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Registered 2001 SLK320
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24 Posts
Discussion Starter #1 (Edited)
Hello, just though id share all the information I have on doing this swap as I seem to have found all the issues and have found methods to overcome all of them so we can have awesome brembo stopping power for around £500~ish instead of having to pay £3000 for an upgrade kit.

The stock brakes on the R170 are okay I guess, they stop it pretty good from medium speed but leave a bit to be desired. I have had issues with them getting very hot and loosing braking force.
They also look awful and don’t fill up the wheels and give the stock SLK a pretty pathetic look I’m my opinion.

After the swap obviously the car has much more effective braking and brake cooling, I think the car feels more balanced with slightly more front brake bias because the car naturally isn’t that quick to turn in so the increased front braking compared to the rear helps to tuck it into a corner.

Parts you will need to buy. I can only document the parts used for my car but because of different rims etc you might need different sized parts so before buying make sure you measure things I’ll later mention before buying.

1: W220 4pot brembo brake front callipers. Mine came from a W220 S430 or S500. Make sure you know what car they came from because there are callipers for 330mm disks and 345 mm disks.
The part number is 20704704 for the W220 330mm Calipers. Make sure you know what model car they came from and ensure you know they are for 330mm disks. If you get them from an S430/500 the bleed nipples will end up on top making the bleeding process easier later.

2. Brake disks. Get your callipers first, once you know what model they came from, for me it was an S430/500, google disks for that exact model and buy a set. For my S430/500 callipers I used these: https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/323794431477 The thickness new should be 32mm

3. brake pads: Brand does not matter, I used EBC redstuff. After obtaining the exact model your callipers and disks come from enter the details into your favourite car parts site and get some pads. For my S430 callipers they were 119x71x17mm EBC redstuff.

4. Brake fluid. I got 2 litres of Dot4 fluid. Only used 1/5th of a litre to bleed the new callipers so 2 litres was probably too much but better be safe than sorry.

5. New Caliper mounting bolts. You will need some extended bolts. They must be M12x1.5 x50-70mm so we can cut them to exact length later. THEY MUST BE 10.9 high tensile steel. Do not just buy any old bolt they HAVE to be 10.9 steel or you run the risk of them braking.

6.4x spacers. In order to mount the w220 callipers centrally to the rotor we must use some stainless steel spacers. I needed a 6mm spacer for each bolt in between the wheel hub and Caliper.. They must be stainless steel, outside diameter 25mm, internal diameter M12 clearance and 6mm thick but before buying them you should do a test fit and measure the gap to ensure you get the correct spacing ill go over his later. DO NOT USE WASHERS, you must use the correct sized stainless spacers. Washers are not flat and will the bolt will come loose over time.

7 Wheel spacers. The larger 4 pot Caliper did not clean the inner face of my rims. I have the AMG 5 spoke 17” rims so I can only comment on the fitment for these rims. I used a set of 15mm spacers on the front and 10mm on the rear. This is the most you can get away with without getting bad rubbing issues. (The car feel a much more stable with these track width increases too. With these spacers, slight rub on extreme bumps at speed) The problem with the wheel spacer for me was they did not fit. I got the correct size spacers but ended up having to use a family members lathe to take a tiny bit of material off because they wouldn’t seat properly out of the box. The spacer would not clear the factory wheel bearing dust covers so using a family members lathe I made new dust covers that integrate with the wheel spacers, pics included lower down. This step really depends on what rims you have. Once you have your Caliper centred and mounted you can test the wheel and see how much clearance you have to gain for the wheel to fit on and there fore how thick of a wheel spacer you must buy. You must get longer wheel bolts for the spacers. The length of the thread for the new bolts will be the original length + the thickness of the wheel spacer. Make sure you get the correct type of nut for your rim aswell. Dome vs 45 chamfer.


Id suggest you buy the callipers, bolts, disks first then do a test fit before getting both the spacers required.

Mount the new 330mm disk on the wheel hub then mount The new callipers with the long bolts, don’t tighten the bolts just screw them in a bit so you can slide the Caliper back and fourth to centre the Caliper over the disk so you can measure the size needed for the spacer. I used a set digital callipers to make sure the gap in between the pistons and disk is the same either side of the disk (Ensure all 4 pistons are fully retracted). With the Caliper in position and centred measure the gap in between the wheel hub and Caliper. This is the size spacer you will need. For me it was 6mm for my W220 S430/500 set up. Now the Caliper has a set position you can now see how much clearance you need to gain between the wheels and callipers so you can measure and buy your wheel spacers as described earlier.

