Splitting Brake Calipers? - Page 4 - PeachParts Mercedes-Benz Forum

leathermang · #1 12-24-2014, 08:11 AM

Quote:

Originally Posted by Diesel911

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.

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...

Lucas · #2 12-23-2014, 08:54 PM

Lol. It's not just the FSM. All write ups and articles about mechanics say this. I was ASE certified for brakes and taught this.

However, my rebuild kits came with those o-rings.

But how does it make getting the Pistons out easier? I would understand if you could get behind them.

JB3 · #3 12-23-2014, 09:10 PM

Quote:

Originally Posted by Lucas

Lol. It's not just the FSM. All write ups and articles about mechanics say this. I was ASE certified for brakes and taught this.

However, my rebuild kits came with those o-rings.

But how does it make getting the Pistons out easier? I would understand if you could get behind them.

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

Lucas · #4 12-23-2014, 10:03 PM

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.

leathermang · #5 12-23-2014, 10:17 PM

Quote:

Originally Posted by Lucas

..... "Well I've done it and it was fine." .....

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....

JB3 · #6 12-23-2014, 10:51 PM

Quote:

Originally Posted by leathermang

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....

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.

leathermang · #7 12-23-2014, 11:29 PM

Quote:

Originally Posted by JB3

...
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.

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....

JB3 · #8 12-23-2014, 10:49 PM

Quote:

Originally Posted by Lucas

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.

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.

Lucas · #9 12-24-2014, 12:00 AM

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.

Lucas · #10 12-24-2014, 12:42 AM

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.

Lucas · #11 12-24-2014, 11:14 AM

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.

pedrocamp · #12 12-24-2014, 12:57 PM

Here is a page describing the proper way to rebuild Porsche calipers, applicable to Mercedes calipers as well. I bought the caliper body seals from these guys for my ATE and Girling calipers on my 123, hope to complete a rebuild soon.

PMB - Caliper How To

Diesel911 · #13 12-25-2014, 01:15 AM

Quote:

Originally Posted by pedrocamp

Here is a page describing the proper way to rebuild Porsche calipers, applicable to Mercedes calipers as well. I bought the caliper body seals from these guys for my ATE and Girling calipers on my 123, hope to complete a rebuild soon.

PMB - Caliper How To

Out here in S. CA I have never had any of My Pistons get that rusty but When I see a damaged Caliper Boot I put a new seak kit into the Caliper.

leathermang · #14 12-24-2014, 01:20 PM

On that site they say this....
"" My guess is your pistons look awful right about now. The best method we’ve found for a nice factory finish is to vibratory polish the pistons. This is one of those areas where the average DIY mechanic may not have a vibratory polisher so we will recommend some substitutes that should work just as well. Regardless, the vibratory polisher at about 45 minutes with a mild solvent should net you perfect results for cleaning up your pistons. If not, the next best thing would be a tumble polisher. Nothing more than the rock polisher you had in your youth. With the proper media (we like ceramic) and a mild solvent your pistons should look great in about 1 hour. Finally, 0000 steel wool can clean up the sides of your pistons while a wire brush can handle the task of prepping the tops. I don’t like using fine grit sand paper as it can cause an out of round situation on the piston. ""

There is no time on a car where sandpaper should be used without something backing it....and in this case it seems like mentioning that even a little wood lathe would be great for prepping these pistons while keeping them round....might could even attach to a drill and do a good job....

Diesel911 · #15 12-25-2014, 01:10 AM

There is not any sort of Vibrator at My House.