I have a small leak at my ZF, it appears to be from one of the bolts at the bottom of the transaxle. I replaced the axle shaft seals a couple of years ago and it does not appear to be coming from that area. Is it possible for oil be coming though one of the vertical bolts on the bottom and would it be safe to remove the bolt and but a thread sealant on it?
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My understanding is that this is way common! The ZF unit was initially built to be upright however in our beloved Panteras they are installed upside down hence a gravitational leaks from the bolts. Tightening or playing with bolts will only make it worse.
Can you say ....oil pan??!!
Be careful in playing with tightness of those grade-nothing bolts. They will snap off just like the Easy-Shear oil pan bolts.
Bosswrench, is there a torque spec for those bolts? Also, if I'm going to add sealing washer of some type should I consider upgrading the bolt for any reason?
I see 30 ft-lbs in the ZF Overhaul Manual- available as a free download in the POCA Archives or cheaply as a 40-pg reprint from all the major vendors.
Thank you to all.
stop!!!!!!!!!!!!!! I do not have the spec handy and recall the manual not specific with a torque on these bolts. However, I am extremely confident you will be either twisting the heads off the bolts or more likely, stripping the threads in the case at 30ft/lbs. They are probably closer to 12ft lbs. That is the torque of the trough side bolts cover bolts. You will need to spec the bolt upon removal or search for a similar bolt referenced with a spec in the manual.
Jt, I have not pulled the bolt yet however judging on the size of the head at best it seems like an M6 which would be around 12 ft. lbs.
Mike, I agree. I accidentally sent that post before I verified the hand- written note in the margin. My friend JT is correct- not only is 30 ft-lbs too much torque, but there is no spec on those bolts in the Manual. And I have an original manual from Germany with our car, not a reprint. Sorry for the confusion.
No worries. I always appreciate the vast amount of knowledge you share on the site.
John is correct. The bolts are M8 x1.25. (18 lb/ft )
Ron
The other option is to use acorn nuts with o-rings. There was a group buy a few years ago as the minimum order from the commercial supplier (Zago) was quite large (5000?). I haven't found another source. And they are pricey.
A 3rd option is small washers with bonded rubber seals. My late wife was on oxygen for 10+ years and such washers were used to seal the oxygen regulator to the gas cylinder. Linde and other suppliers nearly give them away by the dozen.
