Tracking down a front-end clunk?

[Jonathan Hanson]

See my "Need an honest mechanic" thread for the background here. Our 1993 Troopy developed a strange front-end knock over the course of 2,000 kms of dirt track. I can hear it, and feel it through the steering wheel. It started out doing it only when I accelerated or decelerated; now it's doing it all the time, including on tarmac, even when just driving over speed bumps.

My friend and I looked at the truck day after day. We checked wheel bearings, U bolts, the steering rack, the track rod ends (which I adjusted), the steering column U joint—basically everything we knew could possibly loosen. The left swivel housing is puking grease at a high rate but the kingpin bearings do not seem to be loose. While I can feel the clunking through the wheel very noticeably, it has not (so far) affected the steering noticeably. But it's definitely gotten worse, and it's weird not to be able to find anything moving.

It seems to be more associated with suspension movement and acceleration/deceleration than steering (i.e. movement back and forth), but of course the track rod does move when the suspension does. It's a mystery that I think we'll only solve with the vehicle on a lift, but I thought I'd throw it out there for ideas.

 

[Rodger]

When I first saw your post asking for an honest mechanic neath Perth I was going to put you on to a mechanic mate of mine in Scotland - aah wrong Perth!
Did you check the shock absorber bushes? As you are not noticing a deterioration in the steering and it only happens on vertical movement of the truck, it suggests to me that it may be a SA bush. Once they start to go the decline is quite rapid - especially off road.
Regards,

Rodger

 

[Jonathan Hanson]

Yes, the Brit habit of giving cities across the planet the same name can be confusing!

We did check the shock absorber bushings, which seem to be fine. Springs seem fine too. It's really odd to have such a noticeable noise and absolutely no visual clue to its origin.

 

[alexy]

did you tried to drive in 4x4 to see if theres any change? could be something inside the axle?

 

[Jonathan Hanson]

Yep . . . same in 4wd. The worse it gets the more I'm convinced it's something in the steering. We're in Perth now and will be taking it in today. I'll update when I know more.

 

[mettisse]

Hello, had the same on a 7.5 tin lorry, ( truck) turned out to be a broken leaf in the spring bundle, ( front of the vehicle) infuriating to say the least and very hard to detect, on another occasion ( different lorry) it was the near side shock absorber was playing up, again difficult to detect, the problem was the bottom bush which was fine but it was the location of the SA, it had a tiny amount of play which allowed it to move enough to clunk although the nut and bolt was very tight, shiny metal revealed the issue. The noise does make you worry though, especially if you can’t readily see the problem. Best regards to all, Bill Westley

 

[Jonathan Hanson]

Robson Brothers 4x4 in Welshpool took us in on no notice and diagnosed worn-out front springs—possibly original to the vehicle? They are replacing them. I feel a little better about my failure to locate the issue because it would be difficult to figure that out in the field without a lift.

Thanks very much for all the input!

 

[StarCruiser]

Robson Brothers 4x4 in Welshpool took us in on no notice and diagnosed worn-out front springs—possibly original to the vehicle? They are replacing them. I feel a little better about my failure to locate the issue because it would be difficult to figure that out in the field without a lift.

Thanks very much for all the input!

Seems like good service so far. The proof of the pudding being in the eating, I’d be most interested to hear if this cures your clunk.

 

[Jonathan Hanson]

The proof of the pudding being in the eating, I’d be most interested to hear if this cures your clunk.

Indeed. I will report.