Philosphically, why do you choose NOT to perform a home DIY alignment on your E39?

Ok I give. What, exactly, are we supposed to put in the power steering res?

Um... Power Steering fluid. I use Royal Purple. But as long as it conforms to the standards of BMW which all you to do is read the bottle, then it'll be fine. And since some people feel they want to flame me, this is a forum. It's meant to share info and help. Whether you want to believe what I say or not, I'm just informing you. It's that simple.

I just am curious why you think ATF does not mean Automatic Transmission Fluid, and that it will somehow harm the system when it is listed in the BMWs own ETK reference?

I read it a few different places. And was told by a few different people. That's why I think that. And for the record even if I was given wrong info. I'll stand by what I use. But regardless of that, who actually trusts BMW recommended maintenance? It says never change trans fluid or PS fluid or dif fluid. They also say don't rotate your tires and do oil changes every 12k-15k miles.

Good points on BMW maintenance. But I have to disagree on the ATF for the steering though.

Power steering aside, this weekend I bought some tools for measuring toe.

Bear in mind there are various approaches for measuring toe:

1. Plumb bob & tape measure:
   • Hang a plumb bob at the 3 o'clock & 9 o'clock location of the tire tread; mark the floor where the plumb bob hits; measure between marks; and trig out the angles based on the measured distances
   • Here's a laser variant where you mark the floor and trig out the toe (1)
2. Toe plate & tape measure:
   • Strap flat plates to the outside of the wheels on an axle; measure between them with a tape
   • Here's a much fancier take on the toe-plate concept (1)
3. Sliding bar & tape measure:
   • Adjust a pointer and lock into place; then measure the distance with a measuring tape.
     • Here's a single square tube approach (where the fingers slide on the outside of the tube) (1)
     • I opted for a similar approach, only with the cheaper circular tube (1)
     • Personally, I like the dual square tube approach (where the outside ends slide into the central tube)

My first idea was to simply slide two lengths of smaller square tubing inside a larger central length ... and I really liked the solid feel of this sliding-bar approach ... but at roughly $18 to $22 for each 6-foot length of square tubing (steel vs aluminum), I just couldn't justify the cost over the vastly less expensive steel 1/2 inch EMT circular tubing which was a mere $2 for a 10-foot length at Lowes.

It would have cost about $40 if I used the sliding steel/aluminum rectangular tubes, which is too close in price to a professional toe gauge to be worth it.

A matching sliding EMT clamp for each end cost about 50¢, and I added two more of these clamps for the optional central mount.

A threaded rod for the feelers that touch the tire was less than $2, and wingnuts to replace the hex nuts on the two clamps cost a total of $1.

EDIT: Here's a pic of the parts ... (total cost is roughly about $7 not counting the extra nuts and wingnuts I bought):

Sounds good BB. I cant tell exactly what your method will be without the pics, but I highly suggest (and maybe your already doing this) taking measurements from the metal rim and not the tire. When measuring less than a mm, tires are not perfect. Rims should be within a few.01 mm.

Originally Posted by Flybot

I cant tell exactly what your method will be without the pics

Here's a pic of the simple $7 toe measurement tool so far:
a) At least 5 feet of EMT tubing ($2)
b) EMT clamps ($50¢ each, you only need two but I have four mounted so I could reference the centerline if found)
c) Two foot 5/8x18 threaded rod ($2) & nuts ($1)


What I'm missing is a 'pointer' at the top of the threaded rod to hit the centerline tread mark.

Any ideas for that pointer?

Note: I'm thinking of cutting a notch in the threaded rod but, for ease of measurement, I prefer a solid metal block that is the same size as the clamp so that I can simply measure from the edge of one clamp to the edge of another clamp instead of inferring the distance to the centerline of the clamp (where the threaded rod is mounted).

Do you know where I can buy a solid block of metal? Lowe's didn't have any.

Originally Posted by Flybot

I highly suggest ... taking measurements from the metal rim and not the tire

The measurement location for toe has always confused me.

First, it seems we should measure to the known centerline of the vehicle (instead of to the other wheel/tire on the axle).
To that end, I ask:
Q: Do we have a good easy-to-mark centerline point for the E39?
Note: The extra clamps in the middle of the tool are there to take advantage, somehow, of the centerline mark.

