Mark22300 Posted December 17, 2022 Share Posted December 17, 2022 Hey I'm new here, bought my first dump truck for my excavation company and I've noticed my rear drive axle is sitting to the passenger side of the truck about 1.5-2" noticeably out of line with the rest of the truck. I've checked the rubber mounts and what not for that axle and I cant seem to see any obviously worn out parts. Is there anything specifically i should check? I will Update with pictures of the diffs and mounts tomorrow Quote Link to comment Share on other sites More sharing options...
Mark22300 Posted December 17, 2022 Author Share Posted December 17, 2022 Quote Link to comment Share on other sites More sharing options...
tjc transport Posted December 17, 2022 Share Posted December 17, 2022 wow. something is seriously messed up there. sorry i can't help, i never messed with air ride. Quote when you are up to your armpits in alligators, it is hard to remember you only came in to drain the swamp.. Link to comment Share on other sites More sharing options...
Dirtymilkman Posted December 21, 2022 Share Posted December 21, 2022 Broken centering pin on your z leaf. Easily fixed. Could be groken z leaves too. Get new u bolts, center pins, and spacer blocks. Be sure to put spacer blocks in the right way, there is a front and back. They will tapered. They set your axle angle. Always make sure your u bolts stay tight. 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted December 22, 2022 Share Posted December 22, 2022 I would like to add something.. I dont know what years had this style, but, the last set I repaired for this same reason, (2005 CXN) The centering pin was actually made into the Z-Spring. You can knock them out and machine your own replacement pins, but the one that I repaired, 2 of the Z-Springs had spider cracks around the pin's, and because I was replacing all 4, the owner had me buy all 4 Z-Springs.. So if your Z-Springs are healthy, you can make your own centering 'Mushrooms' ..also, the top block on the rear axle may be worn where the mushroom goes.. The front 'X' may not have the spacer block. also take a good look at the pin that is made into the top of banjo housing. They are round, but end up looking like a 'D'.. weld it up, and grind it back in shape.. Jojo 1 Quote Link to comment Share on other sites More sharing options...
2wdiesel2021 Posted December 24, 2022 Share Posted December 24, 2022 Do these have a torque rod like a peternilt air leaf suspension or freightliner air leaf that keeps the axle in line left to right? I see alot of them bend in Tandem dump truck duty from turning sharp on pavement with a shorter wheelbase truck. Quote Link to comment Share on other sites More sharing options...
Mark22300 Posted December 24, 2022 Author Share Posted December 24, 2022 the weather here finally let up so I went out and took another look, found that this crossmember has a bend in it and is cracked. I'm going to bend this crossmember straight and weld up the crack then grab new u bolts and start digging into the leafs once I get it into the shop. -43 with the wind last night. Thanks for the advice and ideas! Quote Link to comment Share on other sites More sharing options...
Mark22300 Posted December 25, 2022 Author Share Posted December 25, 2022 6 hours ago, 2wdiesel2021 said: Do these have a torque rod like a peternilt air leaf suspension or freightliner air leaf that keeps the axle in line left to right? I see alot of them bend in Tandem dump truck duty from turning sharp on pavement with a shorter wheelbase truck. yeah i beleve these are called a torque rod they are on the top of these diffs, its been so cold since i posted this i haven't been able to start the truck and lift the box to inspect them closer but i gave them all a wiggle and they seemed fine before i drove the truck home Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted December 25, 2022 Share Posted December 25, 2022 Judging by the picture of the airbag support. I would say that where the u-bolts clamp the springs in place, there is a good bit of wear.. do you see rust under the u- bolts or spacers, and also a shinny polished look on top of the banjo housing, under the torque arm mounts.. ? Quote Link to comment Share on other sites More sharing options...
Mark T Posted December 25, 2022 Share Posted December 25, 2022 (edited) Sorry to say it, but you need lots of new stuff. That plate between the springs ? Someone already added to it to stiffen it up. Whoever had it off or the spring out of it put the bolts back in the wrong holes. Likely you need saddles, spacers new springs U bolts and the side to side torque rods. These have been known to last only a matter of days in a dump truck sometimes (torque rods). This really isn't crazy expensive and it's easy to do if you have torches, jacks and a big impact wrench. Then there's the nylon wear pads hide'n in the front spring hanger. Spring needs to be able to slide to work or it just accelerates the wear of everything else. No easy tighten something up here.... you're spend'n some money. And if asked, get parts for AL46 ( the spring is thicker and is better for a dump application ). Sometimes you're better off getting a bigger torque rod for the side to side than comes in the truck.. like one of those weld to length but ???? gotta watch it'll fit without hitting the carrier. Someone pointed out the side to side rod may be bent (and it might) If it is and it's the one called for by the VIN, then the rest is worn allowing it to travel too much. It also looks like some genius removed the rear shocks. This suspension needs shocks. They stop it from over traveling . Edited December 25, 2022 by Mark T more information 1 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted December 25, 2022 Share Posted December 25, 2022 Atro makes a strong torque rod for that suspension.. Quote Link to comment Share on other sites More sharing options...
Mark T Posted December 25, 2022 Share Posted December 25, 2022 (edited) You need those ones with the big bushing with the rubber in a "can" that you can just press a new bushing in. They're huge and put up a good fight for a while...then you just press a new bushing in. But ? find a couple (lol) not many parts places wanna be bothered anymore ( uhhhhh model and VIN ?? ..... I can't do anything without that......uuuuhh ) and that's not even mentioning getting new U bolts made that are the biggest thing to fit through the conical washers in the bottom bracket Edited December 25, 2022 by Mark T spelling Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted December 25, 2022 Share Posted December 25, 2022 (edited) Mark, the last time I ordered the big Atro torque arms,. I have the vendor the length ' on center'. And the bolt hole with,. And size,5/8" or 16mm.. jojo Edited December 25, 2022 by Joey Mack Pore cell fone sperring Quote Link to comment Share on other sites More sharing options...
