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  #1  
Old 01-15-2005, 09:56 PM
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Join Date: Nov 2002
Location: Flyover State
Posts: 1,363
Defective new master cylinder? (long)

Regarding '76 300D with tandem master cylinder, second version from 029142

You might be able to add me to the ranks of suckers screwed by that guy bigbabbo, or whatever his name is. After spending 1500 some odd dollars on Fastlane for the front end rebuild, I thought I might check competitors prices and save a few bucks. Based on a thread here, I found a site with better prices, ordered and installed the new looking master cylinder in ATE packaging.
Now after much bleeding, I cannot get proper braking or pedal feel. I've used the manual method with an assitant and opening and closing the bleed screw. Then I bought an eezibleed and ran fluid through each wheel. That didn't work, so I again attached the eezibleed, raised the rear end, then opened both rear bleed screws while pumping vigorously several times on the pedal, then did that on the front. With only slight improvement, I repeated it only opening one bleed screw at a time with the pressure bleeder attached and pumping the pedal. Still, braking is very minimal with brake effect only taking place when the pedal is mashed to the floor, very weak braking at that. I've made SURE that both compartments of the resevoir have been full while doing this.

The pedal should pump up and become firm even if there is air in the lines, only my pedal pumps up reluctantly and then sinks to the floor right away. I beat on the master cylinder a couple times with a brass hammer in case the floating piston may have gotten stuck. Another thing is the brake warning light will not go off, even after "resetting" the fluid level sensor switch.
The fluid level does not drop after repeated pumping of the pedal and no wetness is observed around the calipers indicating no malfunction of the wheel cylinders in my mind. However, there may be the possibility that the rear calipers froze while the car was being worked on over the last three months, while at the same time my front caliper reseal job may have been defective.
The pistons in the front caliper moved fairly easily after I rebuilt them, and I feel confident in my work. The shame about it is that my old master cylinder was probably fine, no pedal fade noticed. I'd throw it on and check but I submerged it in a vat of ATF thinking I would keep it from rusting not know that oil contamination in the brake system was forbidden. (Still new at this $*#!)

What would you do next? I'm considering removing the master cylinder and taking it to my indy for inspection, or should I tow the car to him and let him have a go at the bleeding?
I do have a strong feeling that had I shopped with Phil, I wouldn't be having any of these problems.
Thanks for reading this rant. After 3 months of work and being so close to driving the old 115 again, I'm very annoyed at this delay.
__________________
63 220S W111
76 300D W115
2013 VW JSW TDI M6

previously-
73 280 SEL 4.5
86 300E 5 speed
2010 VW Jetta TDI M6

Last edited by joshhol; 01-22-2005 at 09:47 PM.
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  #2  
Old 01-15-2005, 10:17 PM
boneheaddoctor's Avatar
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Join Date: May 2004
Location: Hells half acre (Great Falls, Virginia)
Posts: 16,007
I think you might have gotten a bad master cylinder...........I special ordered one from Advace Auto and had a simular problem only not as bad....they ordered me a new one and problem solved.

Point of note.......make sure your brake booster is not full of brake fluid......that is a death sentance for it.......mine was full to the brim.....I found out where the occaisional fluid loss was............

Had to replace that as well as the master cylinder..............
__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche
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  #3  
Old 01-15-2005, 10:18 PM
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Join Date: Sep 2001
Location: central Texas
Posts: 17,038
Did it come with instructions ?
Did you read them ?
Did it say anything about " bench bleeding" the master cylinder before installation ?
If it mentioned it...did you do it ? and if yes, then describe your procedure.
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  #4  
Old 01-15-2005, 11:00 PM
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Join Date: Nov 2002
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First, there was some brake fluid in the booster from the old master. It has been cleared now but I don't see how that would affect peddle drop.

leathermang, I was afraid someone would say that. There were no instructions. Later I realized this was odd as my ATE rotors, caliper seal kit and pads all came with instructions. Additionally, I had never received a receipt from this guy listing exactly what I had bought, just email notification of money spent. So, I called him up and nicely asked for an invoice, which I got which may come in handy if there is recourse to be had.

