vettfixr

Okay, this past weekend I finally took the 74 down off the ramps. Projects included a new flywheel and pilot bushing, new 1 piece oil pan gasket (the right one this time), Dynomax Ceramacoat headers, and a Hurst Competition Plus shifter. Took it to the muffler shop and had the headers connected to the exhaust and thought I was done with the mechanical stuff. Well, the next day I pulled it out of the garage and had a nice 4 inch spot of oil under the engine just like I had before. I originally thought it was because I had the wrong oil pan gasket but the new one didn't cure the problem and it's not the gasket leaking again. It looks as though it's the rear main seal because it's dripping from the clutch inspection cover. While I had the pan down I thought about pulling the high pressure pump and replacing it with a regular pressure spring and changing the rear seal but decided not to. I think what's happening is that the high pressure is blowing oil past the rear seal. Has anyone changed a rear seal with the engine in the car and is it difficult. The car usually runs about 40 pounds pressure at idle and about 60 while running. When the engine is cold it can hit 80 pounds. I don't know if I'll tackle it right away but eventually it will have to be done. Any thoughts on this?

tangee-vette

Those damn leaks will get you ever time. Last spring I got every item buttoned up tight and no leaks occurred all summer. This fall/winter I uncovered the shark for its 15 day start-up (during hibernation) and low and behold, tranny fluid was leaking. Coming from the shifter seal. So this spring is starting just like the last....fixing those damn leaks!

vettfixr

I sympathize with you. I swear these things leak more than a 6 month old infant. I thought that because I had gotten a 4 speed car I wouldn't have to worry about tranny leaks. Yeah right, there goes another myth out the window.

jackson

Once oil pan is off, rear main seal can be done from underneath in less than an hour. High pressure pump is can be nothing but trouble in a street motor. However, a high volume pump-normal pressure pump is nice. You can pull the pump and swap the spring while you're down there ... no prob.

Phlash

Are you sure the leaks are from the rear main seal. I once had a rear cam plug leak, and a friend of mine had a rear oil galley plug leak. Both were the pits to diagnos.

Phlash 72 BB Roadster :seeya

TFeld78

I had the same leak, shifter seal. The mechanic has tried to fix it three
times now, each time it would start leaking a few days after I got it back.
Mechanic claims there are some burrs on the shaft that keep tearing
the seal. This time he told me he replaced the entire shaft. I get it back
tomorrow. I'm keeping my fingers crossed!!

vettfixr

Yeah, I'm pretty sure that's where it's coming from. I had the tranny, bellhousing, clutch and flywheel out and was down to the crank this winter. The tranny is bone dry. the only leak there was a slight wetness on the switch that controls the emissions. I sealed that with some RTV and it's good now. The front and rear seals on the tranny were replaced about 2 years ago and they are dry. I put the one piece oil pan gasket on and I'm pretty sure there are no leaks there. The only other possibility is that the rear of the valve covers may have a leak. I replaced them with steel core neoprene gaskets and I'll check this weekend to make sure they are dry. Boy wouldn't it be nice if it was only the valve covers. Wishfull thinking.

Alwyn678

I know the feeling..I fixed my transmission Leak now I have a power steering leak......DANG will it ever end?? I am gonna go thru and Replace all my old hoses for sure

john's '81 mouse

Quote: ". Has anyone changed a rear seal with the engine in the car and is it difficult."

Yep, did it to my '81 S/B, not too bad. Remove pan, remove oil pump, remove rear main cap, then remove rear main seal, installation is reverse.

I used both felpro seal and one piece rubber pan gasket, and installed new stock oem oil pump and screen, wiith new steel oil pump drive shaft.

vettfixr

Thanks for the replies everyone. If the valve cover thing doesn't pan out I'm probably going to be crawling under the beast again. I'd like to put it off but I don't want it spewing oil all over it's belly for the whole summer.

Edzred72

Hey Al:
Help me with mine.. and I'll help you with yours!! :jester Controll valve and hoses that is. I got all the parts..must fight rusted exhaust install first. Da*m P/S hoses are over $60.00 :mad :mad

Alwyn678

Help me with mine.. and I'll help you with yours!! :jester Controll valve and hoses that is. I got all the parts..must fight rusted exhaust install first. Da*m P/S hoses are over $60.00 :mad :mad [/QUOTE]

That sounds like a plan..i am gonna attempt to figure it all out on Saturday..i will keep ya Posted.....Ahh the joys of Hi-po older car ownership...It is WELL worth it

7T6HER

How does the dipstick tube attach to the block ? i have no garage any longer and can't see underneath and that may be where my leak is coming from. :cry

Budman68

I feel you pain buddy. I'm changing mine this weekend. :cry :cry

Edzred72

When you go to do the main seal, someone on this forum suggested stagering the seal joint, 90 degrees from the main bearing cap joint to reduce the risk of further leaks. Man I wish I had that idea when I did mine. Sounds like it would be just a "tad" tricky to get the seal seated properly on the cap, when installing the cap..but worth the trouble IMHO. Now go spank yourself for not doing the seal when ya had it all apart the first time!! :jester :jester