Qu. re Ifor Williams torque settings

[Treewolf]

I have just had to fit four new springs to my IW LM146 trailer, it's the kind with 2-leaf parabolic springs. Does anyone know the recommended torque for the four nuts on the two U bolts on each spring?

 

If no-one knows I'll ask IW in the morning, but it would be nice to get it all finished tonight!

 

Many thanks.

[woody paul]

I would say tight for the pounding they take but even.

[Treewolf]

For now I've gone with 50lbft (70Nm) which is a typical torque for an M12 grade 8.8 fastener. I'll see if IW can give an answer tomorrow.

[Treewolf]

IW has given me the following information which I will post here just in case anyone else needs it in the future.

 

The U bolt nut should be tightened to 140 Nm (103 lb ft). Note, it is essential that the correct flanged Nyloc nut is used rather than a standard Nyloc, since the latter, when torqued to 140 Nm, can cause the U bolts to shear.

 

The spring eye bolt nut should be tightened to 80 Nm (60 lb ft).

 

Note that IW also recommends that the U bolt nuts are checked and tightened every 1000 miles or 2 months.

 

Very helpful people at IW.

Edited April 25, 2017 by Treewolf

[Alycidon]

Sounds like that trailer has had some punishment, parabolics on trucks usually only get replaced when they snap. Maybe thats what happened.

 

A

[Treewolf]

Yes, the two nearside springs had both broken, cracked through the eye. I could have replaced two putting new springs on one axle and both old on the other, but they're not too expensive so I figured four new was the best bet.

 

140Nm is terrifyingly tight for an M12 thread though! I was sure the U bolt was going to fail.

[woody paul]

Because it got a flanged nut it needs to be tight so it bites in and there's were the resistance is so you do not snap bolt.

[Treewolf]

It's a plain flange not a serrated flange.