My GMC 302 has developrd an oil leak. I installed a new front and rear seals 3 months ago while installing a 200R4. Unfortunately the rear seal is leaking worse than ever. I am trying to decide what to do now.
One option is to just remove the oil pan and the lower half of the rear main bearing to replace the seal. This saves a lot of effort but but will this approach work? Has anyone tried this? This might be worth the effort if this has a good chance of working.
The other approach is to remove the entire power train, put the engine on a stand, remove the crankshaft and replace the entire rear seal, and put the whole thing back into the car. This approch i know has the best chance of success, but will take more time and $$.
Another thing I am wondering about is the best way to install the rear seal or half a seal. Please help me decide if you have any experience that you may have had doing this.
The GMC manual says to lay the seal rope matrial into the groves in the block and cap and use a wooden mandrel and hammer to press the seal into the groves. The GMC manual pg 377-8) also says to cut the seal ends with a sharp knife and don't leave any frayed ends which would prevent proper seating of the bearing cap to the block ( and cause leaks). I have a friend making a mandrel now.
The Instructions from Best Gasket are very different. They say drill a 1/16 hole in the bottom of the bearing cap to insert a pin provided so that about 1/8 inch is showing to insert into the seal, or use Ultra RTV sealant across the length of the rope to keep it from shifting in the groove. The other thing is to cut the rope ends using a 0.015 in spacer to add material above the bearing cap and block serface but to pack it down flush and push any loose strands toward the center before tughtening the cap down.
I added 0.015 to the end of the rope but it is now leaking. Maybe some stray rope strands got between the cap and block?
Thanks for your attention to this problem.
Frank Hainey (RADAR)
