Help with Scissor Bolts

[boywonder]

Spring adjustment details.....and you'll need these details for bolt repair.


PLEASE NOTE THAT IF YOU DO NOT FEEL COMFORTABLE, DO NOT ATTEMPT THIS PROJECT.....AND PLEASE UNDERSTAND THAT YOU ARE DOING THIS AT YOUR OWN RISK.....this is just the way I've done these repairs in the past.


It's important to fully understand where the loads are at all times when supporting the roof. Sometimes the springs are supporting the roof, sometimes springs + come-along and sometimes the 2x4's.


If you are just adjusting the springs you can remove the helper springs and cover plates and cut a 2x4 to length and lay in the channel to support the roof. When you relieve tension on the crossbars/extension springs the crossbars will push against the end of the 2x4 and the roof should be supported robustly.

Since you are replacing pivot bolts you'll need each corner supported. You will need the crossbars unloaded to be able to move them for hole alignment, so the 2x4 in the channel doesn't work for pivot bolt replacement.

..and obviously just do one side at a time for safety

There is a large hole/circular cutout along the inside edge of the channel for one end of the come-along to attach to; you'll have to carefully pull back the upholstery at the hole to get to it. It's on the inboard side of the channel away from the extension spring.

You need to hook one end of the come-along into this hole and connect the other end to the end of the extension spring. I use a motorcycle tie down (just for the hooks on each end) to get into the hole in the channel and the loop in the end of the spring. The hooks on the come-along are big/bulky. I hook the tie down hooks to the spring end and the hole, then connect the come-along hooks to the loops in the tie down hooks.

Crank the come-along until the S-hook connecting the spring to the chain has some slack, then remove S-hook and carefully relieve come-along tension. Now that side of the roof is supported 100% by the corner 2x4's.

At this point the crossbars should have some movement to get holes aligned.


If you are just adjusting springs crank the come-along until you can get the S hook in the second link. Then zip-tie the end link back to the second link so it won't rattle, then carefully relieve the come-along tension. If the roof is still harder to push up than to pull down you can shorten by another link. At some point the roof won't come down very easy and/or you may be bending the crossbars, especially if you have solar panels/other weight on the roof.

[DFarkas]

Well...great news!!! The Cross Bolts are in Having not done this before, and reading everyone's advice (especially BoyWonder), I figured it out. I'm including a few pics from it.
I supported the corners with hydraulic car jacks (I happened to have a few) and blocks of wood with rags to protect the ceiling.
Used a come-along clipped into one of the holes in the metal guides and also clipped into the end of the spring's circular metal loop supported by a cam strap (in blue in the pics). Added tension to the spring thus being able to unclip the metal chain.
I took out the bolt assembly that allows the cross member to slide in it's guide freeing up that cross member's arm.
With this free, I was able to pull the cross members together and thread the new shoulder bolt (McMaster Carr) through. I also added a nylon curved spacer (McMaster Carr) into the assembly as well.
Reassemble the cross member into it's location, pull even more tension on the spring to allow the chain to clip back in around the hook, then release tension to allow the system to adjust.
Remove the cam strap and voila...things are back to normal.
Tested the top a few time to make sure all is good.

Thanks again everyone for your advice.

Cheers

[Twoxentrix]

Always rewarding when a plan comes together!

[boywonder]

Nice! Did you adjust any springs while you were in there??

[DFarkas]

BoyWonder, I did not. My roof seems to go up and down pretty much the way I want. When I pop it, I don't have anything up there. I only carry my whitewater kayaks up there and always take them off when the roof goes up. The springs as they are, seems to handle it well. I'm wondering why the cross member bolts sheared...other than the fact that they were soft and cheap metal?
I know that sometimes I'm not on a level area and that closing the roof puts unneeded/unwanted stress on the top and thus, the cross members. I've had to finagle them into place most definitely. And more than once. I'm getting leveling blocks to stop doing this.

I have another question out there...Looking at the setup, I'm thinking it might be prudent to get some type of support system in place for each corner once the top is popped. A "jack stand" or extendable leg of the sort to put in place once the top it up. This way the load of potential snow, wind, whatever could be distributed throughout the corners rather than always on the cross members.

