Rear main seal what works?
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Rear main seal what works?
I have the dreaded leaking rear main seal on my 44 MB. I have researched here about the best options. Is there a sure fire fix? I am not looking for a debate, but what others have done that works to fix the leak. Please let me know what has worked to cure the leak for you.
Thanks in advance.
Tom
Thanks in advance.
Tom
1944 MB work in progress, now driving.
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Re: Rear main seal what works?
I have a rope seal in mine and it doesn’t leak.
James Teel
Retired Police Sergeant/Bomb Tech
SFC OKARNG
Edmond, Oklahoma
MVPA 30889
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
<><
James Teel
Retired Police Sergeant/Bomb Tech
SFC OKARNG
Edmond, Oklahoma
MVPA 30889
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
<><
James Teel
Police Sergeant/Bomb Tech-Ret.
SFC OKARNG-Ret.
Edmond, Oklahoma
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
<><
Police Sergeant/Bomb Tech-Ret.
SFC OKARNG-Ret.
Edmond, Oklahoma
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
<><
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Re: Rear main seal what works?
Hi,
It might help to tell us a little about your problem:
1. Is the seal neoprene or is it a rope seal?
2. Did you trim the rubber rear cap dowels, and if you did, you didn't cut them flush with the block did you? (doing so prevents the rubber from being expanded to seal better). Did you apply any sealer to the dowels when they were installed?
3. Has the engine had any run time/miles on it, or is it newly rebuilt & leaking without having ever run?
A good seal is a good seal, regardless of material. Do you happen to recall which seal you installed? There were some defective neoprene seals around in the not too distant past.
I think the only way to 'cure' the leak will be a replacement seal, but if you end up going down that route, be sure that the crank seal surface isn't undersized or grooved/pitted. Because if it is, the problem will persist over and over again.
I also recall that some people have had excess oil not drain away from the rear cap because they were missing the short tube that reaches down towards the oil pan. Do you recall if this tube was fitted to the bearing cap? They are pinned in place but sometimes missing.
Good luck!
EDIT: I should mention that a transmission leak from the front bearing can allow oil to run into the bottom of the bellhousing, and it will weep/drip from the hole at the front of the bellhousing (just behind the engine). I'm sure you know where the oil is coming from, but I thought I would mention this because in a few cases people thought they had rear main seal leaks, but the leak ended up being from the transmission instead. Gear oil and engine oil will of course be different in viscosity and odor.
It might help to tell us a little about your problem:
1. Is the seal neoprene or is it a rope seal?
2. Did you trim the rubber rear cap dowels, and if you did, you didn't cut them flush with the block did you? (doing so prevents the rubber from being expanded to seal better). Did you apply any sealer to the dowels when they were installed?
3. Has the engine had any run time/miles on it, or is it newly rebuilt & leaking without having ever run?
A good seal is a good seal, regardless of material. Do you happen to recall which seal you installed? There were some defective neoprene seals around in the not too distant past.
I think the only way to 'cure' the leak will be a replacement seal, but if you end up going down that route, be sure that the crank seal surface isn't undersized or grooved/pitted. Because if it is, the problem will persist over and over again.
I also recall that some people have had excess oil not drain away from the rear cap because they were missing the short tube that reaches down towards the oil pan. Do you recall if this tube was fitted to the bearing cap? They are pinned in place but sometimes missing.
Good luck!
EDIT: I should mention that a transmission leak from the front bearing can allow oil to run into the bottom of the bellhousing, and it will weep/drip from the hole at the front of the bellhousing (just behind the engine). I'm sure you know where the oil is coming from, but I thought I would mention this because in a few cases people thought they had rear main seal leaks, but the leak ended up being from the transmission instead. Gear oil and engine oil will of course be different in viscosity and odor.
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Re: Rear main seal what works?
JMP seal worked for me after a lot of try/error attempts.
1944 Willys MB
1978 VOLVO TGB 1111
1978 VOLVO TGB 1111
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Re: Rear main seal what works?
It is a neoprene. It was rebuilt about 18 years ago and just now started. I do have the drain tube installed. I will double check on the transmission oil. I was just wondering which way to go when I replace it, rope or neoprene. I read about the "bad" batch of lip seals, but didn't know the time period they were from. It seems like the rope would be a little more forgiving, but harder to install.
Thanks again, looking to hear more opinions on what worked for others.
