How to Rebuild Zipper Carnival Ride Brake Calipers
Place brake casing into a soft jawed vise with end plug (6) in a vertical position., Remove bleeder screws (19), using a 7/16” socket and ratchet or box end wrench.,Remove hex nut (1) from compensator assembly (9), using a ½’ socket,Remove...
Step-by-Step Guide
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Step 1: Place brake casing into a soft jawed vise with end plug (6) in a vertical position.
Note that clamping should be done at the sides of the caliper on the machined surfaces. , If a combination wrench is used, do not use the open end of the wrench because it may strip the flats before loosening the bleeder screw.,,,, If it comes out with the end plug, this indicates that it had been assembled improperly.,, Save the lining for future use for replacement of worn linings which does not require full disassembly.
This lining is still reusable.
However, notice the quantity of rust and exfoliation which has accumulated between the piston and the lining.
This rust as it built up actually caused pressure and contributed to the shearing of the upper right hand screw.
Before this lining can be reused, it must be cleaned of all these oxide deposits, taking great care not to disrupt the ridge at the bottom where the lining seats into the piston.
This area is where all of the braking force is exerted, and the aluminum screws will not shear if it is seated properly.
Any movement of the lining in the piston under braking pressure will result in the screws being sheared., Notice as well the excessive amount of rust buildup under where the old lining had seated.
This rust has allowed moisture to collect under the lining assembly, accelerating the corrosion process, weakening the aluminum screw due to galvanic effects, resulting in the screw having been sheared off.
Before the new lining is assembled to this piston, the rust must be thoroughly removed, sealant will be applied to the new lining to act as a seal and adhesive, and new screws will be installed.
Never reuse old screws., Notice the use of a folded rag in the jaws of the vise to prevent damage to the piston .,,,, Inspect the housing bore contact area for corrosion, and remove any which may be present., At this time, do not reuse the old linings because new ones are provided with the rebuild kit.
This end plug is not reusable.
Notice in the photo to the left that the center hole has been crushed by impact with a hammer or other object, and in the photo to the right, the edge where the o-ring and backup ring installs has severe pitting corrosion.
The new pressure compensator will no longer fit into the center hole, and the new o-ring and backup ring will not make a proper seal against the pits left from the corrosion.
The end plug in the photos to the left is reusable, and if properly cleaned will provide long service., This is the anodizing which has been attacked by filiform corrosion.
The anodizing or gold coloration was applied to act as a sacrificial anode, and the white powdery substance is the produce after corrosive attack.
This is normal, and if the corrosion has not pitted the groove where the o-ring and backup ring seat, it will be all right.
However, due to the fact that the protective anodizing has been compromised, the bare steel will now corrode under corrosive attack, and protective measures need to be undertaken., If using a flammable substance such as naphtha or isopropyl alcohol, be sure to work in a well-ventilated area, well away from sparks or flames, and for safety's sake, have a safety observer with a CO2 fire extinguisher standing nearby., This area is where the pressure compensator makes its seal, and travel occurs within this area as the piston travels outward during normal liner wear.
Normally, there is a small area of wear, where the anodizing has been worn away, with rust or oxide deposits in this area.
If there is deep pitting in the wear area, the end plug cannot be reused, or leakage will occur past the pits.
Use a folded rag to protect the machined surfaces from damage by the jaws of the vise.
Note that brake fluid eats paint if it is left on a painted surface too long, and if brake fluid comes into contact with a customer’s clothing made of polymers, it will destroy them just as well.
When using a cylinder hone to clean out the bore of the housing, be careful not to hone down the threads inside the housing.
Also, use the finest possible grit stone that can be obtained, normally only glaze breakers are available from most auto parts stores.
If a coarse glaze breaker has to be used, first smear grease onto the stones, so that the fine oxides removed from the inside of the housing will fill the pores of the stones, and make less abrasive.
Doing this means that in the future, these stones will only be good for polishing and honing, so keep them separate from other stones used for rougher abrasive work.
