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#16
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Quote:
__________________
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 |
#17
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Actually it was on a dual system. The right rear wheel cylinder seal popped. It was on an older Chevy P/U. Front disc, rear drum. Icy conditions along I-20. That was not a good time to find out about the problem. Ever since then I check the brake system every time I rotate tires.
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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 |
#18
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#19
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Actually it can. You will feel some resistance just before the pedal touches the carpet. At that point, your proportioning valve should have given full power to the remaining system.
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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 |
#20
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Such a scenario would defeat the entire purpose of a dual m/c with separate braking capability on each system. There must be more to the story.
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#21
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I drove mine about 500 miles with a broken rear line and the pedal was pretty low, but not to the floor. The other brakes still worked.
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#22
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Look at flexible lines and brake fluid
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I would also think about replacing all four flexible lines, the LF caliper (or you can rebuild it, if you can get the pistons out but they may be frozen in their bores) and replace the brake fluid. MB recommends changing the fluid annualy. I always use OEM fluid too. Brake fluid is hydroscopic (absorbs moisture) so when the caliper piston seals cooked, it could allow moisture between the piston and the bore then the brake system starts to rust from the inside out. I think the chances of your brakes just failing are very small because MB uses a dual diagonal system so that if one part of the brakes fail such as the LF, you would lose the RR but still have the RF & LR. Stopping distances go up dramatically, but at least you still have hydraulic brakes and are not totally dependent on the parking brake.
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Doug 1987 300TD x 3 2005 E320CDI |
#23
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This description applies to the W126. The W123 may have a different m/c setup, but it does not have a diagonal system. |
#24
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The vehicle this happened to me in was a '77 Chevy C20 crew cab pick-up. It did not have the diagonal system as the MB. If you lose any hydraulic pressure on the rear, you have no rear brakes, except for the emergency brake. Same for the front, except you lose the front portion. Diagonal set up would have been much better, as you have proportional front rear stopping power, even if it is a partial system.
When adrenalin is pumping, you can push a brake pedal to the floor. I have found that just because something "can't happen" either on paper, or on the bench, does not mean in won't happen in the real world arena.
__________________
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 |
#25
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I very much appreciate the input. The LF caliper piston is not stuck. I got it to move when I put the new pads in. I purchased two reman calipers to be safe. 83 bucks each not bad, and maybe the complaints about brakes will go away. I recognize the points on both sides. Probably not a problem, but there is a difference between something braking and being stuck on the side of the road, and something not braking and being off the road or welded to someone's back bumper. Keep the debate alive. Its informative. But I wanted to say thanks.
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#26
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Oh, and by replacing the fluid you mean draining and bleeding and the whole routine, right? Did that last summer, so I am on schedule.
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#27
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OK, maybe it is VW's or BMW's
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Doug 1987 300TD x 3 2005 E320CDI |
#28
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In any case, the M/B does not have this system. |
#29
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CORRECT, speaking for a W123.
__________________
'83 240D with 617.952 and 2.88 '01 VW Beetle TDI '05 Jeep Liberty CRD '89 Toyota 4x4, needs 2L-T '78 280Z with L28ET - 12.86@110 Oil Burner Kartel #35 http://i16.photobucket.com/albums/b1...oD/bioclip.jpg |
#30
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No responsible shop would let that 1985 300D out the door unless the owner signed a waiver indicating that he understood the brake system was unsafe and refused to have the system repaired. The potential liability is huge.
When the brake fluid boils one day due to a faulty brake hose and/or sticky caliper, the brake pedal will go to the floor and the vehicle will not stop. It doesn't matter if the system is dual or not. All it takes is a long highway run with a sticky caliper to boil the brake fluid in a car that drives just fine around town and doesn't pull to one side during heavy braking. Yeah, brake pads can take alot of heat, however Dot 4 brake fluid boils at under 500 deg/f. The boiling point is reduced when it is contaminated by water, as is the case with most brake fluid that is more than a couple of years old. |
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