Final questions before R230 brake job

Conor

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So I think i'm all set to replace the front pads on my R230 this weekend. That said, I need to clarify a few things.
  • ECP didn't have a brake sensor for the SL, so I just picked another one that should be suitable, since they seem fairly generic. If it doesn't fit, can I run the car without a sensor, while I get a proper fitment.
  • Regarding pushing back the pistons. Will this kit from Halfords work well? I believe it will cover other cars too. I know I can probably get something a little cheaper but I think this kit is good all rounder and should cover other models too.
  • When pushing the piston do I need to be aware of fluid overflow or shall I release the bleed nipple?
  • Grease!? - The WIS document is a bit difficult to understand. Am I just putting this on sides and the back of pad (but not the disc facing side). And then a bit on the retaining pins. Is this the same as copper anti seize (should this be used instead somewhere).
Thanks in advance.

Perhaps this spreader is what I need instead? I'm not sure if the rewind tool works for pistons that need to be simply "pushed in" as opposed to "wound in"
 
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ajlsl600

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if you have keyless go and SBC you need to keep keys far away while doing this to disarm the system . if you walk past with key near SBC where fitted will arm the system, not good when yr working on that job... either research WIS this first or wait for someone to advise more. i never had to change my pads

www.youtube.com/watch?v=J8jaVufCQcg
 

LostKiwi

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Very important to disarm SBC to prevent the system operating whilst fingers are near caliper pistons.
As AJ says, keep all keys well away and don't open/close doors.
 

LostKiwi

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There are 2 schools of thought about pushing pistons back.
1. Open the bleed nipple to release the fluid the argument being that pushing the fluid back can cause the seal lip to invert in the master cylinder.
2. Push the pistons back gently.

I have always used method 2 and never had master cylinder issues.
Typically I use a large screwdriver and piece of wood to pry back the pistons (or the old brake pad). You shouldn't need a wind back tool. An G clamp can be used if you find it easier.
 

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There are 2 schools of thought about pushing pistons back.
1. Open the bleed nipple to release the fluid the argument being that pushing the fluid back can cause the seal lip to invert in the master cylinder.
2. Push the pistons back gently.

I have always used method 2 and never had master cylinder issues.
Typically I use a large screwdriver and piece of wood to pry back the pistons (or the old brake pad). You shouldn't need a wind back tool. An G clamp can be used if you find it easier.
I’ve always done 2 as well and not had any issues (touch wood)
 

ajlsl600

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i open bonnet look at m/c if pads wore out and fluid level at max it suggests that tank been topped up as pads wear in this case i open bleed screw , then push pads/pistons back if fluid level down i gently push pistons back paying attn to fluid level in m/c tank if careful this avoids opening bleed screw and the need to top up. i do one side of the caliper at a time.
 
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daibevan

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I use a G clamp and watch the level carefully, doing 1 at a time. I intend to remove any excess brake fluid from the reservoir with a syringe & discard it. However I've never actually had to do that, obviously I've never had a car that had a brake fluid flush when pads were very worn.
 

00slk

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Very important to disarm SBC to prevent the system operating whilst fingers are near caliper pistons.
As AJ says, keep all keys well away and don't open/close doors.

How can the SBC activate? I've replaced a few brake disc's and pads on the r230 cars and never had any issues, though I don't leave the keys in the ignition anymore, (self locking on the Bentley once :rolleyes:) I just drop the drivers window and leave the key on the seat. Just a simple thin angled lever slid in and cox the pads back into the caliper until the pads are fully back...simples....Or am I missing something?? (oh and keep an eye on the brake fluid level in the clear plastic thing)
 

SL63 Mark

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I don't think you can replace the pads without replacing the discs, due to grooving. I did discs and pads on my car. I had an issue with the pads I bought being too tight in the calipers I ended up grinding a few thou off them. I should have bought them from MB, not cheap with 4 pads each side at the front. I followed all the instructions about disconnecting both the batteries and removing all keyes from the car. There is a standard set of step by step instructions for the 230 to follow on here somewhere.

The "grease" you mention is for anti-squeal. There are special anti squeal compounds you can use. These are specialist cars, so for a beginner like me I would just use the stuff MB supply, rather than try to work it out for myself. Most people put it on the sides and back of the pads.
 

ajlsl600

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well ,stand to be corrected, my understanding .IF car thinks yr approaching,detects key it thinks yr about to head off with the car ,and fires up the SBC to ensure press avail to brakes , this aint really something you want with fingers/tools near calipers. now thats just my understanding . do feel free to correct me . many times i walked past my SL with key and heard pump run for a few seconds ? no keys no sounds ? think vid tho not 230 explains.
 

