What to do about scratch in Rear Main Seal bore? Options

[frank_c]

I'm in the process of replacing a leaking Rear Main Seal, and after pulling the old seal I noticed two scratches in the case bore (honestly, it wasn't me - I have the proper tool for this (IMG:style_emoticons/default/smile.gif)).

From what I've been able to find the RMS should be installed dry, but what is the best practice to address the two scratched areas to avoid a leak? Here are some of the suggestions I found when searching:

1. Use an emery cloth to knock-down any raised edges
2. Fill scratch with high-temp JB Weld
3. Use some type of sealant at the scratch

Do I use none, one, or some combination of the above (or some other) to address this? Any help would be much appreciated as I'd like to get the new seal in this weekend.

[rfinegan]

1. Use an emery cloth to knock-down any raised edges
2. JB Weld not needed
3. Use favorite sealant at the scratch and around seal

[Ninja]

(IMG:style_emoticons/default/agree.gif)

Those scratches are completely covered by the OD of the seal.

I might put a bit of 3H (case sealant. your choice) in the big one.

[930cabman]

(IMG:style_emoticons/default/agree.gif)

Those scratches are completely covered by the OD of the seal.

I might put a bit of 3H (case sealant. your choice) in the big one.

(IMG:style_emoticons/default/agree.gif) or a shellac based sealant

[Jack Standz]

For your consideration is getting a GoWesty RMS installation tool. Seems that after all these years of just using a wood block or something to pound in the seal dry, there is a better way.

The instructions include using a sealant when you install the seal and drilling a drain hole back into the case at the bottom of the seal bore. Also, the tool insures the seal ends up properly positioned (make sure there isn't a Grove on the crankshaft which could cause a leak).

https://gowesty.com/blogs/article-library/f...main-seal-story

[frank_c]

For your consideration is getting a GoWesty RMS installation tool. Seems that after all these years of just using a wood block or something to pound in the seal dry, there is a better way.

The instructions include using a sealant when you install the seal and drilling a drain hole back into the case at the bottom of the seal bore. Also, the tool insures the seal ends up properly positioned (make sure there isn't a Grove on the crankshaft which could cause a leak).

https://gowesty.com/blogs/article-library/f...main-seal-story

Thanks for the suggestion - I've seen that tool before. It looks great, but my plan was to use a bearing/seal tool to tap in the seal. One question I have though is what is the correct depth of the seal? Should it be flush with the top of the bore in the case? Will the seal be "bottomed out" at that point anyway so it can't go any further?

As you mentioned, the GoWesty site for the RMS itself recommends the use of 'Vibra-TITE 550 Blue Core Plug Sealant' on the seal. This is a bonding sealant similar to Loctite 540. I have not found any other references recommending the use this type of product on a Rear Main Seal. Anyone have any experience with it? Will this make the seal difficult to remove the next time?

And regarding the drilling of a hole to allow for additional oil drainage - I've also read about this modification in the past and it sounds like a good ideal, but a concern I have is aluminum shavings falling into the case during the drilling process on a assembled and sealed case. How do you prevent this from happening?

[Ninja]

You could mildly pressurize the case (less than 3 PSI).

or

Drill 90% of the hole, clean up, pack drill bit with grease on flukes, finish hole slowly cleaning up the bit as you go.

or

The best way IMO is to do the Raby mod when you have the engine apart later.

Look at your crank to see if there is a score line. I always set my seal depth depending on where this line is. I AVOID this line if I can. You can see the original seal was not bottomed out.

The important area to have as perfect as you can is where the seal hits the crank.

Depth is not important (within reason), being equal depth is (seal straight in bore).

[Jack Standz]

For your consideration is getting a GoWesty RMS installation tool. Seems that after all these years of just using a wood block or something to pound in the seal dry, there is a better way.

