Tony Ingram Posted February 19, 2009 Share Posted February 19, 2009 Now that I've got the H-63 running, I thought now's a good time to take it around the block a few times. I thought I got all of the brakes dialed in pretty good but I was wrong. When I push the control valve in to release the brakes, I still have to get out and push the slack adjuster inward on the driver side rear can to move the truck. Once I get the truck rolling and begin to brake, halfway down on the pedal and it wants to stop immediately. When I take off the brakes feel like they're draggin a little too. Where do I start? I don't have any more leaks to speak of and the compressor's puttin out alot of air pressure. I replaced both valves in the rear also. Tried taking the covers off the rears to look at the brakes. Took both sets of 7/16" nuts off the top and bottom but noticed four 15/16" bolts need to come off to. Loosened them up and feels like they're spinning behind the brake cover. Do I have to take the rear wheels off to do this? Quote Link to comment Share on other sites More sharing options...
Superdog Posted February 19, 2009 Share Posted February 19, 2009 Now that I've got the H-63 running, I thought now's a good time to take it around the block a few times. I thought I got all of the brakes dialed in pretty good but I was wrong. When I push the control valve in to release the brakes, I still have to get out and push the slack adjuster inward on the driver side rear can to move the truck. Once I get the truck rolling and begin to brake, halfway down on the pedal and it wants to stop immediately. When I take off the brakes feel like they're draggin a little too. Where do I start? I don't have any more leaks to speak of and the compressor's puttin out alot of air pressure. I replaced both valves in the rear also. Tried taking the covers off the rears to look at the brakes. Took both sets of 7/16" nuts off the top and bottom but noticed four 15/16" bolts need to come off to. Loosened them up and feels like they're spinning behind the brake cover. Do I have to take the rear wheels off to do this?Sounds to me like its just an issue from the truck sitting unused.If your lucky,you can get all moving parts greased good,and just keep working them and eventually things will start working.Might also have a weak or broken spring in the brake chamber. Quote Link to comment Share on other sites More sharing options...
rw613 Posted February 19, 2009 Share Posted February 19, 2009 Now that I've got the H-63 running, I thought now's a good time to take it around the block a few times. I thought I got all of the brakes dialed in pretty good but I was wrong. When I push the control valve in to release the brakes, I still have to get out and push the slack adjuster inward on the driver side rear can to move the truck. Once I get the truck rolling and begin to brake, halfway down on the pedal and it wants to stop immediately. When I take off the brakes feel like they're draggin a little too. Where do I start? I don't have any more leaks to speak of and the compressor's puttin out alot of air pressure. I replaced both valves in the rear also. Tried taking the covers off the rears to look at the brakes. Took both sets of 7/16" nuts off the top and bottom but noticed four 15/16" bolts need to come off to. Loosened them up and feels like they're spinning behind the brake cover. Do I have to take the rear wheels off to do this?sounds like your s cam may be frooze up or the spring in the can is weak or broke or the big spring on your brake shoes is broke Quote Link to comment Share on other sites More sharing options...
peterj Posted February 19, 2009 Share Posted February 19, 2009 other than greaseing...could worn brake shoes or drum gettig ready to cam over.try backing the brake of f a LITTLE...also i have had a bad spring brake can cause somthing like this , but was the can on the other side... does this have spring brakes? Quote peterjhttp://forums.aths.org/Instantforum2010/topic72786.aspx57 mack h67 Link to comment Share on other sites More sharing options...
vanscottbuilders Posted February 20, 2009 Share Posted February 20, 2009 Tony,Just like the others have said - start by getting the drums offand greasing up all of the moving parts.That gives you a chance to check over the drums and linings too.I would also take the activator chambers apart to look for broken springs.The only issue here is that you could inadvertantly damage a bladderin the can. They'll be old and perhaps dried out, and easy to damage.They are easy to get and to replace though.The spring in the chamber is to help return the brake to an "off" position,if it's broken or damaged it will cause a dragging brake.One other little item to check is the quick release air valve. Take a look atthe Bendix Air Brake booklet, available at Bendix' web site. It has a simplediagram of a typical tractor/trailer air system, and identifies the QR valve'slocation in the system. The valve could be plugged or damaged, and will causethe brakes to delay on release.Hey man - at least it runs!! What else did you expect?Paul Van Scott Quote Link to comment Share on other sites More sharing options...