The finished product should be as close to mirror-like as possible when done.
If there are obvious signs of scratching from the hone, it is too rough, and should be used on something else to wear it down and smooth it more before final polishing of the housing.
Adding grease will close the pores of the stones with the materials removed.
For quickly wearing down a glaze breaker to smoother polishing, a piece of pipe, a tin can, or other rounded steel item can be used.
It is easier to just purchase the proper stones in the first place, because any scratches put into the housing will have to be removed before going on with reassembly. , These are 10-24 screws, so use a #25 drill bit to drill these out, and follow with a 10-24 tap to clean the threads.
If the proper size drill bit is not available, do not substitute for any other size; these parts are expensive, and a #25 drill bit is very cheap.
Do not use a 5/32 drill bit just because it is close to the same size and do not go to a smaller size drill bit, because the likelihood that the tap will break is increased when tapping the holes out.
When drilling the holes, put the housing, or piston in a vise so that it will not move, and make sure that you drill straight down through the hole, using both hands, and keeping the drill steady.
If it is a piston which is being drilled, use folded rags to protect the outer surface, and test its stability in the vise before beginning to drill to make sure the vise is tight enough, and the piston will not swivel sideways in the jaws.
It is much more preferable to use a drill press, but sometimes they are not available.
Use a 3/8” drill capable of at least 900 to 1000 rpm, do not use a ½’ drill.
Most ½” drills are too slow in rpm, and have such high torque that they might break the drill bit off on breakthrough.
Use a sharp drill bit, start the drill at high speed, but with very little downward pressure so it can start its way through the aluminum of the screw, and very slowly let the drill bit do all the work., If drilling has been done, the old thread material needs to be removed.
This thread material should be of aluminum, if someone in the past has not put steel screws into the part.
Aluminum has a tendency to clog up the tap, so a lot of back and forth tapping should be done.
Turn the tap in just a little, then back it almost all the way out again, never putting more than just the minimum of torque on it each time it is turned in.
This is a long tedious process, but if performed in this manner, it will prevent the tap from binding in the steel and breaking.
When running the tap through the housing, the tap is traveling through almost ¾” of steel, and there is a very high likelihood of binding.
Use the tee handle in the tap set for this, and use wrist action to twist, do not use both hands on either handle as some persons prefer to do.
By using wrist action and one hand, it makes sure that too much torque is not applied, and helps keep the torque straight down the axis of the tap, reducing the chance of breakage.
If the tap breaks off inside the piston or the housing, then you have just ruined a very expensive part. , If necessary, scraping it will help, followed by a small wire brush and brake cleaner to remove all traces of oil and dirt.,,, Make sure they are installed in proper position in groove. -
Step 2: Remove bleeder screws (19)
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Step 3: using a 7/16” socket and ratchet or box end wrench.
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Step 4: Remove hex nut (1) from compensator assembly (9)
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Step 5: using a ½’ socket
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Step 6: Remove belleville spring (2) wedge ring (3) washer (4) and o-ring (5) from compensator assembly (9).
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Step 7: Using a spanner wrench
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Step 8: remove end plug (6) from housing ( 18)
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Step 9: when removing the end plug (6) from the housing
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Step 10: the compensator assembly should remain in the piston.
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Step 11: Remove piston (10) and lining (11) assembly from housing bore.
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Step 12: Remove flat head screws (12) to separate lining (11) and piston (10).
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Step 13: Notice that the right hand screw has been broken off.
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Step 14: Remove compensator assembly (9) from piston (10)
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Step 15: using an 11/16” open end wrench .
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Step 16: When the compensator assembly has been removed
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Step 17: carefully inspect the threads for damage
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Step 18: making sure that all old locktite material has been removed from the threads
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Step 19: Remove o-ring (8) and backup ring (7) from end plug (6)
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Step 20: Using a thin blade tool
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Step 21: or a pick tool
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Step 22: remove backup ring (14)
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Step 23: o-ring (13)
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Step 24: and seal (15) from housing bore.
