I have a big foot 3000 2001 with happi jacks 4500 front and 4100 rear and they act up and are expensive and not serviceable.
This year i extended them fully (removed the jacks) drilled a 1/4 hole at the red line and added about 1/4 cup of 5w30 oil and rotated the jack to get the oil sumehow to the center operating screw as i feel these jack sit in one position and then rust up and drag there .
This seems to help, also change the amount they extend each year so they are never in the same spot for storage.Mine all drag about the 11 in mark ,so i stay higher,so lub them and exercise them manually crank them in and out ,,maybe they will last.

I have the same jacks on a Arctic Fox. They have the same problem and Happijack says it is normal. Their solution is to remove the motor and spray white lithium grease on the gears.

I will have to give it a try. The lithium grease from the top didn't fix the noise. I need a new sticker for mine that says
"CrappiJacks"

Hemi,
I tried your method and the hole in mine must not go through. It won't take any oil. I have tried 5w20 and wd40 and they both just sit there. Even after a couple of hours.

I suspect that the weak point of the happijack is the thrust bearing which is located just below the support plate. There is a horizonatl weldment on opposing sides of the jack just below the manual crank hub. I drilled a hole carefully 3/8" below this weldment. I used a winter grade chainsaw oil for lubrication. Then I removed the electric motor and used a drill to drive the jack up and down via the manual socket. Things got loosened up pretty fast. I used short machine screw to plug the holes after lubing. I made sure the screws were short enough that they didn't extend into the cavity. If I was going to do it again I would drill the holes near the corners of the jack rather than in the center.
I took apart one of the 4100 jacks before and replaced the the RUSTY thrust (I believe called Torrington) bearings. This bearing looks like a washer that has approximately 1/16" diameter radially embedded rollers in it. Half of these rollers were rusty and seized. This bearing is sandwiched between two very thin (less than .015" !!) washers (probably hard steel). Since I couldn't see these tiny bearings last I bought two 4500s and returned the 4100 to the manufacturer. We've had the camper for 6 years now and had the same problem with 4500s last summer as well. I suspect it has the same da..ed thrust bearings. I'm beginning to wonder if a lubricant impregnated brass washer would work better. Drilling a hole one runs the chance that some of the filings may get inside. May be one day when I feel adventureous I'll to take the 4500s apart.
Larry.

I guess I am lucky, the camper always stays on the truck except when taking truck in for servicing.
so I removed the camper jacks completely, if I think we may need them I put them in the camper basement. these jacks are 8 years old and look almost new.
when I park the truck/camper for any length of time I pump up the airsprings to 100 psi. this unloads the truck springs.

Larry,
Any chance you have some pics of your mod? I'm pretty sure I get it but a picture would be great.

Went to a camper show in Richmond, VA this weekend and noticed all of the new Lance campers had Attwood jacks. Didn't Lance use Happi jacks before?

quote:

Originally posted by stankern:
I have a big foot 3000 2001 with happi jacks 4500 front and 4100 rear and they act up and are expensive and not serviceable.
This year i extended them fully (removed the jacks) drilled a 1/4 hole at the red line and added about 1/4 cup of 5w30 oil and rotated the jack to get the oil sumehow to the center operating screw as i feel these jack sit in one position and then rust up and drag there .
This seems to help, also change the amount they extend each year so they are never in the same spot for storage.Mine all drag about the 11 in mark ,so i stay higher,so lub them and exercise them manually crank them in and out ,,maybe they will last.

Stan,
I did the same you did, but drilled a hole in the bottom of the foot. I used a drill operated pump to fill the inner leg of the jack, exercised the the jack a few times and then drained all the oil till it stopped dripping. I guess time will tell how long this remedy will work.
I wonder if a stainless steel screw jack would finally put an end to this problem? Or go back to hydraulic operated jacks that never had any problems? Anyone heard of a electrically operated hydraulic jacks? I suppose the drive head may add to the weight. Would need the hydraulic fluid reservoir, electric motor, pump, and hydraulic cylinder. Seem kind of complicated and weighty?

Based on my experience with Happijac, they have been very helpful with all of my questions. I asked regarding the maintenance of their jacks and they explained exactly what to do to loosen up the mechanism. They said that running the jack up and down at least once every 6 months will keep the jack in very good working order. They also said the more work that is requred the more wear and tear occurs on any mechanical device. That says to me that if my camper is very heavy then the jack required more maintenance. Happijac is an excellent company and is very good to work with.
Drilling holes in the tubing and adding grease or oil is very bad idea and absolutely NOT recommended. If oiling the crank hole mechanism does not help and removing the motor or top cap and adding marine grease to the top end does not help, then Happijac recommends contacting them and working through the details and maybe sending it to them for repairs. They said they don't charge very much for an over-haul. In my estimation, Happijac makes very high quality products and spares no expense in providing the very best for the money.