Brake repair advise sought

I find that I need to repair/replace a leaking caliper on the left front of my '87 300SDL. My question is should I go ahead and replace/repair both front calipers or just the leaky one? Hoses too?
TIA.
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Cheers,
Kurt
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why do both? no reason really. also if hoses are good, why replace? it's not difficult to get at those parts again if you need to. On the other hand, rotors I would replace in pairs.
cheers, guenter
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snipped-for-privacy@sciborg.uwaterloo.ca (Guenter Scholz) wrote in wrote:

Thanks, Guenter. For the sake of economy in this insane season I guess that I'll opt for doing just the left (leaky) side.
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Kurt
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If the rubber hoses have never been renewed, it is time. Mine was replaced 3 years ago and they were VERY bad. In fact, I did all four wheels, since it is almost the same effort to bleed.
Guenter Scholz wrote:

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I was planning on replacing the hoses in the spring on all four wheels. Have found good prices on them at autohausaz site. I suppose that I could get a set and be done with the whole thing. Thanks for the suggestion.
[snippage]
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My past practice was to replace only the bad caliper, but to replace the pads on both sides. Last time, since the pads on the other side were less than a year and 10K old, I opted to not even put new pads on that side. My reasoning was that if a caliper has started to go bad, putting new pads on just forces you to push the piston, which may be starting to corrode, back into the caliper, leading to even sooner failure. The other obvious benefit is less work.
Downside of course is, will the braking be even? I figured nothing to lose by trying it. I did, and it worked perfectly.
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Kurt wrote:

Always repair brake callipers as a pair, better all four. You can get up to 60% in brake force difference if you do only one. Check carefully for damage to the bore, scratches or pits, if so replace the calliper.
Rob
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RobP wrote:

I'd like to see how you can get a 60% force difference between calipers that work. A caliper is just a piston, that should move with little friction, compared to the huge pressure exerted by the hydraulics when you apply the brakes. If the piston resistance is to have any significant effect on the clamping force, the caliper has to be shot. IMO, you'd have to be crazy to replace all four calipers, when only one is shot.
Plus, I haven't seen any consistency in rebuilt calipers, which is what many of us use. Meaning, I've seen rebuilt ones that last a year and ones that last 4 years. So, unless you want to use brand new ones, which is very expensive, I think replacing functioning ones, with no symptoms, isn't doing much good. I've replaced single ones many times, with no problems.
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    Agree with all of your points. re you last comment though; not crazy .... just a typical car mechanic. A shop gave me a estimate recently to repair a couple of brake lines... cost was $720.- (included new cylinders that were 'supposedly' leaking etc etc...) went to another shop and the cost was $200 and everything was considered good except he pointed out one of my rotors contact area was getting to small. He was right, I knew that, and yes, I had replaced the cylinders in summer myself.
- cheers, guenter
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snipped-for-privacy@sciborg.uwaterloo.ca (Guenter Scholz) wrote in wrote:

Thanks to all for the advise. I've ordered remanufactured caliper and hoses for the left side. I'll consider re-building the right side *if* it begins to be a problem. I have to weigh the need for repairs and preventative maintance against SWMBO sreaming about the "money pit on wheels". I did the front and rear brake pads less than 5 weeks ago, replaced all four tires three weeks ago and the read parking/emergency brakes two weeks ago. Still, considering that the car is 19 years old with 289K miles on the clock, the repairs are justified. Next step before the calipers get here is to do an oil change. Then try to diagnose the head lights going off when switched to hi-beam.
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.... Kurt, glad to see that you've learned to take orders. Life is much happier that way. I learned that as well :-) re your 'money pit' it is worthwhile.
cheers, guenter

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snipped-for-privacy@sciborg.uwaterloo.ca (Guenter Scholz) wrote in

[snippage]
It, the taking of orders, is one of life's many lessons, yes? And I agree that the "mobile money pit" is quite worth while. I've often asked myself why I did not begin driving M-B's sooner.
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The hoses themselves are stupid cheap and you should relpace all 4 at this age. Major safety issue "honey it has new brake hydraulics, safety issues".
Sounds like the high beam circuit in both bulbs is fried. Take the bulb out and test it manually to verify. Use only German bulbs from any import car place. Buck or so.
"Honey I fixed the lights for $3".
Keep reminding her it's really hard to die in this car. Safety issue.
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Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
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snipped-for-privacy@news.vrx.net (Richard Sexton) wrote in [snip]