Tony Ingram Posted February 20, 2009 Author Share Posted February 20, 2009 (edited) I'm glad it runs now. The thing has actually smoothed out really well. It doesn't take but a cuople seconds of the start button and it lights off now. I took the driver side dust cover off today in hopes I could see all of the brake parts. Couldn't see nothing though. The shoes still have atleast a 1/2" of pad left though. I'm going to pull the hub off this weekend while mama's out of town. I think I can get alot more accomplished without having to break away every few minutes to help her do something. I started the truck up and let it build air pressure after I removed the dust cover. I set the brakes and then released them. I looked at the driver side bottom shoe and noticed it was still lying against the drum. I pushed the slack adjuster forward and it lifted up and stayed put. I'm assuming the spring inside the hub is broke but who am I to say. I'll start there and work my way to the cans. If everything is good and I get to the can and find out something is broke would I be better off in the long run to just buy a new one? Also I have a crack in the side of my tranny case about four inches long. I talked to a friend who is going to tig weld it up for me next week. I had drained the fluids and inspected the inside as much as I could though the foll hole on the side. Can't see a whole lot though. No shavings or metal debris casme out when I drained it. Any ideas what might have caused it? It seems to go into all gears fine so I don't think something is broke inside. It's an aluminum housed tri-plex. ALso I'm looking for the rear exhaust manifold for this too. Paul, you might be able to help me out here. The rear manifold turns down at almost a 90 degree angle after passing the #6 cylinder. I think mine is off of a B model cause it turned down at a 45 between the #5 and #6 cylinder. I modified it to work but would like to go with an original. Need the MACK emblem and vetical trim strip to. Bought a new PP1 valve and showed my old valve (a Gustin Baker) to the old boy at the brake shop. Said he hadn't seen one since the sixties and had a buddy who rebuilds them. He sent it off to try and get it rebuilt cause he said it would be cool to put it back in the truck. I've got the new valve in already but who knows. If he can rebuild it I might put it back in later or just hold onto it. He's got an early 50's bullnose KW he just finished so I finally found somebody in this farm town who's into old trucks like me. I knew somebody had to be out there. Will try to post a few pics of the tranny and exhaust if I can figure it out. Forgot to tell you it does have spring brakes. Edited February 20, 2009 by 16390 Quote Link to comment Share on other sites More sharing options...
peterj Posted February 20, 2009 Share Posted February 20, 2009 i'll try to add a picture of my exhaust...this is a maxidyne transplant... Quote peterjhttp://forums.aths.org/Instantforum2010/topic72786.aspx57 mack h67 Link to comment Share on other sites More sharing options...
vanscottbuilders Posted February 20, 2009 Share Posted February 20, 2009 Tony,I'll have to take a look at the exhaust manifolds.I never noticed the difference between the H and B models.Have both apart and visible in the shop.The decision to start with the simple brake parts is smart.As for the brake chamber - I usually rebuild mine, unless I'm updatingthe truck to new spring brake chambers. So many new parts say"Made in China" on them that I try to use old stuff whenever possible!Paul Van Scott Quote Link to comment Share on other sites More sharing options...
Tony Ingram Posted February 20, 2009 Author Share Posted February 20, 2009 I keep trying to post pics of the exhaust but it keeps telling me the file is larger than available space. I've seen numerous pics posted on other forums so I don't know what I'm doing wrong. I have some pics of an H-67 exhaust manifold from a guy in Virginia. I'll try and scan it so I can post it and a pic of mine so you can see the difference. Wish me luck. It will be later tonight so all of you east coasters will probably be done for the evening by the time I get it on here. Quote Link to comment Share on other sites More sharing options...
Tony Ingram Posted February 22, 2009 Author Share Posted February 22, 2009 Got it working right by lubung the heck out of everything and shooting it full of grease. Problem solved, now I'm just waiting for the next one. Thanks for the advice.. Quote Link to comment Share on other sites More sharing options...
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