Popular Post JoeH Posted December 23, 2021 Popular Post Share Posted December 23, 2021 So we bought a 2003 MR688S, and are prepping it for a brand new CemenTech volumetric concrete mixer. Have about a month to complete the following: Pull frame rails, separate, sandblast and paint. Reassemble. (One side at a time.) Shorten wheelbase by approximately 16.5 inches. (Slide tandem forward, shorten driveshaft, possible relocate crossmembers) Add 20k lb lift axle. Truck was a tandem axle trash truck, 20k front axle, 44k rear tandem. Replace driver door shell (fiberglass PoS cost $2,000) Paint cab. Trying to figure out how to post pictures. 6 Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/ Share on other sites More sharing options...
JoeH Posted December 23, 2021 Author Share Posted December 23, 2021 (edited) Currently the left frame rail is out & sperated. So much work just to alleviate less than 1/4 inch of rust jacking. Monday will be sandblast the frame in the rain. Will tent it with the boom of our crane and a 30x50 tarp, then run it inside the garage for paint. Then crank up the heat and cook the paint! Edited December 24, 2021 by JoeH Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-485823 Share on other sites More sharing options...
Popular Post JoeH Posted December 25, 2021 Author Popular Post Share Posted December 25, 2021 In my lifetime to date, (I'm 32) we (I'm 3rd generation) have only had R models and a DM. This is our first MR cab, and so far this has been a dream to work on. All the cab electricals are under a massive plate in the middle of the cab that completely comes out to give access to everything. Terminal blocks, circuit breakers, dash switches, etc. 6 screws and you're into everything. The cab tilts forward and you can get to everything on the engine. You can get to the front of the engine, the back of the engine, both sides... Truly the easiest truck I've ever had to work on. Our DM is easily the worst I've ever worked on, you can barely even get to the sides of the engine. We have yet to drive this truck on the road, I'm hoping it will be a relatively smooth ride, but I'm expecting it to be a bit rough. I may wind up only buying MR's from here on out, these things are that nice. I'm sure there's very few MR fans on here, but no one will argue that these trucks are built with the same great reputation we all know Mack had. The R model will always hold a place in my heart, but the MR is moving in next to it! The mixer body going on requires 168 inches from "back of cab" to center of tandem, which on a traditional cab would be far too long for the type of maneuvering we have to do every day. Thus in keeping with traditional Mack philosophy: Out with driver comforts, In with functionality! Merry Christmas! 4 Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-485914 Share on other sites More sharing options...
1965 Posted December 25, 2021 Share Posted December 25, 2021 I’m thinking & hoping you will like that automatic 1 Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-485917 Share on other sites More sharing options...
Popular Post Joey Mack Posted December 25, 2021 Popular Post Share Posted December 25, 2021 I know what you mean about having room to work... I have done a boatload of work on MR's and LE's... it's really great compared to other truck's Iv'e had the diss-pleasure of working on... The 2000'ish DM cracks me up.... I had to remove the right corner cab mount and jack the cab to get the engine brake spacer out of the rear head.. I thought it was a joke... but my co-worker said.. yep, that's how you do it.. I was just doing a valve adjustment.. I still think there was a worn out cab mount or something... but I would still work on one today.. great trucks.. and as you know, pulling a transmission in an 'R' chassis is much more work than many other trucks, even if they have a wet system.. I have a KW W900 at my shop with a 3406.. I have to run the valves, and whatever else I find.. you know... open the hood... and there it is.. Almost as much room as a superliner.. jojo... 3 Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-485919 Share on other sites More sharing options...
JoeH Posted December 25, 2021 Author Share Posted December 25, 2021 1 hour ago, 1965 said: I’m thinking & hoping you will like that automatic I think I will too, I've driven automatic oil/propane delivery trucks and they're easy. What I'm nervous about is off-road capabilities. We get in people's back yards and find soft ground sometimes. I need to inspect the automatic power divider. Full lockers would be sweet but they're hard to come by. Truck has Automatic Traction Control, piggy backed into the ABS system, which I had hoped was on all 4 drives wheels, but it's only on steer and rear drive axle. I may buy toner ring hubs for the intermediate axle and steal the steering ABS sensor system for the intermediate axle so I have traction control on 4 drives. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-485922 Share on other sites More sharing options...