Use the digital callipers to measure the distance the bolt will have to travel through. (Hub+Spacer+Caliper) for me it was (18+6+16)mm ish I can’t remember exactly but I had to cut my bolts to 41mm for my setup. I used an angle grinder to cut them and a bench grinder to remove the burr. Make sure the thread still works.

From now on it’s a straight brake swap + installation of wheel spacers, all the parts should fit together if you’ve done your measuring and test fitting correctly. You will need to bend the brake shield back slightly at its highest point 6 o’clock ish on the shield or it will rub and made baaaaad noises.

For the Caliper bolt torque I used the W220 spec which was something like 115nm, just find the torque spec from whatever model you got the callipers form and use loctite on the threads.

Front tyres wheels, if your running 205/225 front tyres you might have problems with grip. I run 235 Michelin pilot sports on the front and they struggle to deal with these brakes so if your thinking about this and make sure you have at least 225 front tyres with a good brand of tyre.

I think I included everything here but if you have anymore questions ask away. I’m also not responsible if you have a brake failure and crash I’m just sharing my experience on how I did this.
 

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Premium Member 1999 SLK 5.4 M113
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1,437 Posts
OK.. you got CLK rotors and S-class calipers. That explains the spacing issues.

If you get S class rotors and S class calipers, everything works out without the need for spacers.
 

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Registered 2001 SLK320
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24 Posts
Discussion Starter #3
If you didn’t have to use spacers the disk would be 6 mm further in which would mean you would have to completely remove the dust shield and you need that to mount the abs sensor I believe.
 

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Registered 2002 R170 SLK V8 5.0
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2,606 Posts
Hi Guys,

Thanks to @Sir_Wizington for the excellent pictorial write up :smile:

However I'm totally confused now, are their different Hub Carrier Uprights, my Car which I based my conclusions on is a V6 320 too so I'd imagine they will be the same ????????????

Due to extensive research I thought it was W220 Calipers, 330mm C Class Discs and no spacering malarky !!

The Disc Height is the critical dimension here ;)

Certainly the Discs on my 2001 W220 S500 have way too much distance between the Disc rear face and hub face (Disc height), other dimensions are all the same except obviously the diameter and Disc height............

Standard SLK V6 320 Discs

300mm Dia, 28mm Thick, 46.5mm Height, 67mm Centre Bore

W203 C Class 330 mm Discs

330mm Dia, 28mm Thick, 46.5mm Height, 67mm Centre Bore

Guess I'll find out soon, when the time comes :wink:

HTH, Cheers Dave
 

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Registered 2001 SLK320
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24 Posts
Discussion Starter #6
Well if C class 330mm rotates fit right on that’s awesome. I just sort of went for it when buying pars as I couldn’t really find any detailed accounts of how and what etc. I just wanted people to know about the wheel spacer issues because if you don’t have access to a lathe you might get a bit stuck when they won’t fit on and you can’t use the OEM bearing dust covers.

I really wanted to go for the C55 amg spec brakes with the 345mm rotors but the AMG callipers for the 345mm rotors were very expensive at £500 used. To be honest 4 piston/330mm rotors are definitely enough for a 1350kg roadster.
 

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Registered 2002 R170 SLK V8 5.0
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2,606 Posts
Hi,

I'm going to see what I can do with the Rears as well, SLK32 looks to have W220 Rear Calipers, with Vented Discs, I think the W220 Vented Rear Discs may fit straight on, certainly the heights look very close with the 2 cars stood next to each other and looking through the Wheels, haven't done any further research / Measuring yet .....................

Fronts first, very soon prior to imminent V8 Install :grin:

Cheers, Dave
 

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Registered 2001 SLK320
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24 Posts
Discussion Starter #8
The upgraded rears are 300mm vented disks I think, most of the bigger Mercs seem to have used these. I guess if you could source the callipers from an 32AMG it would be a straight bolt on swap. Once my new stock rears have worn out I’ll probably go down this route too.

With the v8 swap I think you’ll need all the help you can get in the braking department haha.
 

