glenn_reid Posted February 5, 2008 Share Posted February 5, 2008 I have owned lots of old [1-ton and similar] trucks but never a venerable Mack, until last week. I'm getting to know her; what a great, great truck! I have a dumb question...It feels like the brakes are stuck on. The truck won't roll in neutral, and when I start it and drive it, even with the air brake off and the hand brake seemingly off, it feels like the brakes are on all the time.Before I start digging into all the various braking systems to figure out what's wrong, I thought I would ask if there is something obvious I'm missing, and if it's even reasonable to expect this truck to roll when in neutral.Thanks for any thoughts...Glenn ReidCalifornia Quote Link to comment Share on other sites More sharing options...
Lmackattack Posted February 5, 2008 Share Posted February 5, 2008 are the slacks and S-cams greased up good? they can start to stick after sitting long. jack up each corner and see what wheel is not released, the wheels should all turn by hand with not much effort. if that hand brake is the issue the pads are sticking and the mechanics of the assy needs grease or some help. Go for a spin and see if the park brake drum gets warm/hotTrent Quote Link to comment Share on other sites More sharing options...
Freightrain Posted February 5, 2008 Share Posted February 5, 2008 Seeing you have hand brake, I'd start there. Take a quick spin around the block and then check temp of parking brake drum. Real hot? Then it's hangin up. Like Trent mentioned, try rolling each tire, as that would determine if it's a wheel brake.I had a rear brake/s-cam hanging up on mine when I first got it. I had to bump the clutch to get truck to release and roll. It would be fine there after, but first trip of day it would hang up. With the constant greasing now that problem has faded away.There is a grease point on all brake shoe hinge points. If that bushing gets dry, the brake shoe will stick at where ever it's put. Another issue with mine was front brakes were unhooked(no air) and the shoes were froze tight. It took heat to get shoes off pins. After some honing and grease they work flawless now. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment Share on other sites More sharing options...
sbrem Posted February 5, 2008 Share Posted February 5, 2008 One other simple thing to check is make sure the brake pedal isn't sticking down just a little. Sounds dumb, but I got fooled by it once. Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted February 5, 2008 Share Posted February 5, 2008 One other simple thing to check is make sure the brake pedal isn't sticking down just a little. Sounds dumb, but I got fooled by it once. I may add to this , one simple way to check this is to crack a air line to a sevice chamber to see if any preesure is applied because a foot valve can hang down on the inside with out the thredle holding it down.glenn Quote glenn akers Link to comment Share on other sites More sharing options...
MACKS Posted February 5, 2008 Share Posted February 5, 2008 It could also be week or broken springs on the brake shoes or a flat spot or rust on the s cam,the brakes or drums could be worn to mush causing the s cam to get hung up,you might try to spray some wd40 or something like it directly on the s cam where it hits the brake shoe that will work for a while.And yes your truck should roll free when in neutral,you might also have a hard time shifting if a brake is hung up.Good Luck Quote Link to comment Share on other sites More sharing options...
m5040 Posted February 6, 2008 Share Posted February 6, 2008 One other simple thing to check is make sure the brake pedal isn't sticking down just a little. Sounds dumb, but I got fooled by it once.Another sign of this problem is the brake lights stay on. Quote Link to comment Share on other sites More sharing options...
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