RS Disposal

update on what is happening Like I stated previously the cylinder got to the point it would move after sitting a couple of weeks on the bench. Hooked up to the lines and bleed multiple times. Was able to extend and retract the cylinder with the pump multiple time. hooked up to the truck and locks up with the weight when trying to lower cab. unhooked from truck and again was able to extend and retract the cylinder. Only thing I can think of is, even though the pump is new, it is a 2 way pump and worked for a while, it is not specifically a cab tilt pump. So I ordered a cab tilt pump from PAI. Maybe something specific about a cab tilt pump that this pump isn't compatible with my system pump

This ram has a c clip type on the end

The hydraulic guy said he hooked it up to his test bench and wasn't able to get it to move either direction. There is no debris in the screens that are in the in ports. His theory was that even though new the internal checks valve malfunctioned. I know when I first put it on and bleed the lines the fluid came thru nice and clean with no debris to indicate hose failure I guess I try hooking it back up tomorrow and see if I can work it without the weight of the cab

Ok, after the ram just sitting on the bench for a couple of weeks cause I got frustrated. I can now by hand move the piston all the way in and out with no problem. Mu questions is now , how would be the proper way to bleed if there is an other way from the normal of just cracking the respective line and working the pump until all air is expelled. Should I be using something other than regular jack hydraulic oil?

This is a single cylinder setup. The pump was replaced a while back and worked quite awhile with the old ram before the same thing happened. I just assumed the old ram had dies being over 40 yrs old. I never did try working ram with the ram un installed but still hooked up. I did take it to my hydraulic guy and he wasn't able to do anything. Pretty sure there is something that I can do being i'm sure i'm not the only one that has had this problem. I just need to find the correct solution. As far a hydraulic oil, i used just regular jack oil. Didn't consult the factory manual.

I haven't been able to locate a bleed procedure in the factory trk shop manual. Haven't had alot of time to research on the internet yet.

Did a quick search and didn't really find an answer. Hopefully someone here has some hydraulic knowledge. While doing some major engine work (long story in another thread) my tilt ram stopped working. It just locked up solid Would collapse or extend, even with external pressure. Just figured it had gone bad being the truck is older. A new pump was installed and it worked for quite awhile before this happened. My hydraulic guy wanted almost $800 to rebuild and I was able to get a new one thru Mack for $900 so I went that route. Installed it and it worked for just one cycle and the it also locked up. My understanding of a hydraulic ram is very limited, but I for the life of me can't figure out why this has happened. I do know that the ram has a safety feature in case of a hydraulic line rupture so the cab doesn't come crashing down. What could I have done to of caused this problem again. I am thinking that for some reason the safety feature has locked it up for what ever reason. Any pointers as to what I might be able to do to correct the problem. If I cant figure it out then I guess I need to take back to dealer and see what they will/can do. Ram is only 1 week since purchase and only worked for one cycle. Even took it to my hydraulic guy to put on his test bench to eliminate a possible bad pump on my end. We are both at a loss as to why a new ram would act up unless I just happened to get a bad ram to start.

The 3/4 nut is easily accessible without pulling the drum. Once wheels are off the nut is just behind the flange on the drive hub. Only one needs replaced. not sure why Mack says the right hand is available but not the left hand. They also state that the 3/4 nut is no longer available, but that I am sure I can get at my local nut and bolt supplier

yes I do. The studs have nuts on the back side of the drive hub (are not the press thru type) that don't require the removal of the drum etc to replace

I admit I haven't done any "Googling" on this yet. It is a pain in the butt on a cell phone, so I thought I would ask the amazing people (who have helped me multiple times over the past 8 months) on this site for a recommendation on a source for these. The dealer says the left hand thread is no longer available, just the right hand thread. Anybody have a referral to a supplier that might have aftermarket studs? TIA Rob

the factory thermostat does have a bleed hole that does state either forward or up depending on orientation. the hole is now where near 1/8 th. Should I enlarge this?

Are these engines difficult to get all the air out of the cooling system? I know my daughter's jeep is a major pain in the butt to get the air purged out

Changed out the water filter (definitely was totally plugged up) and even though it only takes a sampling of the coolant, being plugged it impeded the flow of the water to a certain extent. The truck now runs about 15-20 degrees cooler in town than before. Still gets hot climbing the canyon though, but it cools down in about half the time.

