*#*^@* frinkn tight plugs

[Z3 freak]

Whisky Tango Foxtrot went to change out the fluids in the trans, and diff. and was anxious about doing to check the results after introducing my 3.0L to Amsoil in both. The differential wasn't bad at all except the plugs being tight. No sweat, a little cheater bar broke both loose. Next, on to the trans and forgetting the first rule of loosening the fill plug first, I proceeded to loosen the drain plug. I was using a 1/2" breaker bar, no budge. So the cheater bar again, still nothing. A bigger cheater bar, and not much room only resulted a twisted extension. I remembered now to loosen the fill plug, but to no avail. Getting PISSED, I got my impact gun, which finally broke it loose and sent fluid everywhere. It made me wonder if the fluids had ever been changed, both being fairly clean for 115000 miles. But then I remembered the TOOL I purchased the car from didn't even know there was a power button for the top. He might have changed the fluids and over torqued the plugs!

[328 Power 04]

Manual transmission?
The drain plug is conical, and threaded in a place where the casting can split apart if severely overtorqued. Hope you don't have any damage.

[Z3 freak]

Yes, it is MT, but with BMW claiming that the trans, and diff. fluids are lifetime, maybe POs bought into that crap. Could explain why it was so hard to loosen. As I don't have any maintenance records to go by, I've had to start from scratch At least when I'm done doing all the routine maintenance, I'll have a good base to go by. Next thing on my list, is to replace the fuel filter......it could be OEM. Then my bushings.

[s8ilver]

I recall the fill plug on my Roadster to be awfully tight was well, but I swapped fluids around 55k. I used a 30" long 1/2 "breaker, and it almost wasn't enough. I used a little pork torque and all was well.

Fuel filter is probably original. They're so massive I doubt they ever really need to be changed.

[Z3 freak]

I hear you, after draining the fluids from the trans and diff. it was hard to tell if it was from the factory and stayed REAL clean, or if some time in its life, they had been changed. I get more worried about breaking a bolt, plug, or whatever on the car than I do about breaking a tool.

[raubritter]

In this case I'd be more worried about the diff and transmission housings than the bolts/plugs... In fact, I'll say that with those plugs (and engine oil drain plug for that matter), I don't go by the official torque numbers for tightening. I just tighten them until snug with a short-handled ratchet, then a little more. If for some reason it leaks, you can always tighten a little more. Replacing a cracked housing, on the other hand... little more difficult (and costly). Yes, this happened to me (also 2002 3.0). Not sure if it was a faulty torque wrench I was borrowing at the time or what, but quite a sickening feeling when the diff cover cracks.

[Mr Bingley]

In this case I'd be more worried about the diff and transmission housings than the bolts/plugs... In fact, I'll say that with those plugs (and engine oil drain plug for that matter), I don't go by the official torque numbers for tightening. I just tighten them until snug with a short-handled ratchet, then a little more. If for some reason it leaks, you can always tighten a little more. Replacing a cracked housing, on the other hand... little more difficult (and costly). Yes, this happened to me (also 2002 3.0). Not sure if it was a faulty torque wrench I was borrowing at the time or what, but quite a sickening feeling when the diff cover cracks.

Torque values are set for brand new (unstretched) fasteners of a precise metallurgy and grade going into perfectly clean threads. What's more, they may be set for fastening with a specific lubricant or no lubricant, or they may be set for use with a particular thread sealant or thread locker, which may be a dry or wet compound or film. All of these variables can radically effect how tight a fastener gets for the the relative torque applied. The torque values reported in repair manuals or on the web often do not include this crucial information, and there is a necessary finesse that must be used in tightening fasteners--especially if you are reusing them, lubricating them, using locktite, or just don't know the full specification. If, for example, the drain plug torque settings are meant to be dry when torqued, and there was gear oil on the threads, the case could easily split before reaching the factory torque value. Torque wrenches also require regular and routine calibration in order to maintain accuracy. Only good (i.e. expensive) calibrated torque wrenches should be considered to be even remotely accurate. Absent these professional tools and conditions, you should not blindly believe your wrench is accurate, but rather believe that it gives you an approximation of torque that can vary quite wildly at the extremes of the wrench's particular range.

[Z3 freak]

Thank you members for all your sound advice. Wouldn't it be great if we could all learn from others mistakes.......uh but not so maybe for them.