Author Topic: General Oil Leak Question 280 SL 1969 Automatic (Read 17126 times)

Rolf-Dieter ✝︎ · « **on:** November 06, 2013, 16:01:02 »

Hello everyone,

My car had some serious engine and trabsmission oil leaks. Apparently the engine oil leaks have now been stopped by replacing all the gaskets and seals. However, the transmission vertical joint (transmission to motor sealing face) is still leaking.

My questions to you fellow is as follows.

1) Can the vertical sealing face seal/gasket for the transmission to motor be replaced without removing the engine?

and

2) Has anyone experienced similar transmission oil leaks and how have you correct it (i.e. what was done to correct it)?

Thank you in advance for your feedback.

PS. My transmission oil leak is about 1/2 ounce per day.

EDIT…. I am thinking it should be possible to disconnect the drive shaft and then move the transmission back or remove it to address installation of the new vertical seal/gasket? Am I wrong in assuming this? Your feedback is appreciated. My engine and transmission are working fine and I like to leave well enough alone if you know what I mean

GGR · « **Reply #1 on:** November 06, 2013, 17:54:53 »

There is no gasket between the engine block and the trans bellhousing. On one side is the engine that shouldn't leak. On engine side leaks may come from the back crankshaft seal (rope seal I think) or the oil pan. On transmission side leaks may come from the converter to trans connection ot the converter itself (Though I don't really know how it works, I know manual trans better). So you need to determine where the leak is coming from. Red: trans is leaking. Black: engine is leaking. And yes, I think you can take the trans out from underneath. It is possible with a manual trans so it should be also possible with an auto one.

Benz Dr. · « **Reply #2 on:** November 06, 2013, 19:02:54 »

You have to drop the trans before you can work on it. There are two seals that are most likely to be leaking. The main input shaft seal and large O-ring that goes around the primary pump. Either one or both can leak.
Smaller seals and gaskets can also leak on the trans. Many of them can be difficult to stop completely but you can often slow them down to a point where they only seep a small amount of fluid.

Rolf-Dieter ✝︎ · « **Reply #3 on:** November 08, 2013, 18:17:59 »

Thanks fellows for the feedback … it has been confirmed that front seal(s) (closest to the sealing face of the transmission to motor mounting face) need to be replaced. Also the rope seal needs to be replaced. All this can be done by only removing the transmission and the motor stays in place.

I will collect the leaking transmission oil in my garage in a container in the meantime also check the transmission oil level very carefully. The job will have to be done next spring. Meanwhile I shall put my baby to sleep for the winter.

Thanks again fellows!

Benz Dr. · « **Reply #4 on:** November 09, 2013, 01:45:00 »

Quote from: Rolf-Dieter on November 08, 2013, 18:17:59

Thanks fellows for the feedback … it has been confirmed that front seal(s) (closest to the sealing face of the transmission to motor mounting face) need to be replaced. Also the rope seal needs to be replaced. All this can be done by only removing the transmission and the motor stays in place.

I will collect the leaking transmission oil in my garage in a container in the meantime also check the transmission oil level very carefully. The job will have to be done next spring. Meanwhile I shall put my baby to sleep for the winter.

Thanks again fellows!

Nope, sorry. The engine has to come out of the car to replace the rear main seal. This is why I tell owners to wait until it gets bad enough to do it.

Garry · « **Reply #5 on:** November 09, 2013, 05:23:11 »

And what ever you do do not go short on the rope seal. Dont ask why I know, except to say the engine came out twice before it was right.

Garry

Benz Dr. · « **Reply #6 on:** November 09, 2013, 18:07:57 »

Garry is right about this. I made a small tool that I place around the seal before cutting so that it cuts above the block or oil pan. Failure to do this step will lead to one BIG oil leak. Use a razor knife or similar when cutting this seal so that you obtain nice clean cuts. This is as important as cutting the seal to the proper lenght.

ja17 · « **Reply #7 on:** November 10, 2013, 02:54:33 »

Use the manufacturer's specs on how to install the rope seal you are planning to use. The dimension for the rope seal "top-cut" has changed slightly over the years, as manufacturers change to newer and improved seal materials.

