Monday, April 2, 2012

Repairing a jack on the RV.

A week ago we camped at Morro Bay with friends. After I put the jacks down on the trailer I pulled the truck out from under the 5th wheel hitch. The trailer on the passenger side suddenly dropped. Fortunately it only dropped a few inches. It was still enough to cause a heart stopping moment. I immediately put the truck back under the hitch and let the trailer rest on the hitch for the weekend.

We surmised that something inside the jack had broken.

When I got home I dropped the jacks and took the weight off the truck but the passenger jack wasn’t holding anything. In fact I could push the whole jack up several inches. To get the truck out from under the hitch I used a floor jack to take the weight on the passenger side and a heavy duty jack stand with a block on it on the main frame member to hold that side up.

This morning I started the process to remove the jack. This required removing the tubes holding the sewer hoses, removing the frame and door from around one of the compartments next to the jack. Then the compartment itself is collapsed on all sides while pulling it out from the body of the trailer just far enough to clear the jack. When it is out far enough I can stand up behind the box and remove the 2 bolts securing the jack to the frame. The jack can then be lowered out of its brackets.

My jack shaft on top.

Taking the jack a part requires removing a cover, a bearing guide, and driving out a tapered pin from the gear head. When that is done the jack shaft can be removed from the jack itself.

It was very obvious what the problem was as the large hex nut through which the jack shaft rotates was stripped. The nut could be freely slide up and down the shaft. Also, threads from the nut were embedded in the grease on the shaft. Further investigation indicates that at some time I had retracted the jack too far up into the trailer. Somewhere in all the literature I have is a warning about doing that.

Now comes the good part. My neighbor Paul had an old jack in his junk pile saved from another neighbor years ago who had replaced his jacks. It took some grinding, a little welding, and shortly we had a good as new jack shaft. A healthy slaughtering of grease on all the moving parts and some assembly and the jack was ready to be installed.

Before the cross coupler was installed we measured how much of the driver side jack shell was extended and set the passenger side the same length.

While doing the final assembly I noted hydraulic fluid on the tray under the hydraulic unit which pushes the slides in and out. Something else to troubleshoot. I also noticed that the bracket that holds the hydraulic unit up had broken welds on both sides and the whole unit was resting on top of the compartment where my generators are housed. This bracket and the cross member to which it is welded are light duty steel.

The builder used too thin steel for the brackets and the cross member. We had heard of this happening to another camper while we were at Morro Bay. I his case the whole pin box of his fifth wheel broke loose and dropped his trailer onto his truck.

In my case, I don’t want to reweld the brackets as the metal is too thin to hold.  I think the fix will be to fashion metal brackets to bolt to the hydraulic unit and over the cross member.