e1000

Ok, so as you guys know, I'm on a big fluid change kick. It's been 2.5yrs since I bought my car and to my knowledge I haven't ever had the brake fluid changed. I just had my brake pads changed out so I figured it this was a good time to change my brake fluid.

There are a couple ways to do this, but I chose to buy a Motive pressure bleeder. Basically, it's a pump that attaches to the top of the master cylinder so you don't have to pump your brakes to get the old fluid out of the lines.

!!!!! DO NOT USE DOT5 fluid !!!!! DOT5 fluid is completely different than DOT4 or DOT5.1. DO NOT USE DOT5 FLUID!!!!!!!!!

I usually stick to Mercedes OEM stuff, but after some research, decided to go with Endless RF-650 brake fluid instead. The big deal with brake fluid is that it's hygroscopic, meaning it absorbs water. As the brake fluid absorbs water, it's ability to resist boiling at high temperatures decreases, which is bad. Boiling causes air bubbles to form and eventually leads to a spongy brake pedal and poor brake performance.

Why RF-650? (For those who don't care, skip this part) - When I decided I was doing this, I started looking into the different types of fluid out there. I found a lot of very good products but chose Endless for a couple different reasons. RF-650 is less hygroscopic than other high performance fluids out there and it has very good wet and dry boiling points. This means that although it's considered race fluid, it will still hold up to being used in a daily driver over a good period of time. RF-650 is used in an impressive list of race cars as well as the factory fill in all Porsche GT3 cup cars. Also to note, RF-650 is one of only 2 brake fluids that is currently used in Formula1 cars, the other being Brembo race fluid, which isn't sold to the public AFAIK. Other brake fluids I considered are Castrol SRF, Motul RBF-660, and MB OEM. The only drawbacks to RF-650 is that it's expensive, about $32 for .5L (still cheaper than SRF), and it's somewhat hard to find.


Tools:
8mm wrench (not socket)
11mm wrench (not socket)
1L DOT4 or DOT5.1 brake fluid
pressure bleeder
clear plastic tubing (comes with motive bleeder)
turkey baster
plastic bottle (i used a 2L coke bottle)
jack
torque wrench

Again, there are MANY different ways to flush brakes but this is how I decided to do things.

1. Prep. - open your hood, remove the dust cover near the driver's side corner against the firewall. The brake master cylinder is underneath this cover. Use the turkey baster to remove almost all of the fluid out of the master cylinder and put it into your plastic bottle. Make sure you don't drip the brake fluid on any painted surfaces, it will ruin your paint.

2. Rear passenger side - Start with the brake caliper farthest from the master cylinder. In this case, it will be your rear passenger side. For the rear brakes, I simply jacked the car up and slid underneath to work. You'll need enough clearance for your plastic bottle.

3. Remove the rubber cover from the brake bleed valve. The brake bleed valve is located at the very top of the brake caliper. Attach the clear plastic tubing to the end of the valve, then put the other side into the plastic bottle.

4. Go back to the front of the car. Pour in your new brake fluid and fill your master cylinder. Attach your power bleeder and pump until you get to about 15-20 PSI.

5. Go back to the rear caliper, you should still have your tubing from your caliper valve to your bottle. Take the 8mm wrench and slowly loosen the valve. Stop loosening once the fluid starts draining.

At this point, you need to watch for 2 things. Hopefully your new fluid is at least slightly different color than your old fluid. If it is, it's easy to tell when to stop flushing that particular caliper. If it isn't, I almost emptied my master cylinder worth of new fluid when doing the rear passenger side caliper. Also look for any bubbles comming out.

Once the new fluid is flowing AND no air bubbles are comming out, tighten the bleeder valve. Remove the plastic tubing from the caliper and replace the rubber cover.

6. Once you are done with a caliper, remove the pressure bleeder and pour in more fluid into your master cylinder. Do NOT let the master cylinder go empty or get below the min line. Replace the pressure bleeder and pump back to 15-20 psi.

7. Repeat for all 4 corners of the car. The only difference with the front brakes is that the brake bleed valve is 11mm instead of 8mm for the rear. The nozzle is the same size however so the same tubing can be used on all 4 corners. Also, I didn't remove my wheels for the rear calipers but you will have to remove them to get to the front bleeder valves. Once you're done bleeding, torque down your wheels to spec..

8. Once you are done flushing, fill the master cylinder to the max fill line, and replace your brake fluid cap.

You're done!

Once you open a bottle of brake fluid, you must use it or throw it away. Don't try to save some old fluid and use it later.

I know the way I did this was a bit unusual. Normally you would just fill the power bleeder with fluid and never take it off and put it back on. This seemed like it would be a big mess so I decided just to fill the master cylinder up about 4 times.



Overall the job took about an hour and half and was WELL worth it. My brakes feel great. I was absolutely shocked at how bad my old fluid looked. I had quite a bit of air come out of my lines too.


