w123 Front calipers - size change in 1980

[misssurferrosa]

Hi All,

Please can any of you confirm this for me? It seems that Mercedes changed the internal dimensions of the front calipers of w123 cars in 1980. Calipers on earlier cars accept 15mm pads, whereas calipers on post-1980 cars accept 17.5mm pads. As far as I can tell everything else is identical with the calipers, but it is just the internal width where it houses the brake pads which have changed. I've gleaned this information from parts suppliers, and I can't find any definitive authority to confirm this for me.

As regards the above, do any of you know why Mercedes changed caliper size? I have a 1982 w123 230E, and have bought a pair of reconditioned front calipers. However, these appear to accept the earlier 15mm pads. What I am wondering is whether it is okay for me to put these on my 1982 car. They look pretty much identical to the Bendix ones I took off, except that these recondition ones are Ate and have just few millimeters thinner gap where the pads slip in - all other dimensions look the same. Will my car stops as well with these? My gut feeling is that it will, but I will need to change pads slightly more often due to them being thinner.

Any advice you can give would be very helpful!

Many thanks,
Jessica

 

[alexander patie]

hi jessica, yes some accept slightly thicker pads, but all pads are the same basic length and width. so if the pads can be fitted they will be fine. these same pads were used on many different models back in the day, including the 108 and 116 IIRC. you are better off with the ATE calipers as the bendix ones are prone to seizing pistons and pins - the latter having a dumb R-clip retainer design which is also naff and troublesome.

 

[misssurferrosa]

Thanks Alexander - that's a great help. Yes, my old Bendix calipers were rock solid when I took them off. I actually had to drill a couple of the pins out - it was like they were just welded in there! I think I will just slap these Ate calipers on and order a set of the thinner pads - I can't understand the benefit of having thicker pads except for longer pad life.

I wonder why Mercedes made this change to wider calipers and thickers pad though. I could understand if they enlarged the calipers to accommodate brake pads with a large surface area, since that would increase friction area and thus braking power, but the only advantage I can see with having thicker pads is longer pad life. I wonder if its anything do with them starting to use vented discs on some of their cars - vented discs requiring wider calipers, which in turn might necessitate thicker pads on their cars which do not have vented discs. Does anybody have any thoughts or theories about this?

Thanks again,
Jessica