Up coming brake DYI .... rotors and pad replacement
01-17-2005, 08:05 AM
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Up coming brake DYI .... rotors and pad replacement
Purchased rotors and pads from ECS Tuning... invested in the brake piston tool.... printed off all the tech stuff and a few other tidbits.
Other DYI advise/trick of the trade stuff would be appreciated.
Chris
Other DYI advise/trick of the trade stuff would be appreciated.
Chris
01-17-2005, 08:16 AM
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Fronts or rear?
For the fronts...
The carrier bracket bolts are a PITA. need a lot of torque.
I use 2 c-clamps to retract the front pistons.
For the rears...
The 15mm wrench used to secure the caliper floating pins (or whatever they are really called) needs to be a skinny wrench. I use a pedal wrench for a bicycle.
I use several (3-4) large flat washers and the stock lugs to hold the rotor on once the wheel is off. This holds the rotor on while removing/installing the caliper. If you don't have these washers, the closed side of a combination wrench (~15mm) works just as well. If you have not removed the rotor before, be prepared to hit it with a hammer to get it off. Brakes are messy, be prepared to get very dirty.
The carrier bracket bolts are a PITA. need a lot of torque.
I use 2 c-clamps to retract the front pistons.
For the rears...
The 15mm wrench used to secure the caliper floating pins (or whatever they are really called) needs to be a skinny wrench. I use a pedal wrench for a bicycle.
I use several (3-4) large flat washers and the stock lugs to hold the rotor on once the wheel is off. This holds the rotor on while removing/installing the caliper. If you don't have these washers, the closed side of a combination wrench (~15mm) works just as well. If you have not removed the rotor before, be prepared to hit it with a hammer to get it off. Brakes are messy, be prepared to get very dirty.
01-17-2005, 08:31 AM
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The tutorials on this site are very good and Windy's advice should be heeded.
Every time I replace the brakes on my car I wish I had used mechanics gloves. Just as he said, very messy.
01-17-2005, 08:39 AM
#4
my personal additions...
Front:
-If you've never removed the calipers, the two bolts are probably tight. You'll likely need a breaker bar to get them loose.
-If you have a lot of front rotor wear, you'll have a huge lip, this will make pulling the caliper off the rotor tough. I rock the caliper back and forth (but some lugs on the rotor to hold it tight w/ spacers) to get the piston pushed back in to get more space.
-Clean the rust off the hub. This is hugely important. Get a wire brush, better still if you have a wire wheel on a drill or die grinder. Get the hub good and clean, once you think you've got it, clean it some more. Remember, if the rotor does not seat flat with the wheels torque, your brakes will vibrate.
-If the new pads don't have wear sensors, cut the sensor off the old pads with plenty of wiring left (i.e. cut the sensor close to the pad, not the clip). Do a decent job soldering it and covering with heat shrink and electrical tape. Don't leave a ton of wire, but don't cut it so close you have nothing to work with. I've seen half-*** soldering jobs stop working once it rains or after a couple weeks of driving. Do it well, do it once.
Rear:
-Clean the rust off the hub. This is hugely important. Get a wire brush, better still if you have a wire wheel on a drill or die grinder. Get the hub good and clean, once you think you've got it, clean it some more. Remember, if the rotor does not seat flat with the wheels torque, your brakes will vibrate.
-Pad springs. These kind can suck. As you're putting the caliper back on the carrier with the new pads in place, you have to make sure the spring clips on the pad stay parallel with the pad so that both the top and bottom leaf make contact with the caliper. You know you've got it right when the caliper resists going on the carrier. If it slides right into place with no effort, the spring leafs have turned. Though the car will operate fine with the springs not in place, the rear pads will rattle around, you will notice this.
-When retracting the rear piston, be mindful of the dust boot on the piston. It will be right where you are turning, it will bind up at times, and it tears easily. So if you are extra careful, the boot won't tear. If the boot tears, decide how much you care about the rear caliper. With no dust boot, dirt and crap will get between the piston and the caliper bore, creating grooves. This wear will allow the piston to move around more, causing weird pad taper wear. Eventually it will fail. So just be careful of the boot.
Both Front & Rear:
-Bleed the brakes. Push through a solid 500ml through the system. Fresh fluid does wonders for brake feel. I've seen S4's that have never changed brake fluid in a couple years. It looks like black sludge in the reservoir. In my opinion, 2 years is 1 1/2 years too long to go. I think a bleed every 6 months is worthwhile and beneficial.
-If you bleed the brakes, use a line wrench on the bleed screws. Don't use an open end wrench, this will damage the bleed screws. When tightening the bleed screws, bear in mind their size. You do not need to use the breaker bar to tighten the bleed screw. There is a reason that an 11mm wrench is only about 5" long. Just tighten the bleeder, don't kill it. If you are using a pressure bleeder through the reservoir, be mindful of the pressure maximum at the reservoir (I believe 12 psi). There is a relief valve on top of the reservoir (that yellow flat head screw), if that leaks air or fluid, you're done. There is an O-Ring in there, it will be broken, you'll need to replace it prior to driving. Just be glad the O-Ring busted and not something more expensive to replace.
-Clean up. Get some brake parts cleaner, and be careful with it. This stuff is basically paint thinner in an aerosol can. It will clear the paint right off your car, but it cleans up brake parts like nobody's business. After you are done bleeding each corner, do a nice thorough cleanup. You are doing this becuase later, when you check for leaks, if everything is clean, it's easy to find them.