00slk

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well ,stand to be corrected, my understanding .IF car thinks yr approaching,detects key it thinks yr about to head off with the car ,and fires up the SBC to ensure press avail to brakes , this aint really something you want with fingers/tools near calipers. now thats just my understanding . do feel free to correct me . many times i walked past my SL with key and heard pump run for a few seconds ? no keys no sounds ? think vid tho not 230 explains.

Now your scaring me, I have to apply a little more anti-slip to the n/s rear pad as it squeals every so often just as you slow down to about 5mph :rolleyes:
 

ajlsl600

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Now your scaring me, I have to apply a little more anti-slip to the n/s rear pad as it squeals every so often just as you slow down to about 5mph :rolleyes:


nothing scary just a procedure watch,check out vid link. and wait for a few others to chirp in ref my theory. then go ahead as you see fit.
 

00slk

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I don't think you can replace the pads without replacing the discs, due to grooving. I did discs and pads on my car. I had an issue with the pads I bought being too tight in the calipers I ended up grinding a few thou off them. I should have bought them from MB, not cheap with 4 pads each side at the front. I followed all the instructions about disconnecting both the batteries and removing all keyes from the car. There is a standard set of step by step instructions for the 230 to follow on here somewhere.

The "grease" you mention is for anti-squeal. There are special anti squeal compounds you can use. These are specialist cars, so for a beginner like me I would just use the stuff MB supply, rather than try to work it out for myself. Most people put it on the sides and back of the pads.

Its not a good idea, have to agree with you Mark on the new pads being fitted to worn or grooved from wear on the disc's.
Our SLK was advertised with new brakes, how ever on closer inspection the pads were replaced, the disc's weren't and it shows when braking :mad:
I fitted Brembo dics's and pads to the 500 and they are a superb kit. I bought the sensors from Grangemouth as I was told there were 3 different types. The sensors were cheaper from MB than ecp and ebay ;)
 

LostKiwi

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No need to replace disks unless they are excessively worn. Most people get 2 X pad changes to a disc change.
 
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Conor

Conor

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  • Thread Starter
  • Thread starter
  • #16
Thanks guys,

* I am aware of the SBC procedures and warnings. Will use my iCarSoft MB V2.0 to disable.
* I plan on replacing the discs on this too as I picked up some Pagids from ECP for a good price. I am hoping they are not too seize and a bitch to get off.
* I will measure the discs for reference before I replace, but to be honest, this car is going to do such little miles that I would be happy to have the brakes fully sorted together, since I probably won't need to renew again, for many years.

The lube I purchased is Pagid CeraTec. I think that is good for the job.

I am going to purchase this Pagid disc brake spreader for ~£30 from ECP.

I have a penchant for buying the right tool for the job because when I have the car opened up in the public area, it's a major headache to have to go away and buy a tool.. happened when I was doing the rear air springs, and I vowed to try and avoid from then on..Also, buying tools kind of pays for itself, because if I maintain my cars for even a few cycles they will have paid for themselves. I think I am currently at about £800 on tools...how far would that have gone if I outsource the following..

* R230 service filters / oil / brakes
* S212 service filters / oil
* S212 replace rear air springs
* S212 spark plug change
* R230 spark plug change
 
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ajlsl600

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i still dont understand why discs are made of such crap, that they need dumping every 2 sets of pads i think it more of keep us spending.... i know different materials have different characteristics , but i still dont get it. every yr something else on a car becomes a regular consumable item ???? even the ones on my 12/13 w166 have a good edge ridge at 54k miles.not impressed..
 

LostKiwi

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It's ever since they dropped asbestos out of the pad compounds
 

ajlsl600

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It's ever since they dropped asbestos out of the pad compounds

surely there must be something that can replace that material either disc or better pad.
 

Wighty

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Just a thought with all your brake plans on an “older car” that hasn’t been used that much is that the calipers may also need an overhaul , especially if they have never been done .
You may end up with a very old piston which has some corrosion on it that hasn’t moved much in years being pushed back and then sticking slightly , ending up with brake judder .
What about leaving this all for a while and doing the caliper overhaul at the same time . It’s a cheap ish job especially as it’s not your daily car
 


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