Mark T Posted December 25, 2022 Share Posted December 25, 2022 1 hour ago, Joey Mack said: Mark, the last time I ordered the big Atro torque arms,. I have the vendor the length ' on center'. And the bolt hole with,. And size,5/8" or 16mm.. jojo You can get them, just depends on what parts guy you have to deal with. One of those Atros, the bushing I'm talking about can be pressed in an Atro rod when that wears out. 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted December 25, 2022 Share Posted December 25, 2022 Yes it can.. he can get this done with minimal Mack involvement, or lack there of... Quote Link to comment Share on other sites More sharing options...
Mark22300 Posted January 13, 2023 Author Share Posted January 13, 2023 Took in to get it fixed, picked it up and the axle was still sitting 2" or so to the drivers side. straightened the crossmember. Replaced both U bolts on the D&P side and saddle on P side. Was told that the torque arm on the top of the diff just needs to be shimmed. They said they checked the centering pins and they where fine. On the D side it looks like the leaf pack has moved on the diff, I feel as if something is still wrong as 2" is alot to get out of shimming a torque arm not? Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted January 13, 2023 Share Posted January 13, 2023 ok. there is an issue on the 'D' side.. that polished look means it moving.. I made a tool many years ago to check the distance between the drive axle hubs.. there is a dimple in the center of the axels.. I assume you know about them.. I drew this diagram because I cant go outside to photo my tool... we are under a tornado storm warning... .... I use this tool to get the axels as close to even as I can. It is NOT an alignment tool, but it will get the truck on the road and to the 'line-up' shop.. of course if your tires are already worn, you can run the truck to see how the wear pattern and axle position looks.. I used a length of 1'' conduit, and made 2 sliding blocks and welded rods to each one to be my pointer's, and drilled a hole in each and welded a nut over those holes, then made my own 'T-Bolts' to use to secure the pointers.. I put one pointer in the axle dimple, then slide the other one till it mates up to the other axle dimple, and lock it down.. then take the tool over to the other side to see how far off the axels are, then I adjust the axle spread accordingly.. I hope I helped... sometimes I make it worse.. Jojo 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted January 13, 2023 Share Posted January 13, 2023 I bet the rear wheels are visible in your mirror when your in the big seat.. that is a transverse torque arm issue as well.. that's the one that goes from the rear carrier to the frame rail. That can be shimmed using grade 8,,, 5/8'' 1/16'' thick washers.. Gosh I wish some of us where there to help you with this. it's not 'rocket surgery'... I still think the centering dowels on the banjo housings are worn out and need to be welded up then ground back to 'Round'... jojo Quote Link to comment Share on other sites More sharing options...
Mark T Posted January 13, 2023 Share Posted January 13, 2023 The side to side torque rod does determine the difference I see on the tape measure. ( most of it anyway ) all those new U bolts are going to need to be retightened before long. FYI, that truck isn't really fixed from what's in the pictures , might be a little better than it was though 2 Quote Link to comment Share on other sites More sharing options...
Mark22300 Posted January 13, 2023 Author Share Posted January 13, 2023 here is a pic of the transverse torque arms, the F one has no shims or washers and is sitting ok i believe. the R one has 2 washers in it and if removed they will pull the axle in to the P side and line it with the F one, will those 2 1/8 washers transfer to 2" that it needs to come over? i feel like there's something definitely wrong with the D spring pack. i just wish i would have done it myself instead of throwing $1000 to the wind and not fixing the issue. Thank you for everyone who has weighed in, this is my first Semi truck and I'm pretty mechanically inclined but i have no experience with air suspension Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted January 13, 2023 Share Posted January 13, 2023 (edited) May I suggest you call your Mack parts house and find out what the length of the correct torque arm is. I think it's 21".. you measure 'on center' if the one you have is the wrong length,. Well,,,, theres an issue right there.. jojo Edited January 13, 2023 by Joey Mack Pore cell fone sperring Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted January 13, 2023 Share Posted January 13, 2023 Another thing I think I see in the pics... Looks like the right rear air bag may have rotated at the top which can exaggerate the appearance of movement.. the axle is still wrong, but the air bag makes it look worse.. Look at the picture of the rear of the truck.. jojo 1 Quote Link to comment Share on other sites More sharing options...
Mark T Posted January 13, 2023 Share Posted January 13, 2023 Joey's right. Never mind shims, if you have a torque rod that's the wrong length to start out with . Someone has nice big bushings in them already.... which don't come in them ( so good chance they could be wrong length ) I see the shocks are on the back (good) You're way closer to being in line than you think as far as making it work goes. Major issue with side to side misalignment is those torque rods (or something to do with them) Quote Link to comment Share on other sites More sharing options...
tjc transport Posted January 13, 2023 Share Posted January 13, 2023 i agree. i bet if you run a ruler on the arms, you will find the rear is longer than the front. Quote when you are up to your armpits in alligators, it is hard to remember you only came in to drain the swamp.. Link to comment Share on other sites More sharing options...
fjh Posted January 14, 2023 Share Posted January 14, 2023 So you have what you have for suspension! Z leaf in my opinion is a road tractor suspension and piss pooor at that job!usually loose within the first year of operation! Unfortunately your stuck with it u got to work with what you have ! I have rebuild a fare few of these an if it hasn’t been said already you need to check the u bolts daily! They are prone to coming loose ! Even new and used for a road tractor they a border line suspension! For dump application you need to keep at it! just sayin! 1 Quote Link to comment Share on other sites More sharing options...
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