Pneumatic Paving Breaker #550660, JCT-4660 #550661, JCT-4661 Operation & Parts Manual M-550660 Edition 2 05/2017 JET 427 New Sanford Road LaVergne, TN 37086 Ph.: 800-274-6848 www.jettools.
Safety warnings General air tool warnings 1. Read and understand this entire manual before attempting assembly or operation. 2. Read and understand all warnings posted on the tool and in this manual. Failure to comply with all of these warnings may cause serious injury. 3. Replace warning labels if they become obscured or removed. 4. Do not use this tool for other than its intended use.
20. Do not use power tools in damp or wet location, or expose them to rain. Keep work area well lighted. 21. Do not leave a connected tool unattended. When not in use, disconnect tool from air source. 22. Shut off air supply and discharge any residual pressure from tool before removing hose, making adjustments, changing accessories, or storing tool. 23. Make sure tool is switched off, and your finger off the trigger, before connecting to air supply. 24.
About this manual This manual is provided by JET, covering the safe operation and maintenance procedures for the JET Model JCT-4660 series pneumatic Paving Breakers. This manual contains instructions on safety precautions, general operating procedures, maintenance procedures and parts breakdown. Your tool has been designed and constructed to provide consistent, long-term operation if used in accordance with the instructions set forth in this document.
Tool specifications Model number JCT-4660 JCT-4661 Stock number 550660 550661 Class/type 60 lb. 90 lb. Hex shank size 1-1/8 x 6 in. 1-1/8 x 6 in. Piston diameter 2-1/4 in. 2-5/8 in. Piston stroke 4 in. 6 in. Impact rate (blows per minute) 1,400 1,250 Energy per blow @ 90 psi 119.32 Joule 248.36 Joule Average air consumption 70 CFM 77 CFM Air Inlet 3/4 in. NPT 3/4 in. NPT Air hose minimum inside diameter 3/4 in. 3/4 in. Required air pressure 90 psi (6.2 bar) 90 psi (6.
Setup and Assembly Any missing parts or damage should be reported immediately to your JET® distributor. Do not use a damaged tool. Read this instruction manual thoroughly for operation, maintenance and safety instructions. 2. Remove oil plug and fill reservoir with air tool oil up to lowest thread of fill hole. NOTE: Air tool oil not provided; it is available at most major hardware and tool stores. SAE #10 oil may be used as a substitute. Do not use detergent oil. 3. Reinstall plug.
Lubrication 5. Remove cylinder, tappet seat, and tappet. The paving breaker should be lubricated with air tool oil maintained in the reservoir, and with an inline oiler. 6. Disassemble front head: Storage Avoid storing the paving breaker in very humid locations which promotes rusting of internal mechanisms. Always oil the tool and disconnect air hose before storage. • Loosen the steel retainer bolt nut. • Remove steel retainer bolts, steel retainer, and retainer bolt bushings.
Back head assembly 7. Install five cylinder plugs into cylinder. 1. Place chamfered side of throttle valve stem guide into the back head and tap into position. 8. Set air inlet screen into the exhaust portion of cylinder. 9. 2. Ream the guide with a 0.312” (7.93 mm) reamer tool. Install air inlet assembly. See torque specification chart. 3. Set throttle valve lever into the back head. 4. Place a 0.312” (7.93 mm) steel rod into the hole and hammer in the pin. 5.
General Air Tool Information If the air tool is not performing according to specifications, the following are among the most common causes. (See also “Troubleshooting” section.) • Contaminated air such as a dirty air system or water in the system. • Using wrong size tool for the job. • Poor maintenance practices, such as using excessive air pressure or air volume. • Improper or no lubrication. Use safety shut-off valves so air flow can be stopped quickly in case of a line break.
Figure 2 Recommended arrangement of air piping and air line system Torque specifications Refer to this chart when assembling parts or tightening after a period of service. Front Head Bolt Back Head Bolt Front Retainer Bolt Oil Tank Bolt GD Plug Air Inlet Assembly JCT-4660 2-2.5mm * 166.3-202.5 43.4-57.8 57.8 7.2-10.8 202.58-216.9 JCT-4661 3mm * 166.3-202.5 43.4-57.8 28.9-32.5 10.8-14.5 202.5-216.
Troubleshooting JCT-4660 series Paving Breakers Any disassembly of the tool should be done by qualified service personnel. For problems not addressed below, contact JET technical service at 800-274-6846. Problem Possible cause Remedy Tool will not start. Air valve closed or obstructed. Open valve; clear any obstructions. Dirt or gum deposits on components. Flush tool with gum solvent. If problem persists, disassemble, clean and lubricate internal parts. Throttle lever malfunction.
Problem Possible cause Remedy Severe air leakage. (Note: Minimal escape of air is often normal for air tools.) Leakage from air inlet swivel. Change O-rings and check for loosening of air inlet swivel nut. Leakage from throttle valve area. Check for wear of throttle valve stem guide. Replace if needed. Leakage from back head and cylinder. Check plug; change O-ring on throttle valve. Also check for foreign matter which may have entered during assembly. Improper lubrication.
Replacement parts Service parts are listed on the following pages. To order parts or reach our service department, call 1-800274-6848 Monday through Friday, 8:00 a.m. to 5:00 p.m. CST. Please have the stock number and serial number of your tool available when you call, so that we may serve you quickly and accurately. Non-proprietary parts, such as fasteners, can be found at local hardware stores, or may be ordered from JET. Some parts are shown for reference only, and may not be available individually.
#550660, JCT-4660 Paving Breaker (60 lb.
#550660, JCT-4660 Paving Breaker (60 lb.) Index 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Part No. P61119 JCT4660-02 P91245 P91220 P91217 P91250 P91252 P91251 P91218 P91213 P91225 P91224 P91210 P91209 P61107 P61105 P91204 P61106 P91215 P91212 P91214 P91216 P91202 Description Oil plug Back head Felt oiler Ø8.5x25L Oil control plug 1/8PT Throttle lever Spring pin 4x40L Stop lever spring Stop lever Throttle lever pin Ø8x30L Rubber grip Back head bolt nut Lock washer 5/8in.
#550661, JCT-4661 Paving Breaker (90 lb.
#550661, JCT-4661 Paving Breaker (90 lb.) Index 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Part No. P91213 JCT4661-02 P91220 P91245 P91217 P91250 P91251 P91252 P91218 P91248 P91225 P91224 P91219 P91210 P91209 Description Rubber grip Back head Oil control plug 1/8PT Felt oiler Ø8.5x25L Throttle lever Spring pin 4x40L Stop lever Stop lever spring Throttle lever pin Ø8x30L Oil tank plug 1/2PT Back head bolt nut Lock washer 5/8in.
Warranty and Service JET warrants every product it sells against manufacturers’ defects. If one of our tools needs service or repair, please contact Technical Service by calling 1-800-274-6846, 8AM to 5PM CST, Monday through Friday. Warranty Period The general warranty lasts for the time period specified in the literature included with your product or on the official JET branded website. • JET products carry a limited warranty which varies in duration based upon the product.
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427 New Sanford Road LaVergne, Tennessee 37086 Phone: 800-274-6848 www.jettools.
