Hey guys, I wrote this 'how to' guide for replacing brake discs and pads on an S Class for a UK MB forum after a request. Anyhoo thought you guys might appreciate it too - it's aimed at newbs, as TBH this is a easy job if you've done a few. Hopefully might inspire someone just contemplating DIY repairs to give it a go! I think there's a large proportion of us out there that first started out with brakes.....

http://www.jamesandtracy.co.uk/howto..._and_pads.html

 

Nice write-up...
Thank you...

Though I wouldn't copper-grease the bolts as it changes the torque value required, which is unknown.
Would also not triple check: do it right the first time.
I have only seen stuck calipers, when the seal was damaged...
Cleaning the hub is a very important step, agree.

 

Very Good write up.

 

The only issue I have about this write up is the notion of getting OEM pads which generate a lot of dust a mention of a "dust free" alternative would have been good.

 

Thanks mate, glad you liked it

Not sure I agree though with the points you raise. Copper slip is well documented with respect to torque because of its historic use in the aircraft industry. For mild steel into steel and at the sort of surface area we're talking about here you're looking at a need to REDUCE the torque settings by 10-20% to meet the specs exactly - i.e. approx 95NM torque rather than 115NM is required. Given your over-torquing and that these are steel into steel large caliper bolts, 10-20% really isn't that critical. Many peeps don't even bother and do it by feel alone...

As to ignoring the triple check - you crack on mate, it's a personal choice. Personally, many many years of experience has taught me that it's essential. Ok it's only actually really saved my life once when a new 'top of the range' brake hose split on a test run on the track, but I'll take that over being dead. There have also been more than a handful of times when disturbing old parts has led to them failing after only a short time which I've picked up early only because of the triple check. As said though, it's your call....tbh I never took it totally seriously despite my background and never truly followed it rigerously until the brake hose failure.

On stuck calipers, I regularly come across chrome corrosion as the main issue for stuck calipers on BR fours although I do agree seals are a strong second. Take my S for example, this had chrome corrosion with a fully intact set of seals. All brake fluids have issues with water - DEG ones because they're hydroscopic and silicone ones because they're hydrophobic. In silicone the water usually pools at the inside bottom of the caliper so piston 2 gets corroded. In DEG the water can corrode any piston but usually 2 or 4 from my experience for some reason. Once it's between the chrome coating of the piston and the inner steel it doesn't take long. However corrosion doesn't usually occur before the 5-10 year mark unless the car has been regularly track raced, so this is a failure for older cars not newer ones. However, this is what I see in the UK (wet, humid environment) it may not be the case in other parts of the world I guess?

 

I've never had a problem with true Mercedes OEM as these are exactly the same as the original equipment. Usually, dust is only an issue with cheap non-OEM aftermarket pads like B&B.

That said I've also found that dust occurs with expensive pads when they are ill matched to the disc/rotor - although this has only happened when racing.

Bottom line: there are so many pads that claim to be dust free alternatives (at least in the UK), and others that are produced specifically for various driving styles, that if you're into this kind of thing then you need to do some current research. Also bear in mind it's a trade off - dust free wears discs faster and often reduces braking distance in some conditions. I've also found that the 'best' track pad one year is no longer the best the following year.... Hence if it's your thing, stay current.

 

I think you're wrong here, a search of this sub forum will bear that out.

 

Which bit? That "I've never had an problem with OEM" part? Well I'm pretty sure I've never had a problem, but I am getting older now so maybe it's dementia or eyesight issues and really my rims have been dusty for years

Seriously, though, this will all come down to well matched products (disc and pad), driving style (aggressive or laid back?) and personal preference (how much is too much dust?) as I said previously. Take it from me, if it's your thing you need to stay current and research it so you meet your very personal preference. I do this for our track cars.

 

His write up is not about what pads "you" will use. Use what ever pad u like. Its a well written diy with good pics too. Takes a good amount of effert to do as well. Nice to have people to take the time to teach others. Thanks!

 

I'm challenging his assertion that the OEM pads are the best, they are not, they generate a lot of dust, a simple search reveals owners complaining about dust as far back as 2006(which would be a brand new car with OEM brakes and rotors).

 

Thank you. How I should have responded in the first place

 

Erm... nope, I never made the assertion that OEM pads are always the best, nor ever would. Read the guide again. I think you'll find the title of that section is 'Should I use genuine dealer parts or OEM equivalent', not which are the best pads on the market. As Dealer and OEM are effectively the same part, the obvious answer is to buy the cheaper warrantied OEM equivalent. That's the assertion I make.

So now we've got that misunderstanding cleared up, can I make a suggestion? If you want a guide on selecting brake pads why not write your own so others can benefit from your knowledge?

​​​​​Cheers guys, appreciated

 

When comparing say Japanese cars with European cars, the brakes on the Japanese cars dust basically zip.
There is a general consensus amongst drivers here in Australia that this is the case.
My S350 is silver, hence, the even shading of the rims with brake dust blend nicely with the car

 

Thanks for the write up, nicely done, very informative.

 

From your write up...

 

@EasyPhil - Gotcha

 

Maybe I missed it but didn't notice any mention of the electric parking brakes and dealing with them.

 

Don't worry you don't have them on your front brakes so there's no need to deal with them. If I ever replace the rear discs, pads and shoes I'll try and write that up.

 

Well, your title says, How to replace brake discs/rotors and pads. Maybe it should have read, How to replace FRONT brake discs/rotors and pads.

 

Not quite sure how you missed it ... the guides title is after all 'How to easily replace FRONT brake discs or rotors and brake pads' and is in big bold letters at the top of my webpage...pretty clear I thought

 

I'm talking about the title on THIS forum.

 

​​​​​LOL.... Really?

Let's take this slow....

​​​​​The thread title is correct - it's a guide about replacing brake discs and pads, right?...

....And there can be no confusion because when you get to the actual guide on my site it very clearly states it's about FRONT brake discs and pads, ok?....

​​​​So given all that, I'm having a really hard time figuring out why you ever thought it had anything to do with rear brakes?
​​
Mind you, you made me laugh on a dull saturday with that reply, so no worries eh?

​​​​​



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Just messin wit you. I was all excited about finding a guide for doing W221 brakes when I saw this post. But imagine my let down after going to the link and seeing nothing about the electric parking brake. I mean, there are plenty of guides and videos for doing front brakes but none for our rears.

 

Dang, thought for a moment there you were a truly 'special' person (I occasionally get a customer like that, but don't we all!!). Still you made my day so thanks!

Rears are a piece of p*** - they are real easy on the 221. I'm actually about to have mine off as the EPB is not holding the car, so I'll be doing a guide at some point in the next month as I've promised it over on a UK site. If you can't wait, just let me know what it is you need to know and I'll probably be able to tell you.

 

I'm ready to go with new front and rear rotors, pads, sensors and fluid.