On Friday, I got my 1981 300D started up again after sitting for about a month. Started and ran like normal, but when I went for a test drive I found that I had no brakes! Fortunately I live on a rural dirt road. If I pushed the pedal to the floor as hard as I could, it felt like one of the rear brakes would lock up and the car would kind of skid slightly sideways and stop. I checked the master cylinder and found that it was empty. I filled it back up and played with the brakes a little with no real change ( I realize that I will need to bleed the brakes at the very least). I was just wondering if there was a common place that the fluid would leak from so that I can start my search there (I did not notice any place that was obviously leaking and I had not noticed a leak prior to this). I have a fair amount of mechanical knowledge and I have worked on brakes before, I'm mainly looking for any advice on any quirks that are unique to the MBZ as far as the brakes go. Thanks

You need to have the air bled out, then check for leaks.

Leaks can happen is lots of places, like rubber lines, caliper seals, metal lines can get metal fatigue or rubbed through. This system is pretty straight foward.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

I'm nut sure if the 300D master cylinder is the same as the 240D cylinder of that year, but I noticed that you have to almost overfill the reservoir to fill both chambers. One of your chambers might be empty. Hopefully it's not leaking into the booster.

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No matter how many times you explain it to me, I'm still right.....Surf-n-Turf

Like I said, I know I need to bleed the brakes, I was mainly wondering if there is a really common place for leaks on these vehicles so I could start my search there.

Personally, I have not seen a weak area as far as brake fluid leaks go, except for all the normal ones found in any other braking system.

Sorry to have offended you.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

A "hidden" leak would be between the MC and booster. An o ring lives there. Remove the four bolts, and try to see if there is any fluid in the booster. No need to remove any brake lines, so you can check anytime without having to bleed system. Hope this helps.

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83 SD

84 CD

I didn't mean to sound offended, I wasn't. I was just trying to clarify what I was getting at in my question.

Not a problem! Thanks for the kind words.

So, a SWAT sniper huh? I bet you hear a lot about ex-wives and services you could provide!

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

I'd look for a leak on the side opposite to which you were being pulled when you applied the brakes. A brake (or more) is not functioning on that side.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Yeah, I'm the SWAT Sniper Element Leader and a Homicide Detective, so I know how to create bodies as well as dispose of them

Yeah, it felt like the front brakes were doing nothing and the left rear would finally catch when I tried to push the pedal THROUGH the floor, but even that was just barely enough to make the car skid slowly to a sideways stop. After I got over the initial shock of no brakes it was kind of entertaining to cruise around the block skidding to a stop periodically.

lmao
John

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

It's about the only way to get tire squeal out of one of these cars.

Have you figured out where the problem is yet?

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

nope! going up hill in the rain on a corner, my turbo kicked in and whoosh both rears spun out from under me...
fun!
John

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I have never had tire sqeal on a wet road. I'll get a fish tail out also on a wet blacktop road during a turn and the famous 1-2 shift.

Before I adjusted the tranny modulator a little softer, the 1-2 shift would bark the tires on dry blacktop pavement, but not on concrete.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K