[superirish]

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.

 

[Mustang5L5]

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.

 

[superirish]

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.

 

[toddturbo]

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.

 

[superirish]

Where are you getting new steel pistons for these?

 

[bassman97]

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.

 

[superirish]

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.

1978 - 1979 CX500 A "Life time" 316L Stainless Steel Front Honda Brake Caliper Piston O.D 43mm

This listing for:Product: "Life time" 316L Stainless Steel Front Honda Brake Caliper Piston O.D 43mm Fits the following machines: Make: Honda Models: CX500A For Years: (1978-1979) This kit is for original OEM FRONT Honda calipers! This listing is for ONE...

www.brakecrafters.com

 

[superirish]

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.

 

[bassman97]

.1-.2mm is quite the size change. I'm surprised they swelled up that much.

 

[Jack Hidley]

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

 

[toddturbo]

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.

 

[Jack Hidley]

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

 

[superirish]

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.

 

[Jack Hidley]

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.

 

[superirish]

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.

Was looking back through this and realized I never answered. I use the smaller discs for the lighter weight on the car I only take to the dragstrip because I run a 15x4 wheel.

The centric piston you listed is 1.76" or 44.7MM, but would that be too small, mine were 44.9

Centric Caliper Piston, Centric Parts 146.45013

Centric Caliper Piston, Centric Parts 146.45013. Ships in One Business Day. Buy it and Save at GlobalIndustrial.com

www.globalindustrial.com

Found this thread on a merkur forum, seems they work:

Replacement for PBR phenolic pistons - Page 5 - The Merkur Club of America Forums

 

[Blackpony_94]

I went through this same thing. Upgraded to 01 PBR calipers for 3 years and fought with them the whole time. Finally just bought an 03 Cobra kit 2 years ago and no issues since.

 

[superirish]

RockAuto sells replacement steel calipers now as well.

2004 FORD MUSTANG 3.9L V6 Caliper Piston | RockAuto

RockAuto ships auto parts and body parts from over 300 manufacturers to customers' doors worldwide, all at warehouse prices. Easy to use parts catalog.

www.rockauto.com

Or, you can buy brand new calipers with steel pistons.
RAYBESTOS FRC11012N

RAYBESTOS FRC11011N

 

[superirish]

So I bought a pair of these listed above based on the info from that Merkur forum, they do not have steel pistons, they're phenolic with a steel face where the piston pushes against the pad.
Looks like I'll just get the steel pistons, I've got these so will probably run them for awhile to see how they behave.

 

[Blackpony_94]

I have a small lathe, but no ss round stock laying around

 

[toddturbo]

I bought steel pistons for mine. So far, 3 years, they're still working as expected. I'll have to go back & look through my notes for the part numbers, but I remember I got em from rockauto. It was like $46 for all 4 pistons, which is probably $146 in today's money.