Ford 600 Main Bearing Surface Question

crselsor

New User
I was in the process of putting a new clutch in my tractor and repairing a rear main seal leak. I dropped the oil pan and took the rear main cap off. The wedge seals and rear main were rope seals. I noticed a bad spot on the main bearing surface in the corner almost where the bearing meets the cap top. Any idea what would cause this. I did not drop the cap when i was taking it out, just hit on the cap to break it loose. Is there a way to tell if they are the original bearings. The bearing has only a faint mark on it that says fordmoco i believe. I will attach a picture of the bearing.
a264838.jpg
 
That looks like the bearing was damaged during manufacturing or the original installation.

I doubt it would have any detrimental effect or contribute to the leak.

If you suspect the bearing might be worn, the easiest test would be with Plastiguage.

Not sure about your model, but some more popular applications offer a rubber replacement seal. If you can't get a rubber seal, probably best to leave the upper seal in place and replace the just lower one. Installing those is a tricky job, getting enough extra length on the ends without catching strings between the cap and block. A very thin application of sealer under the cap helps, along with sealing the wedge seals.

Other causes of rear seal leaks are a restricted crank case vent, excess blow-by, oil level too high, and other leaks blamed on the rear seal, like galley plugs or valve cover gasket leaking and running down.

If you suspect the bearing may be undersize, all I have seen were marked with the undersize. Also typically the crank will be stamped with the undersize grind.
 
There were no marking on the bearing indicating it is undersized so i will have to assume it is std. As far as the rear main seal I have a rubber two piece seal on hand for it. With that being said I see no good way to try and get the upper half out from around the crank as it is still a rope seal. I know you said it would probably be best to just leave the upper seal in place and replace the lower. When I do this do I need to go back with a lower rope seal or would it be possible or even a good idea to replace the lower one with the rubber one i have on hand and leave the old rope one on top.
 
(quoted from post at 02:26:03 04/14/18) There were no marking on the bearing indicating it is undersized so i will have to assume it is std. As far as the rear main seal I have a rubber two piece seal on hand for it. With that being said I see no good way to try and get the upper half out from around the crank as it is still a rope seal. I know you said it would probably be best to just leave the upper seal in place and replace the lower. When I do this do I need to go back with a lower rope seal or would it be possible or even a good idea to replace the lower one with the rubber one i have on hand and leave the old rope one on top.

crselsor, I have installed both rope and two piece rubber seals. Either way it is a major tough job. I recommend a lot of research before doing one. There is a lot of information on the topic here. I have not tried to do one with the engine in place. It is difficult enough with the engine on a stand.
 
If leaving the upper rope in, the lower will also need to be rope.

Getting the upper rope out is not fun, but doable. Remove the other main caps, block the clutch down, and pry down on the crank. It won't move much, but just enough. Then try grabbing the rope with needle nose and pull it out. If it won't come out, there is a tool called a "Sneaky Pete", I assume they can still be found. It is a cork screw style tool that screws into the rope and helps pull it out. Then the rubber seal can be slid into place.
Sneaky Pete
 
(quoted from post at 09:02:31 04/14/18) If leaving the upper rope in, the lower will also need to be rope.

Getting the upper rope out is not fun, but doable. Remove the other main caps, block the clutch down, and pry down on the crank. It won't move much, but just enough. Then try grabbing the rope with needle nose and pull it out. If it won't come out, there is a tool called a "Sneaky Pete", I assume they can still be found. It is a cork screw style tool that screws into the rope and helps pull it out. Then the rubber seal can be slid into place.
Sneaky Pete

I bought a Sneaky Pete before my first rope seal job. Once I got into the job the "Pete" looked like such an unlikely proposition that it is still in its original package. I have had to dig a rope seal out in many pieces after completely removing the crank, because it was stuck so badly in the groove.
 
I have a tool that allows you to drive a small rod/wire between the top of the rope seal and the block. You use this on the top rope seal. This tightens it down to the crankshaft. Then install a new rope seal in the bottom grove.

My Grand Father had this tool and I have not seen any like it in the last 30 years. It is basically a 1/2 diameter steel rod about six inches long with a small hole drilled down the entire length. Then there is a "driver rod" that fits this hole with little clearance. So you take a stiff piece of wire and put it in the hole. You sharpen one end of this wire to a point first. You put the wire into the tool with the pointed end out. You put the pointed end between the rope seal and the block. You takes a small hammer and hit the driver rod and this pushed the wire around the block. I ran out of the wires that came with the tool years ago. I now use High tinsel fence wire ore steel brazing rods to make the wires for the tool.

This makes repairing leaking rear seal on the older Ford tractors really easy. Just drop the pan and remove the rear main bearing cap. Drive the wire in to tighten the top seal. Install a new rope seal in the bottom cap and reinstall it. New pan gasket and your done.
 

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