W202 C200 Rear Brakes Change

[Beast-W202]

Hey guys, The brakes on the merc have been making some really horrible noises lately in the form of a horrible horrible metalling grinding noise from the rear when the breaks are applied, the noise comes at all speeds but is much worse when going slow.

So I took off the back wheels and as expected, the discs were both rusty, scored, and just knackered. And the pads looked pretty damn low! I won't be surprised if the grinding is coming from the backing of one of the pads scoring the disk!

Plan is to replace disks and pads on the back and check the callipers while I'm at it, give them a good clean and oil etc where necessary incl cleaning the hub as I like to be thorough

Luckily the fronts have been done recently so after double checking, all is good!

I've done plenty brake changes and overhauls in my time, and after watching a few vids and reading up, the merc ones should be pretty simple.

My Question is Does anyone have any tips? Is there anything to watch out for / make sure I change or replace? Anything you can offer would be appreciated!

Thanks!

 

[golden1245]

Here are the pages regarding the rear brakes only, hope this might help you a little. I'm going to try replacing my rear pads and discs this weekend too.

 

[andy27168]

Hi,
Rear brakes pads and discs are a doddle on a 202, the only issue you could possible have is removing the disc from over the handbrake shoes.
The Haynes manual states that the Caliper securing bolts should be replaced everytime they are removed, but this has been discussed on the forum several times and the consensus of opinion was this was that the proper MB bolts when new are impregnated with thread lock, I have replaced my rear discs and pads twice now since owning the car and have always reused the original bolts but used a drop of thread lock on the bolts before refitting the caliper.
When you buy your new parts, make sure you get a new wear sensor (if applicable) new disc securing screws, a bottle/tube of thread loc and some proper brake assembly grease, these parts are all available from ECP, and with the forums 25% discount makes it a no brainer.
I also pump out the old brake fluid an replace as i do each caliper.

 

[artz]

Hi,
Rear brakes pads and discs are a doddle on a 202, the only issue you could possible have is removing the disc from over the handbrake shoes.
The Haynes manual states that the Caliper securing bolts should be replaced everytime they are removed, but this has been discussed on the forum several times and the consensus of opinion was this was that the proper MB bolts when new are impregnated with thread lock, I have replaced my rear discs and pads twice now since owning the car and have always reused the original bolts but used a drop of thread lock on the bolts before refitting the caliper.
When you buy your new parts, make sure you get a new wear sensor (if applicable) new disc securing screws, a bottle/tube of thread loc and some proper brake assembly grease, these parts are all available from ECP, and with the forums 25% discount makes it a no brainer.
I also pump out the old brake fluid an replace as i do each caliper.

massive thanks for the info above. Does this follow for doing the front ones too, they were tough to get off so really tightened them as much as possible but didn't put any thread lock on?

 

[DRBC43AMG]

Hope you didn't tighten too much because if they get rusty you may have BIG problems removing them later. In any case, as long as you have a wheel on the dics, the screw is not going anywhere.

 

[Beast-W202]

Hey Guys, thanks for all that info! & Thank you Golden1245 for the pics and instructions! will be a massive help should I get stuck!

Glad to hear that it should be as simple as previously thought, and Thanks for the tip regarding the bolts and thread lock, I had been wondering about these.

Most defiantly will be taking advantage of the discount with ECP!

What about the securing pins and pad retaining clip? should these be replaced or can i use them if there in good nick?

Cheers!!!

 

[andy27168]

Hi,
I just reused my locating pins and clips as they were ok just gave them a wire brushing, i used a torque wrench on the caliper bolts, the figures for these were in the haynes book of lies and were checked on WIS when i had it up and running on my PC, maybe some kind soul can look for you.

 

[NW_Merc]

Hi,
I just reused my locating pins and clips as they were ok just gave them a wire brushing, i used a torque wrench on the caliper bolts, the figures for these were in the haynes book of lies and were checked on WIS when i had it up and running on my PC, maybe some kind soul can look for you.

So you wouldnt trust Haynes torque settings?

