TIMWAR Posted October 11, 2022 Share Posted October 11, 2022 Newbie question….I really like the short wheelbase B42 with a dump body. I had one 36 years ago. I don’t see many around for sale. my question is …can you convert a tandem axle to single axle ? and can the wheelbase be changed ? Are there existing holes in the frame to do this ? Is this a common thing they might have been done “ back in the day”? I hope this isn’t a dumb question .. thanks in advance Quote Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/ Share on other sites More sharing options...
mechohaulic Posted October 11, 2022 Share Posted October 11, 2022 there are no such things as dumb questions . it more of a dumb situation not to ask a question. my point of view to take a tandem and convert to a single would :1- require a lot of parts,another rear end= 2- alot of drilling . your drilling new holes =you can make any wheel base that works for you. 3-do you have a truck already or in the looking stage. Quote Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511502 Share on other sites More sharing options...
TIMWAR Posted October 11, 2022 Author Share Posted October 11, 2022 Thank you for responding.. I am looking for a B model. I let my B42 go years ago and have regretted it ever since. I’m not a trucker…just a hobbiest Quote Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511516 Share on other sites More sharing options...
mechohaulic Posted October 11, 2022 Share Posted October 11, 2022 it would be much easier to find a descent B model single axle tractor = remove 5th wheel add a dump body. if a dump truck is what you are aiming for. to make a single axle from twin- screw challenging. B42 - gas job. I had a '49 EE dump with plow. lots of fun plowing snow. regrettably I let that go. Quote Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511518 Share on other sites More sharing options...
TIMWAR Posted October 11, 2022 Author Share Posted October 11, 2022 I guess I just need to be patient. It’s very frustrating. Quote Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511520 Share on other sites More sharing options...
Licensed to kill Posted October 11, 2022 Share Posted October 11, 2022 It is easy to shorten a wheel base,MUCH easier than lengthening one. If you are starting with a tandem, just toss the t]front diff and move the back one to where you want and drill the holes for the hangers. Easier still if the front axle is where you want the single to go. Depending on how the springs are set up on a tandem it MAY require replacement (single axle) springs and hangars. I shortened my single axle from around 170" to 156" wheel base but I also put air ride. Quote Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511523 Share on other sites More sharing options...
TIMWAR Posted October 11, 2022 Author Share Posted October 11, 2022 Thank you for that information Quote Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511534 Share on other sites More sharing options...
doubleclutchinweasel Posted October 11, 2022 Share Posted October 11, 2022 Most Mack tandems will use camelback springs. Not that easy to just remove one axle. The single-screw springs are different. Like LTK said, you might be able to use the rear axle, relocated forward. But, the spring perches on the axle housing will probably have to be changed. Again, with enough time, money, and work, you can do just about anything. I have seen single-axle Macks with both the top-loaded and front-loaded differentials used. So, there are some options out there. But, like Mech said, it's a LOT easier to find a single axle to start from. 1 1 Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511539 Share on other sites More sharing options...
Licensed to kill Posted October 11, 2022 Share Posted October 11, 2022 (edited) 1 hour ago, doubleclutchinweasel said: But, like Mech said, it's a LOT easier to find a single axle to start from. And the only difficult part of THAT is location. I have one complete with springs and hangars to GIVE away but I suspect you are not all that close to me. Truck transport would be likely $1000 for it (that was the quote for transport of a complete diff from Ontario to here a year ago IIRC) so obviously finding one closer would be the ticket. I don't think finding another one for free would be all that difficult. Edited October 11, 2022 by Licensed to kill 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511546 Share on other sites More sharing options...
mechohaulic Posted October 11, 2022 Share Posted October 11, 2022 as was written in first text;; he's a hobbyist , there are many ways all of which have been explained here to get back the B42 single axle he once had. would take a decent shop set up to convert a tandem to single axle. with time and $$$$$ anything can be done. always easier to shorten one . I did a ford long wheelbase box , made it into a short base dump. as with all forums hopefully updates will follow. Quote Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511550 Share on other sites More sharing options...
Popular Post Licensed to kill Posted October 11, 2022 Popular Post Share Posted October 11, 2022 For the record, by the time I finish my current "B" project I will have completed my 3rd "down to the bare frame" B model mack so will have some experience that I would be happy to share should you need any help making changes. To be clear, the truck I am working on is the ONLY B Mack that I will have done but I have done everything at least 3 times so I figure that this qualifies as 3 complete projects. 😃 3 Quote Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511551 Share on other sites More sharing options...
