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Discussion Starter · #1 ·
I've done a bit of searching and everything I've found is on the 987 not the 981, also most of the links in the articles seem to be dead.

Is there anything I should be looking for in the procedure for flushing brake fluid? I have a Griot's power Bleeder (https://www.griotsgarage.com/product/one-person+brake+bleeder.do) and in my '71 all I do is start topping on the main reservoir, then starting at the outside Right rear (furthest from the reservoir) start sucking fluid through until I see it looking clean. Then move to the inside, LR, RF, LF.

Any other places that have a bleed location, an ABS pump or the like that I need to watch for?

thank you!
 

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Discussion Starter · #3 ·
the one you want is the motive.. presure above .... push into the system not pull from the system..

Lemon
Why is that? I've used this one for a long time on the 911s does it have to do with the abs?
 

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The factory procedure is to put the car in brake flush mode with a PIWIZ, which opens the valves in the ABS making it easier. However, a good job can be done with a pressure based flush. I have the Motive device.

V6
 

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The factory procedure is to put the car in brake flush mode with a PIWIZ, which opens the valves in the ABS making it easier.
That's when you get air in the system, either by mistake, or when replacing a brake component. For a simple flush done regularly (no nasty fluid), you don't need to activate the ABS pump, and you can use any method you want. I always use vacuum myself every 2 years max, with a self-filling bottle, so never a risk of sucking reservoir dry. Works like a charm;).
 

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Same procedure as your '71. Don't worry about the ABS. I bleed every six months to meet DE requirements, two years on the non-P cars and bike.
 

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I find it hard to tell when the fluid is old then new (sure wish we could still use Super Blue and Gold). I go by this formula:
RR 500ml
LR 200ml
RF 150ml
LF 150ml

I also use a pressure bleeder.
 

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I go by this formula: RR 500ml, LR 200ml, RF 150ml, LF 150ml
I don't measure, but pretty much do the same thing. But since calipers have 2 nipples each, will buy an extra pint in case a quart is not enough. The beginning requires the most fluid, to clear both the reservoir and ABS module. The rest 3 corners are just the lines and calipers. But yes, when done regularly, it's very hard to tell the difference between similar shades of yellow. But people need to keep in mind moisture doesn't change the fluid's color, and that's the main reason to replace fluid in the first place.

My car's oil change was due Aug 09 (about 4,600 miles now), and 2 years from build date is Dec, so will do both in-between after a 1K-mile trip to the mountains next week, which would be the last of the year. Will try the bleed job when car is on the air for the oil change, but if unable to do the job well with the rear wheels in place (ramps, vs jack stands in front), will have to lift each corner independently after finishing the oil change, since it's better to start from the rear.
 

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My car was delivered in December 2015 and I bought it in March 2016. Wondering if I should flush the fluid in 3 months or wait till next spring...

When I flushed the fluid in the M5, I sucked out most of the fluid in the reservoir with a new turkey baster first, then attached the pressure bleeder and went in the same pattern as mentioned here. Pumped up the bleeder to 15 psi and went from there.
 

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Wondering if I should flush the fluid in 3 months or wait till next spring.
I'd do it before, if you have the chance, especially if it's humid where you live. And also to comply with the maintenance schedule. But for a few months, it's really not a big deal. Any issues with the braking system would happen well beyond warranty, even with total disregard of brake fluid maintenance. Therefore, it's mostly to treat the car (and future owner) right;). But also to have the best performing brake fluid possible, which is not the case if it has any moisture in it, meaning lower boiling point. And for those who track, it has to be replaced a lot sooner than 2 years, especially in hot climates.
 

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Yeah I plan on buying the car when my lease ends and holding onto it for as long as I can. I'm only at 8700 miles so it's going to be a while before I need to worry about replacing pads/plugs/air filters, although I'll replace the cabin filter in the spring.
 

