Brake fluid change

[oldman42]

My i3 is due for brake fluid service. Has anyone does this DIY yet? I haven't found anything online. Is it the same setup as other modern vehicles? Release the bleeder valve on the caliper, pump the brakes, refill the master cylinder, repeat for all four corner, done?
Also, what brake fluid is needed? Dot 3? 4?
My first BMW, and obviously, first i3. Thanks, all!

 

[jadnashuanh]

Only the very first i3's sold in the USA wouldn't be still in warranty...

Essentially, yes, that's the procedure if you don't have special tools to do it. You need to ensure you don't suck air in when the pedal is released, so you need either someone to close the valve before you let it back up, or use a one-way valve, or have a hose on the bleeder that is in fluid. It's quicker and easier if you can pressure bleed it. Don't remember, but think it's DOT 4...use a good quality product from an unopened can.

 

[alohart]

Only the very first i3's sold in the USA wouldn't be still in warranty...

BMW began limiting the i3's 4 year maintenance coverage to original owners only. That change occurred after the 2014 models, but I'm not sure exactly when. As a result, there are increasing numbers of used i3 purchasers who don't have maintenance coverage.

 

[oldman42]

Only the very first i3's sold in the USA wouldn't be still in warranty...

Essentially, yes, that's the procedure if you don't have special tools to do it. You need to ensure you don't suck air in when the pedal is released, so you need either someone to close the valve before you let it back up, or use a one-way valve, or have a hose on the bleeder that is in fluid. It's quicker and easier if you can pressure bleed it. Don't remember, but think it's DOT 4...use a good quality product from an unopened can.

BMW began limiting the i3's 4 year maintenance coverage to original owners only. That change occurred after the 2014 models, but I'm not sure exactly when. As a result, there are increasing numbers of used i3 purchasers who don't have maintenance coverage.

Thanks for the replies, thus far.
I purchased my i3 used, so I'm outta luck with the maintenance plan. Besides, I like to get my hand dirty every so often.
BTW, the brake fluid cap states "use Dot 4 fluid." Now I have to figure out how much I need.

 

[TOEd]

In my experience a brake flush takes less than 250 ml of fluid to do all four wheels. This is based on flushing until a honey coloured liquid comes out rather than replacing all of the fluid. Major advantage to doing a flush is that it frees up the bleeders that tend to seize due to corrosion. I found a defective solid core bleeder on my Honda CRV. As you probably know bleeders have a hole down the centre to facilitate bleeding. Easy to replace once you get the correct part. After 2 years our smart ED brake fluid was like new. So my guess is that i3 will be the same.

 

[jadnashuanh]

Unless you have the ability to verify the boiling point of brake fluid, it's hard to tell if it is past it's best service life! The stuff has such an affinity for moisture, it can suck some in through the rubber hoses and connections. Once it absorbs moisture, the boiling point drops, and at the extreme, it starts to corrode the internal parts. It's really best to flush the full volume of brake fluid for best effect. Things like the ABS, brake pistons, and master cylinder do not like moisture and corrosion can get REALLY expensive, not counting the potential of brake fade if it starts to boil (not likely on the i3 with the regen).

 

[TOEd]

There are several easy methods to determine moisture content in brake fluid. Please see https://www.linkedin.com/pulse/motor-vehicle-brake-fluid-fundamentals-testing-kiril-mucevski
I prefer the visual discolouration method. I own several voltmeters so will try out this method next time I do a brake flush. I will also check out the $25 tester at Princess Auto next time I am in the store. Will also check out their refractometers as they are often on sale and have many uses including determining ethylene glycol in water and maple syrup concentration.
In the old days we never changed brake fluid. It was only flushed during a brake job. To this day many older guys refuse to do this preventive work. https://bottomlineinc.com/life/car-maintenance/car-maintenance-you-dont-need-including-most-every-kind-of-flush
Corrosion inhibitors in brake fluid must be pretty good to be able to get away with this.

 

[TOEd]

Went to Princess Auto today. Brake fluid tester and refractometer have been discontinued. However both are still available on Amazon. Voltmeter test looks interesting. Based on principle of galvanic corrosion that occurs in presence of moisture, a reading of less than 0.3 volts is ok when measured between negative battery terminal and the brake fluid reservoir. This voltage is temperature dependant so I would err on the side of caution in cold weather. I haven't yet tried this method.

 

[TOEd]

It was mild (5C) today so I tried the voltmeter test on the brake fluid. 2013 Honda CRV reading was 0.020 volts. 2015 BMW i3 reading was 0.012 volts. Low values indicate that brake fluid is very dry. Brake lines on Honda were bled during brake job that I performed last summer. According to the work order, brake lines were flushed on i3 at dealer last summer. I will try this method again after a couple of years.

 

[oldman42]

So... things got busy and I never got around to the brake fluid change. I took the i3 to the local dealer for a software update (and other things) and decided to have them do the brake fluid, cost me $220 (Southern California).

 

[jadnashuanh]

My local dealer charges $89 for a brake line flush...it's still cheaper to do it yourself even if you have to buy tools. For the next one, I picked up a pressure bleeder from a place online ecsTuning.

 

[vinc]

Reviving this old thread. Two questions. From what others are saying, I take that the cost of doing the brake fluid change can wildly vary from dealer to dealer? I was quoted $750 for the scheduled 60K miles service plus brake fluid change at the closest BMW dealer, which to me sounds rather nuts.

And if that cost turns out not to be fully bananas, could I just take the car to a regular BMW mechanic and have them take care of it, or is it too different from an ICE BMW?

I would try doing it myself, but I tend to break things.

 

[jadnashuanh]

Flushing the brake fluid isn't really much of any different on an i3 than it is on another vehicle. You do want to use a power flush rather than the old standby where someone pushes the pedal to the floor while another deals with the bleeder valve...that extra stroke to the end could cause problems down the road.

 

[vinc]

Thanks! Very helpful. I will take the car to a regular BMW mechanic and will report back with anything worth noting