Brake Flush Every 2 years
02-14-2019, 05:46 AM
#1
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Brake Flush Every 2 years
I understand Porsche recommends a brake flush every 2 years. People say brake fluid absorbs water. However, the brake system is a completely closed system so water is never in contact with brake fluid. If you track your car then high temps may degrade the brake fluid and flushing makes sense. Not sure why its necessary on street driven vehicles.
This topic came up when I was going to have my brake fluid flushed at the local Audi dealer. A friend of mine who is a Gold Rated mechanic for Audi and is factory qualified to work on R8's told me to save my money if I don't track my car then its not necessary to flush every 2 years. Comments?
This topic came up when I was going to have my brake fluid flushed at the local Audi dealer. A friend of mine who is a Gold Rated mechanic for Audi and is factory qualified to work on R8's told me to save my money if I don't track my car then its not necessary to flush every 2 years. Comments?
02-14-2019, 06:12 AM
#2
Rocky Mountain High
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Your mechanic can test your brake fluid for water content, which might give you some peace of mind if you choose a longer interval between flushes.
Personally, I tend to stick with the Porsche recommendations. This is especially true for things like brakes. It’s really not that expensive to change your brake fluid, so why not follow the manufacturer’s recommendation? Maybe it’s overkill and I don’t need to to it, but I do it anyway.
On another note, I’ve seen high water content in the brake fluid of cars that were not tracked. I bought a used Audi for my son many years ago, and the brake fluid was in terrible shape, even though that car hadn’t been tracked. Once we flushed it, the brake performance improved dramatically. This may have been due to factors other than water in the fluid, but again, why take a chance with brakes?
Personally, I tend to stick with the Porsche recommendations. This is especially true for things like brakes. It’s really not that expensive to change your brake fluid, so why not follow the manufacturer’s recommendation? Maybe it’s overkill and I don’t need to to it, but I do it anyway.
On another note, I’ve seen high water content in the brake fluid of cars that were not tracked. I bought a used Audi for my son many years ago, and the brake fluid was in terrible shape, even though that car hadn’t been tracked. Once we flushed it, the brake performance improved dramatically. This may have been due to factors other than water in the fluid, but again, why take a chance with brakes?
02-14-2019, 06:47 AM
#3
Its overkill. Think of the number of cars on the road. Think about how many of them don't see fluid flushes 1) every 4 years 2) ever. Lots.
I have helped people refresh new to them used cars many times doing fresh fluid changes. Usually the brake fluid is a nice shade of ick. Car stopped fine, new fluid looks good and we feel good for the $10 of fluid,
Germans like the 2y recommended interval. I follow it on our 3 german cars as I DIY and its trivial to do when swapping winter tires, but I am not the norm of car owners in the US (none of us enthusiasts are in the majority
)
- b
I have helped people refresh new to them used cars many times doing fresh fluid changes. Usually the brake fluid is a nice shade of ick. Car stopped fine, new fluid looks good and we feel good for the $10 of fluid,
Germans like the 2y recommended interval. I follow it on our 3 german cars as I DIY and its trivial to do when swapping winter tires, but I am not the norm of car owners in the US (none of us enthusiasts are in the majority
)- b
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bommerts (03-29-2020)
02-14-2019, 06:50 AM
#4
Rennlist Member
Buy a brake fluid tester for about $10 & you can flush when needed.
I find my brake fluid is good for 6 months and flush it accordingly. Also highly recommend Castrol SRF, you can feel the difference.
I find my brake fluid is good for 6 months and flush it accordingly. Also highly recommend Castrol SRF, you can feel the difference.
Last edited by 991carreradriver; 02-14-2019 at 05:52 PM.
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bommerts (03-29-2020)
02-14-2019, 07:38 AM
#5
Burning Brakes
I think if not tracking it is total overkill. Most daily drivers almost never see a fluid change. With that being said most of us that participate here are a little more fanatical about maintaining our 911's and do so at a higher standard than our normal cars. There is certainly nothing wrong with doing it every two years as suggested. However if you wanna go 3-4-5 years I really dont think it is going to make a huge difference.
Would be interesting to see an actual controlled test with old vs new fluid and seeing the quantitive difference in full braking situations.
