tie road / track rod wear

[nick disjunkt]

Hi all,

In preparation for Jim's annual test I took him to get a full check-over this week.

The recommended repairs were generally expected but one which surprised me was excessive tie rod wear. The steering is not as precise as it has been, but I was surprised that the play was bad enough to be a fail on the test.

I replaced the tie rod a few years ago and it has only covered 36,000km since. This seems an absurdly short life span to me.

Some of the km have been on badly corrugated dirt roads, and I probably hit a few topes faster than I should in Mexico, but it still seems that there must be something else at play.

The armour plating in the cab undoubtedly adds a fair bit of weight over a standard truck, and I have never actually put the front axle on the scales to see the weight on it, but the front axles is rated at 8 tonne and I would be surprised if the load was within 1,500kg of that. There is enough space to have tea party between the leaf springs and the bump stops.

Are there any other factors which might lead to this excessive wear? Things to check?

Thanks for any help.

Nick

 

[Iain_U1250]

Did you buy genuine MB parts or at least decent German made OEM equivalents? Lemforder make the Unimog ones ( MB just repackage them) and they seem pretty substantial.

I would check the weight, they might have put heavier springs in to compensate for the armour.

 

[nick disjunkt]

yes the tie rod was changed at MB main dealer. Your right though about getting axle weights on the scales though. The local weighbridge is at a waste transfer station and it's always too busy to do single axle weights. I'll ask at the testing station if they can do it.

 

[nick disjunkt]

6.1t at the front. 7.0t at the back.

 

[Mr.510]

Out of balance or static balanced tires, front end alignment issues, and lack of a sufficient steering stabilizer can all beat tie rod ends to death. Anything that makes a front tire want to wander or wiggle can be hard on tie rod ends, even if it's not enough for you to feel in the steering wheel. If the front end is tight, properly aligned, and the tires are spin or bead balanced I would replace the steering stabilizer or add one if it doesn't have one. I found that everything in the front of my Unimog including the tires lasts longer with a much stiffer than stock steering stabilizer.

 

[nick disjunkt]

Hi mr.510,

thanks for your help. The front tyres have always been pretty well balanced (spun off the truck in a massive, modern commercial tyre shop in London), but I did have a slight vibration at 50mph which wasn't cured until an old school tyre shop in Oaxaca spun the tire whilst it was still on the truck and got it properly balanced. This may have contributed, although most of the wear was on the opposite side to the poorly balanced tyre.

Alignment has been always been good whilst the truck was on this tie rod. It was checked when the rod was fitted and checked again at about 15,000km.

I am not aware of having seen any heavy trucks in Europe fitted with stabilizers, I'm pretty sure that these are not a common modification. On a heavy 4x2 truck where would these be fitted? between the axle beam and the tie rod? I guess you could pick up the spring perch u-bolts on the axle but how would you fix the damper to the tie rod?

Thanks,

Nick

 

[Mr.510]

On vehicles with limited suspension travel (civilian light trucks) the steering damper usually has one end connected to the tie rod (often with U-bolts and an L bracket if it's not stock) and the other end connected to the frame. On Unimogs one end is connected the tie rod and the other is connected to the front axle. I've mostly worked on Unimog 404s and 406s, but I think every Mog I've ever been under has a factory installed steering damper. I don't know if they're used on OTR heavy trucks, but one could certainly be adapted. It's basically a really stiff shock with equal damping both ways that's designed to work on it's side.

 

[Iain_U1250]

No steering damper on my Unimog, nor any of the square cabs I have seen. I don,t get any kickback through the wheel at all, even driving into a deep rut at an angle. My Land Rover has one, and you can sure tell when it is not working properly, you can feel the wheel wanting to kick when you hit a hole. Maybe the newer mogs have a different steering box than the old ones.

On vehicles with limited suspension travel (civilian light trucks) the steering damper usually has one end connected to the tie rod (often with U-bolts and an L bracket if it's not stock) and the other end connected to the frame. On Unimogs one end is connected the tie rod and the other is connected to the front axle. I've mostly worked on Unimog 404s and 406s, but I think every Mog I've ever been under has a factory installed steering damper. I don't know if they're used on OTR heavy trucks, but one could certainly be adapted. It's basically a really stiff shock with equal damping both ways that's designed to work on it's side.