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I performed my 2 year brake fluid exchange several weeks ago. I pressurized the reservoir to 20 psi and bleed the wheel brake calibers starting at the right rear, working from the farthest to the closest to the reservoir. Only problem I had was that I used more fluid than I should have because the color difference between the old and new fluid was not easily discernible. It would be great to know how much fluid should be bleed from each wheel brake caliber if the old fluid is suctioned from the reservoir and replaced with new fluid. I guess it could be approximated if the lengths of the brake lines were known, assuming they all had the same inner diameter. The shop manual has a diagram but I doubt if it is to scale. Does anyone know the actual lengths of the brake lines?
 

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You can get brake fluid that has dye added that gives you different colors. This way when the color changes you can see it very different.
 
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Thanks for the suggestion, but I thought it would be best not to mix brake fluid brands since you do not flush 100% of the old brake fluid. I used OEM Mercedes Benz Dot 4 plus fluid.
 

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Thanks for the suggestion, but I thought it would be best not to mix brake fluid brands since you do not flush 100% of the old brake fluid. I used OEM Mercedes Benz Dot 4 plus fluid.
Okay to mix brand as you are replacing like 99.9% of it, as when you see the new color you have replaced that line as you moved to the other you are replacing them and the reservoir will be refilled each time with new color. just keep the same DOT rating as required by MB.
 

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I performed my 2 year brake fluid exchange several weeks ago. I pressurized the reservoir to 20 psi and bleed the wheel brake calibers starting at the right rear, working from the farthest to the closest to the reservoir. Only problem I had was that I used more fluid than I should have because the color difference between the old and new fluid was not easily discernible. It would be great to know how much fluid should be bleed from each wheel brake caliber if the old fluid is suctioned from the reservoir and replaced with new fluid. I guess it could be approximated if the lengths of the brake lines were known, assuming they all had the same inner diameter. The shop manual has a diagram but I doubt if it is to scale. Does anyone know the actual lengths of the brake lines?

Thanks for the info. I am about to do this on my 2016.

How much fluid did you end up using?
 

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DOT in the USA banned various colors of brake fluid. This is a major contention on other Forums (Porsche for instance). Brake fluid is cheap. Buy extra. Bleed until you've gone overboard.
 

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When I had my B service in February they charged $27.73 for brake fluid. Doesn't say how much they used.
 

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DOT in the USA banned various colors of brake fluid. This is a major contention on other Forums (Porsche for instance). Brake fluid is cheap. Buy extra. Bleed until you've gone overboard.

Good to know that dye is an issue. I personally haven't had any problems distinguishing between new/old fluid. I use a Mityvac MV6835 Vacuum Brake Bleeding Kit (bought from Amazon) which has a clear drain pipe and works great.

I agree that brake fluid is cheap, I just don't want to have to store the extra or run to the store in the middle of the job :laugh:

So it would be nice to get an idea of how many liters I need to have on hand for the GLA.
 

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Don't store the extra. It will attract water once the seal on the container is broken. The idea of bleeding is to get rid of the water that accumulated in the sealed system that controls your brakes. The opened bottle is no better at keeping moisture out.
 

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Don't store the extra. It will attract water once the seal on the container is broken. The idea of bleeding is to get rid of the water that accumulated in the sealed system that controls your brakes. The opened bottle is no better at keeping moisture out.


Yes, forgot to clarify that. I don't want to store unopened bottles either. My garage is so packed that I keep finding stuff I didn't know I had :)


I guess I will have to do this and then report back about how much brake fluid the job needs. My guess is that the GLA45 probably needs a bit more than GLA250.
 

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Discussion Starter #11
Thanks for the info. I am about to do this on my 2016.

How much fluid did you end up using?
I used 1.5 liters. Through Ebay I paid $15 for 3 liters with a $14.51 shipping charge. You can say I paid $10 per liter. I would think the ease or difficulty in differentiating between your old and new fluid would be determined by how many miles you had driven during the past 2 years.
 

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I just read that you can get blue fluid (rather than the amber) in the USA, but you need to order it from the UK and it is very expensive.
 

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Wayne did some checking and it appears that the US government has now stopped the sell of blue brake fluid after over 15 years of it being on the market. They have came to realize it is blue in color and the US reg is that brake fluid must be clear or amber. This is as of 2013 ruling. I had bought the blue in early 2013.

To change brake fluid you can rotate between the clear and amber to see a color change when bleeding the brake doing a brake fluid change. one change clear and next change amber, next time use clear and so forth.
 

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I used 1.5 liters. Through Ebay I paid $15 for 3 liters with a $14.51 shipping charge. You can say I paid $10 per liter. I would think the ease or difficulty in differentiating between your old and new fluid would be determined by how many miles you had driven during the past 2 years.

Thanks very much WeGla250! I ordered 2 liters of "Febi Dot 4 Plus" fluid from rmeuropean.com (Mercedes-Benz GLA45 AMG 4Matic Sport Utility 156.952 2.0L L4 Brake Fluid) since I could pick it up locally. I paid $18 for 2 liters plus tax (so about the same price).
 

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They just did this on my car. Very weird. Do they not trust their seals? I was happy to do it though, since I don't drive the car as much as I should. Any extra attention to the brakes in that situation is usually a good thing.
 

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Brake fluid attracts water. After a couple years the water can be as high as 2%. There are charts showing reduced boiling rate of various brake fluids based on % water.

Old fluid with water boils at a lower temperature. Boiled water is gaseous. Gas has a high compression. That means the brakes won't work.

Flushing out old brake fluid is a bit paranoid for normal driving, but good insurance.
 
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