Bleeding Brakes ?

[Rootripper]

So how complex is this? Mr. Bentley says I need to have OBDII hooked up to software for brake bleeding procedure. Got a bad front caliper and wondering what I'm getting into?

[TiAgX5]

If you clamp off the brake line with a set of locking hose pinching plyers you will not get any air into the ABS/DSC metering module. A proper full system flush requires the OBD2 hookup to cycle the valves in the block, this removes/replaces the fluid in the module.

[Rootripper]

Thanks, clamping has been pretty much SOP for me. Fakin out technology is one of my favorite pastimes. Kinda hoped that would work. Got software coming but hate to learn that first, been dere

[haigha]

You don't need the OBD II port. There is a write up in the tips'n'tricks page:

Xoutpost.com - Xoutpost.com x5tips.htm [ search for "flush" ]

Easiest with two people.

[TiAgX5]

Originally Posted by haigha

You don't need the OBD II port. There is a write up in the tips'n'tricks page:

Xoutpost.com - Xoutpost.com x5tips.htm [ search for "flush" ]

Easiest with two people.

That DIY does NOT flush the old fluid or any air (if present) from the ABS/DSC valve body ass'y. Everyone doing that DIY will need to replace the module eventually.

The ONLY way to get fresh fluid into the valve body ass'y is to cycle the ABS module while doing the flush outlined in that DIY, in order to do that the OBDII port MUST be used.

[Rootripper]

Thanks again, this has been a great help. Any recommendation on new pads?

[haigha]

Originally Posted by TiAgX5

That DIY does NOT flush the old fluid or any air (if present) from the ABS/DSC valve body ass'y. Everyone doing that DIY will need to replace the module eventually.

The ONLY way to get fresh fluid into the valve body ass'y is to cycle the ABS module while doing the flush outlined in that DIY, in order to do that the OBDII port MUST be used.

Interesting point.

Questions:

Are you saying that the new brake fluid does not mix with any in the ABS valve body after doing the flush and driving around?

How much fluid does the valve body contain?

How would air get into the system unless you've done a fluid change improperly (or a part has broken)?

[TiAgX5]

Originally Posted by haigha

Interesting point.

Questions:

Are you saying that the new brake fluid does not mix with any in the ABS valve body after doing the flush and driving around?

How much fluid does the valve body contain?

How would air get into the system unless you've done a fluid change improperly (or a part has broken)?

Only a small amount mixes with the fluid in the entry ports of the ABS/DSC valvebody.

There's only a few ounces total volume in the ABS/DSC valvebody but brake fluid is EXTREMELY hygroscopic and readly absorbs ANY moisture (even humity in the air).

Some end up with air in the module by not properly maintaining fluid level during a brake bleeding procedure and introducing air into the valve ports.

[haigha]

Originally Posted by TiAgX5

Only a small amount mixes with the fluid in the entry ports of the ABS/DSC valvebody.

There's only a few ounces total volume in the ABS/DSC valvebody but brake fluid is EXTREMELY hygroscopic and readly absorbs ANY moisture (even humity in the air).

Some end up with air in the module by not properly maintaining fluid level during a brake bleeding procedure and introducing air into the valve ports.

Thanks for your follow up. The DIY covers the importance of not introducing air or other contaminants into the system and keeping the fluid in the reservoir full while doing the flush.

I'm surprised that the fluid doesn't mix after driving around. I will check with my mechanic for his thoughts when I see him tomorrow. We just did a flush on mine a few months ago using the DIY method. He used to be the master BMW mechanic at our local dealer.

[Green Dragon]

Originally Posted by Rootripper

Thanks again, this has been a great help. Any recommendation on new pads?

Hey,
As far as pads go, these's lots of options and different opinions out there for you to spend your money on. I decided to go with the $25 dollar semi-metallic from Autozone and love them so far. My rotors are near the point of no return, so I decided the lifetime replacement was worth it. They are quiet and very little brake dust, and bite well. Just thought you'd like to know that price doesn't always dictate quality.

I'm in the same boat with a sticking caliper, which I will be rebuilding both sides this fall as the dust boot has pulled free. They're not sticking now with the new pads and slide pins, but a rebuild is on my radar.