Cost to do king pins on a 2007 Mack MR

[giannid]

I just purchased a decommissioned USPS single axle tractor.  The king pins are wiped out and wonder what they will cost to get done.  The USPS specced these trucks with an automatic greasing system that looks like it hasn't worked in years.  Never done king pins before and not sure I want to tackle the job myself.

[theakerstwo]

I would say you should call mack first and then call around to the shops you want to do the work and ask them.They will tell you what it should cost plus most will tell you plus what else we find needing replaced.

[Joey Mack]

My guess is the top cap on the king pin looks like a giant nut with 2 grease zerks?  If so,  just be sure its the king pins,,  the style im talking about is actually a good set up, and I rarely ever replace them.  they are not made the same way as Mack king pins. they are straight at the bottom like all others, but they have a roller bearing in the top and the pin is held 'UP' by a big nut under the top cap.  they are easy to service if needed.  I have, at times, taken the wheels off and pulled the top cap and bottom cap, (they just unscrew,) in order to inspect them for wear..  of course the simple way would be to jack it up and use a bar to lift up on the wheel.. jojo

[mowerman]

That’s very interesting so you’re saying some of them can just be adjusted:… ??? Bob

[Joey Mack]

not the newer ones,  i was stating that they are easy check and repair... jojo

[Joey Mack]

actually Bob,  I do not know how far back the adjustable tapered king pins go, but if you look at your 'R' model, on the bottom of the king pin, you may see a 'cross' were the large cotter pin goes through...  thats the adjuster. of course its only 90 degrees at a time, and not a fine adjustment.  you may also have shims between the axle beam and the knuckle. if multiple adjustments are being done, I would be concerned about the thrust bearing at the bottom of the pin..  anyway,  he probably has the newer style..  jojo

[mechohaulic]

seems i see a pattern showing up again==old is adjustable ; new is throw away. i had a 3/4 drive "screw driver style socket for adjusting , had to round corners of socket a little for secure fit. hold tension on the ratchet same time slight tapping with hammer on axle in location of king pin. it helps set the pin. 

[mowerman]

  Oh OK that’s very interesting I think I have seen those big slotted nuts … bob

[mowerman]

I know my 66 has a Zirk Fitting  on the water pump bearing I don’t know if they still use them I doubt it … Bob

Edited March 13, 2022 by mowerman
Misspelled

[Onyx610]

16 minutes ago, mowerman said:

  Oh OK that’s very interesting I think I have seen those big slotted nuts … bob

[Vladislav]

I belive those with the slotted nut at the bottom are only adjustable to compensate axial play. And if the bushings or the pin walls are worn no use of tightening the nut.

[mowerman]

I’ll only changed one set 51 Chevy pickup way back around CB 1981 … Bob 

[mechohaulic]

that style  has the taper on the king pin center.  top/ bottom of pin is straight. might be different today. newly installed  bushings had to be reamed out to fit pins. the bottom adjusting nut was mainly for setting the pin to thrust bearing. i have seen tightening the bottom nut  help a loose spindle for a quick temporary fix.  but that usually means bearing is worn and pin dropped . 

[giannid]

10 hours ago, Joey Mack said:

My guess is the top cap on the king pin looks like a giant nut with 2 grease zerks?  If so,  just be sure its the king pins,,  the style im talking about is actually a good set up, and I rarely ever replace them.  they are not made the same way as Mack king pins. they are straight at the bottom like all others, but they have a roller bearing in the top and the pin is held 'UP' by a big nut under the top cap.  they are easy to service if needed.  I have, at times, taken the wheels off and pulled the top cap and bottom cap, (they just unscrew,) in order to inspect them for wear..  of course the simple way would be to jack it up and use a bar to lift up on the wheel.. jojo

Nope.   Here's some pics.  Had to scrape the grease and crud off of it to see what it looks like.  Spent the better part of the day getting rid of the auto greaser, lines and putting regular grease fittings in everywhere.  The auto greaser wires were cut so my guess is they just disconnected and not lubed anything at PM time.  King pins are definitely wore out.  Jacked it up and pried on it with a bar.  Seems like the tie rods/drag link are good.

You familiar with this front end?  I'm hoping aftermarket parts are available as everything at the dealer is stupid money.  Doubt I'm going to do the job myself as it seems like it's a big job and never done them before.  Probably requires some special tools.  Any idea what this will cost?  Going to call around tomorrow.  

