Torque Values Mistaken in Manual?

rrcaniglia · #1 10-12-2009, 08:07 PM

I had my tires rotated at the local shop. The Mini Owner's Manual gave a tq value of over 100 ft/pounds. The shop's book said 88 fp, I think. Has anyone else run into this?

I also think the tq in the owner's manual for the oil pan drain plug seems a bit high, also.

Mini2na · #2 10-12-2009, 08:21 PM

My tire shop wouldn't tq them to 103 ft/lbs either. They would only do 88. I tq'ed them up to 103 when I got home.

I believe that is the correct value. I've never heard of anyone using a different one.

Minidrivr · #3 10-12-2009, 08:56 PM

The service TIS says 140 +/- 10 nm.

pilotart · #4 10-12-2009, 08:58 PM

The 88 ft/lb in the Shop's Book was probably for the first gen (prior to 2007) models. Wheel bolts were changed for second gens.

For the Oil Pan Drain Plug, it is important to properly set a new copper crush washer and if you don't want to bother with a torque wrench, it is 3/4 turn past 'finger-tight' to the 22# value for a new copper crush washer.

Robin Casady · #5 10-12-2009, 09:44 PM

Sometime in 2006 MINI switched from 12mm lug bolts to 14mm lug bolts. The old 12mm took 88 ft-lbs. The new 14mm take 103 ft-lbs. If the shop wont do the proper torque, tell them they will be getting the bills when a wheel comes off.

rrcaniglia · #6 10-13-2009, 05:00 PM

I want to thank all for the responses. I torqued mine to 103 right after reading your responses. It is interesting that the wheel tech used an air gun to initially tighten the nuts--after I had him check the tq. I asked about that and he said the gun would only tq to 60 or 70 pounds at its lowest setting. I also noticed that when he put the TQ wrench on the lugs, it clicked immediately.

When I re-torqued just now, three of the sixteen nuts had a little give before the click.

QUESTION: Should I loosen them all and retorque just to ensure against over-tq?

R

pilotart · #7 10-13-2009, 08:22 PM

I think I would, one lug at a time; loosen and torque to 103#.

Not a great amount of work for peace-of-mind.

Doubt that the Tire Shop's Air Wrench would have over-torqued to damage point,
but better to get them properly tight and no more.

Robin Casady · #8 10-13-2009, 08:23 PM

Quote:

Originally Posted by rrcaniglia

QUESTION: Should I loosen them all and retorque just to ensure against over-tq?

I wouldn't worry about it. My understanding is that the two worries of over-torquing would be:
a) Damage to the bolt or threads. It would take considerable excess to create this kind of damage.
b) Difficulty removing them. A slight over-torque wont cause much problem here, and it wont make much difference if you deal with it now or later.

If your wheels are new aftermarket aluminum wheels, you would want to re-torque them after 40-100 miles. As they heat up and cool down, the aluminium can compress a little and the wheels become loose. I suspect that OEM wheels have already had this issue taken care of.

clutchless · #9 10-14-2009, 02:52 PM

The other problem with inconsistent torque values on wheels is warped brake rotors. It is often caused by use of air wrenches, which are often way out of spec and/or the operator does not know what he is doing or is sloppy. The damage may not show up for weeks.

rrcaniglia · #10 10-14-2009, 05:49 PM

Great discussion. Thanks, all.

someguyfromMaryland · #11 10-14-2009, 06:31 PM

To the question on retorquing wheels, Pilotart replied,

"I think I would, one lug at a time; loosen and torque to 103#.

Not a great amount of work for peace-of-mind.

Doubt that the Tire Shop's Air Wrench would have over-torqued to damage point, but better to get them properly tight and no more."

No disrespect intended, but even on a 4 bolt pattern you are required to evenly torque in a pattern for best results. Back all of the bolts off to hand tight and retighten in a star pattern (ok, it's more like a cross pattern than a star on a 4 bolt hub, but you get the idea) and you should be fine. Remember to recheck after 500 miles like most manuals require.

HTH

pilotart · #12 10-14-2009, 07:48 PM

^^^^ True on cross-pattern, but that could only be done if the wheel were off the ground. Now Becomes a Great amount of work,
if you don't have a lift.

I would follow the star pattern for inital install, but not for confirming Tire-Shop's Torque.

rrcaniglia · #13 10-14-2009, 07:54 PM

Well, I loosened each lug gently with wheels on the ground. No leaning on the car. Re-torqued in a cross pattern, whether needed or not.

