Leak-free rear main seal- is it possible? How?

[Anonymous]

I've been spending so much time in the suspension forum it's been a long time since I've been here- lot's of interesting stuff to distract me

Since I'm installing a freshly rebuilt and painted rearend and front suspension, I am going to try for the 3rd time to dry up the flow of oil from my rear main seal so everything does not get soaked with oil- esp. the new idler arm. Here's what I know you are suppossed to do;

Remove the pin from the main cap

Make sure everything is oil free - I sprayed brake clean on everything last time, including up inside where the seal goes)

Make sure the oil pan rails are straight and clean

Put sealer on the ends of the seal halves, install them and rotate so they are up inside the main cap.

Put extra sealer where the rubber main cap gasket meets the oil pan gasket (I have done this part twice- this will be my third attempt)

Let sealant cure before assembling so gaskets don't slip around (I think this is part of my problem the first time but not the second)

So what am I missing? Last time I put it together, I just did the oil pan and not the rear main so that may be my real problem. I ran it for 1/2 hr on hight idle and no leaks. I put the sway bar, center link, and crossmember back on, drove it 20 miles, and it leaked :x What do I need to do differantly this time to ensure a leak free seal?

Should I be using regular black rtv for sealing the part where the rubber seal meets the gasket, or something else?

And what should I use to seal the main cap to the block at the back? I have a feeling this is where the oil is coming through- between the two metal surfaces and out the back. I really don't want to do this a fourth time- at least not until I rebuild my 200 next winter!

Thor

 

[MustangSix]

I do pretty much what you do and don't usually have a leak problem.

I only rotate the seals a few degrees; just enough that the ends are inside the cap and block. I also don't use too much sealer on the ends. Make sure the seal is facing the right direction.

I apply just a bare smear on the end cap. Too much might cause the cap not to seat properly.

On the oil pan seals the trick seems to be to get it all lined up. just a little sealer in the corner is all it takes to fix that potential leak there.

finally, I use a threadlocker/sealer on the flywheel bolts. They go all the way thru the crank and will leak.

 

[Anonymous]

I don't let my oil pan gasket cure fully when I install them, instead I install the pan and just get everything finger tight, then go at the pan a half turn every thirty minutes, I use a slow cure sealant and it usually takes about two hours plus to get them torqued all the way down....

Good thoughts on the Flywheel bolts, thanks for that I am installing a flywheel this weekend and forgot about those....

 

[Anonymous]

What kind of sealer are you using specifically on the main cap and rear main seal ends where they meet? The guy at the parts store did not think black rtv was good enough.

Jimbo- what is this slow cure stuff you are speaking of? When I did my old comet 5 years back I used the white silcone stuff- never again. It was very slimy and slippery- nothing stayed in place and it really made a mess as it never really firms up. That one leaked a little too- but nothing like this one. I think my 0-60 mph tests last year really turned a dribble into a gusher

Do you guys use the sealer between the rubber oil pan end seals and the main cap? It seems to me my biggest problem was those seals sliding around, and having a hard time compressing them into the "channel" in the main cap all the way.

Regarding the flywheel bolts, I wish someone had told me when I did my trans swap- the trans is not coming out until I put my 200 in! Last time I did this I removed the converter bolts and moved it back so I could lower the crank down at the back end just enough to get the seal out/in.

Thor

 

[Anonymous]

For mine... I used High-Tac on the two rubber seals front and back... on the backside to adhere to the channel, then installed the cork gaskets with number2 Permatex and installed them on the block both sides coated.... then I put a little high-tac on the front and rear rubber seal and installed.... never had a leak.. make sure you get a good alignment on the cork fingers into the rubber seals and put a little tac under there.. then coat over the top of the corner with the number2.... make sure you install very slowly... otherwise the gasket will smoosh out the sides. I did this on the first one... then got it right second time.

Never leaked for 9 months.

Here is a link for the number2, which was recommended for the oil pan and why I chose it..

http://www.permatex.com/products/prodid ... m_no=80009

 

[Anonymous]

Thanks- what did you use between the rear main cap and block?

 

[MandarinaRacing]

Hi, I'm planning to replace my oil pan and I thought that this was a simple process (guess I was wrong) is there any advice anyone could give me on this, this would be my first time doing this

Alex

 

[Anonymous]

I did not have to change the rear main last time... I am this time.


My general rule, right or wrong, is I use high-tac adhesive sealants on rubber and coolant gaskets, and the number2(slow-setting) on cork or oil gaskets, Ultra-copper on intake and exhaust gaskets.

From what I have read here that is my general guideline and it has worked for me so far....



ALEX:

It's not hard really, it's easier out of car, or on a lift... but it does take time and patience to get the four sections of the gasket installed and sealed, then the pan, before the sealant cures. And if you have a leak it has to all come off again and start over. So I try hard to get it right once. My first one took four hours. I had to remove the crossbrace and centerlinnk as well as clean the old one off. I also installed a new pump at that time seemed logical. This time around the engine is on a stand and should be cake.

 

[Anonymous]

Jimbo,

So are you saying that you'd use the ultra copper between the main cap and block?

Thor

 

[Anonymous]

I only rotate the seals a few degrees; just enough that the ends are inside the cap and block. I also don't use too much sealer on the ends. Make sure the seal is facing the right direction.

I apply just a bare smear on the end cap. Too much might cause the cap not to seat properly.

I don't see any reason you could not use copper there, but you need a small amount... you could also use a number1 hard setting sealer from Permatex.... I have not done this yet, so I could tell you better in a couple of weeks, I never changed the main on mine, only the pan. But I like copper.. it is really tough. and has a higher heat rating.

 

[Anonymous]

I just looked at the #2 link Jimbo posted- I think that's the white stuff I tried before on my old comet oil pan gaskets that was really slimy. Like they say, it's better for sealing but not holding stuff in place. That rubber seal is definately something that tends to slide around, so I'll try the high tack stuff there.

If I buy the copper I may as well use it at the rubber to cork joints too, right : There's no sense I can see in buying a 3rd product (the #2 stuff) just to seal the corners if I can use the copper there (or since I have some already, the black???) Those little tubes ain't cheap! :roll:

Thor

 

[Anonymous]

That number2 I used was almost a flesh color... like putty, it went on a little thick, but sealed very well....

As for the copper, I would not hesitate to use it, but it dries fast... you will have to be very quick on the pan install.... that was my reason for the slow-hardening sealer.

Good Luck.


J.