I had read about bench bleeding and asked my indy about it. They seemed to be indifferent about it and said to bolt it on, fill with fluid, pump pedal several times, then bleed.
I later tried a half-a$$ed bench bleed with my brother at the brake pedal, I loosened each line nut and attempted a crack nut, depress pedal, tighten nut sequence. Very messy, results unknown.

Now what?

Thanks
__________________
63 220S W111
76 300D W115
2013 VW JSW TDI M6

previously-
73 280 SEL 4.5
86 300E 5 speed
2010 VW Jetta TDI M6

Last edited by joshhol; 01-15-2005 at 11:06 PM.
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  #5  
Old 01-15-2005, 11:02 PM
boneheaddoctor's Avatar
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Location: Hells half acre (Great Falls, Virginia)
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Quote:
Originally Posted by joshhol
First, there was some brake fluid in the booster from the old master. It has been cleared now but I don't see how that would affect peddle drop.

leathermang, I was afraid someone would say that. There were no instructions. Later I realized this was odd as my ATE rotors, caliper seal kit and pads all came with instructions. Additionally, I had never received a receipt from this guy listing exactly what I had bought, just email notification of money spent. So, I called him up and nicely asked for an invoice, which I got which may come in handy if there is recourse to be had.

I had read about bench bleeding and asked my indy about it. They seemed to be indifferent about it and said to bolt it on, fill with fluid, pump pedal several times, then bleed.

Now what?

Thanks

Brake fluid should NEVER be in the booster.......it will shorten its life.....but no you are right it will not effect pedal drop now.
__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche
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  #6  
Old 01-15-2005, 11:08 PM
boneheaddoctor's Avatar
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Join Date: May 2004
Location: Hells half acre (Great Falls, Virginia)
Posts: 16,007
Quote:
Originally Posted by tangofox007
It's okay to bleed the master cylinder on the car. But there is a difference between bleeding the MC and bleeding the brakes. Did you actually bleed the MC first? If you didn't, you will likely have the symptoms that you described.
It just takes a little bit longer to prime and bleed.............its not going to damage anything. if you crack the lines at the pump with two people you can do it on the car......but clean up spilled brake fluid.....it does unkind things to paint if left there.
__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche
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  #7  
Old 01-15-2005, 11:09 PM
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Join Date: Nov 2002
Location: Flyover State
Posts: 1,363
The factory manual said something about bleeding the master by opening the brake pedal bleed screw. Maybe that is only on the older version.

So I should attempt a loosening of each line nut with pedal down kind of thing again?

Thanks to all.
__________________
63 220S W111
76 300D W115
2013 VW JSW TDI M6

previously-
73 280 SEL 4.5
86 300E 5 speed
2010 VW Jetta TDI M6
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  #8  
Old 01-15-2005, 11:10 PM
boneheaddoctor's Avatar
Senior Benz fanatic
 
Join Date: May 2004
Location: Hells half acre (Great Falls, Virginia)
Posts: 16,007
Quote:
Originally Posted by joshhol
The factory manual said something about bleeding the master by opening the brake pedal bleed screw. Maybe that is only on the older version.

So I should attempt a loosening of each line nut with pedal down kind of thing again?

Thanks to all.

Have someone press down on the brake. crack each line and fluid should come out. then move down to the calipers/wheel cylinders.
__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche
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  #9  
Old 01-15-2005, 11:27 PM
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Join Date: Sep 2001
Location: central Texas
Posts: 17,038
" I was afraid someone would say that."

Maybe I have been lucky .... only had to replace perhaps four master cylinders in my life... but the one that said in the instructions that it had to be bench bled... I had to take back off and do exactly that...

If you do bench bleed it... try to find some plugs the size of the lines which will be hooking to it when you install it... keeps you from introducing any air just from the fluid running out.

