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Trans Cooling Line Leaking at Case (Banjo Fitting Bolt Torque Specs & Seal Info?)
I have a slow leak from where the transmission fluid line connects to the trans housing on the driver's side of the E55, at the banjo fitting bolt shown in the pictures below. (I've already cleaned it up & wiped it down, so there's no visible fluid.)
I cannot find any info, ANYWHERE, about the torque specs for this bolt. Also, I don't know if those two washers (they look copper - one under the bolt head and another where the line mates to the trans) are one-time use crush washers, and if there's a grommet or rubber o-ring in under there. I want to try tightening it to stop the leak, but I need to know the torque specs first because it's pretty snug and I don't want to snap the bolt or damage the fitting. I'm pretty sure this is the outgoing oil line to the trans cooler.
Anyone had a leak from here before? Part number? Torque specs?
Last edited by SlickVick; Sep 11, 2019 at 09:46 PM.
Reason: Edited for clarification
I sincerely appreciate the reply, but there’s no way in HELL that’s supposed to be torqued to 5nm.. That’s less than 4 foot-pounds.. I tightened it by about 90 degrees and I probably was putting about 60 foot-pounds on it to do that..
I agree I set my torque wrench to 5nm and I tightened it much further past that
im also glad to have fixed the leaking , new crush washers is critical for this job. I even recommend getting a new 14x1.5mm bolt, they are very cheap
i had to tap my fitting because I cross threaded this fitting badly a long time ago, now that I have lift access at work, I decided this job needed to be tackled
I agree I set my torque wrench to 5nm and I tightened it much further past that
im also glad to have fixed the leaking , new crush washers is critical for this job. I even recommend getting a new 14x1.5mm bolt, they are very cheap
i had to tap my fitting because I cross threaded this fitting badly a long time ago, now that I have lift access at work, I decided this job needed to be tackled
Last year I had a shop install a new trans that I purchased (would have done it myself but was short for time) and common sense tells me that they probably didn’t use new washers or a new bolt - although I could be wrong.
When I found the leak it was very small but had been leaking long enough to coat the trans pan and the connectors for 02 sensors with fluid. Anyway, it was already torqued to probably 40 pounds minimum before I cranked it down some more. I may not have turned a full 90 but I was really cranking on it as it was clearly leaking from that exact spot. I didn’t bother using my torque wrench since I never found a proper spec - just tightened it, then drove it and checked it for drips each time after driving. 500 hard miles since and it’s dry as a bone.
I should probably replace the washers but I won’t do that since it’s not leaking anymore.
Can’t believe none of the manuals or forums have a clear spec for this (although I don’t have an official Benz shop manual). There’s no way any trans fluid line mounted to the case with that big of a bolt would require less than 4 foot-pounds of torque. Maybe 40 at the very least.
Here’s to hoping someone will eventually post the factual numbers.
Glad to hear yours stopped leaking too.
Can you imagine having one of the ultra-rare 4matic E55s and trying to find specs and/or parts for it?!
Quick question, did it snug up rather quickly when you got past 5nm or did you get a couple full turns more out of it? Mine is as tight as I felt safe with. I mean, it’s extremely tight. I think another 90 would snap the bolt or break the banjo fitting.
Last edited by SlickVick; Oct 12, 2019 at 07:20 AM.
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