Mack Disease...

[Mother Deuce]

My day included a large dose of Mackaroni today. It suffered from Mack disease, that is it won't like most of it's sisters in my experience won't turn right ... Can anybody tell me how it is or was, that Mack for years built trucks that only turn one freakin' direction. I have driven R 700's, 600's, DM800's and 600's 713's and so on. Some of them handle well most of them go left good and have a right turning radius that you could handily spin a 793 around in. Just kind of curious how it is that it was never addressed by Mack.

 

[RZucker]

Super single steers? More than likely the stops were set to keep the tire from eating the drag link with a steering box in front of the axle. I've seen the opposite with a rear mounted box. Also seen a few with twin power boxes that didn't turn well in either direction.

 

[Mother Deuce]

Interesting. They took our truck in to fix the radiator and rented a amazingly clean 86 DM600 with as you surmised Super singles. We can't leave any dirt in the street so I was DM600ing for a couple days. Went left great... to make the turn in to the lay down I had to get in the oncoming lane against the curb and crank it hard right. It would just make it and I ended up offsetting a pin 5 feet cause I couldn't miss it. Fun little truck to drive except for that. You might be right about the stops. I have encountered several of them that won't go one way. I was wondering if it a Mack design oddity.

 

[crane operator]

I have a RD600 with a national crane mounted to it. It has the dual steering boxes ahead of the axle. When I got it, it wouldn't turn in either direction very well. 3 point turns to get through a highway to highway T intersection isn't great for a construction type vehicle.

It was horrible- absolutely unable to get anywhere with. How the previous owners had lived with it all those years,(probably since the wide steers were put on), is beyond me. It was either fix it or it was going on to some other owner.

A different set of rims with more offset pushed the 425 steers out. That enabled me to crank the stops in, and then I had to adjust the steering box relief points. It now turns fine. Either direction. And its a pretty long wheelbase with the crane on it, and there's no changing that, but its possible to at least make a corner now.

With it not being your truck, I don't see much you can do about it.

If they have fitted it with the "standard" offset rims that most trucks have for 425's, I don't think they have enough offset. So like RZucker says, they cheat the stops out, to keep it off the steering linkages. I had to order my rims with the extra "out", which took a bunch of measuring and guessing where that would put the tires. With the wheel pointed straight, the steers are actually just a little outside the rubber fender flares mounted to the hood. It looks a little odd, but its the only way to keep the tires off the hardware. And it was kind of pricey buying new rims, but that was cheaper than a different crane.

 

[Mother Deuce]

I have a RD600 with a national crane mounted to it. It has the dual steering boxes ahead of the axle. When I got it, it wouldn't turn in either direction very well. 3 point turns to get through a highway to highway T intersection isn't great for a construction type vehicle.

It was horrible- absolutely unable to get anywhere with. How the previous owners had lived with it all those years,(probably since the wide steers were put on), is beyond me. It was either fix it or it was going on to some other owner.

A different set of rims with more offset pushed the 425 steers out. That enabled me to crank the stops in, and then I had to adjust the steering box relief points. It now turns fine. Either direction. And its a pretty long wheelbase with the crane on it, and there's no changing that, but its possible to at least make a corner now.

With it not being your truck, I don't see much you can do about it.

If they have fitted it with the "standard" offset rims that most trucks have for 425's, I don't think they have enough offset. So like RZucker says, they cheat the stops out, to keep it off the steering linkages. I had to order my rims with the extra "out", which took a bunch of measuring and guessing where that would put the tires. With the wheel pointed straight, the steers are actually just a little outside the rubber fender flares mounted to the hood. It looks a little odd, but its the only way to keep the tires off the hardware. And it was kind of pricey buying new rims, but that was cheaper than a different crane.

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I appreciate it crane operator... the truck belongs to a superintendent in training father. I will forward your experiences to him. It would really be a decent sanitary old horse if you could get it around a right hander.