The vacuum is being shared with the booster, by blocking off some of the other vacuume items
that may be an issue it may help some.

what is the thing in picture vm1? that green thing and the big white thing it goes into. What does that do/what is it? (because it is holding no vacuum)?

How long have you had this car? Any records?

had it for a month. Very few records. The brakes work fine... the pedal is just fairly hard. It seems like the only vacuum lines that seem really bad are for the door locks. Everything else holds vacuum well (except the two mentioned in the earlier posts).

Plumb everything back together except the items that you've diagnosed are leaking. See if this makes the brake booster response better.

If so then your booster is fine. You'll need to fix the source of the leak. Once done reconnect everything back as it should be.

__________________
http://farm8.staticflickr.com/7271/7...144c3fc1dc.jpg

the only thing that seems like its leaking really bad was that big green squishy thing and what its connected to, and that black wire in the pic i posted. Can i disconnect those? It sounds like the green thing only has something to do with altitude (manual transmission car). But it goes into a piece that seems to connect to other things as well??

You took the words right out of my mouth!!
Test the brakes with the yellow check valve blocked
Off. Reconnect all the other lines except yellow check valve.
See if the brakes are better.
There is a recent thread here that has George Murphy's
Website
He has the rubber
Replacements for your doorlock pods $6 each

You can also search this forum and probably get vacuum diagrams for
Your car. They'll show what you can block off
If you choose to.

The black line that goes from engine bay into the cabin and holds no vacuum may not supposed to hold vacuum, it may be the vent. The purpose of a vent is to provide a source of air. In this case, this vent line provides clean air to your vacuum system from inside the cabin. Air needs to flow through all the devices which use vacuum through those devices too the vacuum pump. Clean air from the cabin prolongs the life of those devices.

ambush276, is this your first Mercedes? First European car? If all you have ever driven are American cars, which generally have really mushy brakes and no pedal feel at all, you may simply be experiencing a different brake pedal feel. If your brakes stop the car just fine, there may be no problem at all.

Please try isolating the problem by blocking off those things like the green thing and the yellow thing to see if they fix the problem (if you have a problem, see paragraph above).

Also note that pulling the booster down to 15 inHg of vacuum may not be a sufficient test, you may need to pull it down to 22 inHg to make the leak leak, if there is a leak.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

ive owned BMW's before and these brakes do feel too hard. Ill try holding it at 22 and see if that works and diagnose each vacuum line as well.

How do the brakes perform? That is my point, if they are stopping the car just fine, then do you really have a problem other than the feel?

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Perhaps just really glazed brake pads? It happens and car will have your symptoms. Not that common on these cars but still possible.

Deglazing of the pads is what I have done on a few cars. The pads on these cars are about the easiest to remove and check as well. Basically you do not even have to really disturb the calipers to do it.

I am not suggesting it is not something else but just something for you to consider.Especially if the car was this way from the time of purchase a month ago.

If its a new to you car, would probably be a good idea to do
brake hoses and flush fluids. Our kind of brake fluid tends to accumulate water and needs to be flushed every 2 years or so.

I forgot to mention that I sand the pads to break the glaze on the pads if present . Wear breathing protection though as the dust can be dangerous. If heavily glazed pads they have just vastly reduced their coefficient of friction giving you a much harder pedal. Hyundai brake disk pads and their drum brake linings are very prone to this disorder.

I was having some dragging problems on the front brakes of the Honda beater we acquired a year or so ago. It had just had a brake job before we purchased it on the front end.

When I had a look two days ago suspecting at least a sticking caliper. I found instead that the sliders where dry and ungreased. It took the use of a light hammer to get the pads freed up.

I only had some oil at the cottage and really the caliper holders also need to be removed and the slots wire brushes plus some high temperature grease on the sliders etc. The front brakes are not dragging anymore. Still I will take them apart and clean and lube them properly at home before fall.

I assume the brake job was done by some mechanic not caring about doing it properly. It is not rocket science and takes little time to do it properly. Rotors and pads where still pretty fresh. I think a lot of garages just do not care enough even to do the simple stuff properly anymore.. Too many people ignore this issue unless the brakes are really almost totally seized up or just can no longer drive the car. Or have a hard pedal.

It never hurts once in awhile to feel each wheel with a finger of any car for too much heat compared to its opposite side. It really hurts milage and wears parts excessively to operate with less than free brakes. There for example is not much force available to drive the pads back off of the rotors available so all parts must move pretty freely. I have heard the pads are displaced backwards by the sealing ring in the calipers. My belief is it is the force applied by the rotor that has some natural run out that pushes them back. If there is a lack of pad movement available it will just still apply pad pressure to the rotor by them still tracking the run out instead of backing off. Old car brakes should be checked periodically and at least cleaned up and lubricated.

ok all great advice. I will do a fluid flush on the brakes next most likely and take a look at the pads as well.

After going through most of the vacuum system last night, i found a few erroded rubber parts and replaced them. Still, the brakes are somewhat hard but like i said before they are working ok.


That being said after replacing the vacuum lines that seemed broken and rubber connectors i did a test once again and i finally heard a whoosing sound coming from the black box in the picture below. I took out the connector and tried plugging the connector with my finger and that holds vacuum fine. Therefore, it has to be something related to that black box in the picture. When using a handpump i can hear whooshing coming out of that box. If i remove the line that goes to the passenger side of the car and test it, it holds vacuum perfectly fine. Therefore, it seems this culprit is this black box.

What is it? what does it do? (maybe may affect the vacuum for the brakes?)

Thanks!

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