You may can " bench bleed " it yourself in the car if you make things sorta like the " drip " tube used for setting start of delivery for fuel on our engines... with the end of the tube going back into the top of the master cylinder resevoir. So when you push on the piston the fluid which comes out is recycled into the top of the master cylinder. A self recovery system.
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  #10  
Old 01-15-2005, 11:29 PM
boneheaddoctor's Avatar
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Join Date: May 2004
Location: Hells half acre (Great Falls, Virginia)
Posts: 16,007
Quote:
Originally Posted by leathermang
" I was afraid someone would say that."

Maybe I have been lucky .... only had to replace perhaps four master cylinders in my life... but the one that said in the instructions that it had to be bench bled... I had to take back off and do exactly that...

If you do bench bleed it... try to find some plugs the size of the lines which will be hooking to it when you install it... keeps you from introducing any air just from the fluid running out.

You may can " bench bleed " it yourself in the car if you make things sorta like the " drip " tube used for setting start of delivery for fuel on our engines... with the end of the tube going back into the top of the master cylinder resevoir. So when you push on the piston the fluid which comes out is recycled into the top of the master cylinder. A self recovery system.
In the last three years I have had to replace leaking master cylinders on my truck, Honda and Benz......all leaking down with light pedal pressure. But I did bench blead first also.....
__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche
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  #11  
Old 01-15-2005, 11:41 PM
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Join Date: Sep 2001
Location: central Texas
Posts: 17,038
My Gosh, Have you looked to see if a black cloud is following you around ?
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  #12  
Old 01-16-2005, 12:01 AM
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Join Date: Sep 2001
Location: central Texas
Posts: 17,038
The rule is to bleed the brakes starting at the one furthest from the MC measuring along the brake lines... sometimes this changes according to years or models...
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  #13  
Old 01-16-2005, 12:23 AM
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Join Date: Sep 2001
Location: central Texas
Posts: 17,038
I have had American cars which routed the main line on the right side... making the left rear the furthest...
On my Subaru's either rear brake can be done because they are paired in the dual system diagonally, left rear with right front,etc .. very strange.
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  #14  
Old 01-16-2005, 06:29 AM
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Join Date: Nov 2002
Location: Flyover State
Posts: 1,363
Don't forget Japan and Singapore.

The 115 has one line running to the rear which T's on the left side; right rear is furthest.

Castrol LMA seems to be well respected, can't find ATE SL down at the corner.
__________________
63 220S W111
76 300D W115
2013 VW JSW TDI M6

previously-
73 280 SEL 4.5
86 300E 5 speed
2010 VW Jetta TDI M6

Last edited by joshhol; 01-16-2005 at 06:54 AM.
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  #15  
Old 01-16-2005, 10:29 PM
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Join Date: Nov 2002
Location: Flyover State
Posts: 1,363
Greetings everyone,

Today I've reached my wits end. I've given it my best effort and will now turn to professional help. I followed the bench bleeding procedure carefully and bled all wheels in turn. Still brakes are weak with pedal drop and a persistant brake warning light. There was a marginal improvement, perhaps a second round of bleeding the master and wheels might be in order, but my gut feeling from the start has been that this master cylinder is defective.
So, we'll see what Mr. Bigaboo says about all this. I have the reciept and an army of free lawyers on my Air Force base probably with nothing to do if it gets to that. I don't care to get a replacement from him, just my money back so I can buy one from Phil. The money I "saved" buying from him has been eaten by the 5 litres of brake fluid, time, gas and frustration.
Lesson learned. Buy from reputable source ALWAYS.
Now, maybe this guy will be honest about this and didn't know it was defective. Still I would like to open it up and see what the bore and cups look like.
Thanks for the help. I think I've gotten pretty good at bleeding brakes now.
__________________
63 220S W111
76 300D W115
2013 VW JSW TDI M6

previously-
73 280 SEL 4.5
86 300E 5 speed
2010 VW Jetta TDI M6
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