GT4 RIGHT REAR CALIPER ISSUE

Im doing a complete suspension, brakes and steering rack resto for a new GT4 owner. When I removed the calipers I noticed the right rear caliper had TWO shims behind the Caliper and that it didn't have the typical pistons, but looked much newer and different design to the piston. I sent them in for restoration and I told the company of the differences in the rear calipers. I instructed them to inspect and make it the same as the factory pistons if possible, and if not , I would want a new caliper regardless of cost.I relayed this info to the order taker and the owner of the Brake shop in separate calls. Received calipers, install- bleed. Outer adjuster leaking when setting venting clearance. I thought it was the 6x 1mm outer adjuster seal. picked up new seals same thing happened. Sent it back, supposedly the wrong adjuster . got caliper back again today. same thing again! but worst. step to pump pedal then go back to the caliper and it leaks down to my lift. Wth its just a caliper. This cars history is unknown as it was just purchased in march on BAT. But my clue was the mismatched caliper.
My only idea is that the outer caliper half adjuster bore is out of wack, meaning it doesn't feel flat where the adjuster shoulder would sit, any ideas? im not looking too bright with the owner

 

thx all, I have rebuilt a few of these on my own with no issues its really easy actually. The shim issue is that the inner piston wont retract enough to install the pad. This is not my problem, the issue is that the outer adjuster has leaked on two separate occasions and rebuilt 3 times,and the shop which was named here by another member has not been able to correct the problem. So what makes this caliper different? There are only two types of outer adjusters a 8x8mm and a 8x10mm, So, why was this caliper on the car? and what is different on the halves that make it need 2 shims? and why does the adjuster continually leak after being rebuilt 3 times by the premier 914/6 caliper resto shop. if you re read my opening post, they claimed it was the wrong adjuster, I believe there is something wrong with the recessed bore in the piston bore which holds the adjuster . but what?

 

thx. they have more experience than all of us combined. ive rebuilt them before, had this one apart after the first leak which lead me to believe the adjuster was the problem, it wouldn't seat when I replaced the Oring. that's when they said it was the wrong one. now it has been supposedly replaced and pressure tested according to them. this is not a poke to the shop just yet as ive had calipers restored from them before, but why such a continual removal and shipping of a part when they were instructed back in april that if it was not usable for any reason to scrap it. and now im 3 weeks in with BS of parts removal and shipping. just looking to see if anyone has encountered this type of leak

 

I here ya, pretty dumb how the calipers have a purpose built spacer for the halves but still needs a 1mm spacer to center. my trick is to rub a light film of red locktight on the spacers and lay on the caliper hole then insert the bolt and press down on it to achieve absence of air for 10minutes off the car. then the shim will stay in place with no juggling of caliper shims and bolt for install. super easy

 

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adjuster in question. the top most groove is for the c clip to hold the adjuster in place, the lower groove just above the wide shoulder is where the Oring is placed and s

 

I’ve never had any problems before. I just installed a rebuilt unit from another vendor so far so good

 

I believe the Orings were no good and not really sure where that caliper came from it didnt match the otherside. This was a car I was working on.

 

Its a real easy job.