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Ask Dave: One truck camper jack is weaker and slower than others

Dear Dave,
I am having trouble with my electric leveling jacks on my truck camper. They are working, but one of them seems to be getting weaker. Three of the four jacks are the same, but one jack (the weak, slow jack) has a different model number from the other three jacks. The weak jack is located on the driver’s rear side of the camper. I suspect that the previous owner damaged the original jack and had it replaced as there was also some damage to the back wall of the camper. I have removed the weak jack, lubricated the bearings, and checked all connections. Voltages delivered to the jack are within specs and the other jacks seem to be working well.

Here is the info on the jacks:

TRUCK CAMPER JACKS
Atwood MPD87199 (entire jack)
Motor#: MPD71119
PC-44F-1001
E186696 I/P
200w AOM
serial# 031411
(Made by Chiaphua)
Gear Box#: 0408
The weak jack: Atwood MPD86065 (entire jack)
Motor#: MPD71119 (same as other 3 jacks)
Gear Box#: 75722
(7/30/2012)

Any suggestions? —Arn, 2004 Palomino 8801 truck camper (made by Vanguard)

Dear Arn,
Thanks for all the specifics on the jacks and model numbers. Many small trailer and truck camper manufacturers used the Atwood electric jacks, and it was common for truck campers to “bottom out” the back end and damage the jacks. So I believe you are correct about the model numbers being different.

According to the Atwood Owner’s Manual, you should perform the following maintenance on the jacks:

1. Before each use, inspect jack tubes and replace if bent or damaged.

2. If wiring is connected to the battery terminal, inspect at least twice each year for corrosion. Clean with a solution of baking soda and water, then apply a thin coat of grease. NOTE: The motor ground screw and mounting bolts must be cleaned, too, if a ground continuity problem occurs.

3. Once each year, extend the jack as far as possible and clean the inner ram tube. Coat tube with a light coat of silicone spray lubricant.

Other things to try for weak and slow truck camper jacks

The Lance technician recommended using white lithium grease and not a “light” coat, then retracting the jack and wiping off any excess grease.

I would recommend extending the jack and checking to make sure it is not bent slightly. It doesn’t take much with an electric motor to cause resistance and slow it down. If it’s bent, this could be why one of your truck camper jacks runs slower and weaker. To test, use a straight edge such as a metal yardstick or run a string line down the shaft around all sides.

I cannot find the same model numbers referenced. However, the 3K and 4K service manual states the motor operates from 8 amps to 45 amps. You stated the voltage to each was the same. However, if you can test the amp draw you might find the weak jack is drawing a higher amperage. This would indicate either resistance or a weak motor.

When you extend and retract the jacks, is the truck camper plugged into shoreline power? If not, try plugging the camper in so the converter is supplying max power, or use a battery charger. I know I go to this procedure quite a bit. However, batteries are “gremlins” when it comes to many issues.

Check the weight, too

One other thing to check would be the weight on that corner of the rig. You might want to get a scale and check the individual positions of the jacks to see if that corner is heavier. It’s easy to get more weight on one side or position with LP tanks, water, and storage compartments. However, if the jack is slow when the pad is off the ground, the weight would not matter and it must be the motor.

Let me know what you find out.

Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.

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Bob Palin
4 months ago

The solution seems obvious, replace the jack with the right model!

Matt
4 months ago

Did you not notice that the gearboxes are different. They probably don’t have the same ratio.