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Old 11-03-2015, 12:50 AM   #51
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Drawing on old mechanic days (we're talking high school here!) and ample experience since then (who's counting?) spongy brakes are almost always due to air in the brake lines that needs to be bled out. This is a simple fix and I would say it's not a warranty issue at all (although certainly a good "new delivery" issue for a new buyer). If you keep getting air in the line after bleeding, then that's another issue. But rather than writing NHTSA (which I otherwise surely support for any serious vehicle defect, which a brake defect would be), I would go get the air bled out of the lines.

PS: Brake pads are NOT soft and spongy.
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Old 11-03-2015, 10:52 AM   #52
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I'm a retired mechanic after 45 years in the business. I would agree that the brakes need to be bled to correct the problem, but that is a simple fix and I'm sure that Mercedes would have done that long ago instead of having so many complaints about the spongy brakes. I have read all of the supposed fixes that didn't work and believe that is an inherent problem with the vehicle, such as soft brake pad materiel.
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Old 11-03-2015, 12:58 PM   #53
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Who Else has Soft Spongy Brakes on their MB?

Quote:
Originally Posted by paul huyck View Post
I'm a retired mechanic after 45 years in the business. I would agree that the brakes need to be bled to correct the problem, but that is a simple fix and I'm sure that Mercedes would have done that long ago instead of having so many complaints about the spongy brakes. I have read all of the supposed fixes that didn't work and believe that is an inherent problem with the vehicle, such as soft brake pad materiel.

I will certainly defer to your years of experience, however if one calls MB corporate about something that calls for bleeding air out of the brake lines, I wouldn't expect much help there. Help for that would be found at the MB dealer service department, a brake shop or a trusty service station.

I would love to see and touch a soft brake pad. Not sure how it wouldn't be ripped to shreds by truck wheels turning at 65 mph when the brakes are applied. All the ones I have ever handled were hard. But then hardness has its levels apparently.

If one steps on the brake pedal and it travels down 3" before engaging (which I believe some are complaining about), I would say that is compressing air in the line not brake fluid and the force hasn't even gotten to the brake pad yet. But I can't rule out some other issue like a master cylinder problem too. I'm just saying most commonly one would find air in the lines and it sounds like you agree on that point.

Air could be getting in the line due to a leak in the system letting air in or letting the fluid level get too low. A leak can be verified or ruled out by a mechanic when doubt the bleeding. Also pavement spotting or visually observed leaks could be a symptom.

Many thanks - appreciate hearing from someone with long experience in the field!
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Old 11-03-2015, 01:07 PM   #54
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Good article:

http://www.winbrake.com/training_spo...diagnosis.html
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Old 11-04-2015, 11:52 AM   #55
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If someone came into my shop with the spongy brake complaint the first thing I would do is to bleed the brakes. My brakes were spongy compared to my previous 3 motor homes, all Fords, and they were spongy from the first day. With everyone experiencing the same problem why wouldn't Mercedes bleed the brakes, a very simple fix.
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Old 11-04-2015, 12:47 PM   #56
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AT the risk of touching off a model v model flame war, or violating some prohibition aganst posting from other forums....

this topic has also been discussed at length in the Navion discussion groups.

Here is one post that quotes a often cited Sprinter expert.

FWIW...


It is somewhat normal for the Sprinter chassis to have a soft brake pedal feel. It was a bit alarming for me too when we first were getting used to the chassis.

Dr. A, a foremost expert on the Sprinter, put the below test together a few years ago. Here's the test procedure that Byron shared out in a post:


Here's how to tell if your Sprinter brake pedal action is "normal" OR in need of immediate service attention:
Engine running, push lightly on the brake pedal. Mushy and sinking seemingly endlessly toward floor? This may be NORMAL.
Engage Park and handbrake. Shut off the engine and then step on brake pedal 4 or 5 times. This releases the vacuum from the booster servo and reservoir-you should hear a loud hiss when pressing pedal each time until the vacuum is expended.
Engine still OFF, ALL vacuum expended, now step on brake pedal and exert a steady force. Pedal should move a relatively short distance (compared to before) and stop hard without further sinking- REGARDLESS of how long you exert foot pressure.
This is the TRUE test of the brake master cylinder. If pedal slowly sinks to floor during this test- you have a problem.
Now step on pedal again and exert steady pressure while starting engine. With engine now running- the pedal should begin sinking steadily toward floor. This is NORMAL and indicates the engine's vacuum pump and the brake servo are working properly.
Take foot off the brake pedal and run the engine for a few seconds at 1500 rpm to build vacuum. Go back to idle speed, step on the brake pedal slowly-see the difference and the much greater sink distance compared to engine "off" and vacuum released?
Still convinced it's excessive pedal travel? Try this test-Engine running, move Sprinter to a downward sloping driveway, place in neutral and SLOWLY creep down hill. Gently apply brake pedal pressure and note how little pedal travel is needed to stop and hold the vehicle-now push harder-see how much pedal travel remains?
This long, soft, pedal travel is a normal characteristic of the Sprinters vacuum booster design when engine is running."
From Dr. A via Byron 07NH CA Thursday, March 29, 2012 8:41 AM
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Old 11-04-2015, 04:15 PM   #57
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Very helpful - thanks!
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Old 11-05-2015, 09:35 AM   #58
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The air in brake line theory doesn't explain a firm pedal on the 2nd application of the brakes. If air remains in the brake line, how would one account for a the firmer pedal on the second push?
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Old 11-05-2015, 09:42 AM   #59
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soft brakes

Am now the owner of second Solera. First was a 2011 24s and it had long brake pedal travel. Had the brakes bled by a certified Sprinter tech. No help. He said the brakes were OK.
The present Solera 2015 24R has long brake pedal travel. My opinion is that the brakes are doing exactly what they are supposed to do. Have had panic stops and they worked just fine.
Just for the heck of it, will probably perform brake test as per cousin01.
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Old 11-13-2015, 10:58 AM   #60
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Spongy brakes

Yes, I have the same problem. As an old time mechanic I thought I would have to bleed the brakes and have not yet got around to it. It seems however that bleeding the brakes would not solve the problem after reading some the efforts put forth on this forum. There has been no solution yet put forth by Mercedes???????????????
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