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  #16  
Old 07-25-2002, 02:08 PM
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Join Date: Jun 2001
Posts: 259
This might be your problem...

I had that happen to me awhile back on my 380 sl. Turns out the vaccum assist had blown out (big circular black thing that fits between the master cylinder and the firewall). I had virtually no brakes but it would stop if I pushed all the way to the floor.

There is a hose with a check valve that could be leaking or the cylinder itself.

Turn the car on, pump the brakes, if your pedal comes back up a bit your vacuum is working. If when you apply the brake, it slowly goes back down, you have a leak in the vaccum assist.

3 different brake places I went to missed it so you might as well check it out.

J. Boggs
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  #17  
Old 07-28-2002, 03:38 PM
debbiemarlow
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Guess what?

It HAD some kind of tape already on the brake line and it was covered by electrical tape! I have NO idea who or why... but, I didn't do it. Perhaps some other person feels like duct tape can solve most any problem, too!

My mechanical friend called and reported I need two front brake lines which he'll put on this week. He's very good and hopefully this will solve my brake problem until I get home. Then I'll see about a thorough replacement of old brake lines. Should I replace or have the master cylinder rebuilt? Or leave it alone until it goes bad?

I have learned more than I ever imagined there was to know about my brake system. Thanks to all who helped me here!! But, don't go away because if this fixes my brakes, I know, it won't be long before something else "brakes".
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  #18  
Old 07-28-2002, 10:29 PM
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Join Date: Mar 2002
Location: S.F. Bay Area
Posts: 502
Brake problem

Debbie,

When you eventually repair your brakes, make certain that the brake fluid that you put in the repaired system is the correct one recommended for your year Mercedes.

My 123 has a hydralic clutch that did exactly the same thing as your brakes did one year after replacing the clutch master cylinder. That's when I found that I'd used the wrong brake fluid which dissolved the seals in the system.

Good luck.

Ben
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  #19  
Old 07-30-2002, 06:49 PM
debbiemarlow
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Oh, good tip on the correct brake fluid... dot 4, right?... I'll check with the garage and see what type they used.

Here's an up to date:
They replaced the two front brake lines and still no brakes. They replaced the master cylinder and now there's a very hard pedal. I haven't driven it yet, but they said it is VERY HARD to stop the car pressing pedal VERY HARD. It's getting expensive. Last phone call and they were thinking the vacuum line.

Note: I found out this afternoon that the master cylinder was replaced not long before the car ended up parked (due to minor traffic accident). Does anyone think it could have really have gone bad? And a bad master cylinder is (1.) the whole thing or (2.) an O-ring seal or (3.) what? (I'm out of guesses). I'm uneasy about this $230++ replacement - should I ask for the "old" one back?

And the former owner's son says it was parked for three years, not five.

I've gotten really good information and am reluctant to ask... but... Besides the vacuum booster going bad, what else could cause a HARD PEDAL such as I described? I had no trouble shutting off the car when I cut it off several times and didn't notice any accessory malfunctioning.

As always, all advice appreciated!

Debbie
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  #20  
Old 07-30-2002, 08:08 PM
debbiemarlow
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More questions:
Looking through the forums I have seen various prices such as:

Vacuum boosters:
One posting said "less than $50" another said "new booster is $240 and more from MB"

Master cylinders:
One posting said "$60" while mine cost approximately $230.

Am I shopping in the wrong places?
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  #21  
Old 07-30-2002, 09:53 PM
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Join Date: Apr 2002
Location: eastern ND
Posts: 657
If the hard pedal means very little movement then then the calipers are crudded up, and not letting the pads move. The pressure you develop has to go somewhere, and that's why the line blew, and probably the "new" master cylinder. Replace the front calipers (click FastLane at the top of the screen, then Catalog at the left) and see if you have enough for emergency braking to get home. If your helpers didn't bench bleed the master cylinder then make them take it out and do it right. You're going to have to do the rear calipers and rear brake lines ASAP, so at this point you might as well buy all four rotors and pads for all four brakes and get the pain over with. Dollars to donuts the previous owner didn't bleed the brakes every year, and his neglect is now your problem and expense.

You can get home without vacuum (power) assist on the brakes. Just pretend it's the old days when nobody had power brakes.
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Last edited by dabenz; 07-30-2002 at 10:16 PM.
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  #22  
Old 07-30-2002, 11:16 PM
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Join Date: Mar 2002
Location: S.F. Bay Area
Posts: 502
Bad Brakes

Debbie,

Trust me, trust me, the problem with your brakes is in the mastercylinder. There may be nothing wrong with the master cylinder itself, just there's at least one air bubble trapped in there that causes the brakes to have lots of pedal but very little braking . I just solved this probelm myself, thanks to my son who suggested cracking the individual brake lines at the master cylinder and bleeding each one in turn right at the cylinder to get the air out. If your mechanics have a pressure bleeding device they might acheive the same thing.

Bleed, bleed, the master cylinder. Don't buy anything new until you're certain that they did that. If necessary stand right there and make them do it while you watch, they're going to be very embarassed when a female sovles their problem.

Put your foot on the pedal, press hard and long, if the pedal eventually goes all the way to the floor, it's air in the master cylinder.

When they eventually do it your way and bleed the master cylinder make this test again, if you now have brakes but the pedal eventually goes to the floor, bleed it again.


