Happijac motors

bigfootgrey wrote:

HMS Beagle wrote:

bigfootgrey wrote:
I also spoke with Bigfoot Industries regarding the clearance issue for the new jack motors and they had to alter the jack mount to the swing out brackets to achieve clearance. This lowered the jack height to the road a few inches. Happijac says the new style motors are 8” above the top of the jack

I have a Bigfoot 10.4, 2008, same as you. I recently replaced the jacks with 4800, and at the time measured the motor clearance thinking I might need new motors. As I recall, I decided they would fit. My old motors still worked so I didn't change them. I'll measure them again but pretty sure you don't have an issue.

I replaced my front jacks with4800’s. The rear jacks are original 4150’s from 2008. If the clearance is ok for the fronts to swing in under the cab over that would be great. Does the control board need to be changed? Mine is original,with the cord.

OK, I just measured it again. I have 8 1/2" from the top of the jack tube to the camper overhang. From the PantherRV website (where I bought the 4800 jacks):

"Will not work with every camper
Requires 8-1/2" of clearance from the top bolt to the top of the motor. Some cab overs don't allow for the clearance necessary to install the motor on the front jacks. Please measure carefully before ordering."

The top bolt is the one fixing the motor to the jack. From that bolt, I have 9 1/8. It is the same both sides. From that description I'd say I have enough. What you posted shows 9 1/8 for that measurement, not 8 1/2". If that description is correct it would just touch. You might be able to drill new holes on the dually bracket, probably need to be 3/4 down to have clearance betwen the two 3/8 hole sets. It might be fine just touching - this is in the folded and unloaded position after all.

The board doesn't really care, it just puts out a reversing current. From the descriptions of everything, the 4800 jacks with the new motors might draw more current at the limit, and might blow fuses in the old board (15A vs 20). The old motors have a ball clutch in them which slips in the event of overload. Apparently the new ones don't, and rely on a current sense scheme in the board to prevent overload. This would not bother me, I'd just be careful at the ends of travel - I am anyway. The 4800 jacks may require a little more current than the 4150 as they are Acme rather than ball screw. But they seem to run just about as fast as the 4150 that I took off. The load rating on the 4800/new motor is quite high, and a 10.4 doesn't push that limit at all.