Reverse lockout solenoid

[Matt S]

I finally got an adapter and hooked up the blue wire for the backup solenoid on my single axle disc brake EZ Loader. Problem is when I hit that same tree root bump on my driveway it still locks up the brakes. There is voltage at the pin with the vehicle in reverse. I still have to hit that bump with some momentum or I just spin my tires trying to back it in the spot on the driveway. Eventually I still had to spin the disc covering the reservoir that locks out the brakes to get it to back up. Seems like it's not doing anything. Thoughts?

 

[bruceb58]

Re: Reverse lockout solenoid

It is possible that the brakes are already engaged before you put it in reverse. There are lockout valves that have another port thant release the pressure from the line to the brakes into the master cylinder.

Not sure of your situation but if the boat trailer combo is already angled down hill before you put it in reverse, you will have your problem.

One thing you could try is to block the trailer wheels from going forward...put the car in forward gear to relax the brake master cylinder nad then put it in reverse and see how it works.

 

[SuperNova]

Re: Reverse lockout solenoid

You also need to make sure the solenoid is grounded well. Just for a test go out and put your hand on the solenoid and with your tow vehicle hooked up, have someone put it in reverse and feel if the solenoid clicks, if it does it is probably working and if it doesn't, then check it out.
--
Stan

 

[Wide Open]

Re: Reverse lockout solenoid

It is possible that the brakes are already engaged before you put it in reverse. There are lockout valves that have another port thant release the pressure from the line to the brakes into the master cylinder.

Champion Trailers recommended part # 1504 (bleed solenoid valve) when I ordered my brakes. It is supposed to bleed off line pressure when you are backing up in addition to locking out the master cylinder. Page 28 of their catalog if you are interested.

 

[Matt S]

Re: Reverse lockout solenoid

The setup is a fulton swing away with a Buddy brand hitch bolted to the top of it. I can see the back of the MC where the solenoid is threaded into (with Buddy label on it). The solenoid has a rubber hose on the side going back to torwards the reservoir and there's a steel brake line coming out of the back of the solenoid that then goes around the outside and into the full square framing for the brakes.

So by this I gather it should be releasing full pressure. My street is angled slightly uphill, I pull perpendicular to the driveway coming to an easy stop, then swing it slightly down hill and 90* to the left to the side of our garage. The only time I have any problem is hitting the almost speed bump size tree root pushing up the asphalt driveway.

I'll check to see if I feel it click. Otherwise I assume it can't bypass all the pressure regardless.

 

[dingbat]

Re: Reverse lockout solenoid

Not necessarily. The bleed off is pressure coming from the coupler. Any residual pressure in the line between the solenoid and the brake caliper is still there. The extra forced required to get you over the root must just put you over the edge.

Mine did the same thing under similar circumstances and the only thing that resolved the issue was to manually lockout the coupler.

 

[bruceb58]

Re: Reverse lockout solenoid

Not necessarily. The bleed off is pressure coming from the coupler. Any residual pressure in the line between the solenoid and the brake caliper is still there.

That is not true...the bleed off should be between the valve and the brakes.

 

[SuperNova]

Re: Reverse lockout solenoid

No, dingbat has it right. The solenoid isolates the M/cyl and redirects the pressure from it back into the resevoir. If the solenoid has three fittings. The reason for doing this is to prevent damage to the m/cyl piston seals (cups). But any residual pressure in the brake system behind the solenoid will get trapped there when the solenoid activates, I believe.
--
Stan

 

[bruceb58]

Re: Reverse lockout solenoid

This is from the Champion Trailers site:

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.

May be that pressure on both sides gets returned to the master cylinder.

 

[dingbat]

Re: Reverse lockout solenoid

This is from the Champion Trailers site:

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.

May be that pressure on both sides gets returned to the master cylinder.

That?s not possible to dump both ports to vent on a with a 3 way valve. I guess you could switch up and put the trailer side on the input and block the coupler and vent the trailer pressure but then you would be full pressure on the seals of the coupler without any dampening at all and that certainly isn?t good.

I?ve had 3 of them and they all acted the same. If push came to shove which was rare I just got out and used the manual lock-out

 

[bruceb58]

Re: Reverse lockout solenoid

From the description on Champion trailer, the in and out ports between the coupler and the brakes are always "flow thru". The bypass port is the one that is activated/deactivated. Here is the description on the site:

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.

http://www.championtrailers.com/REVERSING_SOLENOID_VALVES.HTM#block

 

[Matt S]

Re: Reverse lockout solenoid

Good info thanks guys. I should clarify:

I can feel the solenoid "click" when reverse is activated on my Ranger, so I know it's working.

The "uphill" quote meant the nose of the truck is uphill, the trailer is definatly *NOT* pushing on the truck when I stop to back into my driveway (my house is on a hill). The hitch is fully extended in forward mode before I begin backing up, and before I place the truck in reverse. I'm sure it's not a problem of residual pressure trapped in there.....

So by the discussions I would guess this is normal behavior. I guess even with the bypass it doesn't "lock out" all pressure to the brakes, just gives the fluid somewhere else to go (back to the MC) but *can* still let fluid flow to the brakes. So the bypass apparently can't handle all the volume when backing up and some of it makes it to the calipers.

The reason this is a pain is because of that root pushing up the driveway. The driveway itself is not uphill, it's flat. Just the street going by my house is uphill - as in I go up hill to overshoot the driveway then back downhill and 90* into the level driveway. When I spin that manual lockout on top of the MC fill reservoir it always self rights when the trailer bumps around back there. So it seems this lockout is useless as, either way, I have to block the trailer tires, pull forward so the hitch is fully extended, turn the lockout again, and try again.