Joey Mack Posted December 26, 2021 Share Posted December 26, 2021 How about buying an air locked power divider housing and shift fork assembly, and the cam drum, peanuts and inner cam, and building it and shimming it to fit back into the carrier housing, then get the drive shaft shortened by the difference between the auto power and the air locker set up? then you can run an air switch to the dash and hook a light or buzzer to it so you know if it's locked in.. you can use the current bevel pinion that is in the carrier and set tooth pattern the normal way after you convert the housing.. jojo 1 Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-485923 Share on other sites More sharing options...
JoeH Posted December 26, 2021 Author Share Posted December 26, 2021 An interesting proposition, perhaps a project for down the road. Budget and time don't allow for it now, truck needs to be in Iowa in February to get the body mounted on. Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-485928 Share on other sites More sharing options...
Joey Mack Posted December 26, 2021 Share Posted December 26, 2021 yes sir... My words make it sound easy... but it can be done.. it would be best to pull the carrier out and mount it secureley on a table, even if you made a 'jig'... jojo Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-485929 Share on other sites More sharing options...
Joey Mack Posted December 26, 2021 Share Posted December 26, 2021 there is always the option of buying a rear end with the correct ratio and of course in good condition, and building it on the bench.. The last 'whole' one I bought from Re-Mack was $4300.00....5 years ago.. don't know if they still offer them.. "Overdrive rebuilders" Is who I've been using since... not sure if they are in your area, but it's a thought.. jojo Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-485930 Share on other sites More sharing options...
james j neiweem Posted December 26, 2021 Share Posted December 26, 2021 I often wonder why the MR isn't used more broadly in the construction industry such as mixer(non pumper), dump and even HD tractor. As stated they are easy to service and work on. This would apply to Autocar and Paccar as well. I have seen some older MR dumps (Galasio from East Granby)from time to time. We even have a twin steer White expeditor running around here in CT.🙂 1 Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-485938 Share on other sites More sharing options...
Mark T Posted December 26, 2021 Share Posted December 26, 2021 They'd make it much easier to get the weight on the steering axle if used in dump application. Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-485939 Share on other sites More sharing options...
mowerman Posted December 29, 2021 Share Posted December 29, 2021 wow i usually dont come to this section,,,,,thats way cool....ive always liked th MR,,,just a real neat looking ride.perfect for city work. looks like your well on your way .bob Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-486080 Share on other sites More sharing options...
JoeH Posted December 30, 2021 Author Share Posted December 30, 2021 Left rail is primered painted and installed. Right rail has been removed and separated, tomorrow is hopefully sandblast, primer, paint. Supply chain issues are a bit screwy. In our hurry to get going we have had to reuse a lot of bolts before sourcing new ones. Last truck we did like this was 10 years ago, and I dont think we had any trouble getting bolts. Pictures show left rails laying flat vs right rails still with rust jacking. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-486220 Share on other sites More sharing options...
JoeH Posted December 30, 2021 Author Share Posted December 30, 2021 Right frame rail has the cab tilt mechanism, and since the right frame rail isn't in the truck right now..... We had to improvise. Left rail cab hinge is installed, right cab hinge is suspended by strap, and the cab gutter line is suspended from another strap, from beams going from our A frame to our pallet shelving. Redneck ingenuity is heavily at work here... 2 Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-486221 Share on other sites More sharing options...
Popular Post JoeH Posted December 30, 2021 Author Popular Post Share Posted December 30, 2021 Yes there is a wagon hiding in that last picture. While most people set old wagons in their front yard to rot away we prefer to keep our 150 year old (rough estimate) wagon up high and dry in our garage.last time it came out was for Chalfont, PA's bicentennial parade in I believe 2002 or 2004. Next time it comes out will probably be my 4 year old daughter's wedding in 20 years. 5 1 Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-486222 Share on other sites More sharing options...
