A/C flush and Brake pads question
01-28-2010, 03:32 PM
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A/C flush and Brake pads question
Hello Audi fellas!
I have 2 questions for you.
1. I am replacing seized up a/c compressor on my 03 2.7T. I got new compressor, filter/dryer, o-rings, and orfice tube. The problem is I cannot find the location of the filter dryer and the orfice tube on the car. I followed the a/c lines from service ports and from a/c compressor and still don't see it. Also please advise me on how to properly flush the system and on any needed parts/tools. I do work on my a6 and I do have a/c experience (I work on Prevost buses). I'm familiar with a/c machines, vacuum pumps, gauges etc. On buses to flush the system I use special alcohol solution that is forced into the system though HI side service port. Then with a blow gun or compressed nitrogen it is pushed around and exits though LOW side service port (not attached to the compressor). Is there anything else I should know before I start to put new compressor in?
2. My front brake pads are due for replacement. I have original OEM pads and rotors right now. I'm looking on the net for just front set of pads but there are tons of them out there and they have different dimensions. Does anyone know what is stock measurement of the front rotors? Also any recommendations on good brand that will pair up with my rotors? I'm not a race driver and I am very happy with original pads, just I'm on a budget with the a/c job. Thanks for any help!
I have 2 questions for you.
1. I am replacing seized up a/c compressor on my 03 2.7T. I got new compressor, filter/dryer, o-rings, and orfice tube. The problem is I cannot find the location of the filter dryer and the orfice tube on the car. I followed the a/c lines from service ports and from a/c compressor and still don't see it. Also please advise me on how to properly flush the system and on any needed parts/tools. I do work on my a6 and I do have a/c experience (I work on Prevost buses). I'm familiar with a/c machines, vacuum pumps, gauges etc. On buses to flush the system I use special alcohol solution that is forced into the system though HI side service port. Then with a blow gun or compressed nitrogen it is pushed around and exits though LOW side service port (not attached to the compressor). Is there anything else I should know before I start to put new compressor in?
2. My front brake pads are due for replacement. I have original OEM pads and rotors right now. I'm looking on the net for just front set of pads but there are tons of them out there and they have different dimensions. Does anyone know what is stock measurement of the front rotors? Also any recommendations on good brand that will pair up with my rotors? I'm not a race driver and I am very happy with original pads, just I'm on a budget with the a/c job. Thanks for any help!
01-28-2010, 06:54 PM
#4
AudiWorld Super User
Look up ECS Tuning on the web or call them they will hook you up with the brakes I had no problems with our 01 and 04 A6's just stay with Zimmerman rotors and ATE pads.
Good luck.
Good luck.
01-29-2010, 07:32 AM
#5
AudiWorld Super User
I've been happy with Hawk HPS pads on the rear. I've just ordered HPS pads for the HP-2 (4 pads per caliper) fronts from topbrakes.com. The Hawk HPS have a nice initial bite and don't fade.
You can often just replace pads rather than pads and rotors, notwithstanding the meager wear limits on the OEM rotors. Takes awhile longer to bed the pads but the old adage, if it ain't broke, don't fix it applies. Only problem might be a worn pad on a worn rotor might extend the piston further than is desirable. I think I've gotten that far with the rear caliper pistons because they were difficult to twist/force back into their bore...once started they moved easily. I'll probably have to replace the rear rotors next time around (get some cool–looking slotted rotors to monitor rotor wear visually) but that's thirty k miles down the rřad!!
You can often just replace pads rather than pads and rotors, notwithstanding the meager wear limits on the OEM rotors. Takes awhile longer to bed the pads but the old adage, if it ain't broke, don't fix it applies. Only problem might be a worn pad on a worn rotor might extend the piston further than is desirable. I think I've gotten that far with the rear caliper pistons because they were difficult to twist/force back into their bore...once started they moved easily. I'll probably have to replace the rear rotors next time around (get some cool–looking slotted rotors to monitor rotor wear visually) but that's thirty k miles down the rřad!!
01-30-2010, 04:44 PM
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Thanks for all your posts, its a very big help. As I expected Audi way of flushing the system requires A/C machine with "flush" option plus a bunch of special connectors. Can't be done that way in my garage so I will have to improvise. Anyway its cool to see how it's done by the "book" (thanks Jcman for your files). As far for the pads I ordered ATE pads so they should pair up with the zimmerman rotors that I have. Thanks for SloopJohnB for your input, it is greatly appreciated. I will post some info after I'm done with A/C project, someone else may find my "home" solutions down the road...Thanks!