Ben
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  #23  
Old 08-01-2002, 12:19 PM
debbiemarlow
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I'll check to see if the master cylinder was bench bled and what he thought about the caliphers. I've got the car back and the brake is hard and braking is harder and the car doesn't stop easily but I can manage I hope !!

When I get home all of your ideas will be passed along to my neighboring mechanic and I'll ask him to "help me" (means: fix it for me) get replacements to rear caliphers and front, if needed, rotors... think I oughta bite the bullet and do rotors, too?... rear brake lines checked to see if they are clogged. Anything else?

Sam, the mechanic here in Germantown (where I am visiting), checked the vacuum and said it was good. I remember a post discussing a broken check valve... but, he would've detected that right off, huh? Sam is a trusted friend of my family here and I know I and my little 220D have been in the best hands. I spoke with him about many of the ideas presented here and he patiently listened but he already knew (much more than I).

I've ANOTHER PROBLEM! The car's huge Interstate battery will not start the car, even after being jumped off and driven for 1/2 hour. I turned it off and tried... dead. Here's what I think has happened: Before I left, the car's alternator light was slightly aglow (and I knew the former owner's soldering job that he was unsure about and said "have it resoldered by someone who can reach it") so I checked the wires he showed me. Sure enough, they were apart and when I touched them together the alternator light went out. So another helper friend and I took the wire, stripped it slightly more, and attached it to a bolt. No more light, no more problem....
In the Chilton manual for '68-'73 MBs, on page 84, it says:
4. If the molded connector is disconnected from the alternator, do not ground the hot wire. There MIGHT have been some sort of molded metal connector on the wire that we stripped. I can't remember... but, could we have grounded the hot wire? I think we attached it to the alternator and not the engine block. The alternator was recently rebuilt by an expert mechanic and reinstalled by the former owner.

Oh, yeah. The car started when jumped off with another battery.

Debbie

I am going to talk to Sam this evening. Please help me some more!!
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  #24  
Old 08-01-2002, 12:47 PM
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Join Date: Mar 2002
Location: S.F. Bay Area
Posts: 502
Troubles

Debbie,

Sure sounds like your brake problem will be solved by your local mechanic if he bleeds the mastercylinder where the brake lines are screwed into it. You must have introduced some air into it when your brake line burst. By the way, where are you located in Tennessee, I'm from Nashville.

Ben
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  #25  
Old 08-01-2002, 12:54 PM
debbiemarlow
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"There's only one"

East of Knoxville there's a community called Strawberry Plains, that's where I currently live. It got it's name from the pioneer days when horses hooves were colored red from all the wild strawberries there. Of course, it's in the Tennessee Valley and it's not a plain but after crossing the Smoky Mountains it must have seemed like one!!

And I love the Nashville and highland rim area. It's beautiful and as a collector of fossils and Indian and prehistoric relics, it is fabulous!!
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  #26  
Old 08-01-2002, 01:10 PM
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Join Date: Apr 2002
Location: eastern ND
Posts: 657
Debbie,

Sounds like you bought the jimmy-rig special.

Yes, bite the bullet and do all the brakes when you get home. It's only your life (and other lives) at stake.

Sounds like the alternator regulator was jimmy-rigged. If your on-the-road mechanic is willing, then have him test the alternator after replacing the regulator. If he/you can't find a regulator then you can get home without the alternator. The car needs electricity for the brake and turn signal lights. If they work then pull the belt off the alternator, jump the car for an hour (STOP if the battery gets hot - it's shot and may explode) and get home so you can relax and fix the stuff right. Worst case is new regulator, new alternator brushes and/or alternator, and new battery.

I'm signing off as I just realized I'm not in Diesel Discussion. This part of the web site is for the 'real' mechanics, not us backyard yahoos.
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  #27  
Old 08-01-2002, 08:06 PM
debbiemarlow
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What do you mean "jump the car for an hour"? You mean attach jumper cables from my battery to another and let the other car RUN for an hour? to build up my battery?

I'm almost afraid to start out.

debbie
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  #28  
Old 08-03-2002, 02:38 AM
debbiemarlow
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I'm going to head out this Sunday a.m. for home. I appreciate the enormous generousity so many forum members have poured out in excellent advice and "maybe-check-this" pointers on my 220D's brake "blow-out".

I didn't understand the alternator/battery information but, I believe, if I get the car jumped off then, if I don't turn it off, it will "diesel-on" home. I think I'm going to love diesels -- it may not be this exact car though unfortunately.

Again, thanks everyone for sharing... and if you think about it Sunday, please pray that I'll have a safe trip home.

Sincerely, Debbie

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  #29  
Old 08-03-2002, 01:32 PM
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Join Date: Mar 2002
Location: S.F. Bay Area
Posts: 502
Going home

Debbie,

Let us know when you make it home. Good Dieseling!!

Ben
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  #30  
Old 08-13-2002, 04:41 PM
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Join Date: Mar 2001
Location: Strawberry Plains in East Tennessee
Posts: 61
I'm home

MB roadside assistance jump started me. Details about trip home on the "Desperately Seeking...." thread. I "dieseled" on home, safely.

Thank you all for your help, concern, prayers.

MB'ers ARE AWESOME!!

Wouldn't it be nice if we had such a supportive system in all areas of our lives?!

db
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