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Discussion Starter #1
Hi all, I’ve got an ‘88 bronco 351, c6 trans. So I just buttoned everything up after replacing my rear main and lo and behold the truck still leaks oil, and it only leaks when the truck is running. It’s leaking at about the same rate as before. I did notice the the oil pan gasket was a little wet right under where it dips for the crank. Could that be the culprit?
 

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When I did a 4r70w swap on my daily driver I thought I had a rear main seal leak so I ordered a new seal off RA. Turns out the pan rtv? around the crank was starting to spread apart so I tightened up the oil pan it decreased by 50%. When you remove the fly wheel you have to put thread sealant on the bolts that hold on the flywheel that go into the crank or they will leak like a RMS.
 

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Man of endless projects
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did you use a rubber or PTFE main seal? rubber seals need some oil on it durring install but the PTFE seals install dry or else they leak. i made that mistake on my F250 and its leaking like crazy despite not leaking before i replaced it

if the crank has a groove worn into it by the old seal it might need a repair sleeve put on it

getbent, the 302 have through drilled crank holes so they need something to seal. the 351 do not so they dont need anything. tho i normally loctite them regardless
 

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Yo MetallicTurdBrown,

Ditto on what Kingfish999 advised ,"if the crank has a groove worn into it by the old seal it might need a repair sleeve put on it"

BikerPepe` suggested "^^^ Micro or Speedy Sleeve it if you're going through the trouble."
 

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1996 EB w/5.8 TOO much lift, 44" Mudders & 5:43-5:38's
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X 3 on the Speedi-Sleeve; it's the only way to stop them from leaking once the seal cuts a groove in the crank. I usually just install one automatically these days; cheap insurance.
 

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Discussion Starter #7
did you use a rubber or PTFE main seal? rubber seals need some oil on it durring install but the PTFE seals install dry or else they leak. i made that mistake on my F250 and its leaking like crazy despite not leaking before i replaced it

if the crank has a groove worn into it by the old seal it might need a repair sleeve put on it

getbent, the 302 have through drilled crank holes so they need something to seal. the 351 do not so they dont need anything. tho i normally loctite them regardless
I used a rubber seal
X 3 on the Speedi-Sleeve; it's the only way to stop them from leaking once the seal cuts a groove in the crank. I usually just install one automatically these days; cheap insurance.
Ok I guess I’ll go thru the process of yanking everything out and throw a sleeve in. Thanks everyone for the reply’s
 

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1979 Bronco Ranger XLT, 400m engine, C6 trans, D44 front with Dick Cepek manual locking hubs
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X 3 on the Speedi-Sleeve; it's the only way to stop them from leaking once the seal cuts a groove in the crank. I usually just install one automatically these days; cheap insurance.
can you indicate by picture of the seal what part to double?
This will be helpful for my future "business" as well.
 
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