Shocking! Part II...

In Part I, I showed the start of this project to install new Bilstein shocks and Bavarian Autosport springs in the Z3 Coupe.  That ended with the rear done - now it's time for the front.  This is well-documented on the web, so I won't do the step-by-step procedure.

I will, however, post a picture of a technique that I read somewhere.  Everyone who saw it laughed at me, but it worked great.  See, after you remove the strut, you have to support the suspension and brake assembly so that it won't swing out and damage the brake lines or other components.  The idea is to insert one lug bolt, and tie a rope from there to the engine lift point at the front center of the block.  Worked great!

Speaking of removing the strut, it is attached to the bottom of the king pin with two strong bolts, and at the top with what they call a "pinch bolt".  Those two lower bolts were seriously in there, and I had to hammer them out with an air wrench.  One tip: remove the links to the sway bar on both sides, and that will allow you to rotate the bar out of the way so you'll have clearance for the air wrench.

I was really cussing the previous guy, because those bolts had a very heavy coat of permanent thread locker on them.  I decided to use new bolts there, and of course, that's when I discovered that they come from the factory with the thread lock.  Sorry about that, anonymous prior mechanic!

As it turns out, I used almost nothing from the old strut in building the new ones.  All that I reused was the top spring plate, two washers, a grease cap and a plastic cap that fits on top.  In addition to the new struts and springs, I replaced the rubber spring seats top and bottom, and replaced the big strut bearing that the strut bolts to.

The scary part of this task is compressing the spring.  Here's a tip: don't buy the $15 Harbor Freight spring compressor!  I did, and it jammed while releasing the first spring.  I went to Sears and picked up a nice Craftsman set, and it worked great.  Lifetime warranty, too.  I particularly liked those locking pins that keep the spring from jumping out of the pockets.

Incidentally, you can see part of the piece-of-crap compressor from Harbor Freight sitting on the bench. Really, DO NOT buy that!  I buy a lot of cheap tools at HF, but stick with better brands when the procedure is life-threatening...

As with the rear, shocks, you need to use an Allen wrench to hold the shaft from rotating, while tightening the nut on the strut shaft.  In Part I, I showed you the cool set of pass-through sockets I bought.  Unfortunately, that set only goes up to 19mm, and the big nut at the front was 22mm.  I asked a mechanic at Faulkner BMW, and he said he just hammers them on with an air wrench.  Not for me, so I called the tech line at Bavarian Autosports.  (To do that, you call the main number and ask for "Bavarian Otto."  Cute.)  They suggested modifying a standard socket by grinding flats to use an open end wrench.  That's what I did - bought a new 22mm deep socket, and ground the sides to fit a 25mm wrench.  That worked great too.

Just as I was finishing the first strut, Matt Sware dropped by the shop (not in his M Coupe, though - he was in his new-to-him F150 shop truck).  I had him be the model for the "beauty shot" of the completed strut:

While doing this project, I also decided to replace my flexible brake lines with braided stainless steel ones.  I wound up with fancy ones that have a red Teflon coating - pretty good bling! Photo below - there are six lines because there are two at the back on each side.  The longer ones are for the front.

To safely remove these you need special wrenches called flare wrenches.  Way back in Nov, 2012 I mentioned the set I use: the Craftsman #44096.  The cheaper HF set skips the very size I needed, 11 mm.  Even with the flare wrenches, there were two fittings I could not get to crack open: the left front, and one of the two at the left rear.

When brake lines seize, a variety of bad things can happen if you put too much stress on them.  The worst case is when

the brake line itself shears, and you have to bend a new hard line.  I don't have the tools to do that, and don't really want to buy them.   SO, I've got an appointment with Jack Miller to get him to to the last two.  That way, if the line shears, at least I'll be at a shop with the equipment to fix it.  Kind of stinks, though, because I had to bleed the brakes just so I could drive it to Jack's, and we'll have to do it all over again once those two lines are changed.

Once both sides were done (Dave Russell was a big help getting the passenger side finished), I bled the brakes and put the car on the ground.  Remember this picture from Part I?

Yes, it's all the stuff I had to remove from the interior trim just to get to the nuts for the rear shocks.  I wasn't anxious to go through that again, so I left it all out for my initial test drive.  I was VERY pleased with the difference in the handling.  Of course, the old shocks were so dead that I could easily compress them with one hand, but with these Bilsteins, the handling is very crisp, and the ride isn't bad either.

The only small disappointment is that the car was no lower, even with the new springs that were to drop it an inch - in fact, it looks a little higher to me!  I've heard of that happening with new gas shocks, and supposedly they settle in time.  We'll see.

After the test drive, I checked the torque on those rear shock nuts.  All secure, so I was comfortable putting the trim back in.  Since I've kind of been dissing the tools from Harbor Freight this post, I'll point out one HF tool that was invaluable in removing and replacing that trim - an ultra-stubby screwdriver.  The clearance on the screws for the amp surround and some other parts is so close that even a one-inch driver wouldn't fit.  These did, and they are cheap!

One of the nice things about doing this as a hobby is that it doesn't matter how long it takes to get it done.  Time is literally money for a real mechanic, but I was very comfortable taking extra time to clean each plastic part, and comb and vacuum the carpet parts before reinstalling.  The rear hatch area looks about 10 years newer!

So, now for a four-wheel alignment.  The car is tracking very well now, but the steering wheel is about 10 degrees off, and I might as well get it perfect.  Bill Durland tells me that there is a fine alignment rack and a very good technician over at LLM Motors, so they will probably do the honors.

It's nice to have the car on the ground again!