Now, on to something completely different...

So, now that I own an old Alfa, I've become an Alfa snob. It tends to happens to owners who drink from the AR cool-aid bucket, and God knows I take a few swigs every day. And so, I'll post a few Alfa-related tidbits in between my car work posts.

Here is one of the new Alfas that may be coming to the US in the next few years - the Mi.to:
http://www.autoblog.com/2008/03/14/alfa-romeo-releases-the-new-mi-to/

This one may be sold starting in 2010. It's supposed to compete against the Mini pricewise and segment-wise. I'll have to wait and see, but I like its looks (although I don't like the name at all.)

In the interim Fiat will probably import the current Alfa 159, and the Alfa Brera.
http://www.autoblog.com/2006/05/04/alfa-romeo-returning-to-the-u-s/

The 159 is a bigger Sedan, while the Brera is a mid-size hatchback. They are both higher-end cars (BMW/Audi range).

All of these cars are built on platforms shared with other Fiat models. In essence, Fiat (which owns AR) and Alfas are pretty much the same cars nowadays.

I am hopeful they Fiat/AR will be successful in their return to the US. I might have to get a bigger garage...

Undoing the Front Suspension (driver side)

Last time, we removed the springs from the front suspension. We also saw indications that the springs are stock springs. The eventual goal of all this excercise is to renew the front suspension and make any changes necessary to prevent the car from bottoming out.

So, in order to renew the front suspension, you need to:

a) Take it apart - remove every part from the car.
b) Clean up the parts
c) Replace any non-usable parts with new parts
d) Put it all together.

Part A is easy, especially now that the springs have been removed. Basically, it comes down to: "if you see a nut or bolt, remove it."

Part B is a bit more involved, since it involved removing years of dirt, undercoating, overspray paint, rust, and other nasties that have deposited themselves on the suspension.

Part C is simple: order needed parts, use a credit card to pay. How simple is that?

Part D is the reverse as A. Easier said than done. I hope not too bad, though.

I think a brief description of the suspension is in order:
- The front suspension is made up of two A-Arms and a vertical upright member. The upright holds a spindle/axle on which the front wheels revolve. The spindle carries a hub and rod bearings, as well as the disk brake rotors. The brake caliper is attached to the upright as well.

The lower A-arm is made up of two separate arms, bolted together with a ball joint assembly which connects the lower a-arm to the upright.

The upper A-Arm is made up of a single control arm mounted almost transversely from the upright to the car chassis, and a diagonal caster arm, connecting the top of the upright to the front inner fender, towards the front of the car.


The lower A-arm have rubber/metal bushings that attach them to the chassis, as well as a lower ball joint that attach the arms to the upright. All three of these (ball joint, bushings) need to be replaced in my car, since they are worn and dirty and all.

The upper A-arm also has two ball joints that wear out (at the inner fender, and at the top of the upright.) There is also two bushings on the transverse control arm that need to be replaced. However, this control arm is not adjustable, and there are aftermarket replacements that allow you to adjust camber and the such. So rather than replacing the control arm bushings, I'll just buy a complete control arm assembly.

So, the total number of parts I need to get (per side)
2 A-arm bushings
1 lower ball joint
1 upper ball joint
1 inner fender ball joint
1 adjustable control arm.

This takes care of Part C - see, simple! And we were not even trying, yet.


Back to A:

First, I removed the brake caliper. This adds some clearance, allows me to move the brake lines out of the way without worrying too much about breaking it. Of course, the line want to spill all of its contents out, and so I had to collect it all with a spill tray. Note that brake fluid is corrosive, and will eat paint! I did not catch this in time, and some of it spilled on parts of the suspension.

After the brake caliper was gone, I wanted to remove the disk brakes. On this kind of car, the disc rotors are bolted to the inside of the hub. Which means: you must remove the hub before removing the rotors.

Hmmm.. how does one do this?

