: On My 3 Rear Main Seal



musgttang
04-23-06, 11:01 PM
Hey Guys I Just Dont Know What To Do.this Is My 3 Rear Main Seal Havent Used The Tool Yet.just Doing It The Old Fashion Way Hammer.i Have Put Silicon ,shalac Amd Still Leaks Can Enyone Help Me Out A 1994 Cadillac El Dorado 129,000 Miles.and Its Not Easy Taking The Tranny Off.

Loose screw
04-24-06, 12:36 PM
It may not be the seal but the gasket. Is the shaft scratched or durty? Is the block scratched, cracked or deformed?
Where exactly is the seal leaking, at the OD or the ID, the block split line?
If it is at the block, you can get a small siringe with a tinny needle and inject a small amount of Silicon or hylomar into the trouble spot (first inject carb cleaner to clean out oil, wait and let it evaporate) when you pull the needle out inject a tinny amount while doing so to make sure you back fill any hole you made. Do not inject any more than is necessary to fill a gap or hole. You don't to want any in the oil

sts96
04-28-06, 09:38 AM
Check for oil leakage in the valley under the intake manifold which drains thru to the flywheel area.
sts96

musgttang
05-02-06, 11:48 AM
the seal is leaking right at the bootom dead center.

chevelle
05-02-06, 12:44 PM
The thing you need to determine is where the leak is... Is the seal leaking against the crank or on the OD of the seal where it presses into the block. Rear main seals are pretty uncommon so to have a leaker and a repeat leaker indicates something is wrong that you need to identify to make sure it is repaired. Clean the area thoroughly and use the ultraviolet dye in the oil to determine the specific leak source. Any leakage is bound to run to the bottom of the seal so the actual leak source may not be there.

If you have the seal out make sure and clean and inspect the bore of the block that it presses into. Also inspect the crank surface carefully for scratches from previous installations. Look at the seal bore at 3:00 and 9:00 and you will see the ends of the lower crankcase side seals. Those seals press against the rear main seal when it is installed and complete a "T" joint in the lower crankcase sealing mechanism. Possibly the ends of the side seals that protrude slightly into the rear main seal bore are clipped or cut or damaged from previous installations. This will cause seepage past that T joint. If in doubt clean the area thoroughly and apply a dap of RTV to the area where the ends of the side seals protrude into the rear main seal bore just before installing the rear main seal. If there is any doublt about the rear main seal bore you can apply a VERY light skim of RTV to the entire perimeter of the bore before pressing the rear main seal into place to fill and scratches or voids. The RTV will also act as a lubricant for the seal install into the bore so you can clean it thoroughly, apply the RTV and then immediately press the seal into place. You want to apply the RTV very sparingly and then wait for 24 hours to let the RTV set up before running the engine. RTV works very well as a sealant if you let it cure before oil hits it but if oil hits it before it has a chance to completely cure it will contaminate the RTV and the joint will not seal well at all.

If you do elect to try the RTV to make the joint more robust be very carefull to not use too much and not to let the RTV block the oil drain hole at the bottom of the seal cavity. That is really the only concern with using RTV. Use it very sparingly in that area. Speaking of that, check the oil drain hole while you have the seal out to make sure it wasn't blocked by debris from an earlier repair... It must be open to let the oil coming past the rear main bearing escape from the seal cavity or the seal will leak due to pressure build up from the rear main oil flow.

I would encourage you to install the seal with the correct tool. It MUST be installed to the correct depth and square to the seal bore and the seal must not be distorted during the install or it will leak. The seal has a steel inner core so it can bend if you pound on it non0uniformly and then later distort the seal even though it looks sqaure in the bore and flat.

Loose screw
05-02-06, 09:59 PM
Clearly there is something wrong. Identify all the possiblities.
A couple things I noticed on my crank (which had 142,000 miles) was some deposites and even some corosion just outside were the seals rides on the crank surface and were the seal rides there was a wear grove caused by the seal and dust. There may in fact be an exact idea position for the seal, but with that grove worn into the crank it was no longer my first choice. I did not want to have the new seal ride in it or in it - no way. I examined the case and found no reason that I could see that would preven the seal from being positioned 1/32 or even a little deeper into the case instead of flush with it. So I carefull taped the seal in a little deeper all around the seal, making sure it stayed perfectly square and flat so that the seal would then ride on perfectly flat and a perfectly smooth area of the crank. Did it work - yes, after 7000 mile not one drop of oil has leaked out. Make sure you grease both the crank and the seal well. Use RTV on the outside or Hylomar. The seal must start in square and equal and continue until seated where you want it. Clean and polish the crank spotless and the case. Also make sure your PCV is clean and moves freely.

musgttang
05-03-06, 12:18 PM
I feel stupid but let me tell you guys .I bought the rear main seal tool # j-38817-a on e bay. I got it on monday opened the box it was alright it was used.I looked at it and left it on the car.i went to the store wen i came back it was gone I dont know if someone took it or what looked all over couldnt fing it its probably an unsolved mystery.

musgttang
05-03-06, 12:21 PM
[quote=musgttang]I feel stupid but let me tell you guys .I bought the rear main seal tool # j-38817-a on e bay. I got it on monday opened the box it was alright it was used.I looked at it and left it on the car.I went to the store wh:confused: en I came back it was gone I dont know if someone took it or what maybe I left It on top of the car or what I looked all over couldnt find it its probably an unsolved mystery.

Loose screw
05-03-06, 02:08 PM
I will keep a look out for it around here:bouncy:

I just used a small hammer and tapped it in, in a crossing star pattern a hundred times until it was in perfect, it took a couple minutes. The tool would makes it faster but no better and it also limits the depth.

parts68
05-05-06, 06:14 AM
what part# seal have you been using?
Have you solved it yet?

musgttang
05-05-06, 09:12 AM
I just finished yesterday I hasnt leaked yet.and using gm seal.

parts68
05-05-06, 06:44 PM
What part#?
there are 3 different #s I know of.





I just finished yesterday I hasnt leaked yet.and using gm seal.