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| Question: | "I would like to know what's involved in fixing up my brake system, without getting too technical." |
| Answer: | "Let's discuss." |
| Level of Difficulty: | Midly arduous |
| Time: | Between 4 and 10 hours |
| Pictures: |
| Master Cylinder |
| What happens w/o good brakes... |
| Pads |
| Drilled rotors |
| Shot of 'Vette rotors |
Intro:
Brakes wear. That's their thing. As soon as your warranty runs out, brake maintenance is going to be your job, so you might as well learn now.
| Symptom | Fix |
|---|---|
| Sqealing or grinding | Lube/replace |
| Mushy Pedal | Flush brake system |
| Brakes don't work | Get towed to mechanic |
Sqealing
Squealing brakes usually fall into two groups (since that's all I'm going to discuss here):
Take your wheel off and take a peek at your rotors and pads, do they look worn? When was the last time you replaced them?
If it's within 6 months, thenI would seriously consider lubing them with anti-sqeal.
Read the package for directions on how to apply anti-squeal.
If your pads are older than 6 months, look worn or measure below 50% thickness, then the squealing is probably little tabs that stick
out of the pads to actually create a squealing sound, to alert you to how low the thickness of the pads is.
Mushy Pedal
When I say a "mushy pedal" I mean:
Flushing your brake system is not an easy or even clean, job. It's messy, funky and really dirty if you don't own a lift.
Upgrade?
If, by upgrading, you want to stick superior parts into stock locations,
then I call this "Maintenance", and you would stick to this page. Changing the dynamics of the stock setup is beyond the scope of this page. A few ideas for this can be found here.
Simple "Brake-Down"
Audi brakes on the later-modeled cars are more than adequate, and with some of the 1990+ era models, became fantastic. Even still, there are a few ways to tweak your braking. You may not be increasing your brake pressure by messing around with your brakes, but at least you won't be lessening your stopping power.
I'll be following a top-down or even a bottom-up route through your braking system.
| Part | Upgradeable? |
|---|---|
| Foot | No |
| Pedal | No |
| Rod | No |
| Master Cylinder | No |
| Propor. Valve | Yes |
| Hoses | Yes |
| Rotors | Yes |
| Pads | Yes |
One of the more ballyhooed "upgrades" when it comes to brakes, flexible brake hose, to me, is a no-brainer. Your stock brake lines (in the wheel well, mind you) are flexible rubber hose. I assume it's flexible (unlike the rest of your brake line system) so that the caliper has a freer range of motion when a mechanic is working on your car. Keeping your lines hard and in good shape reduces the expansion of the hydraulic fluid when it experiences your foot on the pedal. You are trying to force fluid into itself, which it doesn't like to do. So, it fights back, and in doing so, pushes against the flexible walls of the hose. When the car is new, those rubber lines are tough as nails, and you don't get the line expanding. Over time, the rubber grows a little weary and begins to expand under pressure, giving you a mushy pedal.
To combat this, people replace their lines with the hardest hose they can find, often Stainless steel, teflon, kevlar or whatever. The idea seems to be that if you can increase the bursting pressure then your brake will be as hard as a rock. The other option is to just stick with stock, because the difference between the lines in the first few years is so slim as to be non-existent. How do I think I know this? I've tried both. The verdict? There was no difference between new, stock lines and new, Stainless steel braided hose. Who knows in a few years? The stainless may outlast the stock, but I will probably have a new car by then. Besides, the new stock only cost me 20 dollars total. Stainless will run you about $125 for four lines. You decide, because whatever you choose will give you a better feel then old stock.
Rotors are easy. You are pretty limited in your choices here if you plan to stick with the stock size of 10.1 inches.
Choices:
Vented
Slotted
Cross-drilled
Between these choices, there are lots of variants: vented cross-drilled, vented slotted, non-vented slotted, etc. You get the picture.
What it means:
Vented
Vented rotors are a good idea. There are holes around the edge of the rotor, letting hot gas from the rotor mix with cool air. No appreciable downside.
Cross-Drilled
Cross-drilled rotors work on the principle of "Direct gas venting". Direct gas venting has to do with a buildup of gas over the surface of your rotor when you are braking hard and repeatedly, like in racing. The gas makes your pads "float" over the surface of the rotor, reducing braking capability. If you are braking as hard as you can, 10 or 12 times a minute in regular street usage, then you should ride a bike, because you're doing something wrong. Cross-drilling a rotor has to be done very carefully and professionally or else they can crack under stain and mess up your whole day, nevermind your nice, new pads and calipers. Stay away from cross-drilled rotors, unless you know exactly what you're doing, in which case, you wouldn't be here.
Slotted/Cross-slotted/Cross-cut
All the same name for what amounts to cutting metal away from the surface of the rotor in a a shape, line, curly-q or whatever. The idea is to get anything that isn't your pad, away from the rotor surface. Be it sand or water, snow or pebbles, cross-cut rotors encourage things to fly off of your rotors as quickly as possible, keeping them clean for your pad to clamp down on. The downside is that the rotors don't last as long because of the cross-cuts increasing pad wear. Not a terrible problem, as I've had my cross-cut Ate rotors on for almost two years. Cross-cut rotors are a very good idea. Vented AND cross-cut are an even better idea.
How to remove rotors & calipers:
Nothing too complex, the proportioning valve that comes stock on your car sends a specified percentage to the front and a different percentage to the rear. When you change your braking, or change your set-up, you might need to change that percentage based on where you want the bias to be. Not something you should mess around with unless you know exactly what you're doing. If you are in the area of your valve, and major brake work is getting done, it can't hurt to replace it.
Update November 11, 2000
Just replaced both the proportioning valve and Master Cylinder in one fell swoop.
Tools needed:
A simple explanation of this job would be:
Guided install:
Picture:
MC
Do not get this confused with the clutch master cylinder. They are similar but completely different, if that makes any sense. The MC (as we're going to call it) is probably best described as a tube with holes or cups in the inside. These holes go to hard brake lines and to your calipers. The proportioning valve decides how much of your foot pressure to send to the front and rear calipers by interacting with your MC and regulating the pressure going to these holes. Keeping some sort of balance is important for the same reason that you shouldn't brake really hard on your front bicycle brake. If you know what I mean, you know what I mean. MCs don't usually die until they REALLY die, and shouldn't be replaced unless you have some time on your hands. First you replace the MC, and then you have to bleed every little piece of your brake system. Not too fun.
There is a great amount of noise generated on the quattro list about pads. I'll be honest, stick with a pad that lets you brake as hard as you can in normal driving conditions. This will probably leave you with a pad that generates a lot of dust and has a short life-span. Blah, who cares? Brakes aren't there to be easy or nice, but to stop you from crashing into other people. I stuck with stock, and have never been dissatisfied. Pagid on the front, and Westerfield on the rear. Works great in any conditions. Been up the side of a mountain 300 miles north of Montreal in -10C, and I've been in New York City in 30C heat in traffic, with no difference in the stopping power of the pads.
I hope I've been able to help you through the agonizing decision period when upgrading/maintaining brakes.
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| Page last updated: April 28, 2003 |
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