1948 Standard 8 Overdrive Issue.

Discussions related to engines, transmissions, rear axles, suspension & steering.
studeranch
Posts: 13
Joined: Thu Jul 19, 2012 7:49 pm

Re: 1948 Standard 8 Overdrive Issue.

Post by studeranch » Thu Nov 28, 2019 12:04 pm

I thought of a little more. All of the electrical connections are run with some sort of points, usually on a leaf spring of some sort. for instance the governor will contact when some sort of centrifugal pin or lever is engaged which contacts a couple of points. the Relay on the firewall has points that contact when the small coils are enerjised, and in the solenoid to reduce current when engaged,, and there is a switch on the throttle to break current under acceleration. Every one of these points is subject to corrosion, as are the connections for the little leaf springs, usually a rivet. With points files and a test light, usually the current path can be diagnosed.
And don't forget to check the oil level on the transmission and the overdrive, as there are 2 fill plugs, and both require oil . It may save a trans or overdrive overhaul.

Howard56
Posts: 1162
Joined: Mon Dec 24, 2012 11:35 am

Re: 1948 Standard 8 Overdrive Issue.

Post by Howard56 » Fri Dec 20, 2019 7:12 am

R9 lockout lever is on the passenger side and there is a large black relay on the firewall which will have 6 terminals. For an R11 the lockout lever and cable is on the drivers side and the relay on firewall has 4 terminals with a fuse mounted on the side.

On the R9 when the car reaches the speed where OD can engage there is a light on the dash that will illuminate to indicate the OD is electrically active and awaiting your action. As soon as the light comes on releasing the accelerator briefly should allow the solenoid to fully engage OD. As soon as the solenoid has fully moved the mechanical parts into position the light will go out and you should be in OD. Is the light coming on and going off as described? If so, there should be an immediate drop in engine RPMs when OD engages fully. If the light is working as described but no OD there is probably a mechanical issue in the OD. If you do not see the light at all, it could be the light bulb is burned out or any of several issues could be interrupting power so the electrical portion is not activating. Finding out what is or is not happening will take some troubleshooting.

The R11 has no indicator light so it is a matter of familiarity with the speed the OD is supposed to engage to know when to release the accelerator. After doing the accelerator bit the rest of the OD engagement is similar to the R9. Electrically the OD is much simpler than the R9 but there are still a couple of places where power interruption could be an issue.

Howard56
Posts: 1162
Joined: Mon Dec 24, 2012 11:35 am

Re: 1948 Standard 8 Overdrive Issue.

Post by Howard56 » Sun Dec 29, 2019 11:27 am

You can test the actuating relay out of the car by applying power from one side of a battery to terminal 1 and the other side to 5 but usually it is just as easy and somewhat more convenient to see all functionality by leaving it connected in the car. The ground out relay coil is in series with the hold coil in the solenoid so I would not try to test that relay without some kind of added resistance to simulate the second coil that would normally be in the circuit. As to the price, not surprised. All R9 electrical components are starting to be hard to come by so take care not to damage yours and need to pay that amount for a relay or similar amounts for something else.

I would remove the relay cover and see exactly what is happening. When the cover is off I would also suggest you disconnect power and then take a burnisher or point file to the contacts to get rid of oxidation that could have formed after a long sit. Try not to use ordinary sand paper or anything with a grit because the grit can come off the paper and embed in the contacts causing other issues down the road.

If you have power to relay terminal 1 then by grounding terminal 5 with the car standing still you should see some action inside the box. The solenoid or wiring between the relay and solenoid could have issues and solenoid or ground out relay not respond but there should at least be one if not both relays trying to energize. Grounding 5 will immediately bring in the left or actuating relay (sitting between terminals 1 and 4 in photo on first page of this post) and power should also be applied to the other relay. If the wiring is good to the solenoid then by virtue of the second relay coil being in series and thus connected to ground thru the hold coil on the solenoid it should also come in -- even though the solenoid still might not move. The indicator light is also connected to ground thru the solenoid and if power is being delivered to terminal 4 when the relay closes and the bulb is good, it should also light when the relay comes in.

The reverse safety switch is also used for the back up light. The backup light was an option so if not present on the car the overdrive function of the switch will have only those wires connected. The OD wires should be on the two terminals close to the plunger. The plunger should normally be out allowing power to pass thru except when the gearshift has selected reverse and pushed in the plunger. With the plunger in, power to OD side is cut and the two rear terminals connect and would light the backup light if one were connected.

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