HEXHEAD Tech - R1200R - '07-09 Brake Fluid Flush

[deilenberger]

The articles, posts and comments in this tech section are posted by individual members and reflect their personal thoughts and experiences with repairing, maintaining, and generally working on motorcycles. This information may require specific knowledge and skills, may or may not be correct or current to model.

The authors of information found here and the BMW MOA take no responsibility for ensuring the accuracy of any information (including procedures, techniques, parts numbers, torque values, tool usage, etc.), or further for any damage of any kind or injuries incurred or caused by anyone following the instructions or information found here.

It is the duty of the individual to either assume the liability himself for responsibly using the information found here, or to take the bike or accessory to a Dealer or other qualified professional service.

Lastly, please ensure you dispose of your used chemicals, oils and fuels in an environmentally responsible manner. Most Auto Parts stores and service stations will accept used oil and lubricants, tires and batteries, please check for your local availability.

This article, text and photos are Copyright of the individual authors and the BMW MOA, any copying or redistributing is permitted only by prior written authorization.

---------------------------------------------------------------------------------------------------------------
AUTHOR'S DISCLAIMER: The author takes no responsibility for any damage or injuries incurred by anyone following the instructions given in this DIY. You should assume the author is a babbling idiot, and he knows nothing of which he speaks. If in doubt of anything - or putting a wrench in your hands could result in the end of civilization as we know it - please - take the bike to your dealer. Brakes are CRITICAL - if you mess up you could be dead.

PLEASE PRINT AND READ ALL THE INSTRUCTIONS BEFORE BEGINNING! Make sure you understand what is being said, and what the concept is. If it's confusing, or I haven't explained something well - feel free to PM me, I'll try to clear it up, and it may help make the DIY better!

And this DIY is a work in progress - there are several photos I'd like to add, but that is held up by some editing restrictions currently in place on the forum.

[deilenberger]

TOOLS REQUIRED:

• 6mm Box end wrench (front master cylinder bleeder)
• 8mm Box end wrench (rear caliper bleeder)
• 10mm Box end wrench (front caliper bleeders)
• T45 Torx driver (R&R of front and rear calipers)
• 20" 3/16" ID clear tubing (Caliper bleeding)
• 20" 1/8" ID clear tubing (Front master cylinder bleeding)
• Drain Jar (all bleeding)
• Wood wedges (To keep calipers retracted)
• Large flat-blade screwdriver (To retract calipers)
• Spray brake cleaner (To clean up any mess)
• Large shop towels

If installing Speed-Bleeders you also need:

• 1/4" box wrench (Rear bleed nipple)
• 5/16" box wrench (Front bleed nipples)

[deilenberger]

BRAKE FLUID FLUSH:

First lets discuss what we're trying to achieve.
Part of the regular service for the R1200R is a biennual (every 2 years) brake fluid FLUSH. A flush is different in some ways from a brake-fluid bleed, in that there should be no air introduced into the system when doing a "flush". Bleeding brakes is the process of getting any air trapped in the system (after opening the system for some repair) out. Flushing is getting old fluid out, and replacing it with new without getting air into the system.

Why do we need to do this?
Brake fluid is hygroscopic - ie - it absorbs and traps water. As the fluid ages, the fluid becomes contaminated more and more with absorbed moisture. The water is a bad thing in brake fluid. It has two undesirable properties:

1. It lowers the boiling point of the brake fluid. Fresh brake fluid has a boiling point of well over 400F - so even if your brakes get quite hot, the fluid doesn't turn to vapor. If it did turn to vapor - it's easily compressible and you'd have no brakes. Once the fluid starts absorbing moisture the boiling point of the brake fluid starts dropping. Given enough moisture in the system - it could lower the boiling point to where it becomes dangerous.
   
   
2. It causes corrosion of the brake components. Since dissimilar metals are used through the brake system - any moisture in contact with them will cause electrolysis - ie - corrosion of the parts. The corrosion can cause sticking of the brake components, causing brake failure.

Why doesn't my car call for doing this?
Because you don't own a BMW car. BMW cars have called for 2 year flushes about forever. Most car makers don't - counting on the greater volume of fluid in an automotive brake system to get the car out of warranty without a brake failure. Bad on them. ALL cars should receive a 2 year flush.

Why don't I just use DOT5 (silicone) fluid and be done with it?
DOT5 is not recommended or approved for use in ABS equipped brake systems. It has poorer lubrication properties than standard glycol based brake fluids, and the ABS modulator may not work correctly with it. I know someone is going to PM me with a message telling me that they used DOT5 for the past century in their ABS equipped bike and it works fine.. well - here is my reply - Good for you. Please DO NOT follow me when riding. At least not closer than a mile or so. I'll continue following BMWs recommendations.

OK - So what fluid should I use?
BMW recommends using DOT4. I see no reason to recommend anything else.

