some info
FAQ - Subject - Solenoid valves used for trailer hydraulic brake systems.
Solenoid valves are used on hydraulic trailer brake systems to lock the brakes out while backing up.
[1] What is the difference between a blocking solenoid and a bleed type solenoid valve?
***Blocking solenoid valves are inline [ normally open valves] that close when 12 VDC is applied.
This locks out the potential for any further brake pressure to be induced into the brake tubing system
while the solenoid is electrically activated.
This type of valve does not require a return line back to the master cylinder reservoir.
One potentially negative feature of this type of valve is that if brake fluid pressure was trapped between
the master cylinder and the wheel brake devices before the electrical activation of the solenoid,
this brake pressure will remain trapped and may inhibit the trailer from being backed up.
******* BLEED SOLENOID valves are typically 3 way [ 3 port] valves. Three way bleed solenoid
Valves allow free passage of brake fluid thru the valve during normal braking operations,
when not electrically activated.
The third port of the valve is connected to a return line back to the master cylinder reservoir.
This port is closed when the valve is not electrically activated.
When electrically activated, this third port opens allowing release of pressure back to the reservoir
& atmospheric pressure [ 0 PSI gage pressure].
Because this bleed valve releases all brake line pressure, it is an excellent choice for applications
where backing uphill are necessary. However, it does require a return port machined in the
master cylinder reservoir.
****** 2 way bleed SOV - It is possible to install a 2 way normally closed valve into the system
by installing a TEE in the brake line tubing & using one port of the SOV to connect to the
return line back to the reservoir. Again when electrically activated this valve opens & pressure
is released.
If the master cylinder in your
brake coupler is made from a composite
material & is not metal then you will need
to provide a ground wire connection
directly to the brass body of the solenoid valve.
Solenoid valves do not operate well
if there is a poor ground or a poor
connection of the 12VDC power to the
valve.
Champion Trailers* cannot control the user's application of the
information contained herein, & is not responsible for the user's
application of that information.
It is the responsibility of the user to determine the applicability of the
information contained herein, as it applies to his trailer or system.
All Technical information & Specifications
Contained herein are the property of
Champion Trailers* & may not be
reproduced with out specific written
permission.
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REVERSING SOLINOID VALVES
REVERSING SOLENOID FAQ
BLOCKING SOLENOID VALVE
12 VDC - IN-LINE - NORMALLY OPEN SOLENOID VALVE.
CLOSES WHEN ACTIVATED
PART# 1507 WT .5# PRICE EA. $49.95
- THE MALE THREAD ON THE BLOCKING SOLENOID IS 1/8" M.P.T (MALE PIPE
THREAD). THIS IS A TAPERED THREAD.
- INSTALL TEFLON TAPE ON MALE PART OF THIS THREAD.
- THE FEMALE THREAD IS 3/16" I.F. (INVERTED FLARE). THIS IS THE THREAD OF
STANDARD AUTOMOTIVE BRAKE LINE TUBING, AS WELL AS CHAMPION TRAILER'S
STAINLESS BRAKE LINE TUBING.
- 3/16" BRAKE LINE TUBING OR MALE BRAKE HOSE THREADS WILL SCREW
DIRECTLY INTO THE FEMALE THREAD OF THE BLOCKING SOLENOID VALVE.
- 3/16" I.F. THREADS SEAL AT THE FLARE JOINT AND DO NOT REQUIRE TEFLON TAPE
AS THREAD SEALANT
- THE SINGLE WIRE COMING FROM THE BLOCKING SOLENOID NORMALLY
CONNECTS VIA A PLUG TO THE TOW VEHICLE'S "WHITE" BACK-UP LIGHTS. WHEN
THE TOW VEHICLE IS PUT INTO REVERSE THE BACK-UP (WHITE) LIGHTS COME ON
AND THE SOLENOID VALVE IS ACTIVATED BLOCKING FLUID PRESSURE FROM
BEING APPLIED TO THE BRAKES.
- BE SURE THAT THE [WHITE] BACK UP LIGHTS DO NOT COME ON IN ANY OTHER
GEAR OTHER THAN REVERSE. IF THEY DO, THE BRAKES WILL BE DISABLED IN
THAT CONDITION.
- BLOCKING SOLENOID VALVES ARE VERY EFFECTIVE AND ARE USED ON MANY
DISC BRAKE APPLICATIONS, HOWEVER IF YOU ATTEMPT TO BACK UP, IN AN
UPHILL CONFIGURATION, IT MAY OCCUR THAT YOU WILL HAVE A PARTIAL
ACTIVATION OF THE SURGE BRAKE COUPLER DUE TO THE COMPRESSIVE
FORCES BEING APPLIED BETWEEN THE TOW VEHICLE AND THE TRAILER, PRIOR
TO BACKING UP. THIS MAY DRASTICALLY IMPEDE YOUR ABILITY TO BACK UP THE
HILL.
IF THIS OCCURS YOU MAY WANT TO CONVERT YOUR REVERSING SOLENOID TO A
BLEED TYPE SOLENOID VALVE. WITH A BLEED TYPE SOLENOID VALVE, WHENEVER
THE SOLENOID IS ACTIVATED, ALL FLUID PRESSURE IN THE SYSTEM IS DUMPED
BACK TO THE RESERVOIR. THIS IS THE PREFERRED SOLENOID VALVE IF BACKING
UPHILL IS ONE OF YOUR TOWING CONSIDERATIONS.
