X2.
When Disc Brakes started to be common on Cars I don't recall any warning about not splitting the Calipers on those Calipers that it could be done on. I had been doing it for years before I had a Mercedes.

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84 300D, 82 Volvo 244Gl Diesel

I have(had) and expandable tool that grips the inside of a caliper piston by expanding outward, allowing you to work even a rusty piston out of the bore by giving you a handles worth of grip on the piston itself Super useful little gadget. Misplaced it somewhere.

Only works on a benz caliper with it split

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This post brought to you by Carl's Jr.

Why don't YOU offer some theory as to why , given exactly what you have said, they said DO NOT split them... and that is not just MB... but industry wide... clearly it is not that that one item is where they plan on making lots of money... given the instructions for fixing all the way more expensive stuff....

Sometimes in life... given the importance of brakes and steering... and how cheap new calipers are.... and how important... it might be smart to just follow the warnings and put new or rebuilt ones on the car.... and focus on something else.

Calipers CHEAP.
LIFE NOT REPLACEABLE .
It is one of those things in life you would not want to be remembered posthumously for exercising your God given right to show HUBRIS. Just not worth it.

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

I can't find the info, but the bolts are torqued in sequence to avoid warping/future leaks. I believe they have a jig that tightens all four at one time.

There's an episode of how it's made or something.

It's that age old argument. "Well I've done it and it was fine." Maybe that time. But I think something so important shouldn't be messed with.

I don't mean to argue, but being a forum of public record, I voice my opinion.

Not remembering someone saying something way back when, is not the greatest evidence. However, hard physical evidence says not to.

If you rebuild a motor and it goes wrong, you can still stop.

The primary thing to remember about those kinds of anecdotal reports... is that they are ONLY from the ones that are still alive to post them... the failures are not still reading any forums....

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Right. Because all the other brake system components you are allowed to work on that depend on a sealed clean system for your safety are also too dangerous to service.

I guess i should stop bench bleeding my master cylinder, god forbid i replace any brake lines or fittings.

Demonstrate the "industry wide" comment. Last i checked most every auto manufacturer sells rebuild kits. Plenty of data out there to do it correctly. Nothing special about the benz split caliper design, BMW and others use it too, yet you are allowed to rebuild them.

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This post brought to you by Carl's Jr.

Its using an o ring seal, not a full gasket. My experience has been good starting from the middle and working out, but the o ring protrudes 2 or 3 mm past the sealing surface.

For what its worth, the first time i broke one of these apart i was following a haynes or a chilton manual, not the FSM. Never even was aware that there was such a rabid adherance to what the FSM doesnt detail. I i recall, the aftermarket manual shows a diagramed disassembly of the caliper. Ill see if i can dig it up and cooraborate it.

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This post brought to you by Carl's Jr.

Sure. Theres 10,000 dead mercedes enthusiasts who dared to service their braking system in greater detail than just swapping pads.

Personally i feel safer having done so. Especially on the older cars the o ring seals are 30 plus years old and hard as a rock.

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This post brought to you by Carl's Jr.

We are not comparing doing it to NOT doing it... we are comparing doing it yourself against the FSM and other's instructions...
to Replacing it with a professionally rebuilt one...

How much MONEY are we talking about between THE KIT....and rebuilt calipers ?

I suspect the prohibition does have to do with what Lucas mentioned... the potential for warping the contact surface either taking them apart... or putting them back together...and that he is correct that the bolts are all tightened at the same time....

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

I'm still searching for the video. Lol.

This was the first kit I've seen that had the small o-rings.

Learning what they are for does make me nervous. I may return my kits and buy calipers.

I'm one of the worst around for not following directions. You may have seen my post where I put oil in the cylinder and ignited it under compression. Or had my mom pull me with the tractor while I cranked the motor over to pop the rings.

But I still will follow what mercedes says to do in regard to brakes.

The good thing is, you can still rebuild yours how you want. I'm just speaking up for safety and people reading this.

Man who brought this old thread back? Big can of worms.

I understand your opinion on the subject but the rebuilder splits the Calipers reguardless of what the Manual tells you.
So you can split the Calipers yourself or you can let the Rebuilder do it for you.

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84 300D, 82 Volvo 244Gl Diesel

I think there is a procedure for it. Beyond whats capable in a shop or garage. And testing equipment and specifications. And a big insurance policy.

A rebuilder can afford to invest in special tools , if they are needed, to do the job right...

Here is where HUBRIS and Assumptions might make a difference....
WHAT IF the failure mode was not ' a leak ' but a BREAK ?

That with the pressure put on it by the hydraulic system in an emergency stop.. it actually breaks one side of the caliper ...due to unequal loading and the casting configuration.... causing potential loss of steering control at the worst possible time ?

Like a simple rail failure can cause with the very strong double roller chain at the heart of the 617 engine to come to a complete stop and cause bent valves and hole in the top of pistons.....

AGAIN... I ask ... What is the difference in COST between a KIT and rebuilt calipers ? Are you willing to put your life and others at risk for THAT Difference in price... given the warning by manufacturers of these products NOT to do a certain thing to them ?

Remember.... you are not in the ' failure ' report loop. Manufacturers are and I say for the difference in cost between a Kit and a rebuilt caliper is not worth the chance your assumptions are better than the warnings posted by the people who are in the ' failure ' reporting loop...

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

The FSM I have gives a reason for not splitting rhem. They say not to split them because the mating bolts are tightened to a definate torque by the manufacturer. Its in bold typeface so they really mean it.

Alright alright. Here is a good procedure for splitting them, and they give the torque specs. Generic universal numbers, I wouldn't trust them. Interestingly, they talked of having them zinc plated.

https://pmbperformance.com/pages/the-ultimate-brake-caliper-restoration-guide


Here's a pro shop that actually tests the calipers for cracks or leaks.

http://youtu.be/D0J89b1VxrI

Here's boshe. They galvanized them. And test for a gazillion scenarios.

http://youtu.be/GwwM-9MlrGk


And here's an idiot resurfacing a rotor with a polishing disc. He splits them also. No zinc plating

http://youtu.be/CCp4DRBpdW4

I've learned something. I won't buy auto stop rebuilt calipers again. The plating is what makes the magic happen.

I probably won't even do seals and boots again after this.

And I will spend the money for boshe. I came across a few other rebuilders that plating is an option for custom customers.

Although, I saw a 2 year old dodge recently that needed calipers.

I think the importance is in the testing. And the procedures developed learned from the testing.