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I'd do it before, if you have the chance, especially if it's humid where you live. And also to comply with the maintenance schedule. But for a few months, it's really not a big deal. Any issues with the braking system would happen well beyond warranty, even with total disregard of brake fluid maintenance. Therefore, it's mostly to treat the car (and future owner) right;). But also to have the best performing brake fluid possible, which is not the case if it has any moisture in it, meaning lower boiling point. And for those who track, it has to be replaced a lot sooner than 2 years, especially in hot climates.
Didn't feel creating a new thread so thought I'd ask here:

I bled mine using a pressure bleeder about a month ago now and definitely got rid of some air bubbles; the pedal feel is much firmer. But now I have a strange pedal feel only when driving below 10 mph. The best way to describe it is like the feeling when you step on walnut shells and it crunches underneath you. I can also hear the pedal for the first inch of travel, whereas it was quiet before. It kinda sounds like a hand pump you'd use for your bike.

I was having a little issue with the outer bleeder screw on the front right caliper: I wasn't getting enough fluid coming out so I loosened it some more, but then fluid started coming out from the threads that are tapped into the caliper. Pressure was around 20 psi so that should've been enough, but since it wasn't, my friend stepped on the brake pedal and that helped to push it along.

I don't see how that could cause this but that's the only "non-standard" thing we did. It feels like there's air in the system at low speeds up to 10 mph, but it's absolutely fine at high speeds.

Any thoughts?
 

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Any thoughts?
Just to close this out, the dealer diagnosed the problem to be the brake booster. They discovered the noise coming from there and decided to replace it after no luck with lubricating the pushrod/bellows assembly.

Part was expedited from the Motherland and I picked up the car today after driving a base Macan as a loaner for 5 days. For a CUV, it actually wasn't too bad. It's essentially the same instrument cluster so it was a familiar setting, but I felt like I could see the earth's curvature from being so high.
 

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Just to close this out, the dealer diagnosed the problem to be the brake booster. They discovered the noise coming from there and decided to replace it after no luck with lubricating the pushrod/bellows assembly.
I was going to say that the noise thing did not sound right - glad they fixed it.

Agree that either push or pull seems to be okay - have ready many people doing both. I bought a reservoir lid with an air pressure connection and put about 5 psi (air) or so on there and go around the car like you described. Very quick to set up and get it done.

Having fluid come out of the threads is no big deal. Just screw the fitting back in some and continue - you can get any air out that might have leaked in. Also, some bubbles that you may see coming out are actually from air being sucked around the threads and getting into the tube. For example, if you see a steady stream of small bubbles, I would say most likely that is not air from inside your caliper but some air leaking in through the loose fitting.
 

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Having fluid come out of the threads is no big deal. Just screw the fitting back in some and continue - you can get any air out that might have leaked in. Also, some bubbles that you may see coming out are actually from air being sucked around the threads and getting into the tube. For example, if you see a steady stream of small bubbles, I would say most likely that is not air from inside your caliper but some air leaking in through the loose fitting.
The issue with letting fluid just come out from the threads is there's no way to capture it and measure how much you've collected. Fortunately that was in the front right so not much needs to come out.

And yeah it did seem a steady stream of bubbles was coming through the threads. I'm sure finding that sweet spot will be easier next time.
 

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I find it hard to tell when the fluid is old then new (sure wish we could still use Super Blue and Gold). I go by this formula:
RR 500ml
LR 200ml
RF 150ml
LF 150ml

I also use a pressure bleeder.
Sorry to resurrect this post but I have an additional question - the volumes were very helpful, but assuming I start with the outside valve and then the inside valve, I am assuming I need to go the full amount (i.e. RR 500ml for the outside) and then may 100ml, probably less for the inner valve? Thanks in advance.
 

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Sorry to resurrect this post but I have an additional question - the volumes were very helpful, but assuming I start with the outside valve and then the inside valve, I am assuming I need to go the full amount (i.e. RR 500ml for the outside) and then may 100ml, probably less for the inner valve? Thanks in advance.
Correct- outside caliper first, then inside.

Most of the old fluid will come out from the outside bleeder screw so even if you did 400 to 450 ml from the outside and 100 to 50 ml from the inside, that should be enough. No harm in doing 500ml from the outside and 100ml from the inside too; you'll just need more than 1 liter but it's nice to have 2 liters anyway. I think if we budget 2 liters of brake fluid every 2 years, the "waste" is negibile IMHO.
 
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