Would be interesting to see an actual controlled test with old vs new fluid and seeing the quantitive difference in full braking situations.
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bommerts (03-29-2020)
02-14-2019, 08:08 AM
#6
Pro
Try this thought experiment: You are in a situation where you absolutely must stop in 120 feet. Instead you stopped at 121 feet.
I do this whenever I am on the fence about replacing tires or doing brake maintenance. Cheaper than body work.
991Carreradriver: do you test the fluid with that tool from the reservoir and is it representative of the fluid in the rest of the system?
I do this whenever I am on the fence about replacing tires or doing brake maintenance. Cheaper than body work.
991Carreradriver: do you test the fluid with that tool from the reservoir and is it representative of the fluid in the rest of the system?
02-14-2019, 08:22 AM
#7
Race Car
OP: My mechanic says the same thing - closed system, don't open it.
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bommerts (03-29-2020)
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02-14-2019, 09:09 AM
#8
Burning Brakes
I do mine mostly because I enjoy working on cars and my kids are teenagers.... I need the alone time in my garage.
02-14-2019, 09:19 AM
#9
FWIW, it seems that if you are going to run in any type of event at VIR then you have to have had a brake flush within the past two years. So, the track must think it is an important item to pay attention to. That combined with the Porsche recommendation makes it a no-brainer for me.
I've learned over the years that too much preventive maintenance is pretty hard to do.
I've learned over the years that too much preventive maintenance is pretty hard to do.
02-14-2019, 09:46 AM
#10
Nordschleife Master
I am sure that changing every 3 or 4 years instead of 2 for a non track car is not gonna have any adverse effects. For peace of mind, use the brake fluid tester.
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Fullyield (12-25-2020)
02-14-2019, 01:13 PM
#11
Rocky Mountain High
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I remember reading an article about a 959 that was restored in the US. It had essentially been sitting in storage ever since it was imported to the US, and was restored once it became old enough that it could be licensed and driven on US roads. Even though this car had been sitting and not driven, the brake internals (calipers, pistons, etc.) were completely corroded from moisture in the system. I assume that this was also a closed system, and was virtually untouched for 25 years. Obviously it’s a very different situation than the OP is asking about, but to me it shows that there is moisture inside the closed system. Again - I’m not saying this example is a reason to change your fluid more frequently, but it does tell me that even though the system is closed, it’s not immune to moisture contamination.
02-14-2019, 02:02 PM
#12
Three Wheelin'
Try this thought experiment: You are in a situation where you absolutely must stop in 120 feet. Instead you stopped at 121 feet.
I do this whenever I am on the fence about replacing tires or doing brake maintenance. Cheaper than body work.
991Carreradriver: do you test the fluid with that tool from the reservoir and is it representative of the fluid in the rest of the system?
I do this whenever I am on the fence about replacing tires or doing brake maintenance. Cheaper than body work.
991Carreradriver: do you test the fluid with that tool from the reservoir and is it representative of the fluid in the rest of the system?
With that said, why don't you just change the fluid? I track and do my own fluid with SRF. On my BMW, street only, the warning to change my fluid has been bugging me for the past 9 months. I'm not concerned with the car's ability to brake when needed. I'll change it in the spring when it warms up. You don't need to change the fluid every 2 years but every several years is good practice to keep the fluid fresh, seals, pistons etc.. in good shape. However, those will eventually wear out so you'll need to replace it, so you could argue you'll just refresh you r whole system every 10 years and save some money in between.
02-14-2019, 03:18 PM
#13
Race Director
I love it. Everyone whines and cries about they wouldn't buy cars without proper maintenance and spend all day rubbing sealant onto their ceramic coating for the PPF, yet they don't want to spend like $15 to do brake fluid every two years (or $150 at the dealer).
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02-14-2019, 03:29 PM
#14
Nordschleife Master
02-14-2019, 04:25 PM
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Brake fluid will pull moisture through the seals. If you’re going to flip your Porsche after a couple of years then it doesn’t matter. If your Porsche is a keeper then flush the brakes (and clutch if MT) every 2-3 years. DIY takes two hours and ~$20 of fluid.
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Need4S (12-23-2020)