There are some high-performance versions of DOT4 available, and there is a DOT5.1 - which IS compatible with ABS systems and DOT4 fluid - but neither mean you can skip doing the binennial flush. It also was brought to my attention that some auto stores don't carry fluid labeled "DOT4" - they only have fluid labeled "DOT3/DOT4". This fluid is OK to use - the label means the fluid meets the specifications of DOT3 and DOT4, which makes sense since DOT3 has slightly lower standards for boiling point, and wet-boiling point than DOT4 has. Other than that - the two standards are basically the same.

Is there any better DOT4?
As mentioned - there are some performance DOT4 fluids - which start with a higher boiling point. Ford made a DOT4 with some excellent characteristics (due to them putting undersized brakes on one of their trucks - which really heated up the fluid) - a Google will probably turn it up. I use Valvoline DOT4. It's cheap, and easy to find (any auto parts store.) BMW sells an expensive DOT4 - but it's always been "dark" looking right out of the bottle, which is typically a sign of water absorption - and that worried me, so it was back to Valvoline.

Note that most manufacturers do not recommend using fluid from opened bottles of brake fluid. They feel once opened, the fluid has started to deteriorate and absorb moisture. Since I buy fluid by the quart - there is no reason to skimp on the amount flushed through the system.

When should the flush be done?
BMW calls for the first flush to be done 2 years from the manufacturing date of the bike (and you can look that up using your VIN at www.realoem.com), and then every 2 years.

Are there any "gotcha's" in this process?
Sure - there are always opportunities for mistakes. Over tightening bleed nipples can be an expensive experience (best avoided by using the right length wrench and two fingers when tightening), spilling brake fluid on paintwork can make a nasty mess. Your best bet is to be careful with what you're doing, cover any exposed paintwork and read the instructions twice. Once to see what I missed (and letting me know) and once to make sure you understand them.

Anything else?
Yeah - I'll very briefly discuss replacing the stock bleed nipples with "SpeedBleeders." The cost is about $7/caliper, and these makes it much easier to flush or bleed the brake systems. http://www.speedbleeder.com/

Good luck!

WARNING: Brake fluid attacks paint. Depending on the type of paint - the attack can be very fast, or relatively slow - but your goal in doing this job is to avoid getting brake fluid on any paint. IF you do get fluid on painted parts - a rinse with soapy water is a very good thing to do - as soon as you can. If you delay too long you'll be washing the paint off along with the fluid.

[deilenberger]

REMOVING THE CALIPER

Using the T-45 wrench, loosen the two bolts that hold the caliper to the rear-drive assembly. In the photo - the rear bolt has been removed.

[deilenberger]

REMOVE CALIPER - Part 2:

Lift the caliper up and off the brake rotors. You may need to wiggle it a bit against the rotor to get the pads to move back a bit for clearance.

[deilenberger]

SPREADING THE PADS

I use a flat-blade screwdriver to spread the pads. Put in and twisted - about center of the pads - they will move back, forcing the old fluid out of the caliper pistons. I'd suggest hooking your bleed hose to the bleeder at this point (with the other end in the waste fluid jar) and cracking open the bleeder 1/8 turn before tryng to spread the pads. This will allow any dirty fluid in the caliper to go to the waste bottle rather than back up into the brake circuit. It also avoids any possibility of overflowing the brake reservoir.

NOTE: The difference in pad thickness IS normal. The pads are a different thickness right out of the box. The inside pad is designed to wear out first, and expose the rotor through the hole in the backing plate, indicating to the owner that it's new pad time*. Seems a bit crude to me**, but that's the story.

* = That's only visible if the owner is 10" tall, or is of normal height and laying on his stomach next to the bike on the left side. Completely goofy BMW engineering IMHO.

** = At the point that the hole is opened up in the pad, the backing plate is already touching the rotor. That's beyond time to replace the pads IMHO, but perhaps it helps BMW sell more rotors.

[deilenberger]

BLOCKING THE PADS

After retracting the pads and the caliper cylinders - I used a piece of hardwood I had kicking around to block the pads out, and prevent them from moving back together as the flush is being done.

I then rested the caliper on an old shop towel I put over the rear drive to protect it from errant brake fluid, and getting scratched by the caliper.

[deilenberger]

THE BLEED NIPPLE

This photo shows the brake bleed nipple - and the rubber cap that fits over it. The cap is removed, and carefully saved since you want it back on when you're done. The nipple takes an 8mm wrench - and you want to use a closed end box wrench.

Throughout the process you want this bleed nipple to point up and be the highest point on the caliper.

[deilenberger]

OPENING THE REAR RESERVOIR

The rear reservoir cap simply unscrews. You can remove it and the rubber bellows assembly as a unit, and set them aside in a clean place. It's a good idea to use some dry lint-free cloth to clean any fluid/moisture off the internal reservoir bellows before reinstalling them.

NOTE: I'd strongly suggest taking note of the fluid level in the reservoir before doing anything else. This is the level you want the fluid to be at when you are done flushing the rear brake circuit. The fluid level normally drops as the pads wear. When the pads are fully worn out - the fluid level will be near the MIN line. IF you topped up the fluid - then when you install new pads, the fluid will overflow when you retract the pistons in the caliper. What we want to do is keep the same amount of fluid in the system.

