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1955 Buick oil drip problem at rear bearing cap


buick55

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I started my engine for a test and its completely dry except these two spots.

engine was sitting before about 2 years in my clean and dry garage during restoration of the car and was overhauled before some years ago and was running only 2000 miles.

oil I use motul classic 20w-50 mineral, like in all my old cars, never have had problems with it.

 

I inspected the whole engine for oil leaks and also with an endoscope between flywheel and engine case, all is dry there, also the rear bearing itself.

seems to be at the rear bearing cap drips left and right after a short run (1 minute, engine cold) and high oil pressure (what I see on the original gauge) you have after around 30 minutes (engine off) two little oil spots under the car.

after 24 hours engine not running its about two 4 inch oil spots under the car :( after some days no more oil drips there, until I start the engine again, then it begins again.

I have no problem if an old car drips a little bit (my beetle does also), but this seems to be a bit too much in my opionion.

is that only a problem with these little seals which are sideways in the rear bearing cap?

is it possible to change these with engine in the car? if yes, how is the best way and what should I cosnider? (any tip to perfectly seal it is welcome)

or will it be tight again after a while under oil and engine running some times, because of long and dry sitting? (I know some cork seals and so on need more oil to seal)

 

thats really nerving, I was so happy that all other things work and all is dry...

 

 

oildrip.jpg

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@chris

ok really? i will try that first, but I think it will drip from the seals on the side of the cover.

 

@old-tank

the rope itself ist dry around the crank to flywheel.

but when is see your pictures its possible to change the seals sideways of the cover, good to know.

I think these will be the problem.

 

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This is what I have found concerning the  rear main cap.  C.A.R and Nailhead Buick.  "We use sealer on the threads of the two bolts that go into the rear main cap, we have found oil tries to leak past the threads."   Perhaps than not the bolts at the pan you circled.  And my not even be the problem but a tip in case you do pull the main cap. 

Edited by avgwarhawk (see edit history)
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I just had to do this on a nailhead. Somebody installed those rubber side "gaskets" with just the nails. No pookie of any kind. Leaked like crazy. Use Wille's method. My Special is still leak free back there after he and I rebuilt the engine 14 years ago. 

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sorry for my missunderstanding (cause I am from germany)... :)


so it should be much thicker than the groove from the cap to hammer it in until its flat on all three sides?

the sealer should be added before on the cotton and also a bit into the groove right?

 

a pictures would help :)

I do not know which size are the groove in the cap, have never seen one disassembled.

and it would be nice to oraganize what I need before I begin, so I can work directly step by step on it.

 

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I know how the parts looks like, I have an explosion view of the engine parts.
but I dont know which size the groove has and so what cotton twine (and also where to buy something like that in nearly correct size) works best for it ;)

 

that would be easier to know then try and error and have the engine open for days or weeks...

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Check out the Hometown Buick site for a look at the 55 service manual.  http://www.hometownbuick.com/1955-buick-replacement-engine-parts/

 

This page of the manual has a picture of the rear main bearing cap, and shows what Willie is talking about.  It's the grooves on the sides of the cap that Willie is referring to when he says to use string and sealer.  But any seal I've ever bought has included appropriate fillers for these grooves.

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yes I know how the bearing cap and grooves look like.

and I have also a rear bearing sealing set here, but I have heard many times that these parts from the set will leak at the grooves.

if not I can also use them, but I dont want to try and error and do this twice, because I have no car lift and have to do this under the car jacked up.

so willie has the idea with cotton twine an permatex no 2 sealer.

so for me its interesting what exact cotton twine is perfect to use, cause I dont know the size of teh groove ;)

nothing more...

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To try and help here, the size of the twine is not that important, its a messy job, but coat the twine with sealant (put sealant on your fingers and run the string through the sealant to coat it) and then stuff the string into the grooves, the sealant on the string will help hold it in there, The string is really only giving the sealant some "bulk" so you can make sure the sealant gets to cover all areas without air bubbles by being able to pound it in

 

 

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Just so I understand this also.  When the main cap is off , remove the old side cork seals.   Fit cap and torque. Now there is the hole that Willie refers to.  Stuff and pound the cotton + sealant into that until flush.  Correct ?

 

Does anybody have a piece of unused replacement main rope seal that they can measure for me please.  I'll try to buy some locally.

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ok thanks, I think now I understand...

I will try that soon, first I have to order a new oil pan gasket and the other parts.

 

here a picture of the parts the cap which I got with a rear sealing kit.

rubber parts, which will leak as hell when I understand right :) 

sideseal.jpg

Edited by buick55 (see edit history)
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22 hours ago, Rooster said:

Just so I understand this also.  When the main cap is off , remove the old side cork seals.   Fit cap and torque. Now there is the hole that Willie refers to.  Stuff and pound the cotton + sealant into that until flush.  Correct ?

 

Does anybody have a piece of unused replacement main rope seal that they can measure for me please.  I'll try to buy some locally.

Correct.

7.5 inches or 19 cm

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Having just experienced this.... :)   Heres one from Best Gaskets:

 

101_2588.JPG

 

This is the flattened "width" measurement, very close to 7/16, Mike is on the mark with 1/4 inch on the "height".  Length obviously is trimmed to fit.

 

These are the side seals and the wire expanders that are tapped in when you are starting from scratch.  These side seals were heavily covered with permatex #2 before they were inserted same as the "coat the string" approach.  The string/permatex would fill/tighten up these side seal voids in a used setup where the rubber may have shrunk or the seals just fell out. 

 

101_2589.JPG

 

 

101_2590.JPG

 

This particular seal set installed with advice as described has been leak free for 1800 miles.

Edited by KAD36 (see edit history)
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I have used those rubber side seals, and I think that they are much better than the older type I used for the first few rebuilds I did on these engines. The older ones I'm referring to were cork wedges that were squished in between the sides of the cap and the block.

Keith

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You're welcome.  If you choose to use the seals, coat the whole seal just like you would the string,  When you are tapping in the metal expander with a light hammer you should feel some resistance- it should be tight.  I can't quantify that but can pass on what my machinist checked in that the expander could not be pushed in with your finger and the rubber seal was a snug fit prior to the expander going in.   If no effort is required or the seal has a sloppy fit then my recommendation would be the proven permatex and string and pound it in tight or buy a seal from a different manufacturer.

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thanks for your tips...
and when I understand right from the description.

first I put the cap to the engine and then push the rubber incl seal in, then tapping in the metal expanders, flush all and after that fill it with seal, right? 

 

and have I really to chamfer the original cap?

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Didn't chamfer the cap.  What I watched the machinist do was test fit it dry first by only inserting it part way to see how snug the fit of the rubber seal was because he knew this was a historical Nailhead problem area.  Not sure what plan B would have been if it was a loose fit, but he wasn't going to use that seal it if it wasn't snug.  Then a blob of permatex on the end of each seal that goes into the hole.  Smear alot of permatex all around the whole rubber seal, then press it into the hole and wipe off any excess that oozes out, then drive the expander in.

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  • 1 month later...

sorry for being late on the feedback.
some weeks ago I changed these side seals at the rear bearing cap with the rubber parts incl the metal stick.

I could remove the old cork seals with just a screw into it and pull it out, after that I was sure it was dripping there ;)

 

new parts work fine, put them in together with permatex no2.

I started the engine some times last days and checked it everday on leaks.

my engine is now 100% dry, I am very happy. thanks for your help...

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Congratulations!  Its still early so keep your eye on it.

 

My engine is rolling around 2500 miles and the rear seal is bone dry.  Freakin' thing pulls like a freight train.  So far, so good.... :)

 

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