack of a rear slinger on the crankshaft make any difference in the draining operation?
Marshall
 

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It won't work without a slinger for sure. Not a problem though Marshall, ...easy cure. Either ship the crankshaft to James Rogers at Dreamwerks Engines, or Rich Fallucia at Antique Engine Rebuilding to have them put the slinger back onto the crankshaft. The last I heard it was approx. $100.00 plus freight. Easiest way to go back to a tried & true method.
 
Too bad when someone tries to make such "improvements". At this point I'd probably try a Burt's seal or the two piece GM seal.

Antique Engine Rebuilders near Chicago can rebuild the slinger by using solder, and that's what I'd do to save a good crankshaft.
 
Thanks, Brett and Tom. I was kind of afraid that was the answer. Why is the right way to do something always the hardest way? :) Sadly, since this car belongs to a local specialty vehicle business ($$$$$$$), I'm sure they won't pop for the right way to fix this problem. The expense and time element to do the repair properly affect the bottom line. I measured the area on the crankshaft that had been turned down when the slinger went bye-bye and it comes out to 2.1", the exact measurement required for the two-piece seal offered by Snyder's. That repair the owners will probably go for, although I'm skeptical of the rear main "seals" that are available. 'Seems there are too many failures. Hopefully this won't be one of them.
Since the two-piece seal route is the only viable one for us, I assume that area of the crankshaft should be polished nice and bright? It's lifted up out of the block about one inch because the rods are still connected, complete with pistons and rings in the cylinders. So whatever I do for polishing, it will have to be performed with the crank suspended in mid-air by the connecting rods in their bores. What medium would be best for doing the hand-polishing? 100 grit or finer crocus paper, followed by 220 or even finer? Should I end up with some kind of paste polish? New territory for me. I've always had such work done by auto machine shops.
Marshall
 
Marshall, I will tell you from first-hand experience that the seal that you are looking at from Snyders is the one that Ed Barnett is/was making. When these first came out, they were a rubberized cork that did very well however somewhere along the way, the company that supplied the material changed the composition and they are junk now. What happens is when they are not used (within a few months), the material dries out and as soon as the engine is started, the rubber scorches from the friction of the spinning crank. As soon as this happens, there is a pathway right out the back for the oil to travel, and trust me it does!! :eek:

Personally, I would steer clear & walk away right now unless they want to pay to do it correctly. The method you are suggesting of polishing the crank is just setting yourself up for scorn & criticism later on. Yes, the right way may not always be the easiest/cheapest way but there is a reason why we are suggesting this method.
 
Brett -
Experience is 10 times better than theory. I believe what you say is true from your experience. I absolutely, positively, without question KNOW these people will NOT approve sending the crankshaft out to have the repair made properly. This car is a typical half-*ssed amateur messtoration piece of junk that has already absorbed hundreds of dollars in parts and is still in pieces, needing at least a front end rebuild and brake system repair, too. These were almost completely ignored by the previous owner. Jeez, why does our hobby attract such idiots???
Anyway, I am certain I am stuck with an ad hoc repair. What about Terry Burtz' seal? Or maybe I had better just blot the rope seals dry that were crammed in the block and rear main bearing cap, and call it a day. I'll suggest the proper repair tomorrow when I see the owners, but I already know the answer. Translation: the new owner they sell the car to will also be buying a leaking rear main. Gawd, trying to fix these amateur schlock jobs gets old, especially when it's someone else's car and profit from a sale is the main motivator that directs all action. Life stinks right about now. :( I think I'll start collecting postage stamps instead...
Marshall
 
Why not try replacing the rope seal after polishing the surface? Back in the day, they used a Pontiac seal, Fel-Pro # BS-12173 or Victor JV-708. Use plenty of Permatex non-hardening.
 
The Terry Burtz seal works PROVIDING the thrust remains tight. More often than not, the builder does not get the thrust set correctly. I would venture a guess that your customer's engine is out of spec at the thrust.

Now, my only issue with this entire deal is when the owner sells it, he will be quick to mention how a noted Model-A mechanic just finished doing a bunch of engine work. Then, when it all implodes, the new Model-A owner will come to Fordbarn asking questions and showing pictures! :p Then, ...imagine the crucifiction the armchair critics here will be offering up!! I sure wouldn't want to be in your shoes!!! ;)
 
Yup. That's part of my frustration with this engine. I didn't do the damage by making this stupid modification and I can't properly fix it without spending more of the present owner's money and delaying a sale. How many rabbits can I pull out of hat? As usual, I'm caught in the middle. 'Getting old, REAL old. I'll see what the owner says tomorrow. But I think I already know.
M.
 
The other problem is the seal area is probable running out. If it is it will leak, Along with to much end play like Brent said. I think I would tell them there is no way to fix it with out fixing the crank.
 
Marshall, I think I know the car and the situation. Won't reveal any info here, I realize the fellow your working for needs to flip the car and make money that is what spins his wheels. And, he is providing a service for the hobbyist.

I also know the guy that was the last owner. He bought the car 'as-is' and didn't do much to it. Had it maybe a year and a half. The owner, before THAT, had the car since about 1976 and HE was the 'restorer'. The last owner realized he was getting into more than he wanted to handle and bailed.