I want to again thank you for all your insight and help over my journey with the breakdown I had last year. Being a newbie when it came to heavy trk diesel engines, I did learn alot in helping me understand this engine being my goal is to keep the truck in service for a while still.

The fan clutch was one thing that is on the list of replacing. Not sure about a fixed fan though being a cab over and the fan just right there next to the seats. Kinda noisy now when the clutch fan does kick in sounding like a jet engine. It's just not kicking in when I would think it should. Thew truck has been a real good worker even though it is an older truck, 1979. Only has about 145,000 road miles on it, most of which are city miles. But engine miles are more from running the pto for the compactor

I believe the model is MR685. Dealer lists it as a box truck, but it has a garbage compacter body on it

I will definitely look at that when I change out the water pump. Pretty sure the radiator needs rodding out. I'm just trying to understand this engine as I'm sure you are aware of from my "Needing Mack Head" thread

I do have the heat activated clutch fan. I can hear it roar to life at times but not really when I would think it should be. I have a cab over so I'm right there by the fan. That was one thing on my list of replacing as I troubleshoot the problem. Pretty sure my radiator needs to be rodded, but right now my truck can't be down for that length of time so I just watch my temp really close. Its fine all day long in the valley

My truck doesn't have a CAC and have washed off the radiator fins. Was the first thing I thought of. Pretty sure I am going to have to eventually take radiator into the shop. But was just wondering about how much of the coolant actually flowed thu the water filter. I do understand the problems a bad thermostat can cause. Right now just trrying the simple things first one at a time. I'm one that likes to know what fix works and what doesn't work.

From what I understand these brass radiators do need to be rodded out occasionally, Which is something I am planning on. But I thought I would tackle the simple things first. In going thru the maintenance history, I don't see where the water filter was last changed. My question is does all the water flow thru the filter or only a portion of it as the systems circulates the coolant? Could a plugged filter be a problem? Going to change that today anyway just so I can log when it was changed. Also bought a thermostat kit That I will hopefully change out later this week, weather cooperating being I work outdoors, just in case I do have a problematic thermostat. The truck runs about 190 all day long in the city. Only gets hot when I climb the canyon, where I do stop and let it cool.

compressor intake is before turbo

I have thought of that but haven't done it. I wouldn't think that would cause the boost gauge to flutter

If I had a loose valve seat wouldn't I get a mechanical sound rather that what sounds like a muffled pop pop? The sound only changes frequency with engine rpm, doesn't really get any louder or softer whether under load or coasting. Truck doesn't appear to have an engine miss and it pulls smooth. Going to, as I stated in my first post, get a clip of the noise and post. Going to do some trouble shooting, check exhaust temps with an infrared heat gun and also use a stethoscope and see what I can hear and find. Will pull rocker covers and double check valve lash and see if something there has changed. Just frustrated I can't seem to locate.

I just recently had to do a major repair on my engine, a 1979 Mack ENDTB 675 which required replacing the turbo (previous topic was "Looking for 1979 Mack head"). Wasn't able to find a direct replacement but this rebuilder stated this one was speced out to be a replacement. The rebuilt turbo has a larger diameter compressor housing (cold side). I have noise in the intake. The truck seems to be running ok, doesn't appear to be missing, idles smooth. This truck never had a boost gauge before for a reference comparison, but the boost gauge will flutter depending how far I'm into the throttle. A quick question, pretty sure this turbo is producing more boost than the original. From what I have been able to find out, the original was around 15 - 17 lbs boost. This turbo looks like it will boost upwards of around 20 lbs boost. I don't let it run that high before I back out of it. Is there a possibility that this much boost for THIS engine might be cause some mechanical issues? I know my Cummins N14 runs around 20 lbs when going up the canyon where my trucks work, but that that is a totally different and much larger engine. I will try and upload a video/audio file in the morning with the noise. If this is the new normal after this engine repair, I'm good with that, because it was a major repair. Rear head rebuilt and #4 piston replaced. I just don't like noises that I don't remember from before the breakdown.

I am still having this noise in the intake. The truck seems to be running ok. A quick question, pretty sure this turbo is producing more boost than the original. From what I have been able to find out, the original was around 15 - 17 lbs boost. This turbo looks like it will boost upwards of around 20 lbs boost. I don't let it run that high before I back out of it. Is there a possibility that this much boost for THIS engine might be cause some mechanical issues? I know my Cummins N14 runs around 20 lbs when going up the canyon, that that is a totally different and much larger engine. I also think I might start a new topic with this issue where as I am no longer looking for a head.