Tom
Thanks again, looking to hear more opinions on what worked for others.
Tom
1944 MB work in progress, now driving.
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Re: Rear main seal what works?
Hi,
I used a NOS rope seal purchased from Mike Stopforth, but he tragically passed away in an accident a few years ago. It's held up well though, and the installation process wasn't bad. I soaked my seal for a couple of days (because I wasn't in a hurry) in clean engine oil, and then bent it around a little so it would not be too stiff to conform to the seal groove. It's been several years now since I installed it, but I used a big old rivet I have as a mandrel and slowly rolled and worked the seal into the groove. Something like that anyway.
I wish I had made a video then, but I did not. My rebuild kit came with a Felpro rope seal, but I did not use it because I had the NOS one from Mike. [removed mistaken comment about another seal manufacturer to avoid confusion]
I used a NOS rope seal purchased from Mike Stopforth, but he tragically passed away in an accident a few years ago. It's held up well though, and the installation process wasn't bad. I soaked my seal for a couple of days (because I wasn't in a hurry) in clean engine oil, and then bent it around a little so it would not be too stiff to conform to the seal groove. It's been several years now since I installed it, but I used a big old rivet I have as a mandrel and slowly rolled and worked the seal into the groove. Something like that anyway.
I wish I had made a video then, but I did not. My rebuild kit came with a Felpro rope seal, but I did not use it because I had the NOS one from Mike. [removed mistaken comment about another seal manufacturer to avoid confusion]
Last edited by '42 Peep's Motorpool on Mon May 09, 2022 5:12 pm, edited 1 time in total.
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Re: Rear main seal what works?
Hi,
“JMP now make a rope seal too”
Nothing listed on their website, just their two part rubber double lips seal!
Scrumps
“JMP now make a rope seal too”
Nothing listed on their website, just their two part rubber double lips seal!
Scrumps
Dec '42 Willys MB
Aug ‘44 Willys MB
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Aug ‘44 Willys MB
2021 New Defender 90 D250 HSE
2005 Landrover 90 CSW
2024 Range Rover Sport
1967 MGB
Royal Navy Weapons Engineer 1979-2007.
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Re: Rear main seal what works?
Correct, an error on my part. JMP currently only sells the seal you mention.
Per the technical bulletin regarding the rear main seals (copied from Ron Fitzpatrick Jeep Parts listing for the Felpro rope seal: https://www.vintagejeeps.com/p-1903-cra ... elpro.aspx
"Automotive Engine Rebuilders Association, AERA TB2025
The AERA Technical Committee offers the following information on the rear main bearing seal caution on 1939-71 Jeep 2.2L engines. These engines are sometimes referred to as the F & L head engines.
During production of these engines, two different cylinder blocks were manufactured. The early cylinder blocks had a rope rear main seal installed in them while later production blocks had conventional type rear main bearing seal installed in them.
When assembly of these engines is taking place, make sure you have the correct type of seal will help prevent engine failure. If the conventional rear main seal is installed in the early blocks that require a rope seal, there may be a possibility if bearing failure. On the conventional seal is an arrow showing the direction of the crankshaft rotation as shown in Figure 1. This arrow (marked with white) should be visible form the rear of the engine when properly installed.
One way to verify that you are using the correct rear main seal is that the conventional seal is used on crankshafts that have a rear crankshaft seal area diameter of 2.3202 - 2.312. The rear main bearing seal has to be lubricated during installation. If the seal is to tight, no amount of special type lubricant will make it work properly. Rear main bearing seal fit has to be correct or a leaking rear main bearing seal and/or a possible rear main bearing problem can occur.
The AERA Technical Committee"
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Re: Rear main seal what works?
I used PAYEN (right on pic) on several engines - no problem so far.
Petr
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1944 GPW 194969 - Louisville Plant
1945 MB 423482 - ex Greek Army (salad)
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1944 GPW 194969 - Louisville Plant
1945 MB 423482 - ex Greek Army (salad)
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Re: Rear main seal what works?
What you need to know was extensively discussed here: viewtopic.php?f=4&t=324783&hilit=seal+yves
With drawings and special point of attention with the crankshaft.
Yves
With drawings and special point of attention with the crankshaft.
Yves
Ford GPW 1943 - Louisville - DoD 12-7-43
serial 164794
serial 164794
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