The instructions include using a sealant when you install the seal and drilling a drain hole back into the case at the bottom of the seal bore. Also, the tool insures the seal ends up properly positioned (make sure there isn't a Grove on the crankshaft which could cause a leak).

https://gowesty.com/blogs/article-library/f...main-seal-story

Thanks for the suggestion - I've seen that tool before. It looks great, but my plan was to use a bearing/seal tool to tap in the seal. One question I have though is what is the correct depth of the seal? Should it be flush with the top of the bore in the case? Will the seal be "bottomed out" at that point anyway so it can't go any further?

As you mentioned, the GoWesty site for the RMS itself recommends the use of 'Vibra-TITE 550 Blue Core Plug Sealant' on the seal. This is a bonding sealant similar to Loctite 540. I have not found any other references recommending the use this type of product on a Rear Main Seal. Anyone have any experience with it? Will this make the seal difficult to remove the next time?

And regarding the drilling of a hole to allow for additional oil drainage - I've also read about this modification in the past and it sounds like a good ideal, but a concern I have is aluminum shavings falling into the case during the drilling process on a assembled and sealed case. How do you prevent this from happening?

Agree with @Ninja . There are different thicknesses of "standard" RMS seals. This means the seal will end up at a different place on the crankshaft/Case bore when you install it. If you use the GoWesty tool, you won't have to worry about whether the seal is flush with the case,, it'll end up in the right spot and evenly spaced around the seal's perimeter. Just make sure it isn't riding on the crankshaft in a spot than has been compromised or a groove worn into it.

When we used this tool, we didn't use that sealant, we used what we had. IIRC it was some form of Hondabond or Yamabond. Have used loctite 540 in the past on other projects with no complaints.

On an assembled motor, metal shavings are a problem. Much safer and better if you do it during motor assembly. We have performed the GoWesty procedure on an assembled motor by using a shop vacuum during the drilling (nonstop vacuum on the hole along with frequent stops to pull the tool out to vacuum as many shavings as possible before the drill bit entered the case), then spraying brake cleaner in the hole and more brake cleaner via the strainer/oil pickup area using the straw on the can inserted between the case and oil pickup (after draining all the oil). Lots of brake cleaner, almost a whole can. Then filled the motor with oil and quickly changed it along with a new filter. If this bothers you, then don't do it!

[Jack Standz]

BTW if you are performing the GoWesty oil drain hole modification to your case and the motor is still in the car, this (or similar) right angle drill chuck attachment came in handy:

https://www.amazon.com/Cordless-Attachment-...0112203dd5d80ec

[frank_c]

Ok, since I hate oil leaks (this car had many when I got it and I fixed all but the RMS) and you guys are making me paranoid about getting the seal installed correctly, I went ahead and ordered the GoWesty tool (IMG:style_emoticons/default/smile.gif). I'll put off installing the RMS until next week when the tool gets here, but I don't plan to drill the additional drain hole at this time. If the new seal leaks, then I'll look into this when I have the engine out again later this year.

@Ninja , thanks for the suggestion to check the crank for any type of wear line where the old seal was riding on it. I saw on the GoWesty site where they polish the crank where it touches the RMS - something to consider?

@Jack Standz , when you said that you used some type of sealer on the RMS, was that around the entire outer perimeter (where it seals against the case bore)? Or only in areas of the case that had defects/scratches? Just curious because most information I found says to install dry.

[Jack Standz]

Put the sealant around the outside perimeter of the entire seal and lubricate the inner rubber part of the seal with oil or lubricant.

Probably best to just follow GoWesty’s instructions:

[914Sixer]

I have a factory sealing tool I can loan you.

[Ninja]

My polishing "tool" is a piece of purple Scotch Brite and WD-40. I'll remove all of the "ghosting" on the surface, but the little groove (if present) requires machining or a redi-sleeve and I normally just offset the seal to avoid it.

I use Stay-Lube marine grease (Smurf goo) inside all of my seals.

I've pull stuff 2 decades later and had the blue goo still present and the seal still supple.

Some seals come pre-lubed (good OEM stuff) and I clean that stuff off and replace it with the Smurf goo.

