Garage Tech Question . . . - The Unofficial BMW M5 Messageboard (m5board.com)

Rcl4668 · 26th December 2002, 20:03

Hi, I received a 3 1/2 ton floor jack and a mincrometer torque wrench for Christmas. I would like to use these for swapping summer and winter wheels.

I am a complete nove when it comes to tools, so if you can help with the following it would be much appreciated:

1) Where are the best jack positions under the car (the more specific you can be, the better);

2) What are the torque specifications for the M5 wheels ( I have the stock wheels for summer tires and style 66M mixed parallel 17'' wheels for winter tires and use the same bolts for both sets of wheels)? One relative thought 85 ft-lb would be a good start but I want to do this exactly right;

3) Because the bolts are in a five-star pattern, what is the proper order for tightening the bolts?

4) Finally, my understanding of the overall procedure is to (a) lift one corner to the proper height, (b) loosen the nuts with a star wrench (the 'x' shaped thingie), (c) remove nuts then wheel, (d) place new wheel on an put on nuts but do not tighten completely, (e) lower car on the floor, (f) tighten nuts to torque specs, and (f) repeat.

Any thoughts?

Thanks!

/Rich

TCM · 26th December 2002, 23:13

It sounds to me like you are on the right track. Firstly, for jacking points you basically want to get a solid area that is connected to the frame. The provided jack pads are perfect for this (you can see 4 of them, 2 behind the front wheels and 2 in front of the rears).

As far as changing tires go...

1- Once jacked up, remove the wheel with a wrench or air gun of some sort.

2- line up hub so that one bolt hole is top dead center so you can mount the new wheel on correctly instead of having to rotate it to line up

3- insert lugs by hand in star pattern

4- torque the lugs to 50 ft lbs each in star pattern while in the air (optional)

5- let jack down and then tighen lugs to between 72- 88 lb ft (bmw specs) in star pattern

This is a basic outline of how to change the wheels. Step 4 might be difficult to perform using a jack but I am sure you can also just tighten the lugs after letting down the car. The star pattern is important to remember as it allows the wheel to mount squarely on the hub instead of having one side tight against the hub while the other is loose. Hope this helps.

Teutonaddict · 27th December 2002, 04:17

Latest from BMW says the E39 M5 should be torqued to 88.5 ft-lbs +/- 7.4 ft-lbs, seen in this thread:

http://www.bmwm5.com/vbulletin/showt...g+torque+specs

DZeckhausen · 28th December 2002, 03:39

I've found that it's much easier to change wheels on the BMW if I use the wheel hanger tool designed by The Ultimate Garage. I think they are about $25 each, although Steve throws one in free with each big brake kit you buy from him. (Before you ask, I've given away all my extras!)

Remove top bolt, then screw in the wheel hanger tool

Remove the rest of the wheel bolts

Remove wheel, then stare at lovely brakes

A few more hints to add to the ones that TCM and Teutonaddict already gave you:

Assuming you are jacking up just one corner of the car to replace one wheel at a time - place the jack under one of the four plastic jacking pads located just aft of the front wheels or just forward of the rear wheels. Be careful to note that the floor pan comes down below the level of the jacking pad, so you must be careful not to push the jack too far under the car. Centering the saddle of the jack under the jacking pad will result in a crushed section of your floor pan. You should only push the saddle in far enough to support the entire jack pad without pushing up on the metal floor pan behind it.

Once you've got the jack in the right place, give a few pumps of the handle to remove most, but not all of the weight from the wheel you are working on. Before lifting the wheel all the way off the ground, break the 5 wheel bolts free with your wrench. Then pump the jack handle a few more times until the wheel lifts off the ground.

Now, remove the top bolt, then insert the wheel removal tool (you did order one shipped overnight from Ultimate Garage, didn't you??

)

When installing and tightening the wheel bolts, make them as tight as you can while the wheel is still off the ground. Then lower the car so the wheel is just barely touching the ground and torque the wheel bolts the rest of the way. After they are fully torqued, THEN lower the car all the way down.

D/FW M5 · 28th December 2002, 14:52

I have been told that it is better to untighten lugnuts using a breaker bar versus your torque wrench. Also, maybe unncessary/overkill, but I've always tightened my lugnuts in three stages 30, 60, then 90 lbs.

Doug

PS - Dave, you have to stop showing us those gorgeous brakes, it makes me miss my Porsche all the more. Also, any word on the new Movit brake kits?

DZeckhausen · 28th December 2002, 16:20

Quote:

Originally posted by D/FW M5
Dave, you have to stop showing us those gorgeous brakes, it makes me miss my Porsche all the more. Also, any word on the new Movit brake kits?

Mov'it showed off their new caliper design at the Essen 2002 Motor Show at the beginning of December. But the stuff isn't for sale yet, as far as I know. I'll pop an email to Steve D'Gerolamo at Ultimate Garage and see if he can provide any more info.

In the meantime, here's a shot of one of StopTech's CNC machines in Torrance, California cranking out caliper halves.

StopTech CNC machine

Calipers before being assembled