Car is fairly decent, I've seen much worse. Pretty nice interior if I recall correctly. Paint a bit rough maybe a good buffing and/or color sanding in order. After you put your hand to it and get it fairly straight, the car will make somebody a nice little Model A Ford driver. Ain't gonna be a Henry award winner but a fun little car just the same;)

By the way, interesting thread I'm enjoying reading it!!!
 
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Marshall,
I know from my since past mentor/friend, Terry Oberer these were used back in the 70's and early 80's by some.. maybe even sooner. They would cut off the slinger and use a chrysler seal, I still have a box I kept from doing a repair job one time. I pulled one out and replaced it with the same. Worked for a while but then came back.

Fel Pro Part # BS 3139 Circa 1935-1941

Brent and others have said, the problem is they just don't work if there's any runout at all. I don't have any experience with the new cranks, etc, but I am an advocate for the stock slinger as it's as good as anything. Just my 2 cents worth and what I know on the possible seal #
Larry Shepard
 
Have you considered the one piece rubber Modern Rear Main Seal marketed by Snyders A-6336? I have used one but have no miles on the engine yet.

Cheers,
Gavin
 
Hi Guys, Here's, my pennywort. I had a bad oil leak from the rear main area on our 1930 Phaeton. Upon dismantling the engine I discovered some non standard "modifications" Firstly there had been installed an extra drain tube threaded in the bottom of the rear main cap and passed out through the bell housing and back in to the sump below oil level. Secondly the rear flinger had been machined off and a rope seal had been put in the rear most groove of the bearing. This still left the original drain free to do its job. The reason for the excessive leak was the modification tube had broken so the oil reaching this was going down behind the fly wheel and out the bell housing. Big question ! what do I do now ? The following idea I believe originated in USA
General advice was keep the seal in place ( had to as there was no longer a flinger) then carefully scrape a small oil groove in the rear bearing a quarter of an inch in from the rear of the shell then drill a 5/16th hole from the inside centre through the new oil groove and down to the original drain tube, be sure not to go through the drain tube.
The engine is all assembled now and I have just completed a 200 hundred mile trip with no oil leaks and and a very sweet sounding engine. Just anote on history of our car It was purchased two years ago and we have done over three thousand miles of trouble free motoring and would still be going if this pipe had not broken. We were not aware of the mods when we purchased. IGNORANCE IS BLISS!!
 
This is why I don't use or advocate the use of ANY kind of modern seal in a Model A or B engine. I can put the slinger back as Brent stated and it will work as original. The reason yours leaks so bad Marshall, is the slinger was cut completely off and a rope used. For the rope to have even a small chance of working, the slinger is only cut to the same diameter as the thrust ring. The rope seal that you have was originally distributed by Fel-Pro but, is no longer available in any form or, for any application. The 2 piece seal will work as Brent said, for a while but, it will soon begin to leak. The Burtz seal is as bad. I know some here use these seals and Terry Burtz frequents this board and will claim these work till eternity but, I build engines and know what works and what doesn't. The fix Wooden Wheel describes, will work and might get you out of a sticky situation but is only a band aid and won't fix the real problem. If you want Marshall, you can call me and we can discuss how to get you clear of this with the least amount of damage to your reputation. 828-seven seven five-1257.
 
The sleazy used car gusher fix --cut a groove behind the oil well, ahead of the thrust, drill a drain hole at the bottom to re-direct the oil going to the thrust ---some pump packing in the rear groove and off the lot it will go

a long time ago I got to read a handwritten book of used car "secrets" ---rubbing mercury on bumper rust spots--uses for different sawdust ---tapered shims behind bearing inserts (scored inserts already match the scored crankshaft, they just need tightened up)--bolts instead of grease fittings on loose tie rods ---the guy I worked for didn't do much of it ,but wanted me to know about it because I was his condition appraiser for his auction buyer
 
James Rogers said:
This is why I don't use or advocate the use of ANY kind of modern seal in a Model A or B engine.
Click to expand...

James that is good to know. The more I learn about the Model A (and it is a continual process:)) the more I subscribe to the 'keep it original' way of thinking. Reinforces all I learn about Marco's Roadster. Bone stock and performs great.

Some years back it seems like there was an article in The Restorer praising this conversion, cutting off the oil slinger and changing out to a modern seal. Wonder how much oil THAT guy is gushing out today? At least oil changes are simple.... you just keep adding fresh oil, no need to drain the pan!
 
Jeff/Illinois said:
James that is good to know. The more I learn about the Model A (and it is a continual process:)) the more I subscribe to the 'keep it original' way of thinking. Reinforces all I learn about Marco's Roadster. Bone stock and performs great.

Some years back it seems like there was an article in The Restorer praising this conversion, cutting off the oil slinger and changing out to a modern seal. Wonder how much oil THAT guy is gushing out today? At least oil changes are simple.... you just keep adding fresh oil, no need to drain the pan!
Click to expand...
Not very ecologically correct tho.
 
Please see the update to this problem, posted in its own thread: "UPDATE: Crankshaft Rear Oil Slinger Misery ". Posted 8/28/14 at 5:10PM Central Time.
Marshall
 
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