leversole Posted March 8, 2012 Author Share Posted March 8, 2012 WTF? Didnt notice this before!Can anyone tell me if this is rubber or brass bushed? And where are the bushing, on the trunnion stand or the spring mount?Thanks! Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-106113 Share on other sites More sharing options...
David Posted March 8, 2012 Share Posted March 8, 2012 What kind of fifth wheel is that? Is it welded to the frame? Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-106116 Share on other sites More sharing options...
leversole Posted March 8, 2012 Author Share Posted March 8, 2012 An old non functioning gutted Fruehauf, just bolted to the crossmember for show... Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-106121 Share on other sites More sharing options...
David Posted March 8, 2012 Share Posted March 8, 2012 Looks like it was made for a truck with a real narrow frame. Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-106122 Share on other sites More sharing options...
leversole Posted March 8, 2012 Author Share Posted March 8, 2012 Yeah, it came with the truck, it was on a bent up corrugated plate.... Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-106177 Share on other sites More sharing options...
MACKS Posted March 8, 2012 Share Posted March 8, 2012 WTF? Didnt notice this before!Pretty sure it's legal to weld cracks on the trunnion stand,in fact the dot inspector that found a crack on one of mine told me to get it welded asap... Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-106199 Share on other sites More sharing options...
leversole Posted March 10, 2012 Author Share Posted March 10, 2012 WTF? Didnt notice this before!Can anyone tell me if this is rubber or brass bushed? And where are the bushing, on the trunnion stand or the spring mount?Thanks! Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-106493 Share on other sites More sharing options...
leversole Posted March 10, 2012 Author Share Posted March 10, 2012 Did some measuring today...From rear of cab crossmember face to front of trunnion stand crossmember faceleft side 89 1/2" right side 89 7/16"Bolt center cab crossmember to front trunnion (square bracket)left side AND right side 66 1/4"SquareMeasured a point on top of frame rail x distance from cab crossmember (used a square) topoint on top of frame in line with front trunnion bracket bolts (used plumb bob)1st diagonal 77 1/8 2nd diagonal 77 3/8Measured from front axle to front rear diagonally...1st diagonal 139" 2nd diagonal 139 1/2" BUT...The axles housing on drivers side seems to be back almost 1/2" in relation to the spring end...that would also explain why the front of the drive housing is over towards the drivers side more than others have measured...Anyhow, I lools like the frame may be out of square by 1/4" or less...dont know if this a lot or a little?I guess my plans are to find/build/modify a crossmember to stiffen the frame where the frame was spliced, and maybe retro fit some shocks to the front axle...also try to figure out why the front axle is canted..and the sliding joint on the driveshaft is definitely not sliding, will check if it is bottomed out... Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-106562 Share on other sites More sharing options...
Rob Posted March 11, 2012 Share Posted March 11, 2012 Did some measuring today...From rear of cab crossmember face to front of trunnion stand crossmember faceleft side 89 1/2" right side 89 7/16"Bolt center cab crossmember to front trunnion (square bracket)left side AND right side 66 1/4"SquareMeasured a point on top of frame rail x distance from cab crossmember (used a square) topoint on top of frame in line with front trunnion bracket bolts (used plumb bob)1st diagonal 77 1/8 2nd diagonal 77 3/8Measured from front axle to front rear diagonally...1st diagonal 139" 2nd diagonal 139 1/2" BUT...The axles housing on drivers side seems to be back almost 1/2" in relation to the spring end...that would also explain why the front of the drive housing is over towards the drivers side more than others have measured...Anyhow, I lools like the frame may be out of square by 1/4" or less...dont know if this a lot or a little?I guess my plans are to find/build/modify a crossmember to stiffen the frame where the frame was spliced, and maybe retro fit some shocks to the front axle...also try to figure out why the front axle is canted..and the sliding joint on the driveshaft is definitely not sliding, will check if it is bottomed out...Dead on square is best but +/- 1/32" is alright to me. You are about eight times that. Frame squareness is where everything begins. When a frame is out of square, (and lets say left side more forward than right side) the drive axles through the trunion bushings are loading heavily on the left side trying to keep the axles parallel the the imaginary centerline of thrust angle. This puts abnormal pressure upon the trunion bushings/bearings and as these trunion bushings wear, abnormal side loading is absorbed by the "elephant pads" at the ends of the springs. A combination of excess wear in these two sets of bushings are allowing the actual actual axle centerline to shift. What you have here is a lot of worn parts necessatating replacement to be within tolerance.The first thing to do in my opinion is to get that frame square. I would find a set of holes on each side of the frame rails prior to the splicing and check for squarness there before cutting the truck apart. If you have a "diamond" condition starting further forward, this must be straighted also.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/21884-bounce-slow-motion-video/page/5/#findComment-106587 Share on other sites More sharing options...
leversole Posted March 11, 2012 Author Share Posted March 11, 2012 So, I should be able to see this by video-ing a nice closeup that shows the inner part of the tire and the frame, after moving forward, backing up should produce a noticable movement as the axles try to track to the other side right?Guess I will have to drop plumb lines on all major componenets to the ground to measure like I would when rigging an airplane! Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-106601 Share on other sites More sharing options...