Thanks, Richard. I'll check out the lights tomorrow and oder more hoses. If the light fix is only $3 she'll be much happier. Shoot if it's under $20 I'll be happier.
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Kurt
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I believe in maintenance. The rubber parts of the callipers get hard and wear.
If the inner ring gets hard the piston will only move under much greater pressure, the grease in the bore will harden also. Both leading to considerable difference in effectiveness of the brakes if only one calliper is replaced.
If the dust shield is worn water and sand gets in the calliper, between the calliper and the piston. This leads to scratching the surface of the bore and causes the calliper to leak. If you replace all the rubber parts of the calliper every 10-15 years they will not leak for at least 500K mls (personal experience).
Of course you can wait until it is seriously damaged and replace it with a also damaged and somewhat restored part (they call them rebuild). If you like failing brakes and expensive and short lasting repairs thats the way to go. Personally I would never use a rebuild calliper, reconditioning a used not damaged calliper is much better.
If you have an air compressor it is easy to recondition a calliper. Just blow the pistons out (never put your fingers between the pistons). Clean everything with brake fluid and a nylon brush. Put new rubber rings on the piston according to the instructions. Put some grease on the piston between the inner ring an dust shield and reassemble. Check if the bleeding screw can be opened before you start. For the 126 there are two different brands of callipers with different seals.
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RobP wrote:

I believe in maintenance too. But that is very different than stating that calipers should always be replaced in pairs or preferably all 4 at a time. Suppose the front calipers are 1 year old, the back ones 3. Say one of the front ones, which was a rebuilt one, goes bad. You would recommend replacing all 4 or at the very least the other front one, that is only a year old, with no problems? That's particularly hard to understand, given that down below you say calipers should last 10-15 years, 500K miles.

No ring getting hard or grease is going to have any significant effect on this hydraulic piston. The forces either of those could affect are a tiny fraction of the hydraulic force being applied.

In my experience, I've never seen any caliper last 10-15 years or 500K miles on any auto. At least not in areas of the country where they are exposed to even modest winter salt and weather conditons.

Most people on here are using rebuilt calipers. I always use them. Worst case, I've had them last a year. More typical is 4 years or so. Given that a new one would cost about 8 times as much, that seems like a pretty good tradeoff to me.

And how do you square that with your previous advice, recommending replacing all 4 calipers when one fails?
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You seem to have missed the part where I wrote that with basic maintenance callipers will not fail. Im driving Mercedes for 25 years (280, 280S and 300SE) in the Netherlands, mild winters lots of salt on the roads, and never had a leaking calliper and never replaced one. They fail if the dust seal is worn and the grease is to old. If all the rubber parts are replaced in time and the calliper is cleaned and greased it will not fail in a very long time. Even on my old motorcycle that I always used even in winter conditions, I never replaced a calliper. It doesnt have dust shields so the callipers have to be cleaned every year.
Rebuild callipers are usually scratched ones that are honed to get a smooth bore. As a result the piston has to much play and the strain on the rubber seals is much greater than with a original one and the pistons may tilt and scratch the bore. This will lead to premature failure.
I wrote that I would never replace a not leaking calliper, just clean it and put new seals and grease in them. Over here new seals and dust shields are around $ 60,- for four brakes, the work is about 20 minutes for every brake. I think thats a small investment for years of safe breaking.
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Rob, I'll keep this in mind for later. Certainly the cost of replacing the seals and dust shields are significantly less expensive than replacing the caliper(s) with either OEM or remanufactured units. Re- man units run about $72 US versus about $18 for the replacement seals and dust shields. OEM caliper(s) run anywhere from $450+. Local M-B dealership quoted me $750 when I had the pads replaced and the leak diagnosed.
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Kurt
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The "other one" in the circuit is the one diagonally opposite ie, right rear.
Definitly replace all the hoses. They have a date code stamped on them anf if they're 5 yrs old or older they should be replaced immediatly.
You don't need to replace the fornt right. GEt a good used one from car-part.com or if this car is special get White POst Restorations to rebuild yours with stainless parts for $175.
Used calipers are about 80 or so, sometimes less.
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