BRADEN CH175A - Brake Valve Service

36
BRAKE VALVE SERVICE
Standard Braden second generation CH series hoists are
supplied with one of two types of brake valves. Both are
reliable hydraulic valves with internal componentsmanu-
factured to close tolerances. Due to these close toler-
ances, several individual parts are not available as
replacement parts and are noted in the following parts
lists as NSS (Not Serviced Separately).
Before disassembling the brake valve, be sure you have
conducted all applicable trouble shooting operations and
are certain the brake valve is causing the malfuntion.
Thoroughly clean the outside surfaces of the valve and
work in a clean dust-free area, as cleanliness is of utmost
importance when servicing hydraulic components.
1 1/4 INCH BRAKE VALVE
ITEM DESCRIPTION QTY.
1 Valve Housing (NSS) 1
2 Check Valve Retainer (NSS) 1
3 Spring Retainer (NSS) 1
4 Plug (NSS) 1
5 Spool (NSS) 1
6 Damper Piston (NSS) 1
7O-Ring 1
8 Check Valve Poppet (NSS) 1
9 Pilot Orifice 1
10 Check Valve Spring 1
11 Spool Spring 1
12 O-Ring 2
13 O-Ring 1
14 O-Ring 1
15 Back-up Ring 1
16 Back-up Ring 1
17 Check Ball (1/4 in.) 1
18 Check Ball Spring 1
19 Elbow Fitting 1
A
A
SEC. A-A
DRAIN
PORT
3
1
2
4
5
6
14
16
11
12
10
7
8
9
13
15
18
17
19
“BR”
PORT
1 1/2 INCH BRAKE VALVE
ITEM DESCRIPTION QTY.
1 Valve Housing (NSS) 1
2 Check Valve Retainer (NSS) 1
3 Spring Retainer (NSS) 1
4 Plug (NSS) 1
5 Spool (NSS) 1
6 Damper Piston (NSS) 1
7 Damper Piston Extension 1
8 Check Valve Poppet (NSS) 1
10 Reducer 1
11 Check Ball 1
12 Check Valve Spring 1
13 Main Piston Spring 1
14 O-Ring 1
15 Back-up Ring 1
16 O-Ring 1
17 Back-up Ring 1
18 O-Ring 1
19 Pipe Plug 1
20 Check Spring 1
21 Shim as req'd
22 Spring Seat 1
19
4
20
11
19
10
12
2
1
14
19
4
5
15
18
17
16
21
3
13
14
6
7
8
22
0
11
19
10
1 1/2 inch brake valves built after mid-March 1997 contain
a spring seat (item 22) between the spool spring and the
spool. This provides a slightly larger, more uniform area
for the spring to seat against the spool. The result is
increased spring service life and improved repeatability of
pressure/flow modulation over the full compression range
of the spring.