W211 Brake Pad Replacement

[powerman]

I've read here and elsewhere about the dangers of changing pads on W211 fitted with SBC. I can't decide whether to be careful and try. Has anybody out there actually done this without computer-disabling the SBC.
Can you slide in a blocking piece to prevent the piston from coming out in the period between removing the old pad and fitting the new?
Can the power supply to the pump be disconnected at the pump itself(thereby negating both main and standby batteries)?

For the record, mine is March 03 and has done 48,000 on its original pads. It's just been in for service and I was told it needed new discs and pads. They are wearing at the same rate and as such brake discs are becoming a service consumable part! I can't believe it needs new discs - there's a small ridge but the brakes are fine at the moment so what changes when you fit new pads - just thicker pads once they've worn to the disc profile surely?

 

[Blobcat]

Discs became consumables when Asbestos was removed from the pad material. I generally get 35K from the pads and 60K from the discs. You have done well with the pads and the dealer may bit premature with the discs.

 

[malcolm E53 AMG]

Mt E320CDi managed 45K on the original discs and this seems to be the norm nowadays, so I think you have done well. I can't see the point in changing the pads yourself, unless your thinking of doing the discs as well.

The thickness of the brake disc needs to be maintained to stop brake fade (too much heat in the disc). eventually thin discs would also warp easily.

Hope this helps!

 

[powerman]

Thanks for that info. Although I take on board the fact about the reducing heat capacity of the discs as they get thinner, I'm not sure I believe MB. With my last car they told me they would need doing at next service. I took it in two or three times more to the same main dealer and they never mentioned it again. I sold it with original discs fitted at over 90k miles. Would still like any info on safe working with SBC system if possible please.

 

[television]

All manufactures have a tolarence regarding wear of the disc, beyond that point it is a safety issue as the disc can crack or break. All replacement pads are the same thickness. Wear rate is determined on how you drive and where you live.

Malcolm

 

[jberks]

I was a bit surprised when Qwikifit said I'd need new disks when I had a puncture done. The dealer then said the same thing at the service and finally the indie also repeated it when the pad light came on, all without me saying a word and despite my E240 having covered less than 50k.
So I guess they do wear out.
Not knowing enough about the SBC, I wouldn't touch it myself though. I would imagine (guessing) that they put the SBC into a maintenance mode before they do any repairs. As you don't have the computer interface, it would both physically and financially dangerous. I'd leave well alone.

 

[powerman]

Thanks guys, it needs to be right, especially brakes! I guess I'd better book it in and have it done. I didn't want to eat much this month anyway!!

 

[powerman]

For info, in the end, it proved to be quite a simple job, no more difficult than changing pads on any other car. The SBC unit on my car is located on the off side at the front as you open the bonnet i.e. just behind the offside headlamp. It's clearly labelled SBC (embossed in the casting). I disconnected the plug - you have to pull the sort of handle on the top of the plug upwards and it disconnects automatically. I also decided to cut the cable tie on the harness just back from the plug. This allowed the plug to be pulled well clear of the socket - I didn't want inadvertent reconnection during the job. After that it was as simple as changing pads on any other car. I syringed some fluid from the reservoir before I started because I was concerned that it might overflow as I pushed the pistons back into the calipers (to allow for the thickness of the new pads). I didn't change the discs on this occasion but it wouldn't have taken much longer since I loosened the calipers anyway and pulled them away from the discs to allow better cleaning. It took no more than an hour and a half all told including jacking up and getting tools out and tidying up afterwards. The worst job was getting the wheels off in the first place. They are located onto a tapered spigot and where the alloy wheel was in contact with the steel hub, electrolytic corrosion had occured and bonded the two together. I had to knock the tyre hard with a mallet to break the bond. I put a very thin smear of copper grease on as I re-assembled (introducing a third metal !! - didn't think about that at the time) hoping that it aids removal next time.

 

[Dunx]

When replacing pads it is recommended that you clamp the flexible hydraulic hoses (using brake hose clamps) and release any surplus fluid through the bleed nipple when pushing the piston back into the caliper. This reduces the possibility of any 'contaminents' being introduced back into the brake system (dirt, etc) and playing havoc with ABS.

 

[piestore]

sbc

Hi

To help, SBC can run a self test which could pop the pistons out if pads were not in the caliper, this test is only run on wake up signal IE door open or unlock of car from remote, pads can safley be changed by dissconecting both (two) batterys and then changing pads and or disc, no power supply no self test the down side is esp angle sensor requires lock to lock to iniitialise, windows need setting as does sunroof radio and clock.

 

[jberks]

Thought I'd ressurect this thread.
My pads will need doing within the next few months I suspect so I thought I'd get a heads up early rather than having to rush to the dealer at the last second. It should be pretty straight forward so I see no point paying for 3 hours labour for something I can do myself.

So, is it better to disconnect both batteries (is the second one F/NS under the cover by the firewall?), or am I safe just removing the multiplug on the SBC unit?
Also, any special tools required or is it just pop the clips and remove the pins?

 

[madmercdw]

All manufactures have a tolarence regarding wear of the disc, beyond that point it is a safety issue as the disc can crack or break. All replacement pads are the same thickness. Wear rate is determined on how you drive and where you live.

Malcolm

Malcolm,
I am new to the club. I have a W211 E320CDi which needs new discs and pads. I have always stayed away from doing this because of the sensotronic brake system. Did you post some advice saying that there was an easy way to disarm the system.
thanks

David

 

[television]

Malcolm,
I am new to the club. I have a W211 E320CDi which needs new discs and pads. I have always stayed away from doing this because of the sensotronic brake system. Did you post some advice saying that there was an easy way to disarm the system.
thanks

David

Yes there is David, just disconnect the 2 batteries and pump the brake pedal a few times and the whole thing is dead and you change the pads and or disc as on a normal car, I do mine in this way.
All you will have to do on joining up again is to re set the windows, close them and hold the switch up for a few seconds and the same with the sunroof with the ignition turned on or while driving, the ESP lamp will go out once you start driving again

 

[alan782]

I leave the batteries connected and take the plug out the back of the sbc pump itself, then once the work is done plug it back in and use a plug in tool to erase the fault from the ecu.

 

[television]

I leave the batteries connected and take the plug out the back of the sbc pump itself, then once the work is done plug it back in and use a plug in tool to erase the fault from the ecu.

That is one way and the way that MB engineers use when testing while on training but the wake up system is live at all time and it means that you are plugging into a live circuit

 

[Cole@MBS]

Thats ok Alan untill you screw up the interface on the SBC unit, Only designed to be a once only connection!!

 

[alan782]

Thats ok Alan untill you screw up the interface on the SBC unit, Only designed to be a once only connection!!

I have to keep you busy some how colin:lol:

 

[Cole@MBS]

I have to keep you busy some how colin:lol:

What did you do with that cream egg Alan, wasnt in the A,class tonight!!!!

 

[alan782]

What did you do with that cream egg Alan, wasnt in the A,class tonight!!!!

That is a libellous accusation . Dave must have eaten it because it sure as hell was not me. I wish I had now though!

 

[Cole@MBS]

Its ok Alan, it will be on your next bill, 1 cream egg, £0.50!!!!