Goodbar
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Joined: Wed Sep 20, 2017 6:39 am
Delivery Date: 31 Jul 2017
Location: Washington, D.C. Metro

Re: Question on Service Intervals

Wed Aug 07, 2019 8:06 am

My primary concern is that I don't say something to the dealer that lets them twist my arm with a "well, if that's what you did, then you need to let us do it right, or else your warranty is void" argument. So if the Maintenance Guide says "Flush", but there is no maintenance procedure for Flush, what should I tell the dealer that I did?
Rest easy! The maintenance schedule in the service manual points to page BR-495 for brake fluid replacement. That page contains Drain and Refill steps and Bleeding Brake System is on BR-496, which I posted above. The Drain and Refill steps are repeated in the Maintenance section... but not bleeding. Don't ask me...

EDIT: Page numbers are for the 2017 service manual.

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Nubo
Posts: 5397
Joined: Fri May 28, 2010 11:01 am
Delivery Date: 31 Oct 2014
Location: Vallejo, CA

Re: Question on Service Intervals

Wed Aug 07, 2019 11:57 am

Goodbar wrote:
Wed Aug 07, 2019 6:18 am
Nubo wrote:
Tue Aug 06, 2019 8:21 pm
LeftieBiker wrote:
Tue Aug 06, 2019 1:57 pm
That looks like SOP to me.
There's a bit more to it when viewed in the context of *replacing* the brake fluid instead of just bleeding air. There are specific steps listed under "draining" the brake fluid that I suspect pertain to making sure the fluid in the ABS gets replaced. Some cars specifically require connection to diagnostic equipment to flush the ABS so Nissan may have actually thrown us a bone here.

My thoughts in full, as well as the larger section of the manual in this thread: http://mynissanleaf.com/viewtopic.php?f=30&t=20866
Why would the drain procedure be better for brake fluid replacement? My thought was that having the brake system energized would cause the pump to move fresh fluid through the ABS module without introducing air, though I don't have confirmation that it's so. I used the bleed procedure until I could see the fresh fluid — the old stuff (at 2 yrs) was surprisingly dark.
In my mind, because it exists as a distinct procedure and also has specific steps that are pointed at ABS function. You don't need the booster to be energized to move the fluid. With power disconnected the master cylinder still pumps when you push down the brake pedal.
I noticed you're still working with polymers.

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Nubo
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Re: Question on Service Intervals

Wed Aug 07, 2019 12:03 pm

LeafTaxi wrote:
Wed Aug 07, 2019 6:40 am
Nubo wrote:
Tue Aug 06, 2019 8:21 pm

There's a bit more to it when viewed in the context of *replacing* the brake fluid instead of just bleeding air. There are specific steps listed under "draining" the brake fluid that I suspect pertain to making sure the fluid in the ABS gets replaced. Some cars specifically require connection to diagnostic equipment to flush the ABS so Nissan may have actually thrown us a bone here.

My thoughts in full, as well as the larger section of the manual in this thread: http://mynissanleaf.com/viewtopic.php?f=30&t=20866
...which says
the service manual doesn't explicitly give a "flush" procedure. There's a "drain", a "refill" and a "bleed" procedure.
I am personally satisfied that changing fluid in the reservoir plus in calipers and the connecting lines between them will eventually mix with fluid in the ABS, because this is a fluid, and it moves... but that's my own decision (I am frequently wrong). Draining the master cylinder dry sets you up for a lot of extra work, and I suspect that dealers would not take the time. ...
Of course there's no reason to completely drain the master cylinder during a fluid replacement. I just pumped out enough fluid with the pedal until it was low, refilled the reservoir with fresh fluid as needed, and pumped until pristine fluid came out the nipples. As far as ABS, the manual doesn't give much theory. But seeing as how it is the single most expensive part of the braking system, I wanted to do what I could to get fresh fluid through it.
I noticed you're still working with polymers.

powersurge
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Location: Long Island, NY

Re: Question on Service Intervals

Wed Aug 07, 2019 4:53 pm

The ABS is in between the master cylinder and the calipers, so when you bleed the calipers, you are also bringing in new fluid to the master cylinder. No need to worry that it has to be energized.

