Maddox MD12 User manual

Visit our website at: http://www.harborfreight.com
Email our technical support at: [email protected] 58802
Owner’s Manual & Safety Instructions
Save This Manual Keep this manual for the safety warnings and precautions, assembly,
operating, inspection, maintenance and cleaning procedures. Write the product’s serial number in the
back of the manual near the assembly diagram (or month and year of purchase if product has no number).
Keep this manual and the receipt in a safe and dry place for future reference. 21i
When unpacking, make sure that the product is intact
and undamaged. If any parts are missing or broken,
please call 1-888-866-5797 as soon as possible.
Copyright©2021 by Harbor Freight Tools®. All rights reserved.
No portion of this manual or any artwork contained herein may be reproduced in
any shape or form without the express written consent of Harbor Freight Tools.
Diagrams within this manual may not be drawn proportionally. Due to continuing
improvements, actual product may differ slightly from the product described herein.
Tools required for assembly and service may not be included.
Read this material before using this product.
Failure to do so can result in serious injury.
SAVE THIS MANUAL.

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Specifications
Jaw Opening 1-3/8″(35mm) to 5-5/8″(142mm)
Throat Clearance 5-7/8″(150mm)
Valve Spring Adapter Sizes 1″(25mm) and 1-3/16″(30mm)
IMPORTANT SAFETY INFORMATION
1. Block drive wheels before use.
Set parking brake and put
gear selector in neutral for
manual transmission or park
for automatic transmission.
Risk of sudden vehicle movement!
2. Read vehicle’s service
manual before use.
3. Keep away from hot or
moving engine parts.
4. Inspect before every use;
do not use if parts loose or damaged.
5. Wear ANSI-approved safety
goggles during use.
6. Maintain product labels and
nameplates. These carry
important safety information.
If unreadable or missing, contact
Harbor Freight Tools for a replacement.
7. The warnings, precautions, and
instructions discussed in this manual
cannot cover all possible conditions
and situations that may occur.
The operator must understand that
common sense and caution are factors,
which cannot be built into this product,
but must be supplied by the operator.
Functions
Inner Screw
Cup
Release Adapter
Adjusting Screw
Handle

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Operating Instructions
Read the ENTIRE IMPORTANT SAFETY INFORMATION section at the
beginning of this document before set up or use of this product.
Note: Refer to vehicle service manual
for engine head removal process.
1. Remove head, then place head on a
stable work bench or head stand.
2. Secure head in a position where
valves are facing down and do
not make contact with work bench
surface to prevent damage to valve.
3. Place a properly sized socket
onto spring retainer cap.
4. If needed for clearance, place
an extension onto socket.
5. Lightly tap socket or extension with a
striking tool to loosen collets from spring
retainer cap and valve spring keepers.
6. If applicable, remove the clip
from the valve keeper.
7. Determine which Release Adapter best
fits the circumference of spring retainer
cap and thread onto Inner Screw.
CAUTION: TO PREVENT PROPERTY
DAMAGE: ensure Cup and Release
Adapter to not make contact with head
while locking Valve Spring Compressor.
8. Carefully center Cup onto
valve and Release Adapter
onto spring retainer cap.
9. Grip Valve Spring Compressor with both
hands and push Handle forward to lock.
10. Turn Adjusting Screw clockwise to
compress valve spring to expose collets.
11. Remove collets using a magnet.
12. Loosen Adjusting Screw to release
pressure before removing Compressor.
13. Hold valve in place and
remove spring assembly.
14. Carefully remove valve.
Note: Refer to vehicle service
manual for engine head assembly
and installation process.
Inspection, Maintenance and Cleaning
Procedures not specifically explained in this manual
must be performed only by a qualified technician.
TO PREVENT SERIOUS INJURY FROM TOOL FAILURE:
Do not use damaged equipment. If abnormal noise or vibration
occurs, have the problem corrected before further use.
1. BEFORE EACH USE, inspect
the general condition of the tool.
Check for cracked or broken parts,
damaged hoses, loose fittings,
misalignment or binding of moving
parts, and any other condition that
may affect its safe operation.
2. AFTER USE, clean external
surfaces of the tool when necessary
with a clean, damp cloth and mild
detergent. Store the Valve Spring
Compressor tool in a clean, dry, safe
location out of reach of children.

Limited 90 Day Warranty
Harbor Freight Tools Co. makes every effort to assure that its products meet high
quality and durability standards, and warrants to the original purchaser that this
product is free from defects in materials and workmanship for the period of 90 days
from the date of purchase. This warranty does not apply to damage due directly or
indirectly, to misuse, abuse, negligence or accidents, repairs or alterations outside
our facilities, criminal activity, improper installation, normal wear and tear, or to lack of
maintenance. We shall in no event be liable for death, injuries to persons or property,
or for incidental, contingent, special or consequential damages arising from the use
of our product. Some states do not allow the exclusion or limitation of incidental or
consequential damages, so the above limitation of exclusion may not apply to you. THIS
WARRANTY IS EXPRESSLY IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR
IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS.
To take advantage of this warranty, the product or part must be returned to us
with transportation charges prepaid. Proof of purchase date and an explanation
of the complaint must accompany the merchandise. If our inspection verifies
the defect, we will either repair or replace the product at our election or we may
elect to refund the purchase price if we cannot readily and quickly provide you
with a replacement. We will return repaired products at our expense, but if we
determine there is no defect, or that the defect resulted from causes not within the
scope of our warranty, then you must bear the cost of returning the product.
This warranty gives you specific legal rights and you may also
have other rights which vary from state to state.
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