02-10-2010, 06:06 PM
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This past Saturday I've finally completed A/C compressor replacement job. From all the posts about flush vs no flush I determined that it should be a good idea to at least flush the lines and the condenser. I got the solution from auto zone. Then you need a good air compressor to blow it out for a good period of time, but let me start from beginning...
To do this job make sure you have enough time available. When my ac compressor pulley fell apart I had to tow the car and it stayed in the garage for 2 weeks. This is how long it took me to order and to get all the parts needed. The serpentine belt was smoking but the engine run so I drove it on the portable ramps. Then I drained coolant and removed bumper. Next I pulled out all the front assembly (radiator,fans,condenser, etc.) and supported it on small jacks. The condenser was still connected. Than you need to recover the freon. Now, freon R-134a is not dangerous to ozone layer (like R-12 or R-22) however it is not legal to release it to the atmosphere so the best it to use an a/c recovery machine. If you decide to release it anyway do it on YOUR OWN risk. After the system was empty I disconnected lines from the evaporator (the 2 lines that go into the cabin, just under cabin air filter). Inside the left line close to the service port will be an orifice tube (looks like a small plastic filter). If you had a failed ac compressor it needs to be changed. I ordered mine online for about $3. Very important is to change EVERY o-ring in every ac line connection. (Don't waste your time or money trying to order piece by piece. Order the whole o-ring kit, auto zone can get it for $12). Remember also about ac system oil. Our cars use PAG 46 oil (you need 8 oz.). When installing o-rings dip them in this oil. Now, to remove ac compressor I had to remove driver side inter cooler lines and bottom hose. This is to get the access to the back mounting bolt of the compressor (total 3 bolts). You also need to disconnect oil filter housing hose and remove oil filter. The good thing is you don't need to remove radiator fan. Disconnect 2 ac lines that go to compressor. After the 3 mounting bolts are off just slowly wiggle the compressor out. If you decide to get a rebuilt compressor($200) make sure it is with oil in it(remove the small bolt on top of the compressor in the center). Flip it up side down and let the oil out for 10 min. My compressor had 8 oz. inside which is pretty much all you need for the whole system. Now, you can reuse the oil or use new oil like I did, but don't pour all of it into the compressor. Save like 2 oz for the filter(called the drier or the accumulator). The filter is located just behind passenger side inter cooler and I have to say it.s a bit pain in the *** to remove (3 10mm nuts). To make it easier I removed bottom mounting bolt from the fender. I got my filter online for $50, but make sure you order the right one! The first filter I got had different ports and didn't fit. I thought I made a mistake while typing car info, but it was their screw up. The filter like the compressor is precharged with nitrogen so don't open it until you're ready to mount it. Now, it is time to flush the condenser and lines which should be disconnected by now. Remove the fan assembly from the condenser and dismount condenser(don't forget to disconnect the pressure switch). Pour the solution into the smaller hole (leave some solution for the lines) and using air compressor and a blow gun push the solution through the condenser. It is crucial to remove everything from it so blow it until nothing comes out(close the exit hole with your finger once a while to create more back pressure if your compressor isn't too strong). Do the same with both ac lines. I didn't flush evaporator since I saw clean oil came out from it(oil from the failed compressor was black and had parts of broken reed valves). Evaporator is after the filter and orifice tube so no dirt passed into it. So now put new o-rings everywhere(don't forget and dip them in PAG oil). Install filter last to limit its exposure to moisture. Don't forget to add the rest of the oil into the filter. Reinstall all the other parts in reverse order. Turn the ac compressor 20 times by hand to get the oil where it needs to be. Connect the ac gauges to service ports and to the vacuum pump. Vacuum the system for about 30-45 min (after few min. tighten all hoses on ac gauges and vacuum pump). You should see pressure on the LOW side going to almost -30 PSI. After you're done close the gauges and leave it for few hours to check if nothing is leaking. If the LOW side gauge stayed at -30 PSI the system is leak free. Now you need R-134a freon. You can get it in any auto parts store. I prefer bigger bottle and an ac scale to precisely measure amount of freon going into the system (amount you need is on the sticker under the hood). Mine was 650g +/- 50g. This is why I prefer one bigger container over those cans, you can measure it more precisely. You don't want to overfill the system, this might give excessive HI side pressure and decrease your compressors life. Remember to add freon on the LOW side only and in the vapor state not liquid. This should be it. I realize its not to much detailed description but if you need more info just drop me a line and I will answer. Take care!