-Before you start the car, pump the brakes with the car off for about 1 minute. If the pedal does not firm up and stop before reaching the end of it's travel, you have a problem. The pedal should stop, and be firm. After you reach the "firm" pedal stage, go back around the car and check for any leaks.
-If you've never removed the calipers, the two bolts are probably tight. You'll likely need a breaker bar to get them loose.
-If you have a lot of front rotor wear, you'll have a huge lip, this will make pulling the caliper off the rotor tough. I rock the caliper back and forth (but some lugs on the rotor to hold it tight w/ spacers) to get the piston pushed back in to get more space.
-Clean the rust off the hub. This is hugely important. Get a wire brush, better still if you have a wire wheel on a drill or die grinder. Get the hub good and clean, once you think you've got it, clean it some more. Remember, if the rotor does not seat flat with the wheels torque, your brakes will vibrate.
-If the new pads don't have wear sensors, cut the sensor off the old pads with plenty of wiring left (i.e. cut the sensor close to the pad, not the clip). Do a decent job soldering it and covering with heat shrink and electrical tape. Don't leave a ton of wire, but don't cut it so close you have nothing to work with. I've seen half-*** soldering jobs stop working once it rains or after a couple weeks of driving. Do it well, do it once.
Rear:
-Clean the rust off the hub. This is hugely important. Get a wire brush, better still if you have a wire wheel on a drill or die grinder. Get the hub good and clean, once you think you've got it, clean it some more. Remember, if the rotor does not seat flat with the wheels torque, your brakes will vibrate.
-Pad springs. These kind can suck. As you're putting the caliper back on the carrier with the new pads in place, you have to make sure the spring clips on the pad stay parallel with the pad so that both the top and bottom leaf make contact with the caliper. You know you've got it right when the caliper resists going on the carrier. If it slides right into place with no effort, the spring leafs have turned. Though the car will operate fine with the springs not in place, the rear pads will rattle around, you will notice this.
-When retracting the rear piston, be mindful of the dust boot on the piston. It will be right where you are turning, it will bind up at times, and it tears easily. So if you are extra careful, the boot won't tear. If the boot tears, decide how much you care about the rear caliper. With no dust boot, dirt and crap will get between the piston and the caliper bore, creating grooves. This wear will allow the piston to move around more, causing weird pad taper wear. Eventually it will fail. So just be careful of the boot.
Both Front & Rear:
-Bleed the brakes. Push through a solid 500ml through the system. Fresh fluid does wonders for brake feel. I've seen S4's that have never changed brake fluid in a couple years. It looks like black sludge in the reservoir. In my opinion, 2 years is 1 1/2 years too long to go. I think a bleed every 6 months is worthwhile and beneficial.
-If you bleed the brakes, use a line wrench on the bleed screws. Don't use an open end wrench, this will damage the bleed screws. When tightening the bleed screws, bear in mind their size. You do not need to use the breaker bar to tighten the bleed screw. There is a reason that an 11mm wrench is only about 5" long. Just tighten the bleeder, don't kill it. If you are using a pressure bleeder through the reservoir, be mindful of the pressure maximum at the reservoir (I believe 12 psi). There is a relief valve on top of the reservoir (that yellow flat head screw), if that leaks air or fluid, you're done. There is an O-Ring in there, it will be broken, you'll need to replace it prior to driving. Just be glad the O-Ring busted and not something more expensive to replace.
-Clean up. Get some brake parts cleaner, and be careful with it. This stuff is basically paint thinner in an aerosol can. It will clear the paint right off your car, but it cleans up brake parts like nobody's business. After you are done bleeding each corner, do a nice thorough cleanup. You are doing this becuase later, when you check for leaks, if everything is clean, it's easy to find them.
-Before you start the car, pump the brakes with the car off for about 1 minute. If the pedal does not firm up and stop before reaching the end of it's travel, you have a problem. The pedal should stop, and be firm. After you reach the "firm" pedal stage, go back around the car and check for any leaks.
01-17-2005, 08:48 AM
#7
Windy has good advice, but to be clear - the most difficult things for 1st timer are:
getting at the thin bolts he describes and fitting the new pads inside the caliper. The rotor must be on and aligned properly against the hub; then place the new pads on the saddle or carrier against the rotor and slide the caliper over the top of the pads/rotor sandwich. Inusre that the piston is retracted all the way back into the caliper or you will not have enough room to fit the new pads in and it will be very frustrating. It will seem like the pads are loose, but they align themselves using the springs on top and they won't go anywhere once all the bolts are back on and tight - if this is your 1st time, this part seems like something might be wrong, but there is some small amount of float designed into the system. If you use anti-squeal goo, it will smear a little but you are OK as long as it doesn't get onto the rotor surface - be sure and let the goo dry for a while. The instructions say something like 10 min, but I always wait like 1/2 hour or let them sit in hot sun to dry significantly before reassmebly.
Also be sure to not let the caliper hang by the flex line; use an old wire hanger or other means to support it to relieve any stress on the flex line - this is important.
Also be sure to not let the caliper hang by the flex line; use an old wire hanger or other means to support it to relieve any stress on the flex line - this is important.