DodgeMan Posted April 4, 2012 Share Posted April 4, 2012 I got to get the frame on my B81 streched 2 foot. Was thinking of taking all the rails apart cleaning them and paitning them.1 Has anyone done this?2 What did you do with the rivets that hold the rails and cross members together?3 Im going to weld the new section of rail into the center. Good or bad idea?( center 2 ft, outside 3 to 4 ft piece and then cap that with a longer pice bolted threw the other 2)Cab cross members cracked.The cross member behind that is a I beam with a 1 inch thick flange (who ever built it did one hell of a nice job). Quote Link to comment https://www.bigmacktrucks.com/topic/24298-mack-frame-rail-questions/ Share on other sites More sharing options...
Rob Posted April 4, 2012 Share Posted April 4, 2012 In order or your questions:1: Yes, I have performed this operation.2: I used a slice disc and take the heads off flush with the frame.3: Most will tell you to graft onto the end of the frame rails, then roll the axles back to the location needed. I've done it this way, and just grafted the section into the middle both without problems. If you add to the middle, you have twice the welding to do. I would weld up the cracked crossmembers myself.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/24298-mack-frame-rail-questions/#findComment-112233 Share on other sites More sharing options...
David Posted April 4, 2012 Share Posted April 4, 2012 Sometimes you can move the suspension back and reuse some of the factory holes. Makes lining everything up much easier. Quote Link to comment https://www.bigmacktrucks.com/topic/24298-mack-frame-rail-questions/#findComment-112235 Share on other sites More sharing options...
DodgeMan Posted April 5, 2012 Author Share Posted April 5, 2012 What did you replace the rivets with?I was going to add on to the end but the rails cracked in 2 spots on one side a one on the other in the center.Thanks rob and david.Was going to start on the LJ but i need to get the 5 ton wrecker off to its new owner soon. So i might as well put the wrecker body right on the frame its going on. Quote Link to comment https://www.bigmacktrucks.com/topic/24298-mack-frame-rail-questions/#findComment-112404 Share on other sites More sharing options...
Rob Posted April 5, 2012 Share Posted April 5, 2012 What did you replace the rivets with?I was going to add on to the end but the rails cracked in 2 spots on one side a one on the other in the center.Thanks rob and david.Was going to start on the LJ but i need to get the 5 ton wrecker off to its new owner soon. So i might as well put the wrecker body right on the frame its going on.I use grade 8 fine thread bolts and either lockwashers and nuts, or Nylock nuts, (hardened). You want these tight.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/24298-mack-frame-rail-questions/#findComment-112405 Share on other sites More sharing options...
daveigou Posted April 5, 2012 Share Posted April 5, 2012 I agree with what's been said here already. As far as replacing the rivets, you really don't have a choice, grade 8 bolts into ream-to-fit holes. For what you're going to do on a truck like that, I think to weld the cracks would be acceptable, cut the inner frame back farther so as to stagger the joints, and to get weld inside and outside of the outer rails. 1 Quote See my Flickr photostream page http://www.flickr.com/photos/96692978@N05/ Link to comment https://www.bigmacktrucks.com/topic/24298-mack-frame-rail-questions/#findComment-112408 Share on other sites More sharing options...
DodgeMan Posted April 5, 2012 Author Share Posted April 5, 2012 Thats why i was going to split and clean them, makes it easyer to weld both sides and grind/ sand them clean. Thought id take the section of rail out on each side that has problems. I took these pics a while back. Quote Link to comment https://www.bigmacktrucks.com/topic/24298-mack-frame-rail-questions/#findComment-112417 Share on other sites More sharing options...
Jamied625 Posted April 5, 2012 Share Posted April 5, 2012 What did you replace the rivets with?I was going to add on to the end but the rails cracked in 2 spots on one side a one on the other in the center.Thanks rob and david.Was going to start on the LJ but i need to get the 5 ton wrecker off to its new owner soon. So i might as well put the wrecker body right on the frame its going on.you are making the b-81 into a wrecker? Quote Link to comment https://www.bigmacktrucks.com/topic/24298-mack-frame-rail-questions/#findComment-112421 Share on other sites More sharing options...
DodgeMan Posted April 5, 2012 Author Share Posted April 5, 2012 Wrecker/ rotary crane. Quote Link to comment https://www.bigmacktrucks.com/topic/24298-mack-frame-rail-questions/#findComment-112429 Share on other sites More sharing options...
DodgeMan Posted April 5, 2012 Author Share Posted April 5, 2012 I still got the complete truck, but the guy that bought the driveline would like it soon. Retired people think us working class have all the time in the world. Quote Link to comment https://www.bigmacktrucks.com/topic/24298-mack-frame-rail-questions/#findComment-112433 Share on other sites More sharing options...
Olivetroad Posted April 5, 2012 Share Posted April 5, 2012 cut the inner frame back farther so as to stagger the joints, and to get weld inside and outside of the outer rails.That is what most guys around here don't do out of laziness and then it shows down the road. Quote Link to comment https://www.bigmacktrucks.com/topic/24298-mack-frame-rail-questions/#findComment-112436 Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.