MACK321 Posted March 18, 2023 Author Share Posted March 18, 2023 Heading to the yard to measure the height Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527436 Share on other sites More sharing options...
Joey Mack Posted March 18, 2023 Share Posted March 18, 2023 good deal.. I have chores to do, so I may be slow to respond. Jojo Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527437 Share on other sites More sharing options...
MACK321 Posted March 18, 2023 Author Share Posted March 18, 2023 Thank you Joey Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527438 Share on other sites More sharing options...
MACK321 Posted March 18, 2023 Author Share Posted March 18, 2023 Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527439 Share on other sites More sharing options...
Joey Mack Posted March 18, 2023 Share Posted March 18, 2023 Go to the front drive, and measure from the bottom of the spring, to the bottom of the frame rail Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527440 Share on other sites More sharing options...
MACK321 Posted March 18, 2023 Author Share Posted March 18, 2023 I will in a bit left the yard Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527441 Share on other sites More sharing options...
Joey Mack Posted March 18, 2023 Share Posted March 18, 2023 Call me.. 704 785 1738 when you get there Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527442 Share on other sites More sharing options...
MACK321 Posted March 18, 2023 Author Share Posted March 18, 2023 Perfect I will Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527448 Share on other sites More sharing options...
Joey Mack Posted March 18, 2023 Share Posted March 18, 2023 Here is my little diagram of how slack adjusters are mounted on your truck.. I hope others add to this tutorial.. I suggest you re-read the posts from Mechohaulic and MrsMackPaul, and MarkT... Jojo Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527460 Share on other sites More sharing options...
mrsmackpaul Posted March 19, 2023 Share Posted March 19, 2023 This might help, or maybe not This is of course a trailer axle, but the same principle applies Some other axles about the place, these come in many shapes and sizes Paul 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527470 Share on other sites More sharing options...
mechohaulic Posted March 20, 2023 Share Posted March 20, 2023 If the issue is height related, wouldn't both wheels on rear act the same . exception might be due to left side wheel is on crown of road right side lower . as with many issues on this site - not being there to physically inspect challenges things. an empty trailer should have enough weight to pressure air suspension. out of round drum if jacked up and manually spun should indicate issue. also out of round would have a tendency to run hotter loaded ? tires /brake shoes/ drums all check out ; i'm back to slack adjuster error == be it over adjusting, or mis aliment. over adjusting would give a lock up / hot wheel run too long. before spending more $$$; the swap right to left drums, possibly shoes has my vote. Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527516 Share on other sites More sharing options...
Joey Mack Posted March 20, 2023 Share Posted March 20, 2023 I would like to be there also . I think I would jack the drives up and try adjusting the brakes till they just barely scrub, kinda like drums brakes on a pick up truck. Then test drive it.. it is tough when you are not there to see the issue.. jojo 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527524 Share on other sites More sharing options...
Joey Mack Posted March 20, 2023 Share Posted March 20, 2023 Is it me, or does the frame look twisted in the second picture? Maybe do like Mechohaulic said and swap the brakes and drums to see if the issue follows .. this test is free. Buying brakes and drums gets expensive quick. 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527525 Share on other sites More sharing options...
mechohaulic Posted March 20, 2023 Share Posted March 20, 2023 now that's what I call expert observations of mechanical nature terms of twisted frame picture two. focus on tape measure till looking toward fifth wheel , cross member looks straight can't be camera angle. my vote also cast for twist some where. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527528 Share on other sites More sharing options...
mechohaulic Posted March 20, 2023 Share Posted March 20, 2023 possible to unplug fuse for speed sensors for road test ? lack lube on cam or rusted pin on slack adjuster? Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527529 Share on other sites More sharing options...
fjh Posted March 20, 2023 Share Posted March 20, 2023 Duno Id try what Joey mentioned there! also with the wheel jacked up set the slack till shoes just touch and rotate the wheel by hand and see of there is a tight spot indicating an out of round drum! Or another scenario loos wheel bearings ! I have seen this issue with out the seal leaking! 2 Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527530 Share on other sites More sharing options...
mechohaulic Posted March 20, 2023 Share Posted March 20, 2023 wheel loose enough to screw up braking should 1 - wobble noticeably-2 have wheel seal leak , should have been noticed by the mechanic. need two people ; one to watch brake action while other applies brakes. leaning towards rusted clevis pin in slack. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527532 Share on other sites More sharing options...
Joey Mack Posted March 20, 2023 Share Posted March 20, 2023 Mech.. my old timer gave me the nickname 'Clevis' 20+ years ago.. I was chasing a front brake issue on a late 70's DM.. after an hour or so,. Well.. it was a rusted clevis pin.. Too funny, and true.. Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527533 Share on other sites More sharing options...
mechohaulic Posted March 20, 2023 Share Posted March 20, 2023 notice the auxiliary helper return spring in picture of blue trailer axle on slack adjuster. possible another slow acting brake can. maybe that's what this truck needs Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527534 Share on other sites More sharing options...
mechohaulic Posted March 20, 2023 Share Posted March 20, 2023 amazing how the mind goes after the technical possibility's before looking towards a simple solution many times. a serviced unit may be greased regular yet the simple items such as clevis pins overlooked. Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527535 Share on other sites More sharing options...
mrsmackpaul Posted March 20, 2023 Share Posted March 20, 2023 1 hour ago, mechohaulic said: notice the auxiliary helper return spring in picture of blue trailer axle on slack adjuster. possible another slow acting brake can. maybe that's what this truck needs They are the only axles I have with springs like those The dolley those axles are on is the most modern thing I own, I noticed when I was at Maxi parts (big truck parts supply chain in Australia) that all new axles they have also have these springs I reckon those springs are a good idea but wonder if proper maintenance would alleviate the need for springs The axles are K Hitch brand, pretty sure they are Chinese but are on a lot of trailers these days out here I have never had a drama with them Paul 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527541 Share on other sites More sharing options...
Mark T Posted March 20, 2023 Share Posted March 20, 2023 I noticed the return springs too. Not sure what I think of them, but they have me think'n Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527561 Share on other sites More sharing options...
Hayseed Posted March 20, 2023 Share Posted March 20, 2023 Might be a dodgey Quick release Valve...........maybe.. Quote "Be who you are and say what you feel...Because those that matter...don't mind...And those that mind....don't matter." - Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527562 Share on other sites More sharing options...
mechohaulic Posted March 21, 2023 Share Posted March 21, 2023 seems to me if quick release valve is faulty; tendency would be both wheels effected ? one valve for two wheels. jack up rear axle so both wheels spin. set on jack stands ; chock front wheels SAFETY IS PRIORITY sLOWLY put in gear while someone watches ' apply brakes and release;; back in gear slowly or after brake release try manual spin each wheel. Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527570 Share on other sites More sharing options...
Joey Mack Posted March 21, 2023 Share Posted March 21, 2023 any news on this?? Quote Link to comment https://www.bigmacktrucks.com/topic/72584-rear-passenger-axle-locking-when-braking/page/2/#findComment-527624 Share on other sites More sharing options...
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