Faulty J-bolts on Yakima rack? - Kayak Fishing Adventures on Big Water’s Edge

makobob · 10-08-2015, 06:21 PM

Quote:

Originally Posted by spudz

Makobob, back plate under truck bed rail and through bolt through the back plate and rail plate section of tower?

YES, it does put holes in truck but it would be bullet proof.

pbb · 10-09-2015, 06:15 PM

I suspect your piece of aluminum is the culprit, possibly combined with over tightening.

Think about the way they have bent. That suggests that the load is all getting applied to the end of the J and there is torque pushing down and out. Whereas without the aluminum block the load would be at the bottom of the J and not pushing out so much.

Mahigeer · 10-09-2015, 09:47 PM

It looks to me that it is caused by having a load (kayaks) at the end of a lever (the uprights) putting sideways pressure on the J bolt/s.

As the kayaks on the top move from center to left and right on the top (looking at the road from driver's seat), they exert load on the j bolts through the up rights. Which are now a lever. One end the j bolts, the other the kayaks.

I think the only thing to do since the level distance cannot be changed; is either to lighten the load, use a thicker diameter j bolts, or jay bolts made from a stronger material.

Some modification may have to be done to accommodate the thicker diameter j bolts.

Good luck.

jruiz · 10-10-2015, 05:44 AM

If you look at the area circled in the picture, there seems to be a wormhole or rip in the space-time continuum. Or your cross bar is bent.

Mahigeer · 10-10-2015, 06:44 AM

One more suggestion which I am not sure it is mentioned by others.

Drill a new hole in the corner plate and the truck, so instead of "j" bolt you can use a "u" bolt and fender washer.

That way the pressure is not at the short section of the "j" bolt, but up to the washer and nut.

A stainless steel "U" bolt and washer will keep from rusting and prolong the life of the fasteners.

10-09-2015, 06:15 PM	#2
pbb Senior Member Join Date: Jul 2013 Location: San Diego Posts: 149	I suspect your piece of aluminum is the culprit, possibly combined with over tightening. Think about the way they have bent. That suggests that the load is all getting applied to the end of the J and there is torque pushing down and out. Whereas without the aluminum block the load would be at the bottom of the J and not pushing out so much. __________________ 2008 Olive Hobie Revolution 13

10-09-2015, 09:47 PM	#3
Mahigeer Senior Member Join Date: Apr 2013 Location: Los Angeles Posts: 1,910	It looks to me that it is caused by having a load (kayaks) at the end of a lever (the uprights) putting sideways pressure on the J bolt/s. As the kayaks on the top move from center to left and right on the top (looking at the road from driver's seat), they exert load on the j bolts through the up rights. Which are now a lever. One end the j bolts, the other the kayaks. I think the only thing to do since the level distance cannot be changed; is either to lighten the load, use a thicker diameter j bolts, or jay bolts made from a stronger material. Some modification may have to be done to accommodate the thicker diameter j bolts. Good luck. Last edited by Mahigeer; 10-10-2015 at 06:38 AM.

10-10-2015, 06:44 AM	#5
Mahigeer Senior Member Join Date: Apr 2013 Location: Los Angeles Posts: 1,910	One more suggestion which I am not sure it is mentioned by others. Drill a new hole in the corner plate and the truck, so instead of "j" bolt you can use a "u" bolt and fender washer. That way the pressure is not at the short section of the "j" bolt, but up to the washer and nut. A stainless steel "U" bolt and washer will keep from rusting and prolong the life of the fasteners.