[Joey Mack]

looks like shit all over it.. that one is the adjustable one, but given the dirt all around it.... you need to clean it real good and check it again... if you are sure that its bad,  the repair is not hard to do..  when you take it apart,  take the king pin and put it back into the axle beam boss to see if it is worn out.. if it is, you can get the beam reamed and re-bushed to accept the new king pin set...  jojo

[terry]

That style you take backing plate off, take cotter pin out of bottom, then there is a cross slot on botton, screw that out, the top is pressed in, pop that out and knock pin out to the bottom , once you break the taper loose it will fall out, alot of the replacements are nylon bushings.

[mechohaulic]

2 minutes ago, Joey Mack said:

looks like shit all over it.. that one is the adjustable one, but given the dirt all around it.... you need to clean it real good and check it again... if you are sure that its bad,  the repair is not hard to do..  when you take it apart,  take the king pin and put it back into the axle beam boss to see if it is worn out.. if it is, you can get the beam reamed and re-bushed to accept the new king pin set...  jojo

 

1 minute ago, terry said:

That style you take backing plate off, take cotter pin out of bottom, then there is a cross slot on botton, screw that out, the top is pressed in, pop that out and knock pin out to the bottom , once you break the taper loose it will fall out, alot of the replacements are nylon bushings.

new replacements nylon; would  that indicate no more reaming ? 

[giannid]

5 minutes ago, Joey Mack said:

looks like shit all over it.. that one is the adjustable one, but given the dirt all around it.... you need to clean it real good and check it again... if you are sure that its bad,  the repair is not hard to do..  when you take it apart,  take the king pin and put it back into the axle beam boss to see if it is worn out.. if it is, you can get the beam reamed and re-bushed to accept the new king pin set...  jojo

After doing some research online, I'm pretty sure it's a Mack front end.  Actually found a couple of complete used axles on online dating back to 1997, so they've been using that axle awhile.

I imagine you still have to take the brakes and backing plate to do the the job.  Never done it before.  How long to these usually take to do at a shop?

[Joey Mack]

yes Mech, however, i have buffed them to get a smooth snug fit, because when they get driven in there will be a bit of a peaned over edge, but it can be buffed/ chamfered with a flapper wheel or by hand with that little wiggly tool that I cant name..  oop's... jojo

[Joey Mack]

if I have the parts, and the beam is good... 8 hours...  

[mechohaulic]

7 minutes ago, Joey Mack said:

looks like shit all over it.. that one is the adjustable one, but given the dirt all around it.... you need to clean it real good and check it again... if you are sure that its bad,  the repair is not hard to do..  when you take it apart,  take the king pin and put it back into the axle beam boss to see if it is worn out.. if it is, you can get the beam reamed and re-bushed to accept the new king pin set...  jojo

steam cleaner is best, if you can use one anymore.  i  had one so packed with old grease/dirt  used an air hose to clean between spindle and axle . worn out was twice as bad without the packed dirt in there.

[Joey Mack]

that is so true Mech..  good point.  once the dirt and hard grease is out, it can be loosy goosy...  so true..  I hope his beam is good.. i expect it is..  not a hard job,  the hard part is the anticipation of the cost..  jojo

[mechohaulic]

6 minutes ago, Joey Mack said:

yes Mech, however, i have buffed them to get a smooth snug fit, because when they get driven in there will be a bit of a peaned over edge, but it can be buffed/ chamfered with a flapper wheel or by hand with that little wiggly tool that I cant name..  oop's... jojo

when bronze bushings were being installed, i used a large C-clamp  two pieces of flat stock. all cleaned and lubed; basically  hand pressed the new bushings in. the reaming was the challenge. too much sloppy spindle.

[Joey Mack]

yes sir.. 20+ years ago I was taught to hand reem the bushing's... but after that the bushings were re-vamped and the reeming became buffing..  it still produces a quality fit.. I appreciate you so much..  not my thread, but i dont care. you have the smart's...  jojo

[giannid]

41 minutes ago, Joey Mack said:

that is so true Mech..  good point.  once the dirt and hard grease is out, it can be loosy goosy...  so true..  I hope his beam is good.. i expect it is..  not a hard job,  the hard part is the anticipation of the cost..  jojo

So there's a possibility the beam is bad and needs to be replaced?  That would be just my luck.  The drivers side is pretty bad.  There's no telling how long they ran the truck without the auto greaser working.  I can't imagine replacing the beam is going to be cheap.