My son now owns and drives the 98 E300. Recently he had a bunch of work done on the car, including new front pads and calipers and one of the brake lines. Drove fine for 700 miles or so...then this...

Driving home after a long drive, brakes completely gave way...nothing when he depressed the pedal. Heard a hissing sound (like the sound of adjusting the seat cushions). Then depressed the pedal again and brakes engaged. Then they didn't, then they did. Until shortly they wouldn't work at all.

So he's getting it towed and we'll see what the mechanic finds. But I thought I'd check in with you guys to see if this description suggests anything as to what might have failed. Other than rotors, pads, and calipers...and the one line...all brake system parts are original.

Thanks for any guidance.

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Cletus mechanic ****ed up.

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CENSORED due to not family friendly words

That is what it sounds like to me too.

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Jim

Entirely possible. But what that would explain symptoms? Hooking up line and calipers such all fluid was lost over course of 700 miles??

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

This happened to me with my truck. I replaced brake pads, bled the system properly and went on my merry way, brakes working perfectly.

Fast forward a couple weeks and the brakes totally failed, pedal to the floor.

Long story short, the brake bleeding procedure had forced the seals in the master cylinder across previously undisturbed areas of the cylinder bore and it damaged them to the point of intermittent seal.

New MC solved it.

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

MC is my chief suspect.

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Sounds like the abs freaked when the master cylinder failed

These cars also have BAS which tries to floor the brake pedal on your behalf if it thinks you're trying to stop quickly but not doing a good enough job of pressing the pedal on your own.

This has caught me off guard a couple times thinking something had failed because with sudden assistance, the pedal goes much lower, with much less effort.

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

Need more details as they matter a lot in diagnosing a failure especially where there is a come and go problem.

Nothing as in absolutely zero stopping power ( not just greatly reduced. ) with pedal has normal firmness and height? Low pedal? Pedal high and difficult to push?

Does the driver know that loss of power brake assist requires one to push the pedal much harder than the normal tip of toes?

"Didn't work at all" is very vague though the noise is somewhat helpful.

Can you offer any details as to what he didn't do correctly or is this just a random post that you can't offer any shred of justification other than " look it up on Google you $R#!@$#@! head"?

There are not enough details to jump to any conclusion yet. The last time there was a jump to conclusions, a valet was , at minimum , put through unnecessary grief and at maximum fired.

Good memory! Yes that was three years ago and valet was innocent! But the research was done before he got any heat.

Mechanic is first rate… Would be very surprised if he screwed up.

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

LOL are still waiting for everything to be handed to you on a silver platter, snowflake? Mommy and Daddy are going to be there to wipe you ass forever.

Grow up kiddo.

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CENSORED due to not family friendly words

Son says brake fluid reservoir almost completely empty… So that’s another data point.

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

I want you to justify some of the things you have said in this and previous threads. Given you are unable to give any sources for your data, I consider your " information " suspect at best and random rantings at worst.

Ok back to the facts

- Brakes were worked on 700 mi ago. What was done exactly?

- Which components in the brake system were replaced during this work effort?

- Any evidence of leaking fluid - at the wheels, under body? Brake fluid leaves an oily mark.

- Did your son notice the BRAKE light coming on? It should have activated as the fluid was declining. Unless it was voided all at once when the failure occurred.

- Are the rubber brake hoses at each wheel original?

On my 1998 E300 someone was ham handed replacing the rubber hoses at some point in the past. When I went to change the brake hoses about 2 years ago (proactive replacement), the union nut on the hose end of the brake line was seized to the brake hose fitting. I had to get a replacement steel line from the JY. Fortunately it was the left front so it was easy to change.

I wonder if something like that happened and the tech uttered the famous last words ‘it’ll be fine’...

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech