Freightliner XC-S Chassis

[broomfieldman]

I have a 2014 coach with a XC-S chassis with about 31,000 miles.

At about 17K I have to replace the king pins and now at 31,000 mile I am told I need king pins replaced again. Any help, suggestions etc would be greatly appreciated.

Thanks Gary

[wolfe10]

Gary,

Welcome to the FMCA Forum.

No, never heard of that unless they are not greased or front axle went under water. These are the same components used in medium and HD trucks and normally go hundreds of thousands of miles.

Guess one set could have been improperly shimmed leading to either too tight or too much vertical play.  But two with the same issue??

Exactly what is out of spec on them?

[broomfieldman]

I have had them greased and it has never been underwater. I am trying to work with Transwest Truck to get to the bottom of it but do not know much about this. About the only thing I know about king pins is keep them greased and they should last almost forever. So just trying to find out if they would be at the very least partially at fault for improper installation?

[manholt]

Do you have a Freightliner garage near you?  If so, let them work on their own chassis and tell you why you even had to get new king pins at 17,000 miles to begin with!

[wolfe10]

Really depends on what is wrong and what caused it:

Improper shimming? Draw keys loose? Clogged grease fitting? Grease channel not drilled (grease not getting in)? etc.

[dickandlois]

51 minutes ago, broomfieldman said:

I have had them greased and it has never been underwater. I am trying to work with Transwest Truck to get to the bottom of it but do not know much about this. About the only thing I know about king pins is keep them greased and they should last almost forever. So just trying to find out if they would be at the very least partially at fault for improper installation?

Very unusual like Brett mentioned !

Solid axles and king pins are like peanut butter and jelly, they work well together, but years ago I had a truck that had axle issues and convinced the truck shop to just replace the entire axle assembly. Never had another issue. Just have to think that something in the forging and boring of the axle where off some how. Never could get an answer from the shop or the chassis builder regarding what was out of spec.  Put over 200,000 miles on it and never had any other issues.

Rich.

[broomfieldman]

Thanks for all of the feedback! I have to ask what are Draw Keys? The shimming I understand.

 

[wildebill308]

4 hours ago, broomfieldman said:

Thanks for all of the feedback! I have to ask what are Draw Keys? The shimming I understand.

 

Welcome to the forum. 

I  would take it some where else like a Freightliner shop.

I can't be more helpful as you haven't added your information and coach information to your profile or signature.

Bill

[broomfieldman]

Transwest replaced them the first time and it is in their shop again. Thanks

[hermanmullins]

When I was a mechanic soo long ago we had lots of solid axle cars coming in for king pin replacement. The King Pin was secured in the axle with a tapered pin and the spindles had 2 Bronze bushings (1 upper and 1 lower). There were zerk fittings for each and the holes in the bushings had to be aligned properly so grease would be able to enter the bushing to lubricate the pins. Then they were line bored of proper clearance. 

The issues here seem to fit miss alignment of the bushings. 

I changed many and had a great teacher when I learned to replace them.

Herman 

[wolfe10]

Draw keys hold the king pin FIRMLY in the steering knuckle. If loose, they allow the king pin to move around-- a 100% guarantee of WEAR. There are two per side and you should be able to find torque specs from your axle manufacturer.

 

And, to Herman's comment about bushing alignment-- The very first tech to attempt to lube it would KNOW there was an issue since he was unable to get any grease in.