I'm half and half regarding a glue/sealant on the outside. With the damage in your bore, I'd glue yours.

On a Honda F series engine (90s Accord) I'll actually use 3m weatherstrip adhesive (Gorilla snot) and seriously glue the seals on the front of the engine in.
They are known for blowing them out with nothing more than a little back pressure.

The next technician will curse me...

[frank_c]

I have a factory sealing tool I can loan you.

Hey Mark,
Thanks very much for the offer. Had I not already placed an order with GoWesty yesterday, I'd gladly borrow yours. I guess I'll have one now that I can loan out to folks (IMG:style_emoticons/default/smile.gif).

[frank_c]

I'm trying to avoid beating a dead horse here, but the GoWesty tool is arriving today, so I'm planning to do the RMS install this evening.

As @Jack Standz recommended, I read the GoWesty installation instructions and also watched the video posted to their site. This raises a question for me:

1. Step 4 of their instructions state:

Apply a thin layer of Reinzosil (or similar) onto the seal and slide it on the tool cup with the flat side of the seal in contact with the cup. Apply an anaerobic sealant/adhesive (of your choice) to the outside of the seal."

Are the above two sentences two separate steps? I don't believe so because what two different surfaces would be getting sealant? But then why do they recommend using Reinzosil and then say apply an anaerobic sealant? Their video shows them simply using Reinzosil ("universal sealing compound") on the outside. From what I read, Reinzosil is RTV and is aerobic (cures with oxygen/humidity), so how would it cure if applied to the outside of the seal? I tried calling GoWesty for clarification, but got voicemail and have not had time to try calling back yet.

Again, I'm trying to avoid over-thinking this, so my plan at this point is to use Loctite 515 (thicker form of 574) on the outside of the seal due to the scratches in the bore (which smoothed out nicely with 1500 & 2000 grit). And then take @Ninja's suggestion and use the Stay-Lube marine grease at the flywheel interface.

I have some more observations on this topic, but I'll post that later.

[Jack Standz]

Yeah, you're probably overthinking it. Especially since you're not taking full advantage of the tool by using it to properly and accurately locate a new drain hole (which GoWesty believes is key to stopping RMS leaks, as does Raby). We did find the tool accurately and easily installed the seal.

Put sealant on the seal and lubricate it, then use the tool to install it. Best wishes with the fix!

[frank_c]

I installed the seal last night and have some comments on using the tool that I will add later, but for now I wanted to address the addition of the new drain hole.

I've seen two different sizes of the OEM drain hole for the RMS bore. Here is the small size taken from the GoWesty video:


And here is a photo from my engine case showing a much larger size drain:


From some quick image searches, the GC cases I saw have the larger drain hole, and earlier cases have the small drain - is this correct? Or is this some common modification done to increase the drain size as an alternative to the GoWesty solution?

I can see some advantage to the GoWesty solution of having a drain hole not at the bottom of the bore (less chance of debris collecting), but does the larger drain I have in my case mostly obviate the need for the drilling the auxiliary drain?

[Ninja]

I believe VW themselves added the big square vents as I've seen another member's pics and the hole looked "cast in" to me, not machined. The cast in passages are HUGE IMO.

If you've got the big square holes in your case you are done, stick the seal in and go for it.

If you've got no holes at all you should add them per the GoWesty instructions.

[Jack Standz]

Never mind (IMG:style_emoticons/default/biggrin.gif).

Since you already have a drain hole, that makes things different, no need to add another one.

This photo shows the original drain hole and where the GoWesty new hole is located. You’ll note that the old hole is above the crankshaft and seal interface when the motor is in the car and level. Which means, without a lower drain hole, the oil that accumulates there just sits there and oftentimes slowly leaks. Also, pressure from within the case (blowby) probably also contributes to the leaking as the pressure pushes the accumulated oil past the seal. The drain may help with relieving pressure there and reduce the chances of an oil leak.

[Jack Standz]

This photo hopefully shows the location of the drain hole better. It’s at the lowest point on the case, just left of the case parting line.