The information for the newer Aramid rope seal is shown in the photo. Specs for older NOS rope seals may have slightly different values for shrinkage and may have a different dimension for the "top-cut".

andyburns · « **Reply #8 on:** November 10, 2013, 03:55:42 »

Does the crank have to come right out to replace this seal?

ja17 · « **Reply #9 on:** November 10, 2013, 05:07:39 »

The top half of the seal cannot be replaced unless the crank shaft is out. The seal is held in check by a pointed pin in the groove in the block and another in the oil pan. Most often, just the lower half is replaced, unless the engine is out and apart for major repairs or rebuild. It's a hard decision to make.

ja17 · « **Reply #10 on:** November 10, 2013, 05:24:28 »

Refer to page 03-4/2 of the late BBB for more "rope seal" installation information. It also shows the "hammer handle technique" if you do not have the special installation mandrel tool.

andyburns · « **Reply #11 on:** November 10, 2013, 05:54:55 »

Cheers Joe, it is indeed a very difficult decision to make. I should have paid more attention to the smell color and texture of the crud that had build up in my bell housing. At the time I thought I would rebuild the entire engine so cleaned off the residue without a second thought. But now the funds aren't so healthy and I am looking for short cuts. Other than the leaks the engine ran beautifully.

Joe I had never thought about doing half the seal. I suppose if you have a bad leak its much better than leaving it as is. Half a seal behaving itself must but much better than a complete but failing seal. Have you ever chosen this path with excellent result ie it has it considerably improved the situation.

The last owner supposedly overhauled the engine only a few km's ago so it is possible that all this mess is from out the front of gearbox input shaft.

I will definitely replace the gearbox seals and also the front crank seal. Just got to figure out what to do with the rear.

Cheers

Andy

ja17 · « **Reply #12 on:** November 10, 2013, 17:30:54 »

I would suspect that the lower seal half is more prone to leak. Gravity holds the crank shaft against the lower seal more than the upper. I would suspect that it could wear faster. In addition if the upper seal has shrunken and the end cuts of the two seal halves are a bit short from shrinkage or mis-calculation, you may be able to compensate for the shortage by cutting the new lower seal a bit long. A little luck and some common sense could improve the situation. Use the right sealer on the oil pan. There is no gasket. I have had good results with Wurth DP 300 or Permatex #2. Where the two rope seals meet I like to use a bit of sealer on the ends cuts. The Wurth is a good choice at the end-cuts since it is more flexible. You can always order the factory approved sealer from the dealer. I have heard it is the same or most similar to the Wurth.

I have not had good luck sealing engines from oil leaks with the popular silicone sealants. However, as time goes on, products and materials improve. Maybe these silicone sealers work these days?

66andBlue · « **Reply #13 on:** November 10, 2013, 17:49:25 »

Quote from: ja17 on November 10, 2013, 05:24:28

.... It also shows the "hammer handle technique" if you do not have the special installation mandrel tool.

Here is a photo of Joe's hammer (and right hand) at work.

andyburns · « **Reply #14 on:** November 10, 2013, 17:59:53 »

Joe, that great advice about the sealant. I was going to use a product from three bond (http://www.threebond.com/LGasket.html) which was recommended to me by a friend who is an A grade mechanic and also builds drag cars. He swears by it. Have you ever used this one before? Lent me a tube of it while I was doing my 280se and its still dry as a bone. I went to buy a tube the other day and got quite a shock at the price (over 100NZD). Guess quality costs. I walked away as I thought I would investigate other alternatives. I might pop down to Wurth and see how much the stuff you recommend is.

Do you know if the seal comes standard in bottom end seal kits. I am just about to get one from Buds.

Also when you are inspecting the 'worn' seal what are the visible cues that its failing. I am picking it has a burnt smooth look? I am wondering if I open up the lower pan and inspect if I find it look ok I should just reseal the pan and cross my fingers.

Cheers

Andy

66andBlue · « **Reply #15 on:** November 10, 2013, 18:20:46 »

You can buy pre-cut strips of the Reinz rope on eBay:
http://www.ebay.com/itm/151058408346
or directly from the distributor down under:
http://www.victorreinz.com/EN/Partner/Sales-Partners.aspx?bereich=15

Rolf-Dieter ✝︎ · « **Reply #16 on:** November 10, 2013, 18:39:33 »

Thank you all for you feedback I do appreciate this. As some of you know my car has been garage bound for the last 3 to 4 years with very little operation (except for the ocasional trip to a car show). I knew the car had oil leak problems when I made my inspection before purchase last May. However I did not realize the problem was so severe. I say sevire since not only the transmission leaked oil also the motor. The motor oil leaks have now been eliminated, however the transmission leaks remain.

I asked the original question about motor removal or not to address the transmission oil leaks only becase I got different answers whenever I ask the question. Personally I cannot understand why the motor and the transmission have to be removed in order to eliminate the transmission oil leak.

