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#1
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Brake overhaul
Can someone tell me, on a car with 62,000 miles and a very soft brake pedal, what would a brake overhaul include?
The rotors seem worn, there is a 3mm ridge or so on the outer skirt and the pad surface. So, rotors and pads for sure, brake bleed, but what about brake hoses? Slave/master cylinder? Will new wear sensors be needed? Is it likely the rear ones need changing or is it mostly just the front?
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Smoke Silver 1994 E220 Coupe Automatic 0 kilometers 6 September 1994 100,635 kilometers - 6 September 2010 |
#2
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You mention a few different issues.
For the soft pedal get the brakes bled. You probably should do that ASAP. If it's been over 2 years get the old brake fluid flushed and replaced. MB recommends DOT 4+ or DOT 4 LV (same). Generally hoses aren't replaced unless leaking or damaged although there is the crowd that thinks braided SS is cool. Same with calipers and master cylinder. Repair/replace as needed not based on any service cycle. Both the pads and the rotors (discs) have thickness specs. To judge their need for replacement find the specs and measure the ones on your car. If your pads have wear sensors then wait until they trip unless you can see the coated wire during inspection. Then it makes sense to replace pads if rotors are needed as one job. Most of a car's stopping power comes from the front brakes. If you have managed 62K on the original front pads then you must be a prudent driver and I doubt the rears need replacement but must be inspected in any event. BTW, if this car is subject to MB's A/B service schedule then whoever does that should have measured and recorded the pad/disc thickness every B service. Note this is based on US recommendations. You may have to compare with your country to see if there are differences. Good luck. |
#3
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It's a box of chocolates. There's no way to no what you're gonna get until you take things apart and start inspecting.
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#4
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On my four various Benzes (all 124's) I have never gotten less than 120K on the rotors before they were deemed too thin. I have never found them out of round or needed turning. If one uses the correct pads and replaces them before metal hits metal, rotors should have a long life.
Anziani '87 300E (sold to my mechanic) '91 190E (sold to my granddaughter) '93 300CE '95 E420 |
#5
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No the pads have been changed already, at the very least 2 or 3 times. Rotors have never been changed, and there is a good chance that the fluid was never flushed.
The cars maintenance schedule is every 6 months, as it is rarely used and only covers about 2,000km in that time. Does anyone know the minimum rotor thickness on the 124 E220 Coupe?
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Smoke Silver 1994 E220 Coupe Automatic 0 kilometers 6 September 1994 100,635 kilometers - 6 September 2010 |
#6
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That's about right. Most owners report 2 or 3 pad changes per rotor replacement. Spirited drivers - not so much.
Sorry I don't have specs for W124 just W210. May be the same but no point in guessing. Specs are at the end of WIS procedure for pad/disc replacement. |
#7
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What are the dangers if I run the rotor below the manufacturers minimum recommended thickness?
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Smoke Silver 1994 E220 Coupe Automatic 0 kilometers 6 September 1994 100,635 kilometers - 6 September 2010 |
#8
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Hard to predict but loss of brake efficiency initially. Eventually overheating and maybe warped rotors with a REAL loss of brake efficiency.
If you drive the car very little and are aware of the danger then you might get by for a while. But bad things have a way of happening at the worst possible time. If you find yourself having to make an emergency stop at highway speeds, it will be too late to do anything about the brakes. I knew a mechanic once who always said a car that won't start is an inconvenience -- a car that won't stop is a deathtrap. Good luck. |
#9
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I would guess that with a 3mm lip you are WAY below the spec. I am not saying it is dangerous necessarily, just that the specs are pretty conservative.
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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine) 1988 F150 144,000 miles (leaks all the colors of the rainbow) Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra |
#10
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That's a good point. I took it to mean an eyeball not a direct measurement.
For example on my W210 the new disc is 28mm and the service limit minimum is 25.4mm or 2.6mm total. |
#11
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The min thickness should be stamped on the rotor somewhere, either the edge or on the hub surface (I forget). There is not a lot of wear tolerance, 2-3mm total is about right. They usually last about 3 pad changes - it's the same ratio for front brakes vs rear brakes too I believe.
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#12
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Ok I might change them in the following few months.
Are OEM rotors best or any other brand is good too?
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Smoke Silver 1994 E220 Coupe Automatic 0 kilometers 6 September 1994 100,635 kilometers - 6 September 2010 |
#13
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Hey Spetz,
I went for the manufacturer of my brake components (ATE)... they seem to be of good quality. I see you are in Europe so perhaps this link to a German site is of use to you:- http://www2.kfzteile24-shop.de |
#14
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Too bad it's in German though...
Google translate did a poor job of translating it too
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Smoke Silver 1994 E220 Coupe Automatic 0 kilometers 6 September 1994 100,635 kilometers - 6 September 2010 |
#15
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I'm not sure what the recommendation is these days, but when I had a W124, Balo was supposed to be a good brand for rotors.
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