Trailer axle. Breaking mount pads.

[Rick1970]

I have a small, light, basic camper trailer. It has slipper springs, 39mm round axle with electric brakes and 14" Holden rims with 185R14LT tyres. Its not overly heavy.....maybe 500kg. No heavy offroad use, but does see dirt roads a lot.

I am having issues with it breaking the little mount pads that are welded to the axle. Lower spring plates bent a bit, axle pads break and the axle rotates forward a little. Thinking the whole lot is working loose, then the force from the brakes causes it to rotate. I have replaced the pads, u-bolts and lower plates twice before, so the novelty is starting to wear a little thin.

Was thinking about making spring perches that are a little longer from heavy wall RHS, more like what you would see on a car/4x4 diff and making heavy (10mm???) lower plates with stiffening plates welded on the edges. Would shocks (if I could find room), help any?

Any thoughts? Would shocks (if I could find room), help any? Anybody else had issues like this and what was your fix.

I would like to change the axle/spring arrangement, but the height is at the max atm for the drop on the tent (Oztrail Camper 6), so guessing choice is limited there.

Cheers
Rick

[101RRS]

Poor welds on the pads to the axle comes to mind. I have had the exact same arrangement of two different trailers for over 40 years and not had this issue.

One alternative suggestion is to put on a square axle - they are cheap around $60 for a smaller trailer.

Garry

[Slunnie]

Flat plates onto round are not all that strong even if the welds are good and the brakes will make it a lot worse by putting forces into the axle that way. Considering its use I would also look to change to a square axle with its greater strength for the first roads also.

[Rick1970]

Yes, was thinking the brake forces may be playing a part in it. Welds are not breaking, the pads themselves are breaking into pieces.

Due to time constraints, I kinda need to get it going this weekend, so mite just repair whats there for now and measure up axle and get a 45mm square axle for when I get time to change it, may as well change to the bigger SL bearings while i'm at it.

[101RRS]

Of you are currently running a 39mm round axle the a 40mm square will be more than enough - but if you want peace of mind then yes 45mm.

[lyonsy]

Pics? sounds like the mounting plates are too long and the spring is pounding them to death, or the wrong type of steel is being used (not spring steel)
square axles would solve the issue but

[Slunnie]

Spring steel will crack from the welding. They are just mild steel. As Rick was saying, they really need to be designed like an car/4WD spring perch if they have brakes rather than just a flat welded pad.

[Rick1970]

Guessing the original mount pads were shop bought ones (40x40x10), I replaced them with the same when they 1st broke. When they broke again I make some from 40x10 flat bar (same diamentions as the origionals).

It now has mounts made from 40 x 4 RHS, notched for the axle to sit in (like a car spring perch) and a 40x5 gusset welded front and back to box them in. Also braced the lower u-bolt plates with 30x6 flat to stop them bending.

I have another box trailer with a round axle and the normal square pads that has never given any issues, but it doesn't have brakes either.