To do this job make sure you have enough time available. When my ac compressor pulley fell apart I had to tow the car and it stayed in the garage for 2 weeks. This is how long it took me to order and to get all the parts needed. The serpentine belt was smoking but the engine run so I drove it on the portable ramps. Then I drained coolant and removed bumper. Next I pulled out all the front assembly (radiator,fans,condenser, etc.) and supported it on small jacks. The condenser was still connected. Than you need to recover the freon. Now, freon R-134a is not dangerous to ozone layer (like R-12 or R-22) however it is not legal to release it to the atmosphere so the best it to use an a/c recovery machine. If you decide to release it anyway do it on YOUR OWN risk. After the system was empty I disconnected lines from the evaporator (the 2 lines that go into the cabin, just under cabin air filter). Inside the left line close to the service port will be an orifice tube (looks like a small plastic filter). If you had a failed ac compressor it needs to be changed. I ordered mine online for about $3. Very important is to change EVERY o-ring in every ac line connection. (Don't waste your time or money trying to order piece by piece. Order the whole o-ring kit, auto zone can get it for $12). Remember also about ac system oil. Our cars use PAG 46 oil (you need 8 oz.). When installing o-rings dip them in this oil. Now, to remove ac compressor I had to remove driver side inter cooler lines and bottom hose. This is to get the access to the back mounting bolt of the compressor (total 3 bolts). You also need to disconnect oil filter housing hose and remove oil filter. The good thing is you don't need to remove radiator fan. Disconnect 2 ac lines that go to compressor. After the 3 mounting bolts are off just slowly wiggle the compressor out. If you decide to get a rebuilt compressor($200) make sure it is with oil in it(remove the small bolt on top of the compressor in the center). Flip it up side down and let the oil out for 10 min. My compressor had 8 oz. inside which is pretty much all you need for the whole system. Now, you can reuse the oil or use new oil like I did, but don't pour all of it into the compressor. Save like 2 oz for the filter(called the drier or the accumulator). The filter is located just behind passenger side inter cooler and I have to say it.s a bit pain in the *** to remove (3 10mm nuts). To make it easier I removed bottom mounting bolt from the fender. I got my filter online for $50, but make sure you order the right one! The first filter I got had different ports and didn't fit. I thought I made a mistake while typing car info, but it was their screw up. The filter like the compressor is precharged with nitrogen so don't open it until you're ready to mount it. Now, it is time to flush the condenser and lines which should be disconnected by now. Remove the fan assembly from the condenser and dismount condenser(don't forget to disconnect the pressure switch). Pour the solution into the smaller hole (leave some solution for the lines) and using air compressor and a blow gun push the solution through the condenser. It is crucial to remove everything from it so blow it until nothing comes out(close the exit hole with your finger once a while to create more back pressure if your compressor isn't too strong). Do the same with both ac lines. I didn't flush evaporator since I saw clean oil came out from it(oil from the failed compressor was black and had parts of broken reed valves). Evaporator is after the filter and orifice tube so no dirt passed into it. So now put new o-rings everywhere(don't forget and dip them in PAG oil). Install filter last to limit its exposure to moisture. Don't forget to add the rest of the oil into the filter. Reinstall all the other parts in reverse order. Turn the ac compressor 20 times by hand to get the oil where it needs to be. Connect the ac gauges to service ports and to the vacuum pump. Vacuum the system for about 30-45 min (after few min. tighten all hoses on ac gauges and vacuum pump). You should see pressure on the LOW side going to almost -30 PSI. After you're done close the gauges and leave it for few hours to check if nothing is leaking. If the LOW side gauge stayed at -30 PSI the system is leak free. Now you need R-134a freon. You can get it in any auto parts store. I prefer bigger bottle and an ac scale to precisely measure amount of freon going into the system (amount you need is on the sticker under the hood). Mine was 650g +/- 50g. This is why I prefer one bigger container over those cans, you can measure it more precisely. You don't want to overfill the system, this might give excessive HI side pressure and decrease your compressors life. Remember to add freon on the LOW side only and in the vapor state not liquid. This should be it. I realize its not to much detailed description but if you need more info just drop me a line and I will answer. Take care!
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02-11-2010, 03:23 PM
#8
AudiWorld Super User
Glad to be of some help and good hearing all went well, and you’re right on with a deep vac the pag and poe also used in commercial refrigeration is a moisture sponge when exposed in the open air. God I miss mineral oil and R-12.
John V.
John V.
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