Macktruckman

Hi all. Can anyone tell me what rears these are? I hope for full lockers but I don’t think they are? Theres no springs just a walking beam. I can see its a 5.73 ratio. This is an RD690S that might be available to me for a parts truck. Its a 1988 or 89. Has a 4 valve EM6 I might use to replace my 2 valve. Possibly. Has what I believe to be a T2080 that I probably won’t use for anything. Its an old mixer truck since new. Thank you in advance Josh

Since i fabbed up the air ride on tbe cab it improved the ride but man bobtailing it’s tough to shift. Definitely bucky. Lol. Good with a trailer and smooth with a load. But bobtail its not nice to ya. Lol

Hahaha.

Yes it is hard to find them. Im lucky enough to have a friend with a small fleet of old mack mixer trucks that sit since he closed down his batch plant and he lets me scavenge a little when im in a bind but even he is careful about what he lets me get at. Lol. If not for him id be out of luck. Lol. Where I live there just never was all that many macks and none now. I’m sure glad to hear you got it figured out. Hopefully you’ll be on the road and running better than ever soon enough. I’m really curious to find out how you like the 4 valve engine in the same truck. My 2 valve went down last week and im hunting an engine now and im curious about the 4 valve as I’ve never driven one. good luck josh

I’m not sure about the linkage other than a junkyard maybe for a donor truck. I happen to have the same Robert Bosch pump and will happily take some pictures of my linkage and post up if it would help anything. Let me know Josh

Good luck! Josh

Now i just can’t remember for sure and i might be mistaken here but im thinking you might get access by taking a front part of the floor pan out and possibly not have to pull the seat? Josh

Am I thinking right is there bleeders on the slave cylinders on the top of the rear end transaxle?

And im a little jealous joey. Those KB internationals are the classiest looking old truck. One of my very favorites josh

I will say broken tractor will usually beat hagen on price but if you need help or have questions then Hagen is my go to.

If you don’t figure it out or need a different route. Hagen tractor is (918)-251-1851. Terry is the most knowledgeable guy on these that I know. If you get it straightened out and dont need him now save his number. Hes handy. Good luck with it. I looked and I don’t even have a book on a 580K around here. Josh.

Ohhh i see. Its been 20 years since i worked on a K. I wish I could be more help. Josh

A very knowledgeable place on older case equipment is Hagen tractor in broken arrow Oklahoma. Ask for Terry. Hes a bit abrasive at times but he knows case backhoes better than case does. Inside and out. And he has lots of used and new parts and parts machines. josh

I want to say I remember bleeding that k at the line out of the master cylinder but i just cant be sure. Josh

Broken tractor guys are a good bet. I use them alot for case backhoe stuff. I haven’t owned a K in many years. I did change master cylinder’s and slave cylinders on it and as I recall a major difference and mistake you can make is that some had brake fluid and some used mineral oil for fluid. The reason i had to change everything was because mine took mineral oil and I didn’t know it and i added dot 3 and it wrecked both masters and slaves. I don’t recall having any trouble bleeding but i don’t remember much about it as its been years ago. Im sorry im not more help. Coincidentally I changed master cylinder’s on my super m last month (got them from broken tractor). These draw hydraulic oil from the main hydraulic reservoir for the machine hydraulics. josh

Joe those DM and DMM always look so tough. My old R came from the oil field and still has an “oilfield bumper”. When i put the cab and hood on it and painted it I kept the big front bumper. And i use it for dragging and pushing the truck out of a pickle now and then. Never rammed anything with it… yet… haha josh

Wow. I just just found this last night and stayed up till 3am reading it all. That was just awesome. Like everyone else said, thank you so much for sharing all this in such detail. Its all been incredible. I hope you enjoy that beautiful B73 and 42 for many many years. Josh

R model mack!!… Everyone knows that!!… Sorry I really don’t know, but I couldn’t resist. Lol. in all seriousness though they are steel cabs and fairly well reinforced. Might rate fair actually?? But i have zero scientific proof.

I’ll be checking on it bob. Lol Josh

Thanks guys I have been pretty fortunate to have some good friends. The folks on here are so helpful and informative. I really enjoy this place. I follow along here and there what others are doing. I love bobs DM project as well as others. Jojo and freightrain and more. Just love this place. Josh

The one with the blue stripe is mine and tbe solid white belongs to my dads old friend. He isn’t in tbe concrete business anymore hes 85 years old now but those old macks are still around and some still run. That white one was gold when i was a kid it was a tractor. Its a 1981 and has a EM6-300 with CAC and air ride cab. 2 stick six. It was never a mixer. It pulled a powder trailer. Still has a wet kit and a blower kit both. Now its a 15’ flatbed dump with guardrails for sides and he loans it to me when I need a bobtail for site work. My dad died of Parkinson’s and this old man just kept on helping me out. Like i said hes 85 and i hope he lives to be 105. Lol. theres my mack history. Lol. Josh

Joe im not positive but I think I remember braided lines. The R i use now which im sure you’ve seen pictures of here is a 686ST in fact. It started life as a R685ST. However when I bought it the EM6-285 was under the hood. The cab was rusted beyond repair so I replaced the cab with a junkyard unit that was a 686ST truck. So i call it a 686 now. Its my junkyard dog. Its built out of a handful of different salvages around. Lol. But I don’t think I could ever part with it. I got my start in macks growing up around the local concrete plant that was owned by my dads best friend. When i was a kid the mixer truck fleet was one old ford with cat 2 and a quarter V8 that everyone hated and one old B with a triplex, one 66 or 67 U or DM, i know it has the offset cab and it was naturally aspirated and also triplex I believe but the majority (4 or 5)were R models with 237 and 2 stick 6 speeds and they were the truck to be in. They didn’t have passenger seats so i rode along lots of times sitting on a rotella box. Tried a 5 gallon bucket once and that didn’t make it to the blacktop and bucked me off between the shifters. Lol. But that place made me respect macks. They would carry 7 yards of mud through stuff I don’t think a pickup could drive through. Lol. Later when i was grown he got 11 yard mixers. 4 valve E6’s. That old man and my dad always told me if you need a truck that lives off road and on both and can drag loads through the dirt you better get you a mack.

Joe I think maybe you’re just a bit like myself. Just rather look at an old R as anything else. Lol Josh.

Ohh yeah. Im with you. Lol. I would definitely like to swap it for an E9!. Lol. MH or superliner! Josh

Thanks bob. My sister and my daughter call it optimus. Lol Josh