hdfx81 Posted October 21, 2016 Share Posted October 21, 2016 One of the top kingpin caps was missing on my 87 superliner went to mack and was told mack changed the style of the caps, the one they gave me looks like a freeze plug(just a disk with a slight curve). I put in on and when I grease the kingpin the it pushes out the cap. I found the original type and was wondering if there is a certin way to install it. I will take some pics later and post them. Quote Link to comment https://www.bigmacktrucks.com/topic/47379-mack-18000lb-steer-axle-top-kingpin-cap/ Share on other sites More sharing options...
blackdog2 Posted October 21, 2016 Share Posted October 21, 2016 tack weld (spot) 2 places 2 Quote Ed Link to comment https://www.bigmacktrucks.com/topic/47379-mack-18000lb-steer-axle-top-kingpin-cap/#findComment-349473 Share on other sites More sharing options...
39 Baby Mack Posted October 21, 2016 Share Posted October 21, 2016 One of the top kingpin caps was missing on my 87 superliner went to mack and was told mack changed the style of the caps, the one they gave me looks like a freeze plug(just a disk with a slight curve). I put in on and when I grease the kingpin the it pushes out the cap. I found the original type and was wondering if there is a certin way to install it. I will take some pics later and post them. The heavy welch plug you spoke of (like a frost plug) was actually the original style. They could only be installed properly with the steering knuckle off the axle. They had to be installed with a special tool which consisted of a driver and an anvil. You would put the welch plug into the bore with the concave down, rest the knuckle upside down on the anvil and drive the plug down with the driver. It would set the plug in the bore about an 1/8" down from the top. On top of all this you couldn't buy the tool you had to have it made! This was a bad design, in my opinion, and were always a problem with them coming lose. The later ones looked like an inverted top hat with ridges on the part that goes down in the pin bushing bore. They were made to be driven in from the top. They also have a screw in plug that goes into the cap. The plug was to be removed so you could install a pusher bolt in the hole to remove the plug when it was time to service the pins. These were better but as was already said tack weld them in. Ron Sent from my SM-G900V using Tapatalk 1 Quote Link to comment https://www.bigmacktrucks.com/topic/47379-mack-18000lb-steer-axle-top-kingpin-cap/#findComment-349485 Share on other sites More sharing options...
hdfx81 Posted October 21, 2016 Author Share Posted October 21, 2016 This is the one I got, does it go in fairly easy or should I chill it in the freezer overnite to shrink it for an easier install then tack weld it? Quote Link to comment https://www.bigmacktrucks.com/topic/47379-mack-18000lb-steer-axle-top-kingpin-cap/#findComment-349494 Share on other sites More sharing options...
Popular Post 39 Baby Mack Posted October 21, 2016 Popular Post Share Posted October 21, 2016 In my experience, they never drove in that hard. Remove the plug and drive in with a large socket. Make sure the plug is out before you weld it, pretty sure there's an "O" ring around the plug. Ron Sent from my SM-G900V using Tapatalk 4 Quote Link to comment https://www.bigmacktrucks.com/topic/47379-mack-18000lb-steer-axle-top-kingpin-cap/#findComment-349498 Share on other sites More sharing options...
TCMack Posted March 20, 2017 Share Posted March 20, 2017 I'm having the same problem I have the drive in freeze plug style. What are the part number for the style with the plug. Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/47379-mack-18000lb-steer-axle-top-kingpin-cap/#findComment-365006 Share on other sites More sharing options...
Casper1988 Posted March 26, 2017 Share Posted March 26, 2017 I bought a king pin kit recently and it came with both styles, my original was not tack welded but prick punched in three spots. I am changing out the pin and will use the newer style, looks like 7/16's FT plug. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/47379-mack-18000lb-steer-axle-top-kingpin-cap/#findComment-365561 Share on other sites More sharing options...
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