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nodrenim
Samba Member
Joined: October 06, 2006
Posts: 843
Location: Dobson, North Carolina
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 Posted: Sat Aug 19, 2017 7:41 am Post subject: Correct rear seal |
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| I am trying to ascertain the correct rear seal for my 1979 2 liter bus engine. I recall reading on this forum about 2 different sized seals. One is 10mm thick, part # 029 105 245B, the other is 12mm thick, part number 029 105 245. I recall a difference in the thickness being somewhat crucial to the longevity of the life of the seal. Can anyone help me, Please? Thanks in advance, Don |
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Tcash
Samba Member
Joined: July 20, 2011
Posts: 12844
Location: San Jose, California, USA
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| Posted: Sat Aug 19, 2017 9:41 am Post subject: 029 105 245 B Flywheel seal |
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I would go with the Viton 029105245B 75x95x12
The "B" denotes a refinement (improvement) to the part.
http://www.autohausaz.com/pn/029105245b
Good luck
Tcash |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21518
Location: Oklahoma City
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| Posted: Sat Aug 19, 2017 10:04 am Post subject: Re: Correct rear seal |
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| nodrenim wrote: |
| I am trying to ascertain the correct rear seal for my 1979 2 liter bus engine. I recall reading on this forum about 2 different sized seals. One is 10mm thick, part # 029 105 245B, the other is 12mm thick, part number 029 105 245. I recall a difference in the thickness being somewhat crucial to the longevity of the life of the seal. Can anyone help me, Please? Thanks in advance, Don |
The only way to actually know is to measure the seal recess. I have found more than a few unmolested engines that came with the deeper seal.
Most of them were on 1.8L 412 engines from 1974. All but two were on automatic transmission vehicles. I have found a couple in buses. The vast majority of type 4 engines...like 99%...have all had the standard 10mm seal
There does not seem to be a particular rhyme or reason. Its just a theory of mine that these cases required an extra depth cut to clean up some imperfection and they used the deeper seal from the Vanagon to salvage the case.
Or....there was some machining oddity of the flywheel that was sa....y different from the flex plates on the automatics during a few years that needed higher seal protrusion to seal properly.
On cases that need and work just fine on the 10mm seal...the seal bore depth ranges from about 9.8mm to about 10.2mm. So the 10mm seal may fit dead flush, be just about .010" proud of the bore to about .010" below flush. Either way it seals just fine on the flywheel or flex plate snout.
The characteristic you will find when you have a deep seal recess and need the 12mm seal is that the 10mm seal when driven down to the ledge....will sit about .030"-.040" below the outer opening....give or take.
What happens is that the seal lips then sit farther down on the sealing area of the flywheel or flex plate snout and do not exert enough seal pressure. The seal will seal well at low rpms....but at highway speeds....it will start bypassing oil.
The deep seal bore is actually somewhere around 11.25 to 11.5mm deep. I can go measure one of mine later and let you know exact depths. I have at least one of each. So the 12mm seal sits about 0.5mm proud of the case when properly installed. Ray |
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nodrenim
Samba Member
Joined: October 06, 2006
Posts: 843
Location: Dobson, North Carolina
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| Posted: Sat Aug 19, 2017 11:12 am Post subject: Re: Correct rear seal |
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| Thanks Guys, I appreciate the help, more than you can ever know!!! Peace, Don |
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