Help replacing front brake pads - Teves caliiper

[Rolo]

I'm stumped.  Short of grinding down new pads, I don't know what to do.  I used a caliper spreader and part of the piston with the rubber boot protrude and I can't get the new pads in.  I have both MB original equipment pads and Pagid aftermarket.  They are the same thickness.  I pull the caliper, used the spreader squarely position over the pistons, and it seems like both pistons are bottomed.  I need about 3 mm more clearance.

Any tips?  Thanks.

[rumb]

Perhaps put old pads back in and use a big screwdriver to lever each side to push piston in more?

[Rolo]

Good thought, but the spreader feels like it's bottoming the pistons.  The pistons and boots protrude about 2mm from being completely flush with the caliper.

[Randys01]

Assuming these are the correct pads, you could try just easing off the brake nipple and pushing the pistons back a  tad further.
Brakes may need bleeding but probably due for a flush.

[Rolo]

Good thought.  I loosened the nipple to back the pistons out.  They are bottomed out.

[Randys01]

Well if u  r satisfied that the pistons are fully retreated then you have a bodgie /mismarked set of pads !

[Rolo]

2 sets of pads, then.  OE and Pagid.

[rumb]

Good thought, but the spreader feels like it's bottoming the pistons.  The pistons and boots protrude about 2mm from being completely flush with the caliper.

The piston should be flush. Try something else to push them in further?  C clamp?


Just ran across these posts:  mixed calipers and pads?  mixed rotors?

https://forum.w116.org/mechanicals/advice-on-calipers-disc-s-etc/
I thought for sure there was a difference in early versus late W116 rotors, to the point where people on this site were complaining about having to pay $200 a rotor for early W116 versus $30 a rotor for late W116. With that said, I think that later rotors will fit earlier hubs, but the calipers have to be changed or something.

https://forum.w116.org/mechanicals/brake-rotors/

[Rolo]

Good stuff.  The discussion about rotor and pad thickness changing may be the issue.  My car has had rotors replaced twice with OE parts, but the car was stored for 10 years, so the rotors are probably 20 years old.

The aftermarket and OE pads are identical in thickness and there is no unique part number for ATE or Teves calipers, so I'm thinking the currently available pads are just too thick. One minute on the grinder.