Correct Rear Main Seal and Flywheel Seal Installation

[Casey79Westfalia]

I have read numerous ways that people are doing this and Jake I know you have mastered this. What is your technique for installing the flywheel seal and rear main seal. Mine has been leaking a bit and I am going to replace it this weekend!! Just wehen the engine is running so well I have to yank it again.

[MASSIVE TYPE IV]

What seal do you have? Never forget that most rear seal leaks are really leaks from the flywheel O ring being damaged on install.

[Casey79Westfalia]

You know I just got the rear main seal and flywheel from you about two weeks ago. I have not yanked the engine yet but will probably try to do it this weekend and will be able to verify hopefully where the leak is coming from. Seaping a bit out of the bellhousing!

[Casey79Westfalia]

Will I be able to see where the oil is coming out. I guess since I have both seals new I will just replace both!!!

[MASSIVE TYPE IV]

You may be able to see.. If the area inside the flywheel where the bolts seat is wet there is a good chance its the O ring..

The other trick is to lube the seal WITH OIL as well as the O ring..

Seals that are installed with grease burn up in minutes after the grease film is gone... The grease impededs further oil from travelling to the seal- like a barrier..

People make this mistake a LOT of times...

Also install the seal with a flat piece of wood squarely in the case..

[Casey79Westfalia]

Jake I am assuming you mean lube the insides of the seals, not where they contact the case and the inside of the flywheel!

[MASSIVE TYPE IV]

I even lube inside the flywheel to aid in the flywheel install- this keeps the O ring from tearing but go light on the oil..

Oil the ID of the seal and the OD surface of the flywheel that rides inside the seal.. DO NOT oil the OD of the seal..

IOil the entire O ring and ensure its installed evenly around the circumference of the ID..

[raygreenwood]

Be careful. There are juuuust a few mid to late 412 engines that came with the vanagon rear seal. It has the same exact ID and OD of the stock type 4 seal but is 2mm thicker. The bore easily accepts the type 4 seal. Problem is it recesses too far. You will...like me...maybe not notice this. At low rpm and low oil pressure...it leaks not a drop. At high rpm highway oil pressures and in cold weather...it leaks like hell. The oil collects around the edge of the crankcase and then runs out when teh engine stops. I went through 3 seal replacements while in Atlanta...before I figured this out. I have found 3 factory cases made this way. I don't know why. They were all 1.7L. The last of them before the 412 switched to 1.8L Ray

[Casey79Westfalia]

What about the spring in the back of the rear seal does that need to be greased!

[Piledriver]

OIL.
No Grease.
Grease is for wheel bearings and CV joints.

OIL.

OD of the seal and bore in block clean and dry.
(No silicone/permatex...DRY)

Oil the OD of the seal, and you'll discover why you don't oil the OD of the seal. You may add to your vocabulary!!!

(*My Dad's a Marine, and HE blushed when he heard me figuring this out for myself. (I was ~16...))

It will pop back out immediately (if you are lucky), assuming you ever get it in.. For unlucky folks it pops out after the motors back in...

[plynch]

this is strange to me i rebuilt an engine thaty was just a stock 1600 and i put new bearings -all- in and new seals the bearings fit tight to the case and this wasnt a full time driver so i didnt have the case checked out it is put together with honed cylinders and new rings no smoke runs great... turns 33's on a baja with 3.88 r&p but it leaks oil from the rear of the engine....... endplay is good tight but not too tight, i didnt check it either just the same shims that came off, i put a new seal in and a new flywheel o-ring...