The important thing is to no let the fluid stagnate and rust the system or the calipers... I have seen some NASTY calipers with tons of rust and crud in the pistons when you rebuild them..

LeafTaxi
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Re: Question on Service Intervals

Thu Aug 08, 2019 6:25 am

powersurge wrote:
Wed Aug 07, 2019 4:53 pm
I have seen some NASTY calipers with tons of rust and crud in the pistons when you rebuild them..
Agreed. I'm working on my cousin's 1977 Kawasaki. It had been parked 10 years, and it took some extra effort, as the brake piston and seals are no longer available.

LeafTaxi
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Re: Question on Service Intervals

Thu Aug 08, 2019 6:50 am

Goodbar wrote:
Wed Aug 07, 2019 8:06 am

The maintenance schedule in the service manual points to page BR-495 for brake fluid replacement. That page contains Drain and Refill steps and Bleeding Brake System is on BR-496, which I posted above.
I have access to the 2011-2014 maintenance manual. It shows
- Inspection
- Draining: shut-off all electric things, shut all doors, wait 3 minutes, disconnect battery; then hook-up bleeder tube, open, and pump brakes until empty
- Refilling
- Bleeding: "Turn the power switch without depressing the brake pedal"; hook-up bleeder tube; pre-pump the pedal 4-5 times (remove residual vacuum from the booster); "Loosen the air bleeder and bleed air with the brake pedal depressed, then quickly tighten the bleeder" (2-man method); repeat, adding fluid as necessary. Interesting wheel order for 2011-2014: RR, FL, RL, FR

There's no "Replace" section, unless Replace means Drain+Refill. But draining completely would be stupid, so I expect that the dealer does the Bleed procedure, but removes sufficient fluid to call it "replaced." Which is what I'll do, and tell them I did, if they ask. I'll also have the rotor thickness and runout numbers written on the printed-out procedure to make it look official :)

Goodbar
Posts: 28
Joined: Wed Sep 20, 2017 6:39 am
Delivery Date: 31 Jul 2017
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Re: Question on Service Intervals

Thu Aug 08, 2019 11:58 am

LeafTaxi wrote:
Thu Aug 08, 2019 6:50 am
Goodbar wrote:
Wed Aug 07, 2019 8:06 am

The maintenance schedule in the service manual points to page BR-495 for brake fluid replacement. That page contains Drain and Refill steps and Bleeding Brake System is on BR-496, which I posted above.
I have access to the 2011-2014 maintenance manual. It shows
- Inspection
- Draining: shut-off all electric things, shut all doors, wait 3 minutes, disconnect battery; then hook-up bleeder tube, open, and pump brakes until empty
- Refilling
- Bleeding: "Turn the power switch without depressing the brake pedal"; hook-up bleeder tube; pre-pump the pedal 4-5 times (remove residual vacuum from the booster); "Loosen the air bleeder and bleed air with the brake pedal depressed, then quickly tighten the bleeder" (2-man method); repeat, adding fluid as necessary. Interesting wheel order for 2011-2014: RR, FL, RL, FR

There's no "Replace" section, unless Replace means Drain+Refill. But draining completely would be stupid, so I expect that the dealer does the Bleed procedure, but removes sufficient fluid to call it "replaced." Which is what I'll do, and tell them I did, if they ask. I'll also have the rotor thickness and runout numbers written on the printed-out procedure to make it look official :)
Yeah, the service manual seems needlessly unclear on this. Makes me hark back to the good ole days... when I alternated ATE "super blue" and clear brake fluid in my VWs and motorcycle so it was really easy to tell when you had fresh fluid. Apparently blue brake fluid is no longer allowed in the US(!) so that method is defunct. Many Euro cars have a 45mm screw-on reservoir cap, making it easy to use a pressure bleeder. SO much better than the two-person method.
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