 

[artz]

Hi,
Rear brakes pads and discs are a doddle on a 202, the only issue you could possible have is removing the disc from over the handbrake shoes.
The Haynes manual states that the Caliper securing bolts should be replaced everytime they are removed, but this has been discussed on the forum several times and the consensus of opinion was this was that the proper MB bolts when new are impregnated with thread lock, I have replaced my rear discs and pads twice now since owning the car and have always reused the original bolts but used a drop of thread lock on the bolts before refitting the caliper.
When you buy your new parts, make sure you get a new wear sensor (if applicable) new disc securing screws, a bottle/tube of thread loc and some proper brake assembly grease, these parts are all available from ECP, and with the forums 25% discount makes it a no brainer.
I also pump out the old brake fluid an replace as i do each caliper.

Doh... 25% discount at ECP, how do you access that please Andy?

 

[artz]

Doh... 25% discount at ECP, how do you access that please Andy?

Good Thread here about this

 

[andy27168]

So you wouldnt trust Haynes torque settings?

If it was my only source of info I would use the info but there were so many different variables on the 202 with the various engines and some engine variants it doesn't even cover etc and the fact that the manual is a bit hit or miss especially where the electrics are concerned it doesn't fill me with confidence.
Hence the reason I will always try to source info from WIS where ever possible.

 

[golden1245]

...so I shouldn't trust the Haynes manual torque values??

I've been following them for doing everything so far. Brakes, front shocks...

if the torque settings are off by just a few foot-lbs, is it dangerous?

 

[BlackC55]

We are finding that some of the rear calipers on 's are so rusty on the inside that the pads are loose when fitted. Make sure that this is not the case. Also depending on how rusty they are you may need new pins too.

 

[grober]

...so I shouldn't trust the Haynes manual torque values??

I've been following them for doing everything so far. Brakes, front shocks...

if the torque settings are off by just a few foot-lbs, is it dangerous?

Torque figures are normally related to the size /tensile strength of the bolt. There is normally an "operating range" rather than an absolute figure. For example M10 high grade steel 17mm bolt has a range 38-54Nm {the grade is usually a number on the bolt head e.g. 8.8, 9.8,10.9 higher the better} Obviously a couple of Nm's either way is not going to be crucial bearing in mind the accuracy of most torque wrenches. On the other hand on an M6 bolt with torque figures 9-12Nm a couple of Nm's represents a much bigger error. That's why a smaller torque wrench is a good idea for small bolts or even just "feel" because the danger of over-torquing is so much greater. Remember also if you use threadlocker this reduces the chances of the bolt becoming undone so you don't need to over tighten "to be sure" The Haynes figures are going to be fine.

ps interestingly on old Mercedes the original "from factory" bolts were usually the best quality judged from their strength markings. The later after market bolts supplied with OEM quality replacement components like shocks etc [ altho perfectly adequate] were always a grade or 2 less.

 

[golden1245]

ah ok, thanks grober

 

[Beast-W202]

Right, all info taken on board now. I will be sure to look out for everything mentioned, thanks again!

I will take a load of pic's when I do mine and post them up for everyone to have a look at if wanted too.

 

[LawrenceMB]

Hi, you've obviously got some instructions from a manual posted above so it should all be covered. All I'd add is do make sure you've got the handbrake shoe adjusters backed right off & have then tapped that inner 'drum' part of the disc with a hammer a few times to be sure the handbrake shoes have fully returned so you don't rip them out & bend all their retaining clips when you are pulling the discs off. Be aware I seem to remember to back the adjusters off you turn them different ways on the 2 different sides of the vehicle, which can be confussing. Just make sure you are loosing them right off & not tightenening them. The disc should obviously turn freely if you've done it the right way.
Also, when refitting the discs, we used to put just the lightest smear of very high melting temperature copper grease on the inner circle of the disc where it fits over the wheel bearing hub cover itself, just to stop it seizing on there overtime so making it easier if you have to replace the parking brake shoes. But I'm talking only the very slightest smear of copper grease, & only round the inside of that small hole in the middle of the disc, and don't even use wheel bearing grease, as the wrong grease or too much of the right stuff will end up on the brakes themselves which is not good for obvious reasons! If you're unsure, or don't have any copper grease, then don't bother - I imagine most people don't! Cheers.