replacing front brake pads - w202

[c13tay]

just about to replace the pads - haynes suggests that the caliper bolts should be replaced - is this essential or can i clean them up and use a little thread lock ???

 

[anyweb]

it is not essential but recommended. they are cheap anyway so why not replace them while doing the pads...

 

[c13tay]

only asking because, when I spoke to the MB dealer about a price for these he quickly asked if I wanted new sensors but never mentioned the bolts.

By the way, the pads are almost down to the metal but no warning light !!!!

 

[nicky]

only asking because, when I spoke to the MB dealer about a price for these he quickly asked if I wanted new sensors but never mentioned the bolts.

By the way, the pads are almost down to the metal but no warning light !!!!

Some pad manufacturers actually supply the new bolts with the pads,but it is not critical that you change them...You will need new sensor wires though...

 

[c13tay]

Thats tonights job then !!

 

[paulcallender]

This might be a schoolboy error on my part, but - are you sure you need to remove the calipers to change the pads on this model? I know that its not necessary on a W114, W123 or W124. You simply push the pin out, pull the pads out, open up the gap and push new ones in.

 

[c13tay]

according to Haynes !!!!! you undo the lower caliper bolt and swing the caliper up and out of the way, pivoting on the upper bolt

It says that on later cars both the top and bottom bolts have to be removed

 

[996jimbo]

I seem to remember Haynes saying that about every car (with disks) I've had. The only time I've ever actually removed the calipers was to change brake seals though.

It could be that they're actually right this time of course...

 

[c13tay]

well never changed the pads on a merc before so we will find out tonight !!!!

 

[996jimbo]

Good luck!

And should you have to change the brake seals chuck your lying Haynes manual over the nearest wall - the pistons will not easily blow out with a bicycle pump. Not even if you canabilise the pump and any number of adaptors and anything else in your toolbox you think might do the trick will the pistons be easily blown out Arghh!

Sorry - another bitter memory just came back to me.

 

[nicky]

well never changed the pads on a merc before so we will find out tonight !!!!

Good luck,and i think you will find it is one of the best cars to change pads on..

 

[190surgen]

Piece of **** to cange if your light is not on you wont need new sender wires.

As for the bit about the seals you dont have to replace them unless they are leaking. Dont fancy moving the pistons with a hand pump.

 

[Vangogh]

Hi
Just replacing discs on my SLK and the caliper bolts as suggested. Bought new bolts cost around £7.00 for four and they are already dipped in lock tight.
Vangogh
C180 2001
SLK230k 1998

 

[turnipsock]

I think that is the deal; the new bolts are dipped in thread lock cos we are so stupid to not put this on ourselves.

This reminds me I'll have to get my torque wrench back and torque up my rear caliper bolts (after putting on some thread lock of course)

 

[nicky]

well never changed the pads on a merc before so we will find out tonight !!!!

Well tonight has gone and no report on the pad changing,,,,,What has gone wrong.??????????????????

 

[c13tay]

Job done !!!!!!

Bolts werent an issue - bought the pads from MB and they came with bolts.

I wish changing pads on other cars was as easy as this - remove bottom caliper slider bolt, swing slider up, remove pads, quick clean up, push piston back in, new pads in, caliper down, new bolt in and off we go !!!

I will have to get my pad warning system checked though, the warning light should have come on - Im embarrassed to say that the pads were worn past the sensor !!!

Anyway just got to let them bed in and ill be back to full braking effort.

Chris

 

[tom7035]

Think you can check your warning lamp by simply raising brake fluid reservoir cap, ignition on.

 

[cobra427]

re: the getting the pistons out of the calipers...

what I usually do is remove the caliper off the disc but WITH the brake line STILL CONNECTED.

1. On a 4 piston caliper I would use 3 small G clamps to stop 3 of the pistons from moving outward by clamping from behind the piston (outer side of caliper) to the pad face of the piston.
2. Then get someone to press the brake pedal gently until the unobstructed piston starts to move out (DONT LET IT COME OUT - just leave it at a point where its pretty well exposed.) Takes a bit of judgement.
3. Now use a G clamp to stop that piston moving out any further.
4. Remove one of the G clamps on one of the other 3 pistons.
5. Again apply the brake until that piston becomes exposed and reclamp it.
6. Do the same with the other 2 remaining pistons.

If you also need to do the calipers on the other side also make sure you don't pop the pistons out otherwise you'll lose pressure on the pedal and wont be able to repeat the process.
If you've got 8 G clamps great! I only have 4 and to stop the already exposed pistons coming out of the 1st caliper I put a block of wood or preferrably steel between the exposed piston faces to stop them moving out any further when the brake pedal is applied for the other caliper.

Once the pistons are pretty well exposed you'll find you can tap them out or use a mole wrench to tease them out.

 

[clive williams]

just about to replace the pads - haynes suggests that the caliper bolts should be replaced - is this essential or can i clean them up and use a little thread lock ???

I'm not sure about the bolts in question but on ATE and Girling style sliding (hateful things) calipers the torque setting on the bolts is well within their capability. As Nicky says, some pad suppliers provide new bolts, which I suppose is a safe way of ensuring that only good quality bolts are used and thread locking compound is applied - its the blue stuff on the new bolts. Personally, I reuse the bolts if in good nick and apply my own locktite.

I always, always torque up the bolts as the setting is usually very low i.e. 7lbft.

Clive

500E
E320CDIT210

 

[clive williams]

re: the getting the pistons out of the calipers...

what I usually do is remove the caliper off the disc but WITH the brake line STILL CONNECTED.

.

The other way I use is to detach the caliper and blow them out with an airline with a blower gun attachment through the hose connection. The only problem I've encountered with this method is that the first time I did it I didn't expect the force at which they came out and a piston squashed /hammered a finger against the caliper body - they come out like a bullet especially if you have something like 120-150 psi behind them!

Clive

500E
E320CDIT210