Well, I decided - "I am not sure how to do this, so I'll just remove the complete upright first - hub, disc rotor, and all." After removing a few brackets from behind the upright, I used my handy tie rod ball joint separator, and separated the bottom and top A-arms. Of course, the whole thing fell down onto the ground, making a big racket and scarying the crap out of me.

So, I picked up the complete upright assembly, and after pondering for a few minutes, I decided to put it aside and work on the A-arms.

One thing I noticed right away was how badly worn were the a-arm bushings. The A-arms are supposed to rotate up and down. They did this OK on my car, but they also could be slid about 1/2" forwards and backwards! Holy cow - can only guess how much they slid under heavy breaking! Thinking about it, I am a bit lucky I made it home when I bought the car.

The bottom A-arm is held in place by a cast-metal pivot arm, held in place with the chassis by for bolts. Taking them out was simple - soak in PB Blaster, get a breaker bar, and undo the bolts. This took about 10 minutes, and the whole lower a-arm assembly come out.

The upper a-arm was not as easy. The front caster arm was simple - unscrew the two bolts from the ball joint, and the thing comes out. The problem is that, once you do that, you must loosen the adjusting nuts and rod. This is tricky once you take these out of the car. So, first, add a bunch of PB blaster to the adjustment rod and nuts, and loosen them. Then, you proceed to removing the front arm. Once removed, undoing the adjusting rod is simpler, since it's already loosened up.

The next thing was removing the control arm. This involves loosening a nut and bolt from the inside of the engine compartment. To get to it, I had to go through the front of the car to access it (the radiator, alternator are not installed, as I am also replacing the water pump - see older post.) I must admit, I do not know how anyone can remove this without removing half the engine - I am sure there is away, though. After a bit of work the nut/bolt came loose, and out came the control arm.

At this point, all the parts were separated from the car. I must admit, it is kind of weird to not see anything in the wheel well. Kinda scary, too!

Next up, it's time to separate the lower a-arms from the pivot rod. The a-arms are held to the pivot rod with a pair of nuts, which are covered by metal caps. These metal covers are pressed into place - how to remove them? Hmmm..

- First, apply liberal amounts of PB Blaster (penetrating oil.) PB is my friend.

- Then, I tried vise grips. After about 20 minutes, I gave up. These things are a pain in the butt!

- After chatting with a few folks (including my dad), we figured a chisel and some encouragement provided by a Big Freaking Hammer might help. And guess what - it worked. Chisel and hammer take the things out in about five minutes

What I found under the caps was depressing - tons of dirty, old grease, and nasty goo. Hidden in there were a nut and a washer. After cleaning things up a bit, I went at it with a 24mm wrench (and my little friend, Mr. Impact Wrench) and took the nuts out, and separated the A-arms from the pivot.





Finally, the hub and upright remained, waiting to be taken apart. The hub and disk assembly has a metal cover similar to the suspension metal caps. So I figured, if the chisel/hammer worked before, maybe they will work here, too. And guess what - they did. The cap came off in a minute. Inside the hub, I removed the castellated nut/pin, and the whole hub/disc assembly came off from the axle/spindle. Piece of cake. Removing the two screws that hold the rotor to the hub freed them from each other.

I also took a picture of the caster arm (the front member of the upper A-Arm,) just in case how it goes together. The whole thing was covered in grime, overspray, and greasy dirt. I am assuming the notch in the middle of the arm is there on purpose (to allow mechanics to use a wrench to adjust,) and not some overly-zealous alignment specialist...

That's it - all the pieces were now separated. They all look nasty dirty! Part A is now done - for the driver side. I still have the passenger side left to go. That will be next.

Springs, Part 4: Finally, some work gets done.

So, I've been away from the keyboard for a while. But things have been a bit busy at the House of Speed. It's time to catch up on things online.


If you remember, I was wondering about spring sizes and the such. The two important things to figure out are:

- spring rate
- spring free length.

Once we decide on spring rate, we can compute the required spring free length using the math I've discussed in previous posts.