Hook n ladder 1 Posted January 4, 2022 Share Posted January 4, 2022 Good luck with this project...you did a lot of work so far. I'm a big MR fan. Drove one for Waste Management. I did want to buy an MR tractor (old USPS rig) and either stretch it and make an RV out of it or put a sleeper cab on it. I have a CH midrise sleeper that i was going to use but, there isn't enough time in the day. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-486491 Share on other sites More sharing options...
JoeH Posted January 4, 2022 Author Share Posted January 4, 2022 New Years Eve had the paint store closed, so we didn't get as much done last Friday as we hoped. Finally got the right frame rails and about 10-15 miscellaneous brackets sand blasted and painted. Everything is sitting in the garage baking at 75 degrees overnight. 8am tomorrow starts the install process. Should go smoothly, no reason for it not to. Lift axle should arrive end of the week, hopefully the shortened driveshaft will be back soon too. One of my tenants is a collision center, I may ask them to prep the cab for paint. That's one task I don't enjoy so much. More pictures promised as progress continues! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-486516 Share on other sites More sharing options...
JoeH Posted January 4, 2022 Author Share Posted January 4, 2022 4 hours ago, Hook n ladder 1 said: Good luck with this project...you did a lot of work so far. I'm a big MR fan. Drove one for Waste Management. I did want to buy an MR tractor (old USPS rig) and either stretch it and make an RV out of it or put a sleeper cab on it. I have a CH midrise sleeper that i was going to use but, there isn't enough time in the day. Sleeper would be interested on an MR, it couldn't mate to the cab as there's part of an engine in the way. Would definitely be a neat rig if you could pull it off! Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-486517 Share on other sites More sharing options...
Joey Mack Posted January 5, 2022 Share Posted January 5, 2022 that would be cool... you reckon youll need a cab jack from a fire truck?? jojo Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-486518 Share on other sites More sharing options...
Popular Post JoeH Posted January 6, 2022 Author Popular Post Share Posted January 6, 2022 Today's progress: right frame rail installed, tandem slid forward to the new wheelbase. Miscellaneous brackets installed for bumper, skid plate, cab tilt, exhaust, fuel tank, etc. Shortened driveshaft should arrive tomorrow or Friday, hopefully the lift axle is coming by Friday, though the tracking number TForce Freight provides is bogus. All in all I think we've made a lot of progress in 2 weeks. Won't be particularly pretty when it's done, but we've always had more interest in structural integrity than chrome. These trucks just get covered in concrete dust. All this work is simply to eliminate the Rust Jacking in the frame, not to make it cute. 3 1 Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-486591 Share on other sites More sharing options...
keg1 Posted January 8, 2022 Share Posted January 8, 2022 My nephew just bought 2 2008 garbage trucks which i believe are MR,s and he said when you turn the key off the 2 outside cab lights stay on you have to turn key back to acc then they go out. Ive never been around one so i was wondering if there's a seperate switch for the lights like how the R models have 2 switches. He said its a rotary style switch rather than toggle switches like the R model Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-486675 Share on other sites More sharing options...
Joey Mack Posted January 8, 2022 Share Posted January 8, 2022 look for a battery switch on the batt box or near it... trash companies do that so the drivers cut the batts off after thier shift... jojo Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-486676 Share on other sites More sharing options...
JoeH Posted January 8, 2022 Author Share Posted January 8, 2022 Could be daytime running lights that stay on like modern cars do. You shut the car off, go inside, and the lights shut off after a minute. That's my best guess. This is my first MR too, haven't had much play time with it. Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-486685 Share on other sites More sharing options...
keg1 Posted January 9, 2022 Share Posted January 9, 2022 thanks for the replies. I'll let him know Quote Link to comment https://www.bigmacktrucks.com/topic/68973-mr688s-frame-work/#findComment-486719 Share on other sites More sharing options...
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