backup solenoid adjustment?

[Thad]

I have a 23 foot Heritage tandem trailer (2001) with disk surge breaks.
I replaced the solenoid two years ago because I could not back up. That did not work. I replaced the master cylinder last year (found the push rod was broken), I still cannot back up. I get power to the solenoid. The breaks work (obviously) but I am running out of patience. I see there is a set screw on the top of the solenoid. Is this an adjustment? It is almost all of the way down, assuming that is the length of the solenoid itself. The breaks lines have been bled and the calipers adjusted. If I lock out the head, it will back up, but I am wearing out the pin hole. Thanks.

 

[Silvertip]

Re: backup solenoid adjustment?

Driver error sir. When you stop, the brakes are set. You then shift to reverse so the solenoid now seals the brake line but the brakes are still engaged. To prove the theory, stop going up a hill. I think you will now be able to back up because the trailer brakes were not on when you stopped.

 

[drrpm]

Re: backup solenoid adjustment?

Have you checked the reverse brake lockout relay in you vehicle's fuse box? A bad or missing relay can cause that problem.

 

[Silvertip]

Re: backup solenoid adjustment?

If there is such a relay and it it is not there, the solenoid can't energize and therefore the system remains functional. That's not the problem. If there is such a relay and its bad (as in the solenoid remains energized) then the brakes would be locked in forward as well. I feel there is no problem here. The solution to this a bypass that allows hydraulic pressure to be released when the reversing solenoid is engaged.

 

[bruceb58]

Re: backup solenoid adjustment?

Here is a test...drive up a hill...stop...put in reverse and see if you can back down the hill.

There will be no such relay.

 

[nlain]

Re: backup solenoid adjustment?

If you do not have an uphill area to stop on try this, after you stop ease forward until you fell the thump of the trailer tounge sliding forward, trailer wheels move forward just a little, brakes are then released, shift to neutral, roll to stop or use brakes very gently, shift to reverse, should be able to back up then.

 

[Thad]

Re: backup solenoid adjustment?

Thanks for the advie.
I thought I was smarter than that. But I did the hill thing, and I am an idiot
I never imagined something so simple as to be sure that all of the pressure was off the cylinder could cause so much headache.
I feel like a rookie. Thanks again guys.

 

[trooplewis]

Re: backup solenoid adjustment?

Does your trailer wiring coupler have 5 pins or 4? If 5, are you using all 5, like with a 5-to-7 adapter? The 5th connects to the back-up lights and should deactivate your surge brakes., hill or not.

 

[bruceb58]

Re: backup solenoid adjustment?

troop...you need to read the posts.

The backup solenoid doesn't deactivate surge brakes, it is just a valve whose purpose is to close off the brake fluid flow from the mater cylinder to the brakes. If the brakes are already applied, like they are when you stop on a hill, energizing the back up solenoid keeps all that brake pressure applied still. It can't go back through the solenoid back to the master cylinder so the brakes stay applied.