Does anyone have any recommendations for something like this? Is there a product already developed? Or is it fabrication time again?
Cheers

[boywonder]

Originally Posted by DFarkas

I'm wondering why the cross member bolts sheared...other than the fact that they were soft and cheap metal?
I know that sometimes I'm not on a level area and that closing the roof puts unneeded/unwanted stress on the top and thus, the cross members. I've had to finagle them into place most definitely. And more than once. I'm getting leveling blocks to stop doing this.

Popping/closing the roof on un-level ground will have little effect on the pivot bolts.....they see way more load than the weight of the roof.

The pivot bolts fail for a couple of reasons, all stemming from a fairly poor design/implementation.

The biggest issue is that you have threads bearing against the edges of the holes in the cross members. This tends to wear both the holes (many holes end up egged out....best to drill those to 5/16" and use 5/16" shoulder screws) and the screw threads. When applying shear loading to screw threads the root diameter that is used to calculate shear strength is significantly less than the unthreaded shank diameter, so they fail at the root diameter of the thread or right where the threads meet the shank (also the root diameter).

Shoulder screws address both of these issues since the full diameter shoulder bears the load from the cross member holes and there are no threads wearing material away.

A lazy-mans way to do this would be to buy fasteners that have an unthreaded shank of at least 2 1/4" and then cut the threaded portion down to a bit more than the thickness of the locknut. That gets the shank bearing the shear load of the cross members instead of the threads.

But if you are going to spend the time doing this repair, consider shoulder screws, it's a perfect application for them. I'd also use std steel shoulder screws, since their yield strength is higher than stainless shoulder screws. Shoulder screws also come regular variety and precision..you don't need precision.

[Twoxentrix]

Originally Posted by DFarkas

... I'm getting leveling blocks to stop doing this.

I have another question out there...Looking at the setup, I'm thinking it might be prudent to get some type of support system in place for each corner once the top is popped. A "jack stand" or extendable leg of the sort to put in place once the top it up. This way the load of potential snow, wind, whatever could be distributed throughout the corners rather than always on the cross members.

Does anyone have any recommendations for something like this? Is there a product already developed? Or is it fabrication time again?
Cheers

If you have larger tires & a Van on the heavier side, I would consider leveling pads that can handle the load: Something along these lines (12" wide to accommodate wider tires, 14" long, and 2" thick) - You can't break them!:
https://www.amazon.com/Flex-Leveling...productDetails

Supports for the roof - all kinds of options out there from wood or metal dowels to ratchet or cargo supports (probably don't want to mount anything to the roof that would require bolts going through):
https://www.amazon.com/gp/product/B0...JT1MIMZ4&psc=1

[Youngster]

Originally Posted by boywonder

A lazy-mans way to do this would be to buy fasteners that have an unthreaded shank of at least 2 1/4" and then cut the threaded portion down to a bit more than the thickness of the locknut. That gets the shank bearing the shear load of the cross members instead of the threads.

I'm all about lazy. But using jacks in 4 corners and a come-along seems involved, especially if one doesn't have all that on hand.
What about these, 'Adjustable angle Hinge connectors'?
https://makerpipe.com/collections/mo...inge-connector

Use those with an appropriate length of pipe top and bottom to cross clamp the support system in place, keeping the bolt holes lined up, then simply swap out to the shoulder screws mentioned.

Could that work?

[doublevan2]

For DFarkus -- any chance you could supply the McMaster part numbers and specs on the cross member bolts (length/diameter) and neopreen spacers uyou used on your PH pop top fix ? I'm probably going to have to do the same repair. If springs are OK - is it easy to replace the cross member bolts without doing all the shoring up in the corners, etc. ?

I'd be grateful for any assistance ! Thanks !

[simplesez]

Shoring up the corners is 100% necessary.

Come alongs are found cheap at Harbor Freight. I get that city folk don't have them handy but once you have one or two you'll find them useful for projects.