Rear Main Seal in a Can...

Tue Oct 16, 2012 11:55 pm

I have never been one to use any type of mechanic in a can magic formula to repair a mechanical problem with the exception of radiator stop leak. I have had permanent success with both Bar's Leak and the roll of quarter size tube of silver powder for minor leaks caused by corrosion or vibration, not holes created by tree limbs.

Repairing a problem the proper way is the right way to roll as far as I'm concerned. I have never been a fan of any type of additives or conditioners either.

Everyone is entitled to their personal preference and my preference is to stick with factory recommended fluids and lubricants changing them religiously at factory recommended intervals, if not before. If fluids or lubricants that surpass factory specs become available, I will switch to those.

I theorize if a conditioner or additive was really that important or necessary, it would come installed from the factory and would be recommended to be replaced at every service interval.

Earlier this summer, the rear main seal in my '49 mowing cub took a dump. And dump it did. It was a leak that would leave a steady trail of oil, not just generous size drops.

My parking spot was starting to look like the fuel island at a truck stop after a 2 stroke Detroit had been parked there.

I had 2 options, move the mower and turf tires to another tractor, put the '49 in the shop and split it in half, or try something I have never done before... Twist the top off a bottle of rear main seal in a can and see what happens.

I studied the canned fixes at the auto parts joint to see what was available. There were several brands and varieties of engine oil stop leak, many targeting specific leaks such as pan or rocker cover gaskets, valve seals or oil control rings.

Amongst them all, I spotted an additive that was especially formulated for rear main seal repair due to leaks caused by a combination of normal wear and shrinking of the main seal. This formula advertised itself to "restore the seal to like new condition", replacing the elasticity and flexibility lost due to age, "America's most trusted stop leak brand since 1947". (Any semblance between the year 1947, Cubs, and leaky seals?)

Sounded good but of course, expensive. Almost $12.00 for 16.9 oz. Expensive, but as the old adage goes, (which I do believe in), you get what you pay for.

This product was manufactured by Bar's Products the company who's rabbit pellet in molasses radiator fixer has saved my butt on more than one occasion over the years.

If I was going to try an additive to avoid spending my time and money on a rear main seal job, I may as well spend the money on a product sold by a company I have had success with their other products.

I came home, stuck the oil level which was down about 2/3 between add and full on the stick. I added the product to the crank case nearly bringing it to the full mark and noted the engine hour clock reading.

Almost immediately, the trail of oil was reduced to a slow drip. The instructions stated results should be observed after 100 miles or 2 days of driving but the first trip out to mow proved to be almost instant success.

After about 2 hours of mowing, I pulled off the hand hole cover, removed the flywheel cover, then worked a rag between the two holes under the clutch on the inside soaking up the residual oil inside, then replaced the covers.

After the thorough cleaning, It took somewhere around 10 minutes of run time before the first drop hit the deck of the mower.

The next 5 hours of run time was spent mostly mowing, the drip continued at a near non existent rate with the engine running, then dripping into my collection pan when shut down forming a small puddle about 1 1/2 inches in diameter.

As the engine runs, the oil is thrown against the insides of the clutch housing, then while the tractor rests, the thrown oil runs down the sides, dripping into the collection pan.

At the 6 hour mark, most running time spent at wide open throttle mowing, the oil level was again down about 2/3 between add and full on the stick. The additive directions read to add additional treatments every 6,000 miles or at every oil change so I dropped another $12.00 on the same stuff, adding it to the crank case again bringing it nearly to the full mark.

Unlike after adding the first treatment, I noticed no real change in the rate of drip. I noted the same amount of oil leaking, an occasional drop while operating the tractor, so little I don't even notice it on the mower deck until I get down there and wipe it before I put the collection pan down.

Previously my collection device was a plastic coffee can. Now I use the coffee can lid with a magnet to hold it to the deck. It still leaves a spot in the coffee can lid about 1" to 1 1/2 inch after use.

I can honestly report the stop leak product stopped the leak by about 97%. The second treatment was probably wasted by adding it prematurely. The first treatment provided almost maximum results, and very quickly I may add.

