HELP!! 272 Rear Main Rope seal
#1
HELP!! 272 Rear Main Rope seal
Hello
I have put 2 rubber rear main seals and 3 rope seals in this Y block and it still leaks. I asked around and found an old time mechanic with experience in them and it leaks worse then ever. I'm sure it's the seal/block as on my 2nd rope seal I was 99 % leak free untill a few miles and it started dripping again(two much to drive with). every attempt has produced a different amount of leakage. You can see oil on the crank flange so its above the pan. The crank appears smooth all around. It appears that maybe the top half of the seal is turning slightly after startup and alowing oil by?? Should a small amount of the seal be left proturding out? if so how much? What is the best way to trim (cut) the top seal flush or close to it while in the block. I've been using sizzors and it works ok but not perfect( hard to get them in there after the upper seal is installed). A razor blade will hardly touch it, that stuff is tough. What type of sealent if any should be used and how much and where? I know i've asked a lot of questions but this is getting really frustrating and you guys are my last hope. I plan on pulling the trans/flywheel this weekend to see if I can see anything and one more attempt at installing this seal. I've been getting the rope seals at NAPA. Any other sources? better quality? I'm grasping here. Any input would be extremely appreciated.
Thanks
Bill
I have put 2 rubber rear main seals and 3 rope seals in this Y block and it still leaks. I asked around and found an old time mechanic with experience in them and it leaks worse then ever. I'm sure it's the seal/block as on my 2nd rope seal I was 99 % leak free untill a few miles and it started dripping again(two much to drive with). every attempt has produced a different amount of leakage. You can see oil on the crank flange so its above the pan. The crank appears smooth all around. It appears that maybe the top half of the seal is turning slightly after startup and alowing oil by?? Should a small amount of the seal be left proturding out? if so how much? What is the best way to trim (cut) the top seal flush or close to it while in the block. I've been using sizzors and it works ok but not perfect( hard to get them in there after the upper seal is installed). A razor blade will hardly touch it, that stuff is tough. What type of sealent if any should be used and how much and where? I know i've asked a lot of questions but this is getting really frustrating and you guys are my last hope. I plan on pulling the trans/flywheel this weekend to see if I can see anything and one more attempt at installing this seal. I've been getting the rope seals at NAPA. Any other sources? better quality? I'm grasping here. Any input would be extremely appreciated.
Thanks
Bill
#2
Well, a couple of things come to mind. There are two kinds of seal retainers, & one of them is flimsy & tends to leak.
What rubber seals are you using? Some don't fit very well. It's best to slightly offset them & use a small (& I do mean small, not a goober) dab on the ends. Is there anything in the groove, like a pin? If so, it needs to come out. Use a touch of silicone on the back side.
Rope seals generally need to be trimmed with a new utility blade, or something like, with a sawing motion. It's something of an art form to install them, but they work pretty well. I leave a little excess, but not a lot.
Are you using the side seals?
Lubricate the seals with grease before you run it (I'm sure you know this, but if not, it never hurts to remind. )
I'm sure somebody else will toss in what I've forgotten. Welcome to FTE!!
What rubber seals are you using? Some don't fit very well. It's best to slightly offset them & use a small (& I do mean small, not a goober) dab on the ends. Is there anything in the groove, like a pin? If so, it needs to come out. Use a touch of silicone on the back side.
Rope seals generally need to be trimmed with a new utility blade, or something like, with a sawing motion. It's something of an art form to install them, but they work pretty well. I leave a little excess, but not a lot.
Are you using the side seals?
Lubricate the seals with grease before you run it (I'm sure you know this, but if not, it never hurts to remind. )
I'm sure somebody else will toss in what I've forgotten. Welcome to FTE!!
#7
I've soaked them in oil, but was too impatient to do it over night. Then, still oily, I'd press the seal into the bearing cap, and using the biggest socket I had, compress the seal into the groove. After compression, I'd trim the ends, leaving some room for future trim. Install into upper groove. ... Sounds so simple, but seems never is. I used the chinese finger puzzle type seal puller, and the other one that uses hooks and even the one that screws into the end of the seal. Chinese was the best. Loosen all the other mains to allow the crank to drop a little. Use the tool and get the seal mostly in place. Trim one end so that it is above the split line. Do the lower seal with the socket, making sure to trim it even with the split line. Rotate the seal to match the upper - one exposed, one recessed. Fit the bearing into the block. Remove. Check and trim for 'threads' or tails of seal that were compressed between the block and bearing cap. Refit. Remove and check again. You want the cap to fit to the block w/o any seal material being caught.
When you fit the side seals, on your last, I always tried to get them a little higher than the top of the cap as I figured they'd get pushed down as I pushed the cap into place. Being young and stupid, I never thought to measure their length and determine if they were actually protruding the right amount with the bearing in place. Once you figure they are out the right amount, where their top pushes againse the bottom of the block, trim them even with the cap.
This is a messy and artful task. It takes time to fit a rope seal, but they will work well if you do it right.
Now, a spun bearing will allow so much oil to flow that it will spew past any seal. How do I know?....
tom
When you fit the side seals, on your last, I always tried to get them a little higher than the top of the cap as I figured they'd get pushed down as I pushed the cap into place. Being young and stupid, I never thought to measure their length and determine if they were actually protruding the right amount with the bearing in place. Once you figure they are out the right amount, where their top pushes againse the bottom of the block, trim them even with the cap.
This is a messy and artful task. It takes time to fit a rope seal, but they will work well if you do it right.
Now, a spun bearing will allow so much oil to flow that it will spew past any seal. How do I know?....
tom
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