Rhino clamps

[Martin C]

Just purchased a Pair of rhino ladder clamps, used them a couple of times & noticed they come loose, in fact yesterday the rear clamp literally fell off, had to track back & found it in the road.
Now I read some years ago there was a problem with these clamps coming loose, luckily no one was behind me when the rear came loose & fell off.
They lock down tight but within 10 minutes of travel the rear one is loose & the front is also not a sight as it was.
Question is… could this be caused by the roof bars not being level, I had to fabricate some brackets to raise the front & rear rhino bars, as the van has a roof vent & ladders didn’t clear the vent height. So the front of the ladders are sitting higher than the back. Could this be the reason the clamps are coming loose?

 

[Cleanco]

Probs a faulty set. Someone kindly posted on here last week on how to strip down and recondition the internal mechanism but with no avail as it’s the steel shaft that was worn. I’d send em back

 

[Martin C]

Probs a faulty set. Someone kindly posted on here last week on how to strip down and recondition the internal mechanism but with no avail as it’s the steel shaft that was worn. I’d send em back

It seems the rear one is the problem each time, so I swapped the clamps and still the same, that’s why I said could it be because roof bars are different heights, the back is lower, I didn’t know if this was putting extra stress on the back clamp each time?