Anyway, I will monitor the leakage of the transmission oil over the winter and make a decision on corrective action. The photos below show the amount of transmission oil that leaked since last Wednesday afernoon when I returned from a 10KM trip. I estimate the oil on the floor to be about 3/4 to 1 ounce. I've placed a red dog leash as a reference point and as you can see the leak is prodominant from the front vertical joint face (motor to transmission) as well as some leakage toward the rear of the car, I assume from oil that made it's way back there during my drive and then leaked onto the floor in my garage,

Thanks again everyone, as I said I do appreciate it.

GGR · « **Reply #17 on:** November 11, 2013, 13:47:52 »

You should put your car on a lift and see where the trans fluid is leaking from exactly. I had a leak once at it was just the sealing washer of one of the pipes connecting to the trans that was damaged. I never attended to that leak as I assumed it was the trans leaking and it was not leaking enough to justify all the work involved in dropping the trans. It's only when I dropped it for another reason that I discovered it was just a damaged washer. Had I realized that earlier, I would have eliminated the leak much earlier.

Benz Dr. · « **Reply #18 on:** November 11, 2013, 17:48:16 »

You can remove the trans without removing the engine. Those oil spots look like engine oil to me. Trans fluid leaks a more red in colour and this stuff looks very brown to me.

Rolf-Dieter ✝︎ · « **Reply #19 on:** November 11, 2013, 19:29:29 »

Dan, trust me it's transmission oil (wiped it all up with paper towels and it is read).

ja17 · « **Reply #20 on:** November 12, 2013, 05:38:12 »

Yes, remove the transmission by itself, unless you plan on doing the rear engine seal also. Be sure to un-hook the torque converter from the engine flywheel before you remove the transmission.

Rolf-Dieter ✝︎ · « **Reply #21 on:** November 12, 2013, 15:24:46 »

Thanks Joe,

The oil I found on the floor has no evidence of any motor oil (light brown in colour since it is clean fresh oil) only red transmission oil. I was careful to clean the oil from the floor rubber mat using only paper towels. The red oil was highly evident. Having said that once the transmission is on the floor should one be able to see if the rear engine seal needs replacement? or would it require for the engine to be running? Thanks for your feedback! Much appreciated.

ja17 · « **Reply #22 on:** November 13, 2013, 15:21:01 »

Hello Dieter,

The rear seal leak will be happening on the forward side of the flywheel.

Rolf-Dieter ✝︎ · « **Reply #23 on:** November 13, 2013, 19:06:27 »

Hello Joe,

I am slightly confused … about the seals.

Let me put it this way … if I look at the side view of the motor and transmission from the driver side of the car (motor left and trasmission to my right).

Is the FRONT MOTOR SEAL not to my left (near the fly wheel) and the REAR MOTOR SEAL to my right (near the joint face motor to transmission)?

as for the transmission looking in the same direction as above

Is the TRANSMISSION FRONT SEAL not to my left on the transmission inside the bell housing?

I no longer have motor oil leaks they all have been dealt with by replacing all the gaskets. Once the transmission has been removed and there is evidence of motor oil leak from the REAR MOTOR SEAL Then I guess I have to bite the bullet and have the engine removed as well. The FRONT MOTOR SEAL as I understand it has also been changed along with a whole bunch of engine gaskets to deal with the motor oil leak.

BTW Joe as you recommended to me at Williamsburg (also Dan [Benz Dr.] recommended it some time ago when I was at his shop) I removed the A/C Compressor / Pump since the Air Conditioning System was removed during the Restoration at RM also it served no purpose and was just extra weight to carry around. I will put it up for sale. Let me know if you ever need one, or anyone else for that matter.

stickandrudderman · « **Reply #24 on:** November 13, 2013, 19:29:56 »

Quote

Is the FRONT MOTOR SEAL not to my left (near the fly wheel) and the REAR MOTOR SEAL to my right (near the joint face motor to transmission)?

The front "motor" seal, called the front crankshaft seal, is indeed to your left, just to the right of the VIBRATION DAMPER which in turn is just to the right of the front pully (ies).
The FLYWHEEL is to your right, between the engine and the transmission and is a large metal disc with teeth around its' circumference (the ring gear). The rear crankshaft seal is to the left of the flywheel!

Now, the front seal of the transmission is to the right of the flywheel but I am not an advocate of changing the transmission seal on its own. I always change the primary pump bearing too as wear in this bearing is the most likely cause of the seal failure.

Are you glad you asked?

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Author Topic: General Oil Leak Question 280 SL 1969 Automatic (Read 17126 times)