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Registered 2002 R170 SLK V8 5.0
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2,606 Posts
Hi,

Brakes only slow one down, should take them off altogether really >:D

Visually, W220 Rear Calipers look the same as SLK32 Rear Calipers I haven't physically checked and measured them yet, will wait until the W220 Donor is all in bits then it is under half hour to compare side by side / trial fit them :wink:

Cheers Dave
 

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Registered
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25 Posts
I have the calipers from a CL500 and I was wondering about the sensor that is on the original caliper. Where does that mount? I have a SLK32 and put on new 330 rotors. Is the bleeder on the top or the bottom?
 

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Registered 2001 SLK320
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24 Posts
Discussion Starter #11
I used the standard slk sensor because the cl and other cars have different plugs. The standard slk sensor just bolts into the correct place in my experience. With my W220 Caliper the bleeder was on the top not sure of the cl would be the same.
 

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Registered 2002 R170 SLK V8 5.0
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2,606 Posts
Hi,

AFAIK The CL500 (C215) and S500 (W220) have identical Calipers, in fact the 2 Cars share many many parts that are the same :wink:

HTH, Cheers Dave
 

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Registered 2002 SLK320/2001 SLK320
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66 Posts
So do we have a definitive answer to a direct Brake swap for the fronts and rears?

FRONTS - S Class (W220) and C Class (W203) calipers and rotors are an exact match.

REARS - S Class (W220) and SLK 32 calipers and rotors...?
 

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Registered 2002 R170 SLK V8 5.0
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2,606 Posts
FRONTS - S Class (W220) and C Class (W203) calipers and rotors are an exact match.

REARS - S Class (W220) and SLK 32 calipers and rotors...?
Hi,

Nope, S Class Discs do not work, S Class Calipers Front and Rear do with a little Engineering, (Drilling and Tapping Rear Threads to M12 and Fabricating correct Spacer Bars F & R) ;) ................

More than one way to skin a cat, but this is all current and happening right now in my project V8 Thread ..............

Start at post # 293 here:-


Follow it to it's conclusion a couple of pages later, or you won't know the final Incarnation ;)
I will very likely have the Rears Finished today, and get the Fronts done hopefully next weekend.

Rears are the hardest due to Parking Brake Diameter and also I have renewed my grotty Back-plates ;)

Lots of research went into this, including a trial fit of various bits last weekend which busted a few myths ;)

HTH,
 

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Registered 2002 R170 SLK V8 5.0
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2,606 Posts
So there is no direct swap upgrade for the R170 stock brakes?
There may be IDK, I could not find any definitive Info on it when I did extensive research.

I have taken the time to document how I did it in detail in my thread as I'm doing it right now ;)

It isn't rocket science, and I have no Idea if 32 Brakes, AMG C Class, E Class etc are different to V6 N/A, or whether they are a direct fit to the R170 Hub Carriers.

I would imagine buying AMG / SLK 32 Calipers would be hellish expensive, or hard to find good used ones.

The way I did it was because I already had a decent rebuilt set of W220 Calipers on my S Class Donor Car I bought for the Engine Trans etc.

Same Calipers as OP here, they are easily available good used, and plenty for sale ;)

With the Discs I have used, they are OE Mercedes, also Wheel Spacers are not needed, (with the 18" Wheels I'll be using).
The only non standard parts are the Caliper retainer Spacers I made, which are to centre the Calipers .................

That is an industry standard way of doing this when buying Brake Upgrade Kits such as 6 Pot units etc.

HTH
 

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Registered 2002 R170 SLK V8 5.0
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2,606 Posts
Well you have all the info in my V8 R170 Project thread now ;)

The left side is flying together, it is fabrication of stuff like Spacers, and fitting the Backplates (which need trimming to allow the larger Calipers), which eats away at the time, also didn't help yesterday when I found that the Spacers I'd already made were 1mm too thin, so had to do them again lol. Fabricating using 9mm thick Steel Bar is not a 5 minute job lol

Fronts will be much easier in comparison ;)

I'm gonna finish the Left rear tomorrow early morning, only about an hour left on it now .............

Fit Handbrake Shoes, Fit Disc, Adjust Shoes, Fit Caliper and Pads and Bleed, Wheel on Job Done :)

I'd go finish it now, but Mel is taking me out tonight for a Meal so I gotta pack up in a short while ;)

Food or SLK, hmmmmmmmmmmm ...............................

Yeah the Grub wins hands down ;)
 
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