The dastardly 841 engine rear oil seal leak

A month ago I started cutting hay with my 841. A loud thump, crack and the engine spooled down. One of the timing gears came apart, took the other out and departed the engine through the timing gear housing. So I tore it down and overhauled the engine.

Now I'm having a major rear seal leak...like 2 quarts an hour.

I ordered a rear seal kit as part of my overhaul parts from Tractor supply and it didn't come with rope seals, but since I've read mixed results of replacing the rope seals with out dropping the crank, I went ahead and tried to just replace the rear seal, but it still leaks.

I ordered a rubber CONN6701A which is supposed to be the rubber replacement for the EBU6701A and plan to take the engine off and replace the seals this weekend. But, the 6701A looks identical to the rear seal and my recollection is that the rope seal channel is larger than the rear seal channel.

Does anyone know if the CONN6701A is a direct replacement for the EBU6701A rope seal? If not is there direct replacement or do I need to just get the rope seal and "deal with it"?
 
If you look at this site's Parts section you'll find CONN6701A replaces EBU6701A. They have a kit which is described as being "improved". The side seals are often to culprit. Take a look at the link.
YT Seals
 
(quoted from post at 18:30:13 09/25/15)
That improved set up is one of the styles offered by Victor... I found the side seals with the pin to be a challenge to install. I remember having to remove the set up several times then i applied RTV to the side seals and got a seal...

My Tip is you can check them before you install the pan...

http://forums.yesterdaystractors.com/viewtopic.php?t=1188942&highlight=victor

I took the engine off and tried the COON6701A and it [u:08518d722b]much[/u:08518d722b] thinner and shorter than the rope seal channel. The neoprene oil seal fits the oil seal channel fine, but there is no rope seal in the kit. I checked with tech support and he says the rope seal is obsolete, you don't need it and the neoprene seal should hold the oil fine.

I'm dubious to say the least.

It had a rubber seal and a rope seal when I tore it down and never had leaked a drop. I presume they put a rope in for reason. Any Idea if you can get away with no rope seal?
 
If its in good condition and you have your ducks all in a row I have never had a issue replacing the rope seal with a neoprene seal that was offered as a replacement... The hot tip is you can check it for leaks with the engine out and pan off...

I will look over my links in the post and see it there is anything else that will add comfort to this deal...
 

Thanks for the encouragement. I dismounted the engine flipped it over and replaced the rear seal with the neoprene and the larger channel rope seal with a rope seal for YT. Did the neoprene side seals and followed the instructions at http://www.hemmings.com/mus/stories/2009/03/01/hmn_tips2.html. Worked pretty well (a drip or two after shut down, but that's better than it was before the rebuild.

All in all the overhaul went well except for the stupid rear seal problem. Thanks for the support.

Jeff
 

Spoke too soon, or jinxed myself by declaring problem solved.

Went out to rake the cut hay to get ready for baling. Checked oil prior to start and was normal, no drips under tractor, etc. Went out to cut and after about 20 minutes started loosing oil pressure. Got off, checked the oil and it was on low end of dipstick. Went back to house and got a couple quarts of oil and put it in, drove the tractor back, parked it and watched it pump oil out of the gap between the engine and transmission housing as well as steady drool out the weep hole.

So, I got about 10 hours of mowing done with a dry rear seal and then whoosh...

Any ideas what I missed? Or is replacing the rear seals on this engine such an "art"?
 
(quoted from post at 07:04:47 10/14/15)
Thanks for the encouragement. I dismounted the engine flipped it over and replaced the rear seal with the neoprene and the larger channel rope seal with a rope seal for YT. Did the neoprene side seals and followed the instructions at http://www.hemmings.com/mus/stories/2009/03/01/hmn_tips2.html. Worked pretty well (a drip or two after shut down, but that's better than it was before the rebuild.

All in all the overhaul went well except for the stupid rear seal problem. Thanks for the support.

Jeff

I know this is going to sound really stupid, but the YT overhaul gasket kit includes both a neoprene split rear seal and two pieces of rope seal. There are two grooves in the case at the rear seal area.

I am supposed to use both the neoprene and rope seal correct? I don't remember if there was a rubber and rope seal in the engine when I tore it down. A lot of the discussion talks like it is an either or proposition.

I placed the neoprene in the outboard/rear groove and packed the rope in the inner groove. Did I do something wrong here?

Jeff
 
(quoted from post at 17:14:56 09/28/15) If its in good condition and you have your ducks all in a row I have never had a issue replacing the rope seal with a neoprene seal that was offered as a replacement... The hot tip is you can check it for leaks with the engine out and pan off...

I will look over my links in the post and see it there is anything else that will add comfort to this deal...

I know this is going to sound really stupid, but the YT overhaul gasket kit includes both a neoprene split rear seal and two pieces of rope seal. There are two grooves in the case at the rear seal area.

I am supposed to use both the neoprene and rope seal correct? I don't remember if there was a rubber and rope seal in the engine when I tore it down. A lot of the discussion talks like it is an either or proposition.

I placed the neoprene in the outboard/rear groove and packed the rope in the inner groove. Did I do something wrong here?

Jeff
 
(quoted from post at 11:59:38 10/19/15)
(quoted from post at 17:14:56 09/28/15) If its in good condition and you have your ducks all in a row I have never had a issue replacing the rope seal with a neoprene seal that was offered as a replacement... The hot tip is you can check it for leaks with the engine out and pan off...

I will look over my links in the post and see it there is anything else that will add comfort to this deal...

I know this is going to sound really stupid, but the YT overhaul gasket kit includes both a neoprene split rear seal and two pieces of rope seal. There are two grooves in the case at the rear seal area.

I am supposed to use both the neoprene and rope seal correct? I don't remember if there was a rubber and rope seal in the engine when I tore it down. A lot of the discussion talks like it is an either or proposition.

I placed the neoprene in the outboard/rear groove and packed the rope in the inner groove. Did I do something wrong here?

Jeff

Thanks to some PM advice from NCHobo I dropped the oil pan, dropped the crank about 1/16' and removed the rope seal from the 2nd channel which is the oil return channel and buttoned it back up. I ran it for a couple hours today and oil is still at the full mark. I don't want to jinx it but it may be solved.

YT sends a rope and a neoprene rear seal. I understand that the tolerances weren't so tight in the earlier models so the neoprene just won't work on some engines so you must use the rope seals which are more tolerant.

Thanks NCHobo for the help

Jeff
 

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