1985F20 SuperCab "REDRUM"

[CRittaler]

I know it's been a long time since I last posted.

The cable ended up snapping right at the transfercase so I replaced the lower cable.

It's still bouncing like crazy so I have an upper cable on order.

I didn't drive it much between my last post and now, so I had to do some mold remediation from it sitting.  Now I run an AC dehumidifier in the truck when it sits so that I can hopefully pull out all the excess moisture.

All in all the truck is running well.

[CRittaler]

I replaced the upper cable as well, speedometer is still bouncing.  I need to crawl under the truck and try to drive the cable with a drill or something.  I'll check the gears when I do as well.  From what I can remember the gear on the cable is pink or a very faded red.  I have no idea what the gear in the transfercase is, I still need to try and look.

I also had the start, run for a bit then die problem resurface.

I ended up jumpering the oil pressure switch and the problem seems to have gone away, but I've only started it twice since doing that.  I haven't been able to find a direct replacement switch so I'm likely going to install a universal one.

[ArdWrknTrk]

I think Bill has said that one from a Chrysler K car is functionally identical. (Omni/Horizon, Reliant, etc..)

[Gary Lewis]

Right, Jim.  I ordered this Standard Motor Products PS-64 Oil Pressure Switch from Amazon and it worked fine.

On the speedo, I put a new cable in and still had bouncing.  I lubed the new cable with varying things, to no avail.  I finally lubed it with Mobil 1 synthetic wheel bearing grease, the red stuff, and it took most of the bounce out.  That was probably 10K miles ago and it is still working fine, cold or hot.

[mat in tn]

try to be certain of the routing and avoid unnecessarily tight bends. also be sure the connector at the gauge itself is clicked on well and as straight as possible. any kink at all will cause speedo bounce. you might also want to grease the brass bearing of the gauge itself. these are not greased and are often very loose feeling when unhooked yet get a drag when connected. if the cable pulls to the side at all causing the cable (a four-foot spring) to "catch and release".

[CRittaler]

It's been a while.

My speedometer still bounces somewhat, I used some bearing grease on the connections at the cruise control.  I still have to pull the cluster to lube the back of the speedometer.

I think I have finally solved my start-run for a minute and stall issue.  The oil pressure switch had failed so I replaced it with an aftermarket one.  I still had the problem on occasion, turns out the fuel pump relay socket was severely corroded so I've replace both the fuel pump relay and the tank selector relay with a couple of water proof bosch style relays.  I also have the new oil pressure switch bypassed currently while I was debugging.

I like it this way better so I may leave it.  I turn the key on and make sure that I can hear the pump before I try to start the truck.  I may leave the oil pressure switch disconnected and run the wires to a toggle in the cab, use it as a fuel shutoff/anti-theft.

[ArdWrknTrk]

Those sockets (and the ones for the trailer lighting) are notorious for corrosion on the bottom where you can't see it.

As for bypassing the oil pressure switch.
I don't see how the inertia switch wouldn't pop if you ended up on your roof.
It's intention is to stop feeding a fire but can really be a nuisance as components get old.

I do believe that Bill Vose says a Chrysler switch is almost direct replacement and readily available, but I'm sure you have the sense to turn the key off if the truck is on fire.

[viven44]

I made the mistake of replacing my original speedometer cable on my Bronco. The old one was burnt to a crisp in one area from the old exhaust system (I assume) and it was just an eyesore, but still working well.

Unfortunately, in my experience the aftermarket ones often come too long (both inner cable and overall cable length) and what this causes is unnecessary binding in areas since there are too many curves. I also had to chop the inner cable about 1/4 inch.

If you remove the driven gear from the transfer case/transmission and there is difference in tension with/without retaining clip that means the cable is too long, you may also need to chop off 1/4 inch or so on the driven gear end. This sort of tension can become worse if the inner cable gets hot (more length from heat = more tension).

I still have that occasional "jump", so I pulled out the inner cable entirely on the lower cable (from the cruise control end) and doused it in lithium grease spray. Shall see how that holds up.