How strong should a GM reversing solenoid be?

[Casper4104]

How strong should a GM reversing solenoid be?

I had the Horizon Coach guys fix some problems on my 4104 before I picked it up in March. One of the things they did was install a shiny new reversing solenoid.

I brought the bus home and have run it very little since.  The reversing solenoid has been used maybe 20 times.  Now it won't work.

The solenoid actuates, but doesn't pull hard enough to engage the gear.  With the switch thrown, I can easily overpower the solenoid and pull it back out with 2 fingers.

I had my partner hold the switch for a second and checked for 12 volts to the solenoid, and that seems Ok (12.7VDC at the solenoid lead).  So then I thought that maybe I wasn't getting the amperage that I need, so I straightlined the solenoid to the starter lug for a second and got the same result.

I called the bus dealer and talked with the wrench there (he and I really hit it off), and he told me to do the 2 little tests I just described.  I'll call him tomorrow and tell him I think it failed the tests.  He's in contact with his parts vendor about a replacement, so maybe I'll get good news tomorrow.

How strong should that rascal be?  I can pull harder with my, ummmm, nose.  That thing's the size of a soup can - it sure seems like it should be stronger than that.

Any input? Tips? Tricks?

Thanks in advance,

Casper4104

[DrivingMissLazy]

Make sure you have a good solid ground connection. Maybe a hardwire back to the battery negative post?
Richard

[Len Silva]

I don't have the book in front of me but, it seems that I recall something about the solenoid having two coils, the first one pulls it a little bit and a set of contacts inside the solenoid closes and operates the main coil. It's purpose was to limit the arc at the switch. It could that that part isn't working properly.  Those old solenoids could be dissasembled and repaired. That's from memory and from my 1955 4104 manual, may not be current information.
Len Silva

[Len Silva]

I went and dug up Da Book and I was almost right.
The solenoid does have two coils, one called the pulling coil and the second called the holding coil.  I think these are wound together, so you would not actually see two coils but two circuits.

When the solenoid is operated, both coils are in operation. When it hits the end of it's travel, a set of contacts disconnects the pulling coil. If this contact is open, then only the holding coil would be in operation when you apply power to the solenoid.

I think you can pull the back off it and check these contacts.  Probably a simple fix.

Len Silva

[Casper4104]

Good news.  I talked with the mech and described my symptoms and test results, and he agrees that my brand new solenoid is probably fried.  He's getting in contact with his parts vendor about a replacement.

We'll see how it goes.  Elec parts are usually warranted until you get them out of the box.

Thanks for the tips,

Casper4104

[Casper4104]

Good news  the shop is going to replace my bad solenoid under warranty.

Thanks for all the help with this.

Casper

[FloridaCliff]

Casper,

Thanks for the update.

As you know, so many times we never hear the end of the story.

Cliff