What's the difficulty level of doing a brake fluid flush/bleed for a first timer?

[$iriu$black]

I am planning to do this on my stock 128 brakes and wonder if it's something that I can do right (doubting my self though I think I can do it like others). Just worried I will screw it up and not have a car as mine is a DD.

Will having a vacuum bleeder help a ton for a novice like me? Any help/advice will be greatly appreciated!

[Dackelone]

Get yourself a Motive pressure bleeder. The suction ones, well they suck. I really prefer a pressure bleeder. Also have a good quality wrench(flare tool or the like) to crack open the bleed screws/valves.

https://www.amazon.com/Motive-Produc.../dp/B0002KM5L0

No it's not a hard job - when you have the right tools for the job.

DIY Request - Brake Bleeding, Adding/Replacing Brake Fluid Procedure
http://www.1addicts.com/forums/showt...=241217&page=2

[E82MSport]

Originally Posted by Dackelone

Get yourself a Motive pressure bleeder. The suction ones, well they suck. I really prefer a pressure bleeder. Also have a good quality wrench(flare tool or the like) to crack open the bleed screws/valves.

https://www.amazon.com/Motive-Produc.../dp/B0002KM5L0

No it's not a hard job - when you have the right tools for the job.

DIY Request - Brake Bleeding, Adding/Replacing Brake Fluid Procedure
http://www.1addicts.com/forums/showt...=241217&page=2

I'm in total agreement that a pressure bleeder is an invaluable tool. I've have a Motive (same one in the link) and the seals wore out so I switched to the Schwaben and it's a far superior bleeder for the same money. Plus it has a pressure relief valve and a quick disconnect for the cap which makes screwing the cap on easy. If you have a Motive you know what I mean. You basically have to twist up the hose to get it to screw down without hose kink with the Motive bleeder.

https://www.ecstuning.com/BMW-E82-13...ols/ES2774831/

[$iriu$black]

Thank you for the advice! Still quite anxious about the job as it will be a first. But I agree, having right tools will make it easier.

[Ric in RVA]

No problems.

Suck the fluid out of the reservoir....as much as you can. Clean with a lint free cloth if there is any gunk in there.

Add new fluid (now is when I wish they had ATE blue still).

Got to rear of car and using vacuum or pressure bleeder do each rear cylinder. I have never had an issue with a vacuum bleeder that wasn't solved by a smear of grease around the threads of the bleed screws.

Now do front wheels and clutch line too. Take out your CDV if you haven't and you own a manual. Probably have to foot pump the clutch to bleed if you do the CDV.

Monitor fluid level in reservoir. When fluid starts coming out fresh close bleed screw. (made easier by ATE blue/yellow swap each fluid change...someone needs to sell the dye ATE used)

DON'T get air in system and you won't have any issues.

Test your brake pedal before you pull into traffic.

Re check your wheel torque after a few miles.

Pretty hard to screw up.

[$iriu$black]

I see. So lets say I upgrade to steel lines, just suction the reservoir first, let the old fluid drip from the lines til it doesnt anymore, then take the lines out and fill it up w new fluid using the vac pump after replacing lines. Is that a proper way of doing it?

[E82MSport]

If you're replacing the flex lines (stainless braided) at time of bleeding be aware you will most likely induce more air into the system that will require more bleeding.

As mentioned, when bleeding the system first remove the majority of the fluid out of the master cylinder reservoir in order to reduce the amount of new fluid that need to be pushed through the system. A turkey baster or such will do. Once you've removed the majority of the fluid then replace up to the max line with new fluid.

If you're using a pressure bleeder or not, you need to work from the furthest point to the closest. In the case of the 135, the right rear (passenger rear) should be first. Because you really can't tell when the fluid is new or not I suggest measuring. 1500ml should be more than enough for adequate flushing so 250ml per wheel is what you should remove with the expectation of slightly more for wheels that are in the rear. This is enough fluid for all lines and the reservoir.

Get a good catch bottle with hose like the one's pictured here.
https://www.ecstuning.com/BMW-E82-13...ing/ES2765516/


For you guys that loved ATE Blue and Gold

[John_01]

The pressure bleeder is intended to be used with the assumption that you never let the brake reservoir run dry. If you do let it run dry, you may get air bubbles into the DSC Hydraulic unit. When that happens you should probably get the system bled by a shop, or otherwise using a OBD interface that will activate the hydraulic pump and by using the correct workshop procedure. The same probably applies when the brake lines are changed.

I would say that replacing brake lines probably isn't a good DIY for a first timer (My opinion). Also, some of the aftermarket stainless lines are dubious quality, so in many cases you will be better off replacing with OE, or equivalent rubber lines.

[Ric in RVA]

Originally Posted by $iriu$black

I see. So lets say I upgrade to steel lines, just suction the reservoir first, let the old fluid drip from the lines til it doesnt anymore, then take the lines out and fill it up w new fluid using the vac pump after replacing lines. Is that a proper way of doing it?

In that case I would suction the reservoir, fill it, take the sensor off the cap and cover with plastic and put cap back on to create a vacuum to keep fluid in lines.

Just like your finger at the top of a straw.

Then do one line at a time and minimize time disconnected.

Then bleed that line and do the next.

The goal is to not get air in the abs pump since you don't have the tools to cycle it and bleed it.

You drain the system and you might have issues.

[lakefront]

If you really intend to open the brake system to replace lines, the best thing you can do for yourself is get a piece of 2x4 or pipe or something and wedge it between the seat and brake pedal so it pushes the pedal about half way. This activates a check valve in the system and fluid will stop dripping from the lines instantly. Did this on my wife's 335 and couldn't believe how good it worked.

[Ric in RVA]

Originally Posted by lakefront

If you really intend to open the brake system to replace lines, the best thing you can do for yourself is get a piece of 2x4 or pipe or something and wedge it between the seat and brake pedal so it pushes the pedal about half way. This activates a check valve in the system and fluid will stop dripping from the lines instantly. Did this on my wife's 335 and couldn't believe how good it worked.

Forgot about that....good call.

[wjk_glynn]

Originally Posted by E82MSport

...you need to work from the furthest point to the closest...the right rear (passenger rear) should be first

Thanks. I'll be giving this a go myself for the first time shortly. The full sequence (for my own notes) is:

1. Right rear
2. Left rear
3. Right front
4. Left front

And if you have a StopTech BBK installed up front (e.g. ST60), the sequence per their installation instructions would be:

1. Right rear
2. Left rear
3. Right front
   1. Outboard bleeder
   2. Inboard bleeder
4. Left front
   1. Outboard bleeder
   2. Inboard bleeder

Karl.