Online, there are two main schools of though regarding springs:

a) Go with stiff rates, and keep the stock sway bars
b) Go with medium stiffness rates, and make your sway bars heavier.

(I'll explain sway bars in a future post.)

The problem I run into is that most folks seem to favor a racy, stiff, ready-for-racetrack setup. In all honesty, I do not want to race the Alfa; I just want to drive the car around during the weekends, and hopefully not have to work too much on it (once the thing is ready to run, of course.)

So I am of the school of though of "go with springs as soft as possible, as long as the front of the car does not bottom out too badly, and the handling is not too numb". The current springs allow the car to scrape with the ground under heavy breaking, so any replacement springs should probably be stiffer (to prevent nose dive) while keeping a similar ride height (lowered cars tend to scrape on the ground more than non-lowered counterparts.)

So, what what kind of springs do I have in the car, currently? Well, the best way to find out is to remove them and see what I've got!

At first, this sounds a bit scary, since you have to deal with fairly stiff springs (450+ lb/inch; for comparison, my Miata's front springs are 375 lb/in.) And compressed springs are dangerous - if they break loose while you are undoing things, they can get launched like a projectile and hit stuff and people. Dangerous stuff.

Fortunately, there is a cheap and fairly safe way of dealing with this, as explained here: http://www.centerlinealfa.com/tips/images/installation/spring_install.pdf

Basically, this method involves using two 12" threaded rods to replace two of the bolts that hold the spring pan in place, removing the other two bolts that hold the spring pan in place, and slowly lowering the spring pan with the remaining threaded rods until the spring comes free. I used this method, with two variations:

- I used three rods.
- I greased the rods once the upper double nuts were tightened, to prevent any wear on the threaded rod (and potential binding or jamming up.)

The extra third rod was a bit redundant, but it did make me feel a bit safer. It does add to the total time it takes to undo each spring, since you have to do 50% more work (3 rods vs 2 rods.) I also highly recommend adding some grease, as jackscrews will wear quite rapidly and either jam or break the thread (airplanes have crashed due to poorly greased jackscrews - no kidding!)

The whole process took about 1.5 hours per side. I was taking it easy at first, learning the process and all. I suspect once you learn the ropes, you can bring this down to about an hour (with three rods - probably less if you use two rods.)

I did make a mistake: I forgot to loosen the antisway bar at first. That added a about 30 minutes worth of agravation, but I lowered the opposite side enough to loosen up the sway bar and removed it. After that, everything was cake.

Once you are done undoing the springs, you are left with a lower spring pan (which is secured to the lower A-Arm of the suspension,) a spring, and upper and lower rubber isolator pads (two per side.) These rubber pads prevent metal-to-metal contact between the spring, the chassis, and the spring pan. This helps prevent squeaks, and makes the ride a bit more comfortable.

Well, both spring pans were very dirty, and a bit rusty. Plus, the paint and undercoating overspray made things look nasty. On the passenger side, the lower pan had about 1" worth of dirt, and you could barely see the rubber isolator buried in all that dirt! On the driver side, however, the rubber isolators were completely missing (both of them!) Hmmmm...

The spring themselves were dirty and a bit rusty, too. All the overspray covered any present marking (e.g. spring type, part no., etc.) So, I went ahead and measured the length of springs, and they came out to about 12.5 inches. This matches the length of the stock springs. I am starting to think the springs are definetely stock. Go figure.

So, assuming these are stock springs (about 450 lb/in), we know a medium-rate spring (600-800 lb/in) would help with the bottoming-out issues. This is a bit reassuring - I was concerned the already-mounted springs were of the 1100lb/in variety, and any decrease in rates would make the car more likely to bottom out.

Next up - the front suspension comes apart.

Springs - Part 3

On my last post, I mentioned the next step would involve measuring the compressed length of the springs at the stock ride height. How does one do this, you ask?