67RModel Posted October 11, 2022 Share Posted October 11, 2022 15 hours ago, TIMWAR said: Newbie question….I really like the short wheelbase B42 with a dump body. I had one 36 years ago. I don’t see many around for sale. my question is …can you convert a tandem axle to single axle ? and can the wheelbase be changed ? Are there existing holes in the frame to do this ? Is this a common thing they might have been done “ back in the day”? I hope this isn’t a dumb question .. thanks in advance If you find a tandem truck and want to make it a short single axle I would say its fairly easy. You will need to find a single axle rear end with leaf springs with the proper gear ratio for a gas engine (I think a B42 is a gasser). I think @Mean Greenhas one he is willing to donate to a good home. Like others have said a tandem will most certainly have a camelback suspension and using one the tandem axles isn't really feasible. As far as installing the the new single axle onto the frame I would say its a straight forward process if the rear end you get has the leaf springs and hangers still attached. I shortened my R model from 207" to 165" wheelbase with just basic tools when I was forced to stay home for covid19 lockdown. Took about three days of work to complete but I took my time and was methodical about it. Pretty much all I needed was a 1/2" breaker bar with a 15/16" socket, 15/16" wrench, 1/2" drill, a premium quality Cobalt 5/8" drill bit, a tape measure, sledge hammer, and a lot of muscle. I was able to shorten my existing driveshaft. I think the shop charged me somewhere around $150 to shorten and rebalance my driveshaft. You may need to get a new driveshaft made if the yokes are not the same on between the two different axle setups. Not really a big deal though. Attached are some of the pictures of when I shortened mine. Very doable project. IMG_2218.thumb.JPG.d7a3ddd174da412e29a9220f8a8142c1.jfif IMG_2223.thumb.JPG.a81b9cb40800122b8d6882caa8d4673a.jfif IMG_2224.thumb.JPG.bd76e86dfa69ba31639d6eced30c7869.jfif IMG_2244.thumb.JPG.be4a5464f06fe84c009c64a71c17c5a5.jfif 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511556 Share on other sites More sharing options...
doubleclutchinweasel Posted October 11, 2022 Share Posted October 11, 2022 1 hour ago, 67RModel said: If you find a tandem truck and want to make it a short single axle I would say its fairly easy. You will need to find a single axle rear end with leaf springs with the proper gear ratio for a gas engine (I think a B42 is a gasser). I think @Mean Greenhas one he is willing to donate to a good home. Like others have said a tandem will most certainly have a camelback suspension and using one the tandem axles isn't really feasible. As far as installing the the new single axle onto the frame I would say its a straight forward process if the rear end you get has the leaf springs and hangers still attached. I shortened my R model from 207" to 165" wheelbase with just basic tools when I was forced to stay home for covid19 lockdown. Took about three days of work to complete but I took my time and was methodical about it. Pretty much all I needed was a 1/2" breaker bar with a 15/16" socket, 15/16" wrench, 1/2" drill, a premium quality Cobalt 5/8" drill bit, a tape measure, sledge hammer, and a lot of muscle. I was able to shorten my existing driveshaft. I think the shop charged me somewhere around $150 to shorten and rebalance my driveshaft. You may need to get a new driveshaft made if the yokes are not the same on between the two different axle setups. Not really a big deal though. Attached are some of the pictures of when I shortened mine. Very doable project. IMG_2218.thumb.JPG.d7a3ddd174da412e29a9220f8a8142c1.jfif 61.83 kB · 2 downloads IMG_2223.thumb.JPG.a81b9cb40800122b8d6882caa8d4673a.jfif 62.38 kB · 1 download IMG_2224.thumb.JPG.bd76e86dfa69ba31639d6eced30c7869.jfif 59.42 kB · 0 downloads IMG_2244.thumb.JPG.be4a5464f06fe84c009c64a71c17c5a5.jfif 61.63 kB · 2 downloads That just about sums it up! 1 Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511558 Share on other sites More sharing options...
TIMWAR Posted October 11, 2022 Author Share Posted October 11, 2022 Thank you for these responses… I’ll keep searching for a single axle dump truck … but sounds like a conversion is at least a possibility Quote Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511559 Share on other sites More sharing options...
mechohaulic Posted October 12, 2022 Share Posted October 12, 2022 one thought to keep in mind; if you find a single axle dump : 1- check to see if it was a tractor converted to dump{ might have holes in the rails where a 5th wheel was mounted)'a road tractor may have a different ratio rear set up for strictly road use. 2 -road tractor transmission may not work for your purpose. as a hobbyist trying to duplicate a previous truck won't make much difference. just expressing thoughts which might go unnoticed . 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511595 Share on other sites More sharing options...
Licensed to kill Posted October 12, 2022 Share Posted October 12, 2022 12 hours ago, mechohaulic said: one thought to keep in mind; if you find a single axle dump : 1- check to see if it was a tractor converted to dump{ might have holes in the rails where a 5th wheel was mounted)'a road tractor may have a different ratio rear set up for strictly road use. 2 -road tractor transmission may not work for your purpose. as a hobbyist trying to duplicate a previous truck won't make much difference. just expressing thoughts which might go unnoticed . I thought that the B only came with a duplex, triplex or quadplex any of which should be fine in a single axle dump. Again, I have a duplex and triplex for free should anyone want but shipping...............ouch. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511671 Share on other sites More sharing options...
Mean Green Posted October 12, 2022 Share Posted October 12, 2022 The rear out of my B42 originally is gone I put a diesel rear with better gears as I couldn't go over 45 in it but if you can use it you can have it Quote If your going to be a bear be a grizzly Link to comment https://www.bigmacktrucks.com/topic/70541-b-model-wheelbase-options/#findComment-511732 Share on other sites More sharing options...
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