Wanted - 47-50KF Overdrive Relay

[joefrazer]

Hey gang...I'm looking for an Autolite O/D relay for my 50K. I know new/rebuilts are available for $125 but I just can't bring myself to pay that kind of money for one. So...does anyone have a known good used one available? The one in my car worked for years and then gave me fits just before the national. I got it working but it quit again a few weeks ago. I've replaced everything else...including the harness so it's gotta be the relay according to the service bulletins and shop manual. Might swap for something you need...if I have it. Thanks!!

[ben-tex]

What is the AutoLite number on yours? Does if have the upright fuse holder?

[Fid]

That one would've been an Autolite HRT 4001. It's black with a vertical fuse and the wires are held on with bolts. That was the one used on all 1947-50 KF products and that would mean it was also used on the '51 Frazer. In 1951, they went with a Delco-Remy unit which was a silver box with an es*** plug on it and horizontal fuse.
I recently sold an NOS one on ebay and I think I only got about $60 for it.  The Autolite box said it also fits: 1952 - 1955 DeSoto, Dodge, Plymouth, 1946 - 1950 Willys, 1947 - 1951 Frazer, 1947 Nash, 1949 - 1950 Kaiser. 
So you may want to search vendors who sell parts for those cars too.

[ben-tex]

Well I asked because I have several with slightly different numbers. What would be the difference as they all look the same. I bought a bucket of them years ago at the big Pate swap meet and they were claimed to be NOS but not in boxes. No idea whether they work or not.

When I got my 51 K it had this type relay on it and the vertical fuse arrrangement was troublesome. I don't know if it was original to the car or not. Other 51s I have seen had the type with the plug-in on the bottom and that is what is on the car now.

[Fid]

One quick test is to touch a 9 volt radio battery across the rear two solder joints on the rear terminals like this -

The relay should click (make sure the surfaces are free of tarnish where the battery touches). If it does, the coil is good but just because it clicks doesn't mean it is good. The way to tell for sure is to connect an ohm meter or other continuity test across the front two terminals, then put the battery across the rear ones (polarity doesn't matter) and when it clicks, it should read zero or very close to it for continuity between the other two.  One thing that causes problems is the bottom surface where the fuse touches the "tongue" can be tarnished and not making contact. This is critical as it requires about 17 amps to pull the solenoid in and any resistance can prevent that from happening.  If it clicks, then clean that surface under the fuse, also the twist holder that holds the fuse in is made of brass and tarnishs. That holder provides the current path from the relay contacts to one side of the fuse. If it is tarnished, same issue, current flow can be insufficient. Clean the tarnish off the holder and clean the tarnish from inside the round fuse holder. See if that helps and let us know.

[joefrazer]

Hello all...the relay does click, that much I know. I also know that the wiring is good...it's a new harness...and that the solenoid and governor are good. What I'm not getting is the 6V at the blue wire to trigger the solenoid. Either there's a solder joint gone bad or tarnished contacts as Fid mentioned.
I wasn't aware of the trick to test the unit w/a 9V battery so tomorrow afternoon, I'll pull the unit off the firewall and test it. Stay tuned!

[Fid]

If the solenoid and governor are good, look to see if the kickdown switch is stuck in. I had that happen to me once - a tiny drop of oil fixed it. Pretty easy to check on those early cars if I remember right the kickdown switch is mounted on the firewall. If the shaft on the switch gets gummed up, it could stick in  and that would certainly produce the symptom you're having. As I said, it happened to me once.
***Also note, don't hold the 9 volt battery on any longer than it takes to click it. Even though the relay is 6 volt, what really matters is the current, the amps. A 9 volt will push more current through the coil but as long as it is not  held on for prolonged periods of time, it shouldn't hurt it but a quick click is all you need.

[joefrazer]

Good news all! The Traveler OD has been fixed. I tested the unit as per Fid's advice and found that the fuse holder was only making intermittent contact. A good cleaning and tightening of the holder and it works. I also fixed another unit that I thought was NFG. Thanks Fid, I owe you one!!

[mbflemingkf]

That Fid...just how DOES he do it.  We all know he's too young to have all this KF knowledge!!!   LOL!!!

[Weaz]

You do know he was born and raised inside a Henry J, right?



He cried every time they tried to take him out, so they just left him in there until he was 8.

[Fid]

Better get used to that seatback kid!