HOWEVER, THE BLEED TYPE SOLENOID [PART # 1504] REQUIRES THAT A RETURN
LINE BE INSTALLED BACK TO THE BRAKE COUPLER MASTER CYLINDER
RESERVOIR.
WHEN USING A BLEED TYPE SOLENOID VALVE, IF THE MASTER CYLINDER IS NOT
EQUIPPED WITH A RETURN PORT MACHINED INTO IT, IT WILL BE NECESSARY TO
DRILL AND TAP A 1/8" NPT RETURN PORT HOLE IN THE LOWER HALF OF THE
MASTER CYLINDER RESERVOIR.
BE SURE TO KEEP METAL SHAVINGS OUT OF THE MASTER CYLINDER UPON
COMPLETION OF THE MACHINING OPERATION.
BLEED SOLENOID VALVE KIT
PART # 1504 WT 1# PRICE EA. $54.95
PRINTABLE SOLENOID INSTALLATION DRAWING
PART # 1504 - REVERSING SOLENOID VALVE OPERATION:
PART # 1504 IS A 3 PORT (BLEED UPON ACTIVATION) SOLENOID VALVE. IT HAS A 1/8" NPT
(NATIONAL PIPE THREAD) FOR THE (IN) PORT WHICH HAS A STAINLESS SCREEN
INTERNAL TO THAT PORT. THIS IS THE PORT THAT IS CONNECTED TO THE HYDRAULIC
OUTPUT PORT FROM THE MASTER CYLINDER OF THE BRAKE COUPLER.
DIRECTLY OPPOSITE FROM THE (IN) PORT ON THE SOLENOID VALVE, IS THE PORT THAT
IS CONNECTED TO THE BRAKE LINE TUBING GOING TO THE TRAILER BRAKES.
THIS PORT HAS 3/16" (I.F. - INVERTED FLARE) THREADS, WHICH IS THE THREAD FOR
THE STANDARD BRAKE LINE TUBING, AND BRAKE HOSES. DO NOT INSTALL TEFLON
TAPE ON THREADS FOR 3/16" I.F. FITTINGS!THEY ARE SELF SEALING.
THE THIRD PORT HAS 1/8" NPT THREADS AND HAS A 90° BRASS BARB FITTING
INSTALLED. THIS FITTING IS WHERE THE RETURN LINE RUBBER HOSE IS CONNECTED
FOR ROUTING BACK TO THE MASTER CYLINDER RESERVOIR.
IF YOUR MASTER CYLINDER DOES NOT HAVE A RETURN PORT MACHINED INTO THE
MASTER CYLINDER RESERVOIR, YOU WILL NED TO DRILL AND TAP A 1/8" MPT HOLE
INTO THE LOWER HALF THE REAR OF THE RESERVOIR. BE CAREFUL NOT TO GET
METAL SHAVING IN THE MASTER CYLINDER DURING THE MACHINING PROCESS.
THE (IN) PORT OF THE SOLENOID IS COMMON TO THE PORT WITH THE 3/16" I.F.
THREADS, GOING TO THE TRAILER BRAKES. WHEN THE SOLENOID IS NOT
ELECTRICALLY ACTIVATED BRAKE FLUID FLOWS IN AND OUT THRU THESE PORTS,
DIRECTLY TO THE TRAILER BRAKES. WHEN THE SOLENOID IS NOT ELECRICALLY
ACTIVATED, THE RETURN PORT (GOING BACK TO THE MASTER CYLINDER RESERVOIR)
IS CLOSED (NOT OPEN TO THE BREAKE SYSTEM.
WHEN THE SOLENOID VALVE IS ELECTRICALLY ACTIVATED, THE RETURN PORT OPENS,
(BECOMES COMMON TO THE BRAKE SYSTEM PRESSURE). THIS ALLOWS ANY AND ALL
BRAKE SYSTEM PRESSURE TO BE RELEASED BACK TO THE MASTER CYLINDER
RESERVOIR VIA THE RETURN LINE HOSE.
ELECTRICAL ACTIVATION OF THE SOLENOID IS TYPICALLY ACCOMPLISHED BY
CONNECTING THE VALVE ELECTRICAL WIRE VIA A PLUG INTO THE TOW VEHICLE
BACK-UP LIGHTS. WHEN THE TOW VEHICLE IS PUT INTO REVERSE, THE SOLENOID IS
ACTIVATED AND THE TRAILER BRAKES ARE DISABLED.
BE SURE THAT THE BACK-UP LIGHTS DO NOT COME ON IN ANY GEAR OTHER THAN
REVERSE. IF THE BACK-UP LIGHTS COME ON IN ANY OTHER DRIVING CONDITION THE
BRAKES WILL BE DISABLED DURING THAT CONDITION.
THE BLEED SOLENOID IS THE PREFERRED BRAKE LOCK OUT SOLENOID VALVE IF YOU
ARE FINDING IT NECESSARY TO DO BACKING UP OPERATIONS IN AN UPHILL MODE.
IF YOU TOW ONLY IN FLAT LAND DRIVING AND BACKING-UP CONDITIONS THE
BLOCKING SOLENOID [PART # 1507] MAY FULFILL YOUR BRAKE LOCKOUT NEEDS. WITH
THE BLOCKING SOLENOID (PART #1507) IT IS NOT NECESSARY TO HAVE A RETURN LINE
BACK TO THE MASTER CYLINDER RESERVOIR, HOWEVER IF BACKING UPHILL THE
BLOCKING SOLENOID MAY CAUSE DIFFICULTY.