Author Topic: rear main seal  (Read 28477 times)

Offline 75 C20

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rear main seal
« on: March 03, 2007, 10:59:00 PM »
i am going to go ahead and replace my rear main seal in my 75 c20 with a 350. i have the engine pulled out and figured i might as well do that too. how exactly do i go about doin this and should i go ahead and replace my oil pump or not- some places i read say do and others say dont.:lol  

1975 Custom Deluxe 20 350 SM465 2WD Longbed
1979 Custom Deluxe 20 400 SM465 2WD Longbed
1968 Custom Sport Truck 20 327 TH400 2WD Longbed
1985 Silverado 10 305 700R4 2WD Longbed
1969 Pontiac GTO 400 Turbo350
2008 GMC 2500HD 6.0 6spd 4X4 Longbed

Offline 77c15

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oil pump?
« Reply #1 on: March 03, 2007, 11:28:00 PM »
while you've got the oil pan off and the crank bolts loosened for removal of the seal, you might as well replace the oil pump and check all of you crank and rod bearings. the only time you should replace something that isn't broke is when it is incredibly accessable and to save yourself the heartache later down the road. Just make sure you get a new shaft with the oil pump....a lot of the aftermarket oil pumps don't come with it. hope this helps.

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Offline VileZambonie

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Re: oil pump?
« Reply #2 on: March 04, 2007, 08:06:00 AM »
A few tips, since you have a two piece rear main, offsetting the seals so the opening don't line up with the bearing caps can eliminate dripping from that area. I teeny weenie dab of RTV near the corner of the rear bearing cap is ok too, just be careful doing this.

Make sure you use an oil pump driveshaft with a steel sleeve and get a new pick up tube. Make sure you install the pick up tube so it just touches the bottom of the pan. When you install the pan gasket you should have just enough clearance off of the bottom of the pan. If you weld the pickup to the pump use a cold weld like JB weld. Don't forget to prime the oil pump. Packing the inlet with vaseline will allow it to prime easier and it is petroleum base. Do not use grease.

Good luck

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Offline Lt.Del

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Re: oil pump?
« Reply #3 on: March 04, 2007, 01:57:00 PM »
Get a felpro one piece pan gasket...they are awesome.  If you have a four bolt main, torque the outer bolts 60 ft lbs, inner bolts 65 ft lbs.

Definately go with a new pump...being the heart of the engine, they are cheap.  Your labor will be done anyway since you have to remove your pump to replace rear main. Dont forget the gasket for the pump.





















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1979 Big 10 383 stroker
1991 Blu 'Burb 3/4 ton 4x4

Edited by: SgtDel  at: 3/4/07 2:04 pm

Offline VileZambonie

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Re: oil pump?
« Reply #4 on: March 04, 2007, 08:29:00 PM »
Quote:
Dont forget the gasket for the pump.


? there is no gasket used for the pump.

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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline Lt.Del

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Re: oil pump?
« Reply #5 on: March 04, 2007, 08:43:00 PM »
I could've sworn mine came with one, but it has been a couple of years now.  

SgtDel
aka "Andy"

www.delbridge.net

1979 Big 10 383 stroker
1991 Blu 'Burb 3/4 ton 4x4


Offline jason

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Re: rear main seal
« Reply #6 on: July 19, 2013, 12:22:26 AM »
Did you complete this job without raising your engine?
The service manual says that raising the engine 2-3 inches is necessary to remove the pan.

I'm looking at replacing my pan gasket as well as some other gaskets > timing chain cover, intake manifold, etc.

Thanks,
Jason

Offline Fairlane514

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Re: rear main seal
« Reply #7 on: July 19, 2013, 12:38:04 AM »
You can get a copper gasket for the oil pump.

Offline Irish_Alley

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Re: rear main seal
« Reply #8 on: July 19, 2013, 01:21:30 AM »
on mine i didnt have to raise the engine. think all are like that but cant say for sure
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