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Front centre caliper bolt - SLK 55AMG ?

3K views 37 replies 9 participants last post by  Cbaileyuk 
#1 ·
Hi there,

Before I start this job - does anyone know what way the centre bolt is removed from the front calipers? I understand the pins are punched out but that centre one is confusing me. Is it screwed in?

The one in the blue box in the picture below.

Cheers
 

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#3 ·
From your 'performance pack' thread, I mentioned:

The big centre bolt on the caliper frequently seizes solid on these systems (mine has), in which case you will have to remove the caliper itself to fit the pads.

Not even judicious application of heat would get mine to budge.
 
#5 ·
Hi there,

Before I start this job - does anyone know what way the centre bolt is removed from the front calipers? I understand the pins are punched out but that centre one is confusing me. Is it screwed in?

The one in the blue box in the picture below.

Cheers
From your 'performance pack' thread, I mentioned:

The big centre bolt on the caliper frequently seizes solid on these systems (mine has), in which case you will have to remove the caliper itself to fit the pads.

Not even judicious application of heat would get mine to budge.
Yes I do recall that.
 
#6 ·
Hi All
It’s a plain bolt type thing , But with no outside threads only two areas of location into the main body of the caliper, with a bolt screwed into one end , it’s can be very tight to remove once you have the inner bolt removed , Your need a drift less than the diameter of the internal thread size , Please do not use the loosen bolt take the bolt out & fine a round bar so you do not f*** up the threads. I have used a 6” nail before as its softer than this bolt .give the locations a good clean up & some copper grease

Cheers

Andy
 
#9 ·
I worked it out. It was tough but with clever use of a punch and Dremel I got the passenger side done. Going to do the driver's side tomorrow. Many hours of work but it's all cleaned up and copper greased now. Will be fine in the future, even if that isn't me ?
 

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#12 ·
Just done the driver's side...I knew how to attack the centre pin on that one so that wasn't too bad but to make things fun, the inner pad was completely fused into the caliper. That took about 3 hours to get out with plusgas and various hitting implements. Both sides took me about 8 hours ?

All copper greased now so will be much easier in the future. Probably the ****test brake job I have done. Thats old cars for you
 
#13 ·
the inner pad was completely fused into the caliper.

scary to think you were driving a 55 with brakes in such poor condition:surprise:


brake calipers, especially on cars not used regularily, need routine maintenance


I remove and re-fit pads every year, in prep for MOT, to keep them in 100% condition and see if any problems developing.



Now time to overhaull the rears?
 
#16 ·
The brake adventure continues ?

Just thought I would attempt one of the rears. Got the pins out no problems, thought I had retracted the pistons, pulled the old pads. Everything going well.

Compared the new pads with the old, exactly the same shape so right pads. Could I fit the new thicker pads in? Could I heck. It's as if the new pads are slightly too thick. When I look into the caliper, the pistons are not flush and stick out a couple of mm. I tried to get them so go flush on either side but they won't so what seem like an only option is a take a little of the meat off the pad. I don't want to do that though.

Should the pistons go flush on the rears? These are close but not flush. So I've coppergreased it all and put the old pads back in.

The adventures continue ?
 
#18 ·
I'm inclined to agree but this rear passenger side caliper (only chose that one because I had easy access in my garage) the pistons on both inner and outer sit proud by about 2mm. I am used to this sometimes but I wasn't sure if it was a trait of AMG rear calipers. I will have a look at the other side tomorrow and see what that is like over there.

Hand brake is off and I've even loosened the bleed nipple and watched it pump a little fluid out as I press on the piston.

Quite a journey this is
 
#20 ·
I'm going to buy the 14.8mm pads tonight and I'll report back if that was the issue. Hopefully I can save another person falling into the same trap and save them some time.

The reason I didn't buy these other ones first was because they have two little 'add on' bits on the the top, either side which the current old pads did not have....but I have watched a youtube of rear replacements and the mechanic took the old pads out (which looked like my old pads) and replaced them with new pads which also had these upper additions on - so clearly they can be used.

I've added pictures of the two types of pads with their spec sheets if it helps someone. I currently have the pads with no 'doodahs' on the top - they don't fit (too wide) and I am going to try the ones with 'doodahs' on the top, which from the spec sheet you'll notice are thinner. They are taller though so this plan may be entirely futile! I need to try though ;)
 

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#23 ·
BUT


are you absolutely certain it is not a fault with the caliper preventing the pistons fully retracting?


I have seen corrosion on the pistons prevent them from fully retracting on anothe make of car.


Did you check the other side first?


Did you pump out the pistons, enought to check for corrosion?
On the front of my R171 two pots, the chrome plating had corroded away which would have torn the seals when in use.



Hopefully you are correct with your assumption, but are you certain?


Sorry but I make a big thing about brakes being in 100% condition, as , from another (MG TF ) forum, too many people just want them to pass an MOT, not work 100%
 
#24 ·
Absolutely 100% the pads. Both calipers compress to the same depth. The new pads I have bought are for my vin number, the old ones I was provided with were for a later vehicle.

The four pot 2005 require the new pads I have. Thank God I solved another problem. Plus, the driver's side old pads were all fused in too. Nasty braking in this. All good now. Fluid flush on Saturday ? she's getting there folks. Appreciate all the help
 
#29 ·
People, friends, companions...

The big brake ADVENTURE rolls on.

I've just go back from the transmission oil swap and I'm not happy with these discs. There's judderfrom highspeed braking and the state of the inners is not as I like so whilst it's been brilliant advice, I've decided I want to swap them before the new pads get ruined so she's back off the road pending delivery of new Brembo discs all round.

Weekend's next job. I can't bear to think of **** brakes.

The ADVENTURE (and EXPENSE) continues.....
 
#34 ·
Presuming the same as my 350 R171, then yes you need to unwind a small cog!


Dificulty depends upon if the inside of the drum has a raised edge due to dirt or corrosion, like mine did, and was not easy, as even when fully wound in, the drum still would not clear the shoes!


You access the adjuster through one of the bolt holes in the hub/drum


Best descriptive image I could find is https://cdn4.pelicanparts.com/techa...Parking_Brake_Adjustment/images_med/pic01.jpg


On mine I needed to force the drum over the shoes, with some levering with a screw driver.


Make a note of how they are assembled, and re-assemble in same way..obviously :grin: (except I didnt note the way they were assembled, and took about 1 hour to figure out!)


Shoes should not be worn, but everything will be dirty, rusty and need greasing before assembly.


If you remember the good old days of cars with drum brakes (Twin leading shoe fronts >:D) then it will be a doddle.
 
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