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Step 25: Remove flat head screws (16) and lining (17) from housing bore.
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Step 26: If the lining is in good shape
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Step 27: clean and set it aside as spare parts to be reused in the event that anther lining wears out.
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Step 28: Notice the white powdery substance along the perimeter of the threads.
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Step 29: Using a mild wire brush and brake parts cleaner
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Step 30: or any other solvent which does not contain petroleum distillates
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Step 31: such as electrical parts cleaner
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Step 32: naptha
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Step 33: or isopropyl alcohol
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Step 34: thoroughly clean the entire end plug assembly.
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Step 35: Using a rounded object (in this instance a 6” ratchet extension)
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Step 36: and 400 to 600 grit emery cloth
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Step 37: clean out the inside of the end plug.
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Step 38: Since usually one or more of the fastening screws for the lining will be sheared off
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Step 39: now the sheared off portion of the screw needs to be drilled out.
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Step 40: Run a tap through the holes to clean out the threads.
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Step 41: Before installing the new lining into the housing
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Step 42: first double check to make sure the mating surface of the housing is well cleaned of all rust and debris.
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Step 43: Mask off all the areas where paint will not be applied
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Step 44: and prime the area where the lining seats to protect it from corroding again.
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Step 45: Set the housing aside for the paint to dry while working on the piston and compensator assembly.
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Step 46: Carefully install new back-up ring (7) and o-ring (8) over non-threaded end of plug (6) and into groove.
Detailed Guide
Note that clamping should be done at the sides of the caliper on the machined surfaces. , If a combination wrench is used, do not use the open end of the wrench because it may strip the flats before loosening the bleeder screw.,,,, If it comes out with the end plug, this indicates that it had been assembled improperly.,, Save the lining for future use for replacement of worn linings which does not require full disassembly.
This lining is still reusable.
However, notice the quantity of rust and exfoliation which has accumulated between the piston and the lining.
This rust as it built up actually caused pressure and contributed to the shearing of the upper right hand screw.
Before this lining can be reused, it must be cleaned of all these oxide deposits, taking great care not to disrupt the ridge at the bottom where the lining seats into the piston.
This area is where all of the braking force is exerted, and the aluminum screws will not shear if it is seated properly.
Any movement of the lining in the piston under braking pressure will result in the screws being sheared., Notice as well the excessive amount of rust buildup under where the old lining had seated.
This rust has allowed moisture to collect under the lining assembly, accelerating the corrosion process, weakening the aluminum screw due to galvanic effects, resulting in the screw having been sheared off.
Before the new lining is assembled to this piston, the rust must be thoroughly removed, sealant will be applied to the new lining to act as a seal and adhesive, and new screws will be installed.
Never reuse old screws., Notice the use of a folded rag in the jaws of the vise to prevent damage to the piston .,,,, Inspect the housing bore contact area for corrosion, and remove any which may be present., At this time, do not reuse the old linings because new ones are provided with the rebuild kit.
This end plug is not reusable.
Notice in the photo to the left that the center hole has been crushed by impact with a hammer or other object, and in the photo to the right, the edge where the o-ring and backup ring installs has severe pitting corrosion.
The new pressure compensator will no longer fit into the center hole, and the new o-ring and backup ring will not make a proper seal against the pits left from the corrosion.
The end plug in the photos to the left is reusable, and if properly cleaned will provide long service., This is the anodizing which has been attacked by filiform corrosion.
The anodizing or gold coloration was applied to act as a sacrificial anode, and the white powdery substance is the produce after corrosive attack.
This is normal, and if the corrosion has not pitted the groove where the o-ring and backup ring seat, it will be all right.
