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Discussion Starter #1
What's with these things, seems to be fairly common that they drag, won't release all the way, or just plain get stuck. There's several threads on here of people having the same issue. Is the piston coating failing causing the phenolic to swell, or something else?
I've got them on two of my cars, and noticed how they both drag on one, so checked the other car, and found one drags, the other I can spin the wheel and it rotates a couple more times before it stops. With a beam style torque wrench on a lug nut it takes 12-15 foot pounds of torque to turn the rotor. I pulled the caliper, and blew air into the banjo bolt fitting and only piston came out, the other is stuck. I can rotate it, but that's all, can't get it to move otherwise, except to compress it with a c-clamp. Looks like I'll be going back to the cast iron 94-98 calipers.
 

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Yes, it's common with the 99-04 calipers, especially if the car sits for any period of time. Only recourse it to keep swapping out the calipers when they stick and hope you get a "good" one, or swap to a different caliper/brake setup.
 

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Right, that's what I'm doing. Went with these because two pistons is more better, and it's aluminum, so they were lighter. The first pair i got were from the junkyard, but after having issues with those hanging up I got new, or reman'd from either a chain store, or rockauto, and still have that issue.
 

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Rebuild them. They are cheap to rebuild. Buy new pistons. I have been looking around but do not see any other option for the pistons, they are Phenolic and have a tendency to bind in the bores. I would like to see stainless option or steel option but thus far have not seen any. Very common for PBR dual piston calipers to stick. If I still had my lathe, I'd spin a few pistons out and try them.
 

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Discussion Starter #5
Where are you getting new steel pistons for these?
 

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Where are you getting new steel pistons for these?
If you're willing to spend some money, a machine shop should be able to turn some out, for maybe a few hundred. It's not a terribly difficult piece to make up, just you don't get economy of scale for just 4 pistons.
 

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Discussion Starter #7 (Edited)
If you're willing to spend some money, a machine shop should be able to turn some out, for maybe a few hundred. It's not a terribly difficult piece to make up, just you don't get economy of scale for just 4 pistons.
Yeah, that's why I was asking. I sent the link to this thread to Jack Hidley, seeing if they might want to try making some for the mustang market. Typically folks they deal with opt for the cobra brakes though.

Jack Hidley answered my PM, looks like there are steel already available, don't know if anyone tried these yet, but like he said, it's probably cheaper to just put cobra brakes on the front because they're proven.

 

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Discussion Starter #8
So of the 4 pistons in my 2 front calipers that came out easily with air pressure, they measured 44.9MM, the two that had to be pounded out, one through the banjo bolt hole, the other through a hole I drilled in the caliper body behind the piston, they measured 45.1 and and 45.2MM respectively.
 

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The nominal OD for these pistons is 45mm. Shocking Ford engineering data has them listed as 43mm.
 

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great timing for my seeing this thread

I rebuilt my 04 pbr's a year or so ago, got the car going and guess what? Other day on the way back from the race track, right front stuck after a stop at a stop sign. Stupid thing. Brand new pistons too; all 4 of them.

cheaper to buy all new cobra stuff? I don't know about that. I'm into mine for $370 right now--just the fronts so far (Bullit calipers) and haven't even touched the rears yet. Plan on using the GT calipers with the correct pads, and of course I gotta put new brackets on ($200+) and then rotors.

In comparison, rebuilding the GT calipers was under $50 including what I paid for the calipers at the JY, the rebuild kit, and a can of paint to make them look decent. New rotors and new pads were I think $90. Spindles were $28 for the pair including dust shields

cobra/mach/bullit stuff ain't gonna last forever either, supply will eventually dwindle

I may keep the gt stuff and rebuild them with metal pistons if I can find any. I've googled it and it's a problem for sure but I can't find anyone that knows where to get them. Jack's link above is a 404 error not found so that is no help at this point. Figure if I can find a way to properly fix them, they can be used on my 93 coupe once I get the spindles & rear calipers. I'll have the brackets and stuff already from the bullitt caliper swap on my 92.
 

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Centric 14645013 might fit, but we haven't tested it yet. These are steel pistons.
 

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Discussion Starter #13
Centric 14645013 might fit, but we haven't tested it yet. These are steel pistons.
Thanks Jack, that first link I shared with Honda steel pistons is dead now. Those Centric are on Ebay for $28 each piston. I was going to use the PBR calipers on the Dugan wagon, but am just going to go with Cobra or Mach 1 stuff to avoid aggravation of the PBR junk.
 

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Long term, I think that is by far the best solution. Why upgrade to SN95 spindles if you keep using 10.84" front brakes? Waste of time.
 
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