Question.....What happens if I split the caliper to hone/clean the cylinders...ie...any thing i will need to replace between the halves.
Tx....Bob
Original Post
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Bob,
Have not done this myself, so no first hand info. But I have heard the two sides have an o-ring seal that is not easy to locate. Even the rebuild kits from vendors are evidently known to lack this o-ring. Proceed accordingly.
Larry
Have not done this myself, so no first hand info. But I have heard the two sides have an o-ring seal that is not easy to locate. Even the rebuild kits from vendors are evidently known to lack this o-ring. Proceed accordingly.
Larry
The below response is from our Boss Wrench, Jack DeRyke. I am posting this on his behalf. His computer is not compatable with our new Bulletin Board. Dave
Answer:
Only the front calipers split. Between the halves of most 2-piece calipers are two tiny o-rings that seal the cross-over fluid passages (if present). I haven't found it necessary to split Pantera/Girling calipers to fix them.
Splitting can cause a fair amount of trouble since caliper rebuild kits don't include the tiny crossover o-rings, and obtaining the right size, in a brake-fluid-resistent compound, is difficult. In fact, some mfgrs specifically say 'do not ever split our calipers! Replace them if they are pitted'!
In any case, its not necessary, and pit-honing of the bores is not as simple as one might think. Girling brake pistons are hard-chrome-plated mild steel so any pits causing leaks will normally be in them, not the bores. The only 'fix' in such a case is to replace the piston or have it professionally stripped & re-plated, then ground to size; its often cheaper to replace the whole caliper! Internal caliper hard-parts have never been available, and Girling sold off the parts & patterns of all its brakes decades ago.
As I said, the bores are normally OK, with varnish build-up the only concern.
This is the all-too-common 'stuck-piston-syndrome' that is cheaply fixed by blocking 3 pistons with a wood block & a c-clamp, them stepping on the brake repeatedly until the piston of choice pops out (spraying brake fluid everywhere!
Wear old clothes & wipe up spills & spatters promptly.) Note also that each dust seal need not be removed- in fact, trying to pry the dust seals out first normally tears it. The piston will slide right through the dust seal, which afterwards can be pried out with no damage, with a small screwdriver.
There is a spring-wire retainer also holding the press-fit dust seal in place. Simply wipe everything clean & inspect the rubber for tears.
Once a piston is out & the dust seal removed, scour the bore and piston with Scotch-brite pads until both are varnish-free. Carefully pry the piston seal (in the bore) out with a blunt screwdriver and either carefully inspect it (I use a magnifying glass) for deep surface cracks and/or replace. The seal is not often too bad to re-use but are included in the rebuild kits from P.I Motorsports, as are the dust seals. Note also that Brit-car parts stores sell Girling brake-grease which can be used as an assembly-lube for the pistons & internal seals. Good stuff! I like to do all 4 pistons in a caliper at once; note the leading & trailing pistons are of different sizes.
This advanced design for pad-wear compensation was only found on pure race cars in the '70s! Replacing a pumped-out piston in its bore after cleaning, and progressively moving the c-clamp allows all the pistons in one caliper to be removed in sequence, minimizing the slop generated.
In the rear calipers, the single piston pulls out the backside once the ring-shaped steel-plate parking brake is removed, and a single internal seal is inspected. The bore and piston is cleaned as in front, with Scotch-brite.
A spot of chassis grease on each of the plastic sliders on the sides will restore good back-and-forth action. The parking brake is adjusted by rotating the outboard piston-half about 45 degrees relative to the inboard piston. This releases the internal clevis, allowing the inner & outer pistons to collapse against each other & make room for a thicker pad. Do NOT attempt to disassemble the parking-brake section built into the piston.
There are multiple layers of complex parts beneath myriad snap-rings, and you will undoubtably get lost trying to reassemble. There are no directions, parts or even any exploded views of this
mechanism- be warned! Matter of fact, do only one caliper at a time- the unmolested one on either end can serve as a pattern if you get confused during reassembly into the car.
Caliper refurbishment is a filthy, dirty, miserable time-consuming repair that often does not need any parts replaced at all- only thorough cleaning and careful disassembly & reassembly. Once together, back up slowly a few times, hitting the brakes; this automatically readjusts the rear calipers & parking brakes to proper running clearance. But test everything- your brakes are a vital system. Do not attack this job casually. Running your Pantera under a truck 'cause you got in a hurry fiddling with your brakes is a waste of a beautiful car and maybe a driver! Some fresh brake fluid, thorough bleeding, testing and you're good-to-go for another several years, especially if you drive the car vigorously. Garage-queens are usually the ones needing constant brake refurbishment.