However, due to the fact that the protective anodizing has been compromised, the bare steel will now corrode under corrosive attack, and protective measures need to be undertaken., If using a flammable substance such as naphtha or isopropyl alcohol, be sure to work in a well-ventilated area, well away from sparks or flames, and for safety's sake, have a safety observer with a CO2 fire extinguisher standing nearby., This area is where the pressure compensator makes its seal, and travel occurs within this area as the piston travels outward during normal liner wear.
Normally, there is a small area of wear, where the anodizing has been worn away, with rust or oxide deposits in this area.
If there is deep pitting in the wear area, the end plug cannot be reused, or leakage will occur past the pits.
Use a folded rag to protect the machined surfaces from damage by the jaws of the vise.
Note that brake fluid eats paint if it is left on a painted surface too long, and if brake fluid comes into contact with a customer’s clothing made of polymers, it will destroy them just as well.
When using a cylinder hone to clean out the bore of the housing, be careful not to hone down the threads inside the housing.
Also, use the finest possible grit stone that can be obtained, normally only glaze breakers are available from most auto parts stores.
If a coarse glaze breaker has to be used, first smear grease onto the stones, so that the fine oxides removed from the inside of the housing will fill the pores of the stones, and make less abrasive.
Doing this means that in the future, these stones will only be good for polishing and honing, so keep them separate from other stones used for rougher abrasive work.
The finished product should be as close to mirror-like as possible when done.
If there are obvious signs of scratching from the hone, it is too rough, and should be used on something else to wear it down and smooth it more before final polishing of the housing.
Adding grease will close the pores of the stones with the materials removed.
For quickly wearing down a glaze breaker to smoother polishing, a piece of pipe, a tin can, or other rounded steel item can be used.
It is easier to just purchase the proper stones in the first place, because any scratches put into the housing will have to be removed before going on with reassembly. , These are 10-24 screws, so use a #25 drill bit to drill these out, and follow with a 10-24 tap to clean the threads.
If the proper size drill bit is not available, do not substitute for any other size; these parts are expensive, and a #25 drill bit is very cheap.
Do not use a 5/32 drill bit just because it is close to the same size and do not go to a smaller size drill bit, because the likelihood that the tap will break is increased when tapping the holes out.
When drilling the holes, put the housing, or piston in a vise so that it will not move, and make sure that you drill straight down through the hole, using both hands, and keeping the drill steady.
If it is a piston which is being drilled, use folded rags to protect the outer surface, and test its stability in the vise before beginning to drill to make sure the vise is tight enough, and the piston will not swivel sideways in the jaws.
It is much more preferable to use a drill press, but sometimes they are not available.
Use a 3/8” drill capable of at least 900 to 1000 rpm, do not use a ½’ drill.
Most ½” drills are too slow in rpm, and have such high torque that they might break the drill bit off on breakthrough.
Use a sharp drill bit, start the drill at high speed, but with very little downward pressure so it can start its way through the aluminum of the screw, and very slowly let the drill bit do all the work., If drilling has been done, the old thread material needs to be removed.
This thread material should be of aluminum, if someone in the past has not put steel screws into the part.
Aluminum has a tendency to clog up the tap, so a lot of back and forth tapping should be done.
Turn the tap in just a little, then back it almost all the way out again, never putting more than just the minimum of torque on it each time it is turned in.
This is a long tedious process, but if performed in this manner, it will prevent the tap from binding in the steel and breaking.
When running the tap through the housing, the tap is traveling through almost ¾” of steel, and there is a very high likelihood of binding.
Use the tee handle in the tap set for this, and use wrist action to twist, do not use both hands on either handle as some persons prefer to do.
By using wrist action and one hand, it makes sure that too much torque is not applied, and helps keep the torque straight down the axis of the tap, reducing the chance of breakage.
If the tap breaks off inside the piston or the housing, then you have just ruined a very expensive part. , If necessary, scraping it will help, followed by a small wire brush and brake cleaner to remove all traces of oil and dirt.,,, Make sure they are installed in proper position in groove.
About the Author
Patricia Torres
Experienced content creator specializing in lifestyle guides and tutorials.
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