z32 rear brake conversion issue
 

so i recently did a z32 rear brake conversion on my 240 to match the set in the front and the caliper on the drivers side rear is rubbing against the rotor and i cant seem to figure out why? i rebuilt the calipers but it seems one of the caliper pistons isnt engaging fully and it isnt seized. so im thinking it is an issue with not enough pressure, will upgrading my stock BMC and brake booster resolve this issue? i have been unable to find anything on this online so i am curious if anyone has experienced something similar. (pics below)

https://i.imgur.com/VBHKyGb.jpg
https://i.imgur.com/SJ7HNQi.jpg
https://i.imgur.com/32D4jkf.jpg

Did you bleed the brakes.

yes i bled the brakes, the rest
of my brakes are functioning perfectly except for the caliper piston on the outside on the drivers rear.

if the piston isn't moving, its either seized in the bore, or you have a LOT of air in the system.

in the photos it looks like you went metal to metal on the last set of pads, and should replace that rotor.

I don't see in the photos, how the caliper would be contacting the rotor. if the caliper is indeed contacting the rotor, you must have the wrong thickness rotor somehow

The piston isnt seized and i honed the caliper to make sure of this when i rebuilt it and i also bled my brakes a couple times just to rule that out. the rotor is damaged from rubbing against the inside of the caliper. i also thought i had the wrong rotor as well but i switched it with the other rotor in the rear and i am still having the same issue on the drivers rear. the passengers rear is working perfectly but the drivers rear has been consistently giving me this issue.

Rebuild the caliper??

I already rebuilt the caliper which is why I dont understand why i am having this issue

Did they fit properly BEFORE you rebuilt them??? Remove the brake pads, compress the pistons 100%, then measure the gap between the pistons and the face of the rotor and make sure it’s even on the inboard and outboard sides.

Zip ties and brakes are a big NO NO.
I dont think they are backwards. You have them installed with the bleeders on top, right?
While bleeding them, how does the fluid flow compare to the opposite side?

no i rebuilt them in hopes of fixing the issue, but i will go ahead and try this and see what i come up with

they are not installed backwards and the bleeders are on top on each side, and i do not remember i bled them like 2 weeks ago but i will go ahead and try it again to see what happens. and the zipties are for the stock ebrake cables that i didnt get the chance to remove. they pose no danger and are ziptied to the bracket on the caliper for the time being until i get the chance to remove them. if i have a lot more/less brake fluid coming out of the damaged caliper what will this signify?

clogged up line or bleeder.

i did not consider this but it could be possible since the old stock caliper was seized which is why i did a brake conversion. i bought new isr lines for the calipers but how would i go about checking/cleaning the stock brake line? fluid was flowing through it and it didnt look dirty

If you had a bunch of rust form around the hub centric ring on the hub it would not allow the rotor to sit fully flush. It almost seems that was since i can see a gap around where that little hole is on the rotor

What did you ever find out on this issue?

Have a great day,
jared