Wiring for Penthouse Add Ons

[boywonder]

Originally Posted by Greyswann

If you do this could you let me know what the tubing size is? I cant get an answer from SMB Fresno and I dont want to pull everything apart to measure I.D. and leave my van out of use till I get support bars sourced Thanks, Monte

My top is an early 2000's Fresno top.....and 3/4" DOM tubing fit snugly inside the crossbars. DOM (drawn over mandrel) tubing is seamless and the OD tolerance is somewhat tight. The OD of the tubing is 1" so the wall thickness is 1/8".


It appears from other posts on the forum here that newer crossbars may have different wall thicknesses resulting in ill-fitting 3/4" DOM tubing. I suspect that some crossbars are .093" wall, but that's completely a guess.

[Justgosurfin]

Here’s a link to the tubing I bought per boywonder’s thread. It’s 3/4 OD and 0.065 wall thickness. 4 pieces at 6’ length.

I did a light wipe of vasoline on the tubes before inserting the into the crossbars. It took a little encouraging with a mallet but they went in fairly easily. Then I just a cut off wheel to shave off the extra length. Tip* put hold the tube along the outside of the crossbar to guesstimate how much tube will go in and mark that with a piece of tape or marker so you know when it is fully in.

I also beveled the end of crossbars and tubing so it hopefully won’t scrape like it must have before as seen in the last photo.

[Greyswann]

thanks Justgosurfin (answer to most of the worlds problems btw) I decided to go your way on the repair and I ordered my .750 tubing for the job which measured at .752".And now I actually have to do the job which appears to be a bit of a closeted gorilla. From your photos it is obvious you had your mechanism completely dismantled outside the van. I would like to avoid that so can I do the job by blocking the corners of the top in full up position and dismantle only the crossbars? I know i have to pull the roof bolts that hold the panels where the crossbars 90 degree bends support the roof. My top includes a Aluminess rack and a single solar panel so there is not an inordinate amount of weight added to the roof. Thanks, Monte

[boywonder]

Greyswann: Where are you located?


Yes......removing the crossbars of a functioning roof is not trivial...that's why I'm always stressing that when people transplant tops that's the time to sleeve.


Did you get DOM Cro Mo tubing?


This is also the time to install shoulder screws in the pivots...you'll be able to assess the wear on the factory screws when you remove the crossbars.

[Greyswann]

I'm in the Ocean Beach area of San Diego. I did get the chrome moly tubing and i was a bit surprised that it is 2 thousandths over sized but i guess that is probably within manufacturing tolerances. I have no allusions about the challenging aspects of the repair and the shoulder bolts are a good idea. I do have some worries about drilling the tubes out for the shoulder bolts. it seems it could weaken the tubes at a fulcrum point. And if you or anyone has has a tip or two for this I would love to see them

[Greyswann]

BoyWonder: Started the work today and am pleased with the progress. Dismantled most of the mechanism and got both of the tubes out of the van. I countered the tension from the springs safely but underestimated the tension from the weight of the top (it only hurt for a while). Before I begin the challenges of strengthening the tubes and reassembling the mechanism I have two questions.
1) I was amazed when i pulled the tubes upper mount to find there was no attempt to set the tubes in some sort of bearing design..not even an open U-mount. Only blocks of stacked plywood lathered in axle grease. I understand the tubes only rotate a few degrees (15?) but it seemed that during the jerky operation of the top the chattering sound came from that area.
2)somewhere in a similar topic someone sais they were told by the Midwest SMB that the jerky top movement was from the motors not being synced and it would correct itself with a certain number of complete raises and drops. Do you understand how this might work?

[Greyswann]

forgot the question on that first one..Is it worth trying to rig a better system for the bars to rotate in?

[Lopiore]

Looks really great, congratulations! I can see that it takes a lot of efforts and time to organize it the way it is. Would love to have one of this next to my Athens house and drive around the country with it. It's been my dream for a while actually

[Lopiore]

Originally Posted by Lopiore

Looks really great, congratulations! I can see that it takes a lot of efforts and time to organize it the way it is. Would love to have one of this next to my Athens house and drive around the country with it. It's been my dream for a while actually

Do you recommend any brand?

[boywonder]

Originally Posted by Greyswann

1) I was amazed when i pulled the tubes upper mount to find there was no attempt to set the tubes in some sort of bearing design..not even an open U-mount. Only blocks of stacked plywood lathered in axle grease. I understand the tubes only rotate a few degrees (15?) but it seemed that during the jerky operation of the top the chattering sound came from that area.


2)somewhere in a similar topic someone sais they were told by the Midwest SMB that the jerky top movement was from the motors not being synced and it would correct itself with a certain number of complete raises and drops. Do you understand how this might work?

Plywood lathered in axle grease????? That's a new one..haven't seen that on any tops.....


Remember that the front tube rotates and the rear tube slides and rotates. I've been contemplating using a sheet of ULMW PE (ultra low molecular weight Polyethylene.....the white slippery plastic cutting boards are made from) on the sliding tube to reduce friction on top of or in place of the plywood. At this point my manual top raises and lowers quite easily so I'm working on higher priority projects like moving my front axle forward.


If you have a power SMB top, they use Linak actuators. When using a pair of Linak actuators they can be used with or without an optional electronic control box (I think this is the case..it's been awhile). The control box is required for higher loads and/or dynamic loading (again don't remember details) but with lighter loads it's not required, and SMB just uses the actuators. I assume the control box gets position feedback from the actuator to keep them synched. I called Linak and talked to one of the engineers there a few years ago when I determining the scope of converting a top to power.