Rob Posted March 11, 2012 Share Posted March 11, 2012 So, I should be able to see this by video-ing a nice closeup that shows the inner part of the tire and the frame, after moving forward, backing up should produce a noticable movement as the axles try to track to the other side right?Guess I will have to drop plumb lines on all major componenets to the ground to measure like I would when rigging an airplane!Put a block between the tires on one side of the truck, and ease both forward and backward and you should see things move as the blocked side binds against the block.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/21884-bounce-slow-motion-video/page/5/#findComment-106602 Share on other sites More sharing options...
leversole Posted March 11, 2012 Author Share Posted March 11, 2012 Always wondered if they shortened the frame why there were two welds in the inner frame, looked a short section was added...I knew it started life as a tractor and at some point was converted to a dump...looked back at my Mack paperwork and see that it was special ordered at 146" wheelbase. it is now 165"...that explains it, they lengthened it! Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-106709 Share on other sites More sharing options...
Rob Posted March 11, 2012 Share Posted March 11, 2012 Always wondered if they shortened the frame why there were two welds in the inner frame, looked a short section was added...I knew it started life as a tractor and at some point was converted to a dump...looked back at my Mack paperwork and see that it was special ordered at 146" wheelbase. it is now 165"...that explains it, they lengthened it!That was my unknowing assumption all along. Never gave a thought to being shortened.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/21884-bounce-slow-motion-video/page/5/#findComment-106712 Share on other sites More sharing options...
leversole Posted March 12, 2012 Author Share Posted March 12, 2012 That was my unknowing assumption all along. Never gave a thought to being shortened.RobAlways knew you had some kind of extra sensory perspiration! Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-106765 Share on other sites More sharing options...
Rob Posted March 12, 2012 Share Posted March 12, 2012 Always knew you had some kind of extra sensory perspiration! Yes, and of all the things I've lost, I miss my BALLS!!!, Without a doubt, I miss my balls the most.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/21884-bounce-slow-motion-video/page/5/#findComment-106768 Share on other sites More sharing options...
David Posted March 12, 2012 Share Posted March 12, 2012 It would be interesting to see this truck going down the road and look for "doglegging". Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-106769 Share on other sites More sharing options...
leversole Posted March 12, 2012 Author Share Posted March 12, 2012 It would be interesting to see this truck going down the road and look for "doglegging".Same thing I was thinking! Gonna have my wife and son follow me with the video camera! Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-106772 Share on other sites More sharing options...
Rob Posted March 12, 2012 Share Posted March 12, 2012 It would be interesting to see this truck going down the road and look for "doglegging".There would have to be some if ever so slight. New trucks do it also due to production type alignments.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/21884-bounce-slow-motion-video/page/5/#findComment-106773 Share on other sites More sharing options...
220cummins Posted March 20, 2012 Share Posted March 20, 2012 what does your caps look like on the trunnion. does it have a rubber bushing or a cap with with a zerk fitting. post a picture. Those trunnion stands sometimes crack laterally up the center behind the springs. Check for cracks there too. As for the welding of the bottom of your stand goes, if it were done properly it should hold up fine. check those for cracks in the weld.It could be letting the trunnion beam "service spindle" walk or move causing the shake. also check the center bolts, check the bushing caps are drawn up good on the bushing rubber or bronze Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-109069 Share on other sites More sharing options...
220cummins Posted March 20, 2012 Share Posted March 20, 2012 http://truckbusters.wordpress.com/2006/04/24/how-big-is-your-rear/ a pretty good description on spotting rears Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-109070 Share on other sites More sharing options...
David Posted March 21, 2012 Share Posted March 21, 2012 http://truckbusters....g-is-your-rear/ a pretty good description on spotting rearsPat, That's a very good link. Thanks for posting. Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-109095 Share on other sites More sharing options...
220cummins Posted March 21, 2012 Share Posted March 21, 2012 No problem. I just came across that last night. I was going to post a picture of the difference between rubber and brass bushing but then I came across that site. Pretty much sums up the differences. Quote Link to comment https://www.bigmacktrucks.com/topic/21884-bounce-slow-motion-video/page/5/#findComment-109151 Share on other sites More sharing options...
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