Well, in theory, it's not too hard: one just needs to set up the suspension to the stock ride height, and measure the distance between the top spring perch and the bottom spring perch.

The problem is that when the car is sitting on the ground, it is hard to get under the car. But if you lift the car and rest it on jack stands, the wheels come off the ground and the suspension droops towards the ground.

So, the best way (given my tools/resources) is to lift the car onto the jack stands, and remove the springs. One can then raise the suspension up/down with a hydraulic jack until one gets the proper suspension ride height. Once this is done, you can use a string and a measuring tape to get a read on the perch-to-perch length.

The stock ride height is determined by measuring the distance from the lower A-arm pivot to the ground (measurement A) , and the distance from the lower ball joint to the ground (measurement B). The difference between A and B should be 34mm +/- a few mm. (I'll have to post a link to a diagram illustrating this -- stay tuned.)

So, by raising the suspension up/down with the hydraulic jack, one can zero-in on the proper ride height and measure the compressed spring length.

(I'll detail the removal of the springs on my next post.)

The compressed length came out to 204mm, or 8.0315".

This is very close to the 200mm test load used in specifying the spring rates (see my previous post.) At this stock ride height, the distance b/w the center of the hub to the fender lip came out to 14 5/8" (371mm.) Furthermore, compressing the suspension 1 1/8" (18/16") caused a compression at the spring perch of 7/16", giving a 18:7 (2.57:1) ratio in travel b/w the outside of the hub and the spring perch.

Why is this useful? Well, these numbers can be used to compute the amount of force with which the spring is compressed at the stock ride height. Assuming the following spring rate and free length (from my previous post):

Front: spring rate = 7.797 kg/mm, free length = 313.5mm

With a compressed lenght of 204mm, then the spring is compressed a total 109.5mm with respect to the stock ride height. The amount of force on the spring is computed with the spring equation:

Fs = Spring Rate * (Free Length - Compressed Length)
= 7.8 kg/mm * 109.5mm = 854.1 kg = 1879.02 lb (aprox.)

This can be used to compute the required free length for springs with different spring rates. Recall:

k = f/(Lf - Lc)

Where:
k = spring rate
f = load at spring
Lf = free lenght of spring
Lc = compressed length

Clearing out Lf, we get:

Lf = (f/k) + Lc

For example, take an 800lb spring (and rounding out a few terms):

Lf = (1879lb / 800lb/in) + 8.0315 = 10.38025"

So, in theory, obtaing a spring with a rate of 800 lb/in and with a free length of 10.38" will yield a ride height very close to stock ride height. This is a big piece of the puzzle - I can now pick my rate, and by plugging in numbers into these equations, I can compute the free length required for the spring. Wee!

(A caveat: the springs are installed with rubber isolators on the top and bottom of the spring. This effectively decreases the actual compressed length somewhat. I wll have to measure these and correct the compressed length before doing computations "for the record". I will do this in my next post.)

A new problem arises when one asks: "What if I want to lower the ride height by X inches?" Well, we have a numbers for that.

Recall that the ratio between the hub-to-fender length and the compressed length is 2.57:1. We can then assume that a 25.7 mm (about 1") decreased ride height implies a 10mm decrease in spring compressed length. We further assume that the force on the compressed spring remains the same (big assumption - probably off by a bit.) We can then punch the numbers into our previous example:
(Note: 10mm = 0.3937")

Lf = f/k + (Lc-10mm)
= (1879lb / 800lb/in) + (8.0315" - 0.39") = 9.99"

Pretty cool, eh?

So, in summary, the numbers to remember are:

f = 1879lb = 854.1 kg
Lc = 8.0315in = 204 mm
Motion at hub:Motion at spring = 2.57:1

And the key equation:
Lf = f/k + (Lc - (correction))

The "correction" term refers to any adjustments in ride height we may want to do, as described above.

The bigger moral of the story: algebra and high school-level physics are actually useful in real life!
:-)


Next up: Back in the garage, removing parts from the suspension.