[deilenberger]

DRAINING THE RESERVIOR

This is what the old brake fluid in the rear circuit looked like after 2 years. Ugly. New fluid is almost transparent - a very light straw color. I used a turkey baster (long ago purloined from the kitchen for garage duty) to drain the remaining fluid from the reservoir, leaving just enough to cover the connection to the hose going down to the master cylinder.

The reservoir is then filled almost to the top with new brake fluid in anticipation of doing the flush.

[deilenberger]

GETTING READY TO FLUSH

You probably already connected the drain hose when you retracted the brake pads/pistons. Make sure the hose is secured in the waste container, and the painted surfaces in the area are protected (some brake fluid ALWAYS seems to get on them if you don't.)

The hose is simply some 3/16" ID nylon (aka brand-name TYGON) tubing - which may be available at hardware stores or big-box-home-stores. I have also found suitable tubing at pet-stores used for connecting air-lines in fish tanks.

The wrench is put on the bleeder before attaching the hose. The hose should go down over the flare on the bleed nipple, and the other end down into a catch bottle for the old fluid. I used an old windshield-washer fluid bottle, and taped the hose into the top of it (so it wouldn't pop out and flail around spraying brake fluid around.) If the hose is difficult to get on the nipple securely - warm the end of it (with a hair dryer or heat gun) slightly.

STEP by STEP PREPARATION:

1. Connect bleed hose
2. Open bleeder ~1/8th turn
3. Use screwdriver (rotating it - not prying) to spread pads
4. Block pads out so they don't close up when doing the flush
5. Close bleeder gently
6. Open and drain the rear reservoir
7. Fill rear reservoir in preparation for flushing

Procede to flushing..

[deilenberger]

FLUSHING

Now we get to the good part. Turning the wrench about 1/8th turn counterclockwise - I gently push down the brake pedal about 2" - and old fluid starts exiting the caliper. Before releasing the pedal for the next stoke, I tighten the bleed nipple just enough so air isn't sucked back into it.

The routine is:

1. Put a slight pressure on the brake pedal
2. Open bleeder slightly
3. Press pedal gently down - no more than 2" (so you don't go into unexplored parts of the master cylinder)
4. Tighten bleeder gently
5. Release pedal
6. Repeat 1-5 until clear bubble free fluid is flowing through the bleed hose.

You're done flushing when the color of the fluid coming out the hose matches the new fluid color, and no air bubbles are travelling with the fluid.*

Keep an eye on the rear reservoir level so it doesn't go dry.

* = part of the reason to not open the bleeder too far is - air will be sucked in around the threads on it when you're pumping fluid out.. causing you to think you've now gone from flushing the system to bleeding it. And the bubbles will continue to appear as long as you keep opening the bleeder too far.

[deilenberger]

FINISHING THE REAR and SETTING THE FLUID LEVEL

Before closing up the rear reservoir - you want to check the level of the fluid.

• If the fluid has never been topped up - you want to refill the reservoir to the level you noted before we started flushing the system.
• If the fluid was topped up between pad changes - then I'd suggest filling it to the MAX line on the reservoir while the pads are still retracted - this should give you approximately the right level (although next time you change pads - you should check the level after putting the new pads in.)
• If you are installing new pads at this time - install the new pads, then put the caliper back on the rear-drive, and pump the system to bring the pads into contact with the rotor. Top up the reservoir to the MAX line.

Then take the clean/dry cap/bellows assembly and replace it on the reservoir, tightening it gently.

Finally - remount the rear caliper on the rear-drive, tightening the two mounting bolts to 30nM (~22ft/lbs) and pump up the brake to seat the pads against the rotor again.

Point by Point, FINISHING UP REAR:

1. Top off reservoir to correct level. Put cap/bellows back on reservoir.
2. Mount caliper on rear drive and tighten bolts to 30nM
3. Pump up brake and check that it is working correctly

[deilenberger]

The front brake fluid is done much as the back was.

• We first remove old ugly fluid from the fluid reservoir.
• We retract the pistons in each caliper and push the old fluid out to the catch-bottle.
• We do one caliper at a time.
• We then refill the reservoir with fresh fluid, and push it though the system using the front brake master-cylinder and the bleed nipples on the calipers.
• We finish by settling the reservoir fluid level correctly.

[deilenberger]

OPENING THE FRONT RESERVOIR

The first tricky bit in doing the front is getting the cap off the reservoir. While it might seem it should just unscrew - that isn't the case.. it's really a two handed job.

In the photo below - my fingers (thumb and finger) are depressing two small catches that keep the cap from unscrewing (I'd assume for safety and security.) I then used my other hand to actually unscrew the cap (which I didn't show since then you wouldn't be able to see the cap and where the catches are.)

The next photo will show the catches..