Full brake service and fluid flush to Bosch DOT 5.1 - 2018 LEAF SL

[goldbrick]

Any competent auto shop can flush the brake fluid on a Leaf. I do it in my garage at home with a $50 pressure bottle made for the job and it takes me about 20 minutes. I know not everyone can or wants to work on their own cars but there is nothing about this that requires a trip to a dealer. Shop around next time if you have independent shops nearby that you trust.

 

[BillAinCT]

I did the drain and fill yesterday. I was very surprised how yellow the old fluid was considering I never took the cap off or added fluid. I'm at 24,000 mi and the Leaf was manufactured in Oct 2021. So 3 years. It's much slower using gravity draining but it worked. I'll look for the pressure bottle for next time (3 years if not sooner). I ran more than a quart through. I rotated my tires too so it was good to do this while I was moving tires around.

 

[denwood]

I did the drain and fill yesterday. I was very surprised how yellow the old fluid was considering I never took the cap off or added fluid. I'm at 24,000 mi and the Leaf was manufactured in Oct 2021. So 3 years. It's much slower using gravity draining but it worked. I'll look for the pressure bottle for next time (3 years if not sooner). I ran more than a quart through. I rotated my tires too so it was good to do this while I was moving tires around.

I have the Motive pressure bleeder as well as the Speedibleed. The Speedibleed is much easier to use, and they sell the correct cap too. They are set up to use pressure from a tire (their kit includes a regulator to limit pressure to 10-15 psi) , so you don't even need a compressor. I swapped that connection over to use my compressor as I have a setup in my shop.

This is the kit for the 2018 and up LEAF: https://speedibleed.com/product/k1000-nissan-brake-bleeder/

For the 2011-2017, you need to select for either a 2 prong, or 3 prong cap via the product selector on the main page:

https://speedibleed.com/

 

[aqn]

Thanks for all the great info and pics, @denwood !

... like my Audi A3 as I got air in the ABS system. It took 3 hours of repeated bleeding, using a laptop and VAG software to run the ABS bleed sequence.

Did you do anything WRT to the fluid in the ABS system on the LEAF? The 2011 LEAF service manual doesn't say anything about doing anything to cycle the ABS pump when bleeding brakes (page BR-245 "Bleeding Brake System"). Previous cars that I have owned (all VW GTI's, actually) included using a VAG tool to cycle the ABS pump as part of brake bleeding procedure , same as your Audi A3.

 

[denwood]

@aqn , good question. The Audi A3 was a royal PITA to bleed, because I allowed air to enter the system (reservoir empty) during a flush. That did require ABS cycling with VCDS, at least an hour of repeated bleeding, a few test drives and repeats, to get back to a firm pedal. I don't own VW or Audi products any longer...

If you make sure the reservoir/bleed bottle always has fluid in it, no air can enter, and ABS will be fine. On the last two LEAFs I did (2018 both) there was no need to do anything other than flush a liter of the 5.1 through Same thing with our Highlander.

 

[aqn]

@denwood I was more wondering about how much fluid is in the ABS circuit, and whether/how much difference not flushing that circuit will make.

I looked in the service manual for my car. The diagram shows lines from the "intelligent brake unit" to the ABS actuator and from there to the calipers: the ABS actuator is in-line with the brake circuit and fluid does go through the ABS actuator when bleeding.

 

[denwood]

@denwood I was more wondering about how much fluid is in the ABS circuit, and whether/how much difference not flushing that circuit will make.

I looked in the service manual for my car. The diagram shows lines from the "intelligent brake unit" to the ABS actuator and from there to the calipers: the ABS actuator is in-line with the brake circuit and fluid does go through the ABS actuator when bleeding.
View attachment 5167

Yes, 100%..the ABS pump needs to be in line, otherwise there would be no way for it to modulate brake function when the ABS wheel sensors are displaying speed differences during braking. The intelligent brake controller is also in line as it will apply brakes at times using ePedal, when the car has detected you are crossing a traffic line (lane assist), or as part of the stability management etc. That controller can apply braking at any wheel. The ABS system is there to modulate (pulse) the brakes of a wheel(s) that has lost traction under braking.

The point of flushing is to ensure fresh brake fluid, with low moisture and active additives is present in all of those components, as they are expensive to replace! About a liter of fluid will do the trick during a flush to replace all the fluid in the system including the brake controller, ABS system, lines and the four brake calipers.

You also want to make very sure there is fluid in the reservoir at all times during a flush as you do want air trapped in any of those systems!

 

[denwood]

Someone on the forum had mentioned the lack of video material on brake fluid flush for the LEAF. Here you go:

I’m using the Speedi-Bleed system for a solo brake fluid flush. I use DOT 5.1 now for all of our vehicles. This clip is the second flush, 3 years after posting this thread, same car.

You guys might enjoy the Garagejournal “Easter Egg” at the end of the clip

 

[BillAinCT]

I use DOT 5.1 now for all of our vehicles.

For my Leaf I purchased 2 bottles from Nissan at the parts counter. I'm sure any fluid is fine, but I chose to use OEM and it wasn't any more expensive - in fact it was less than some others.

 

[denwood]

For my Leaf I purchased 2 bottles from Nissan at the parts counter. I'm sure any fluid is fine, but I chose to use OEM and it wasn't any more expensive - in fact it was less than some others.

DOT 3 is fine of course. Going to DOT 5.1 gets you much better cold weather performance (about half the viscosity, so much better flow, vs DOT 3 at -40C) and a dry boiling temp of 518 F. There is an advantage in ABS response in cold temps as well.

I use 5.1 now in everything, so I just keep the Bosch 5.1 fluid on hand.

 

[macnut]

Another owner here staying with DOT 3 because of driving pattern, climate and avoiding the need for a fully clean start when changing formulation.
The fluid in the reservoir of my newly-acquired 2015 looked relatively dark compared to my 2012.
Might be partly due to different transparency of the plastic used for the reservoir (USA versus Japan).
Anyway, not knowing when it was last done, I did a gravity bleed/replenishment at the first opportunity.
Took most of a L or U.S. quart to ensure fresh fluid reached all 4 calipers.


On the right is the major part of the bleed. On the left is after the final top off of the reservoir prior to the 1/4 turn tightening up.
(Note that front caliper nipples need a 9mm wrench and the rears an 8mm.)
Drained fluid showed 2% water on a cheap resistance tester, so wasn't quite at the change ASAP point.
Good opportunity to examine tires closely, pick out gravel, clean inside of wheels, apply anti-seize where appropriate, check pads etc.

While doing it I noticed the ABS unit has a grease pencil mark CoG on it (checked out good?).
So presumably had to have an out of warranty repair maybe 5 years ago which might have been last time the fluid got changed.
Could have even been at a dealership - some will source used parts if new unavailable.



Haven't got the impression on this forum that ABS units fail often. More likely to see a problem with sensors or the master cylinder assembly.

 

[denwood]

Looks great. Moisture is only one factor…the additive life is likely the larger factor at play.

You don’t need a full system clean to use 5.1. The Bosch 5.1 fluid (as any 5.1 fluid) is fully compatable with DOT 3, or 4

DOT 5 is silicone and you do not want that.

For DOT3, AC Delco GM OEM fluid was the all star for DOT3 fluid testing done by the US military. I posted that research here: https://bobistheoilguy.com/forums/t...tary-testing-dot-3-v-dot-4-vs-dot-5-1.354498/