Std disclaimer applies- If you don't feel competent to do the repair properly, most Pantera vendors will do this job & no shame is involved. The consequenses of even a minor foul-up are extreme. Good luck.
Answer:
Only the front calipers split. Between the halves of most 2-piece calipers are two tiny o-rings that seal the cross-over fluid passages (if present). I haven't found it necessary to split Pantera/Girling calipers to fix them.
Splitting can cause a fair amount of trouble since caliper rebuild kits don't include the tiny crossover o-rings, and obtaining the right size, in a brake-fluid-resistent compound, is difficult. In fact, some mfgrs specifically say 'do not ever split our calipers! Replace them if they are pitted'!
In any case, its not necessary, and pit-honing of the bores is not as simple as one might think. Girling brake pistons are hard-chrome-plated mild steel so any pits causing leaks will normally be in them, not the bores. The only 'fix' in such a case is to replace the piston or have it professionally stripped & re-plated, then ground to size; its often cheaper to replace the whole caliper! Internal caliper hard-parts have never been available, and Girling sold off the parts & patterns of all its brakes decades ago.
As I said, the bores are normally OK, with varnish build-up the only concern.
This is the all-too-common 'stuck-piston-syndrome' that is cheaply fixed by blocking 3 pistons with a wood block & a c-clamp, them stepping on the brake repeatedly until the piston of choice pops out (spraying brake fluid everywhere!
Wear old clothes & wipe up spills & spatters promptly.) Note also that each dust seal need not be removed- in fact, trying to pry the dust seals out first normally tears it. The piston will slide right through the dust seal, which afterwards can be pried out with no damage, with a small screwdriver.
There is a spring-wire retainer also holding the press-fit dust seal in place. Simply wipe everything clean & inspect the rubber for tears.
Once a piston is out & the dust seal removed, scour the bore and piston with Scotch-brite pads until both are varnish-free. Carefully pry the piston seal (in the bore) out with a blunt screwdriver and either carefully inspect it (I use a magnifying glass) for deep surface cracks and/or replace. The seal is not often too bad to re-use but are included in the rebuild kits from P.I Motorsports, as are the dust seals. Note also that Brit-car parts stores sell Girling brake-grease which can be used as an assembly-lube for the pistons & internal seals. Good stuff! I like to do all 4 pistons in a caliper at once; note the leading & trailing pistons are of different sizes.
This advanced design for pad-wear compensation was only found on pure race cars in the '70s! Replacing a pumped-out piston in its bore after cleaning, and progressively moving the c-clamp allows all the pistons in one caliper to be removed in sequence, minimizing the slop generated.
In the rear calipers, the single piston pulls out the backside once the ring-shaped steel-plate parking brake is removed, and a single internal seal is inspected. The bore and piston is cleaned as in front, with Scotch-brite.
A spot of chassis grease on each of the plastic sliders on the sides will restore good back-and-forth action. The parking brake is adjusted by rotating the outboard piston-half about 45 degrees relative to the inboard piston. This releases the internal clevis, allowing the inner & outer pistons to collapse against each other & make room for a thicker pad. Do NOT attempt to disassemble the parking-brake section built into the piston.
There are multiple layers of complex parts beneath myriad snap-rings, and you will undoubtably get lost trying to reassemble. There are no directions, parts or even any exploded views of this
mechanism- be warned! Matter of fact, do only one caliper at a time- the unmolested one on either end can serve as a pattern if you get confused during reassembly into the car.
Caliper refurbishment is a filthy, dirty, miserable time-consuming repair that often does not need any parts replaced at all- only thorough cleaning and careful disassembly & reassembly. Once together, back up slowly a few times, hitting the brakes; this automatically readjusts the rear calipers & parking brakes to proper running clearance. But test everything- your brakes are a vital system. Do not attack this job casually. Running your Pantera under a truck 'cause you got in a hurry fiddling with your brakes is a waste of a beautiful car and maybe a driver! Some fresh brake fluid, thorough bleeding, testing and you're good-to-go for another several years, especially if you drive the car vigorously. Garage-queens are usually the ones needing constant brake refurbishment.
Std disclaimer applies- If you don't feel competent to do the repair properly, most Pantera vendors will do this job & no shame is involved. The consequenses of even a minor foul-up are extreme. Good luck.