Thanks Karo for letting me use your garage!!!!!!!!!!

samaritrey

lol two days ago i was thinking i really should change my break fluid in my car and my moms qx56. perfect timing thanks now i just have to start my new job and make some cash to go buy supplies.
Thanks for the diy

W203E35

No problem bro, thank you for the lesson and thanks for installing the lip
I learned a lot today

Patrick, thanks for the HID bro

P.S. Remember when I was making fun of Patrick for the hot wings well karma bit me in the *** (literally)

jnjrowland

You can get ATE Blue fluid if you like. It then makes it easier to spot when you are getting new fluid at your bleed points. When I do my car I rotate between the blue fluid and the amber so it's easy to tell when I am done.

e1000

absolutely a great suggestion. Lots of people do this just for that reason. It just so happened that RF-650 was clear, and looked a lot like I was pouring vodka. haha.

ELBMAN

The Motive rocks.....and using a different colored fluid makes it painless.

samaritrey

found a good place to get fluid in northern va
http://www.ogracing.com/catalog/2-Ca...7-Brake-Fluids
i will be getting mine here.

e1000

EDIT!!!!!!!! The rear requires a 9mm wrech. The front is confirmed as 11mm.

W203E35

For Patrick's it was 9mm all around. I think this was because he didn't have the SS brakes.

mtnman82

++1 on the Motive Power Bleeder. Once you use it, you'll wonder why you waited so long to get one... I put the brake fluid into the power bleeder - then no need to keep removing and filling up the reservior. You just have to tilt the Motive so the pickup tube isn't sucking in fluid on the last caliper, so you lower the level in the reservior while you bleed the last caliper. You do have to wash the Motive out afterwards too, but I just let it sit out for a day to dry and all is good.

Nice write-up, e!

W203E35

I agree that the power bleeder will get the job done more quickly and more easily.

Pump pedal pethod
times that by 20


If money is tight you guys can make your own. Here is a good link that shows how to make your own.
http://www.bmw-m.net/TechProc/bleeder.htm

samaritrey

lol are BMW drivers more frugal then Mercedes drivers

Moviela

I would advise against using any brake fluid other than what is specified by Mercedes or ATE. Racing fluid is very nice in race cars, but it offers no advantage in street cars, and can cause damage to them. The anti-lock system has tiny passages that are not suitable for conventional DOT 4 brake fluids. You will impair the function of the ABS system by using anything other than the special low viscosity fluid specified by Mercedes. ATE Racing blue and gold are the same formula, but dyed different colors to make it easier to see when it has changed. It is not a suitable fluid for Mercedes cars. It is true that brake fluid absorbs water, however, the reason to change it every two years is not because it is loaded with water. That can be a serious problem, but the vent hole is so tiny that only minor amounts of air laden with moisture enters the system. There are no suitable substitute fluids readily available in the US. There is an ATE fluid made especially for ABS systems available in Europe.

The reason for changing the brake fluid is because of copper absorbtion. This is a far more serious problem within the tiny passages of the ABS system. This causes corrosion that can damage some very expensive parts. There have been attempts to design a workshop device to measure the absorbed copper, but none has worked well. This is why two years is used as the change interval.

e1000

Moviela is going to keep me honest here. If anyone here has any doubts in thier minds, please use the MB branded DOT4+ fluid from Mercedes Benz. As far as I know, it's the only fluid that is spcifically listed on thier Blatt 331.0 spec sheet as an approved brake fluid. Otherwise, keep reading.

Now, with certain fluids I wholeheartedly agree that MB spec fluids are the only way to go. Perfect example of this is engine oil. I would use nothing less than Mobil1 0w-40 or similarly approved 229.5 oil. Why did I choose a different brake fluid?

- Mercedes uses pretty standard parts for the C-class braking system. No SBC and the calipers made by Brembo not MB, etc etc. Yes there may be some magic in the ABS unit, but I'm willing to bet that the Mercedes ABS unit is not very different than many other cars out there. Lets be honest here, ABS has been around for quite some time and any of the high performance DOT4 fluids are made to accomodate for ABS.

- Blatt 331.0 spec fluid is the fluid for a wide range of Mercedes cars and I believe it's also the clutch fluid. This means that this fluid must meet all the rigorous performance needs of all these different types of applications. Many of these requirements may not apply to the C-class braking system.

- Crossfire Manual states the following: "Use brake fluid approved to MB 331.0, or a DOT 4 brake fluid with: minimum dry boiling point (ERBP) 500°F (260°C), minimum wet boiling point (WERBP) 356°F (180°C), maximum viscosity 1500 mm2/s, conforming to FMVSS 116 and ISO 4925." Now, we all know that the Crossfire is essentially a re-skinned R170 SLK. We also see here a much more specific set of parameters for brake fluid including specific viscosity numbers.


I honestly do belive using standard DOT4 fluid will be fine. Whether or not you choose to do so is at your own risk. Again, if you have any doubts, just stop by your MB dealer and get the OEM fluid.

LILBENZ230

My car has been running standard DOT4 fluid for a long time. No issues whatsoever.

03MBC32

I've been using Motul RBF600 brake fluid without any issues. BTW my bleeder screws are 9mm front and back.

SeaCoupe

E, did you buy a motive unit? Always wanted one, but I'd see the price tag and not buy it.

Want to do this one more time? I got Lobster tails to trade.

Ed

e1000

Yeah I have the motive! Sure Ed! Let me know!!!!!!!

johnand

Ed, keep an eye on Ebay. I picked up the Motive Black Series Euro bleeder, with 1 bleeder bottle for $50 shipped.

gwin

Necropost but i just have to.

RF650 is Dot 5............ have your brake seals given way yet?