The second or follow up treatments should probably be reserved for the point in time when the leak again becomes excessive in your opinion, or at the scheduled oil change. Your mileage may vary.

Did mechanic in a can stop the leak? No. Did mechanic in a can slow the leak to the point rear main seal replacement is unecessary at this time? Yes.

I can live with the consumption of a quart of oil every 7 or 8 hours and would seriously consider pulling it apart if I could not have got the leak slowed to that rate.

Was $24.00 well spent? I believe it was however I was looking for the leak to completely stop by adding the second treatment whereas I could have got through the season only spending $12.00

If you have a rear main leaking less than mine did, there is a possibility this high end treatment could take care of your leak with 100% success.

It may allow you to extend the life of the rear main seal until it is clutch time or another component fails making splitting the tractor necessary.

The season is about over for this tractor, it will see some use when the kids pull their sleds around with it when the snow flies.

I'll be interested to see if the magic formula ever slows the minor drip to a complete stop next summer.

Re: Rear Main Seal in a Can...

Wed Oct 17, 2012 3:40 pm

When you do decide to split it and replace the seal, it's not that bad. If you resist the urge to take care of the "may as well's" while the tractor is split it shouldn't take you more than an afternoon or two.

Re: Rear Main Seal in a Can...

Wed Oct 17, 2012 4:16 pm

You've spent half the cost of a remanufactured seal housing, and seal, and still have a leaking seal. Ed

Re: Rear Main Seal in a Can...

Wed Oct 17, 2012 4:34 pm

I repair my own seal retainers and have had great success

Re: Rear Main Seal in a Can...

Wed Oct 17, 2012 5:17 pm

ScottyD'sdad wrote:You've spent half the cost of a remanufactured seal housing

I sure enough did. I had back surgery last year that didn't work out for me so I'm looking forward to another visit to the surgeon- Not.

I just don't feel up to the task now... the reason I deviated from my normal protocol of splitting the tractor and replacing what needs replaced between the halves.

I thought I would give the stuff I've been looking at in the parts joints for 35 years try and report the results here on the forum. I've been doing this stuff since 77 so the job isn't an issue but it may be for some of the forum readers who may also be wondering if mechanic in a can is capable of repairing a RMS.

If it didn't work as well as it did (which I was pleasantly surprised) I would have parked it and mowed with another tractor.

Re: Rear Main Seal in a Can...

Wed Oct 17, 2012 8:21 pm

Fully understand your back problem. Two titanium pins and eight screws solved 98% of my problem. Must admit it took four times and over 30 years, however I am one happy camper!


Re: Rear Main Seal in a Can...

Wed Oct 17, 2012 9:03 pm

Bill Hudson wrote:Fully understand your back problem.

Yes until you experience a herniated disk for yourself, you have no idea how it changes your frame of mind and how you have to adapt your lifestyle to live with your injury.

Re: Rear Main Seal in a Can...

Thu Oct 18, 2012 1:20 am

lazyuniondriver wrote:
Bill Hudson wrote:Fully understand your back problem.

Yes until you experience a herniated disk for yourself, you have no idea how it changes your frame of mind and how you have to adapt your lifestyle to live with your injury.


I am a firm believer in Farmer Fixes. It is how I grew up. I am also a firm believer in Full disclosure when selling something that has been farmer fixed by me.

Our culture has grown to where, "We are so use to getting things IN a box, we (are losing/have lost) the art of thinking OUTSIDE the box." My grandpa could not afford the box :big afro:

Re: Rear Main Seal in a Can...

Thu Oct 18, 2012 3:27 am

Problem is Dale everybody has a box today... One that has an OBD II OR III port attached to it.

Nobody but old timers* have the ability to troubleshoot or problem solve because with today's onboard data systems (even on agricultural equipment) troubleshooting is no longer required.

If you have a problem, the scanner or laptop will find the malfunction and advise the best remedy too. There is less and less old iron around for people to want to even bother to learn about.

I remember I was 10 or 11 when electronic ignition came out. I thought to myself this is the beginning of the end for the do it yourselfer and sure enough, year by year less and less serviceable parts requiring less and less thinking and more and more software.

* (I sure hate to consider myself an old timer but I need to face the music since I got an AARP card in the mail last month)