Now, I just have to figure out the best way to loosen an oil drain plug that is WAY over-tight. Think I'll try tapping on the end of the wrench rather than applying constant pressure.

Robin Casady · #14 10-14-2009, 09:39 PM

Quote:

Originally Posted by clutchless

The other problem with inconsistent torque values on wheels is warped brake rotors. It is often caused by use of air wrenches, which are often way out of spec and/or the operator does not know what he is doing or is sloppy. The damage may not show up for weeks.

Good Point. As said, the cross pattern is a good idea. When I'm swapping wheels, I'll put wheel hangers in the upper and lower bolt holes. Silde the wheel onto them and put in the other two bolts and tighten with just my fingers holding the socket (no wrench). Remove the wheel hangers, put the other two bolts in and tighten with socket in fingers.

With the socket now on the wrench I'll tighten all bolts gently in a cross pattern. Then more firmly, and finally torque them -- all in a cross pattern. That insures that the stresses are even.

With the front wheels I usually have to lower the car off the jack stand and let it down so there is just enough pressure on the tire to keep it from turning while applying the final 103 ft-lbs torque.

Robin Casady · #15 10-14-2009, 09:47 PM

Quote:

Originally Posted by rrcaniglia

Well, I loosened each lug gently with wheels on the ground. No leaning on the car. Re-torqued in a cross pattern, whether needed or not.

Depending on how much you loosened them, I'm not sure that was a good idea. I'd jack the wheel up to where most of the weight was off of it. Just leave enough contact with the ground to keep it from turning.

Quote:

Now, I just have to figure out the best way to loosen an oil drain plug that is WAY over-tight. Think I'll try tapping on the end of the wrench rather than applying constant pressure.

I would leave it until the next oil change. If there is a copper washer in there, it is already crushed. Unless you plan to drain the oil and put a new washer in place, you could just end up with a leak. Besides, if MINI is the next to do an oil change, it will be their problem. I doubt it is tight enough to damage the threads, and if it is, the damage is done.

pilotart · #16 10-15-2009, 04:24 AM

Quote:

Originally Posted by rrcaniglia

Now, I just have to figure out the best way to loosen an oil drain plug that is WAY over-tight. Think I'll try tapping on the end of the wrench rather than applying constant pressure.

Agree on waiting on next Oil Change before touching the drain plug.

That Copper Crush Washer is strictly a 'one-time' use, loosen it and it would be unlikely to set it again in the exact same spot.

The next oil change that I do, I will finger tighten the drain plug to the New Crush Washer and then turn exactly 3/4 turn.

This was 22 ft/lb on last change, but it was not easy to use my torque wrench ($29.95 Craftsman, not 'click' type)
with car on two inch blocks.

rrcaniglia · #17 10-15-2009, 07:54 PM

I don't intend to mess with the drain plug for another 3k. Just thinking ahead. I don't believe the threads are damaged since it got tight and didn't slip when I was smoothly applying too much torque. When I saw the metal pan begin to flex, I stopped. I may not be bright, but I hope to never be stupid.

No lead from plug or edges of pan.

Robin Casady · #18 10-15-2009, 09:43 PM

Quote:

Originally Posted by pilotart

This was 22 ft/lb on last change, but it was not easy to use my torque wrench ($29.95 Craftsman, not 'click' type)
with car on two inch blocks.

When I took high school autos shop, the teacher dedicated a lecture to how worthless the visual (bending bar) torque wrenches were. Never forgot that lecture...

He was cool guy. Had a '56 T-bird with a big Mercury V8, huge blower. Big slcks on the back... He was about 21 years old and only lasted a few years. Ford offered him a very high-paying job...

pilotart · #19 10-15-2009, 11:08 PM

I have needed to use a torque wrench perhaps a few dozen times in the twenty years I have owned it.
It has been kept inside its original case in its own drawer and has sufficient accuracy for my needs.

There can be no doubt that a Snap-on quality 'click' type wrench would be the thing to have if you needed it a few dozen times in one year.

The accuracy of the torque will depend on the time and care you put into the task,

the advantage with the expensive tool is ease of use and time saved performing the task.

I am certain that my Torque Wrench would do a better job on lug nuts/bolts than any wrench that I have ever seen used in a Tire Shop,
but again; it takes more time than an Impact Air Wrench. No idea what torque they were trying to achieve,
but on removal (for a flat) I have seen well in excess ot 200 ft/lb to remove a lug.

If I desired a High Paying Job with Ford, or wanted to teach Auto Shop at the High School,
a quality, calibrated Torque Wrench Set would be high on my list.