Secondly, it confuses me where to measure on the wheel/tire because the distance from one wheel to another measured at the furthest point forward on the horizontal centerline will be different than the distance measured from the rim (which is a few inches closer to the vertical centerline of the wheel where the toe is, by definition, 0° ... because it's the non-changing pivot point on the ground).

Most DIYs I've seen suggest the 3 o'clock & 9 o'clock position of the tire for front-to-back toe ... but that could change depending on the size of the tires (i.e., depending on the distance between the outside metal rim and the outside rubber tread).

So I'm confused as to the best location to measure toe from.

BTW, do we know the "official" 0° toe distance between wheels on the front and rear axle?

I roughly measured mine at about 59 5/8 inches today from the front of the tire on the ground; but that isn't where the official spec is measured and it doesn't take into account any existing toe.

In summary, these are the questions:
Q1: Do we have an easy-to-use centerline mark on the underside of the E39?

Q2: What is the official distance between the wheels when there is 0° toe?

Q3: Since the toe specification is from the outside tread, how does that take into account the tire size (and would it work to measure from the rim without changing the specification)?

If you're in the south bay, I gotta give kudos to this shop below, which did my friend's car (I came along to watch) and the mechanic (Rich?) was fantastic (which isn't easy for me to say).

Pro Alignment & Brake (4.5 star rating 20 reviews)
2875 Winchester Blvd Campbell, CA 95008 408-370-1421

It's a mom-and-pop operation, but they have a $50K hunter machine, looks brand new, and best of all, they let you watch up close, touch things, ask questions, snap pictures, and see all the diagnostics on the screen, and, in general, be a PITA. They don't seem to mind.

They even give you the $10 Yelp discount if you simply mention that you want it to "Debbie" the counterperson, so, the $100 alignment was $90, all told (no tax).

BTW, watching him align the car (not a BMW) showed me how complex it was to manage caster, camber, and toe simultaneously!

From memory, what he did was:
a) Lifted the car up and attached reflectors to all four wheels
b) Checked that the rear lined up with the front
c) Loosened up the tie rod ends
d) Then he adjusted caster and camber & toe, basically all at the same time
e) Then he put a lock on the steering wheel & centered (readjusting the toe)

The amazing thing was watching him push so hard that the car was literally shaking an inch or two on the floating wheel supports as he loosened and tightened the eccentrics.

The part that struck me was how every adjustment affected the other two adjustments (which I could see in red and green on the monitor).

Clearly, the part that would be difficult to do at home would be to measure all three simultaneously. I'm sure a home alignment can be done - but it took him an hour from start to finish while I watched like a hawk to see that he did it right, so I'm guessing it would take many times that to do the same job at home where we have to measure caster, camber, and toe separately.

EDIT: See also this ride-height measurement information from this thread:
> Replacing ATF: Do you level the car or level the tranny pan

Originally Posted by rdl

Here is another suggestion for determining "level" based on ride height.

Ride height is measured from the lower edge of the fender arch to the bottom of the wheel lip. The key is to take the difference. A level car will have the fender arch front and rear differ from each other by the difference in ride height spec. For the purpose of checking transmission fluid level the absolute height is irrelevant; the higher the better for convenient access to the transmission. For instance, with my car the specs are 592 mm front and 560 mm rear; a difference of 32 mm. When the car is sitting with the front fender arch 32 mm higher than the rear arch, the car is "level." Side to side at each end should be identical of course.

In spite of what you eye may tell you, your garage floor is probably neither flat nor level. For instance, most garage floors have a drainage slope of ~ 1/4" per foot toward the door. Over an E39 wheelbase this works out to 2.3 inches or 59 mm difference in height. Similarly, side to side level isn't necessarily so level either, or flat. You can easily check. Pour a pail of water on your garage floor and watch it run/drain toward the door and likely puddle in some spots. Draining => out of level. Puddling => not flat.

An easy and accurate method to check relative heights both end to end and side to side is a water level. All it takes is a ruler, a length of clear tubing, a few cups of water and perhaps a funnel.

FWIW, I wouldn't worry about being "out of level" by +/- 10mm or so. It's within TIS specs for ride height differences and works out to 0.20 deg front to rear, 0.38 deg side to side. One likely has more difference from "level" due to relative settling in the engine and transmission mounts. It just won't make any practical difference in the fill amount.