Hadley 857 Installation Instructions

Installation Instructions

1. Horn should be mounted on top of cab and tilted slightly downward for
best sound projection.
2. If cab is equipped with roof trim panel, remove to install horn.
3. Drill 1/2" and 9/32" holes (using gasket for a template) in position desired
for horn base. Locate position for front support and drill 9/32" holes.
4. Place gasket between base of horn and top of cab roof and secure to roof
with 2 screws, 2 lock washers, and 2 nuts.
5. Place gasket between base of support and top of cab roof and secure to
roof with 2 screws, 2 lock washers, and 2 nuts.
6. Assemble lanyard valve and curved tension washer to horn.
7. Connect tubing from air supply to inlet on manual lanyard valve.
8. Punch hole in trim panel for valve lanyard. Lace lanyard through panel.
Replace panel, fasten lanyard to convenient trim screw. (not included)
CAUTION: check local noise abatement ordinances to avoid legal violations.
Important – Use pipe compound on pipe
threads to assure air tight connections
All Hadley products carry a limited warranty for 12 months from the date of purchase. We will repair or
replace, at our option, defects in material and workmanship during that period when product is returned to
Hadley
Attn: Warranty Dept
2851 Prairie Street
Grandville MI, 49418
Service Department: (616) 249-8462
Hadley Main: (616) 530-1717
Fax: (616) 530-3283
www.hadley-products.com
MODEL 857
For vehicles with air brakes
our service department at the address below.
ECR 4873 Rev B
H13748.doc