MP24.9734
17JAN17
SECTION II
625/625S SERIES LEVELING SYSTEMS
COMPONENT INSTALLATION
Example: A 13 inch stroke jack should be mounted with 7 to 8 inches of ground clearance. Also remember there has to be
clearance above the jacks to access hose and electrical connections. When determining the mounting height it is also
important to maintain an adequate bolting pattern for mounting the jacks. A minimum of four bolts should be used to fasten
each jack to the frame rail: two upper bolts and two lower bolts.
Bolt Mounting Hole Patterns
Mounting holes are normally provided on the jack pivot bracket or if a weld on style pivot bracket is used, the mounting plate
for that style jack has pre-drilled mounting holes. Some frames may have pre-drilled holes that can be used. Typically, we like
a minimum of 3 inches between the top and bottom mounting holes for 4,000# and 6,000# jacks with a minimum of 4 ½ inches
between the top and bottom mounting holes for 9,000# and 12,000# jacks. HWH Corporation should be contacted for
applications requiring 16,000# or 24,000# capacity jacks.
Due to variations in vehicle weight, jack capacities, frame width and construction, HWH cannot address all mounting
possibilities and variations. It is the responsibility of the installer to recognize possible mounting issues such as mounting
hole patterns or mounting positions on the frame rail. Anytime an issue is suspected, please contact HWH Corporation for
assistance.
If using a jack with a weld-on style pivot bracket, a mounting plate that bolts to the vehicle frame rail should be used. First,
determine the proper mounting height of the jack and fasten the mounting plate to the frame rail in the appropriate position.
The jack can then be welded to the mounting plate. It may be best to tack the jack in place and then remove it from the frame
rail to complete the welding of the pivot bracket to the plate in a flat position instead of a vertical position. WHEN WELDING
TO A PLATE THAT IS FASTENED TO THE FRAME RAIL, PROTECT ANY TUBES, WIRES, HOSES, ETC. ON EITHER
SIDE OF THE FRAME RAIL FROM WELDING HEAT AND SPLATTER.
The jacks or jack mounting plates should be bolted using hardware supplied by HWH Corporation. Make sure all bolts are
properly tightened. A minimum of grade 5 bolt should be maintained if substituting for hardware supplied by HWH Corporation.
Any flat and/or lock washers must be used when supplied in hardware kits. Before the installation is complete, all mounting
bolts for the jacks should be rechecked for tightness.
When installing the front and rear jacks, some means of preventing the frame rail from twisting must be provided. Some jack
assemblies have a cross tie assembly built into the pivot bracket arrangement. HWH Corporation offers an assortment of
cross tie assemblies to tie the lower section of the jack pivot brackets together. If necessary, a cross tie assembly or some
type of frame rail support may need to be fabricated on site. It is allowable to weld gussets and other components of a cross
tie assembly. The cross tie assembly should not be welded to the jack pivot bracket in case the cross tie has to be removed to
access other vehicle equipment.
DO NOT CRAWL UNDER A VEHICLE WITHOUT PROPERLY SUPPORTING THE FRAME OF THE
VEHICLE IF THE VEHICLE IS SUPPORTED ON THE SUSPENSION AIR BAGS. THE VEHICLE WILL RAPIDLY DROP
SEVERAL INCHES WHEN THE AIR IS EXHAUSTED FROM THE AIR BAGS. MAKE SURE THERE IS ADEQUATE
CLEARANCE TO WORK UNDER THE VEHICLE WITH THE AIR BAGS DEFLATED.
WARNING:
Figure 8
ACCEPTABLE
ACCEPTABLE
UNACCEPTABLE
UNACCEPTABLE
to work under the vehicle without interference from any moving suspension or vehicle component.
from the air bags. Suspension components can also move when the air is released. Make sure there is ample room
Before deflating the air bags, the vehicle’s frame must be securely blocked so it cannot drop when the air is released
3.) AIR SUSPENSION - AIR DUMP INSTALLATION (NON PILOT DUMP EQUIPPED VEHICLES)
