RS Disposal

6 hours ago, JoeH said:

Is truck parked outside in the cold or inside in the heat? Are you trying to tilt cab in sub freezing temps? You could have water/ice acting as a check valve flowing back and forth.

You could also have the lines hooked up backwards/in the wrong ports.

the truck is parked outside.  The problem first appeared before it got cold enough for water to freeze.  The plumbing was reinstalled the same way the original cylinder was plumbed.

Im the type of personality that I prefer to do one repair at a time when trouble shooting a problem.. I like to know what works and what didn't.  This problem was starting to get me really frustrated so I actually did two things at once.  Not sure what the end problem was, but I got the tilt cab system working.  I put on a new "tilt cab " specific pump (rather than the generic 2 way pump I had on it) and I flushed and filled the system with the Mil H-5606 aviation fluid.  This fluid is definitely much thinner viscosity that regular jack fluid. Pretty expensive also. $55 a gallon of Amazon.  nobody here in my town had a clue what I was talking about.  LOL. Maybe the newer check valves in the ram are really picky.

7 minutes ago, Geoff Weeks said:

I had two cabovers (IHC's) that had powerpacker pump and "over center" long cyl. They had the cross checks, and I had one leaky cyl, so had to often add fluid, and I found if it was wet petroleum product, it would work. I would use anything and it worked. ATF, PS fluid or 10W-30. never had any opperational problems because of fluid type.

 

In the process of doing rear brakes and this truck the drive hub has to come off so it is a little more time intensive.  Hopefully will get back to my cab tilt problem.  I do have the 5606 spec hydraulic fluid and a new specific cab tilt pump, also power packer.  I normally like to do just one thing at a time until I actually determine what worked, but I think I am just going to put the new pump on and use the fluid.  Just getting frustrated.

On 3/16/2024 at 6:17 AM, Geoff Weeks said:

doubtful the viscosity of the fluid is causing you problem,  The gravity down is the problem, that should not happen on a modern (somewhat) truck cab system. It can trap a man under the cab and crush them if something goes wrong. Somewhere in the system there needs to be a cross-check valve that will not allow gravity to move the cab, it should require pressure from the return side (the side of the piston that is "retracting") to open the check and allow fluid to return.

The cylinders would lock up even during the first half of travel raising the cab.  If I remember right my problems started about the time is started getting cold over nite.  I agree that I didn't think viscosity was the problem.  I also didn't think that a generic 2 way pump might be the problem.  The fluid and the generic pump are the only 2 wild cards in the system right now.  The hydraulic cab locks function flawlessly.  The ram is new from the dealer (power packer-  brand). The new "tilt cab" specific pump (also power packer brand) I will be installing hopefully this week.  As far as oil, all I can think of is that the safety check valves are really picky about viscosity.  Starting to get really frustrated as to what I thought was a simple system repair.

6 hours ago, mechohaulic said:

keep one major thought in mind == you state your a newbie at HD truck repair!! do you think  all  of us just graduated grammar school and became "Master truck mechanics ??? WE ALL ARE /// WERE NEWBIES AT ONE TIME OR  ANOTHER!!! 50 plus years of wrench pushing and following these forums puts me not even a newbie = I'm in "kindergarten and still learning. can't say I want to learn all I read here though. give me old school mechanical over this electronic crap any day.to get back on original topic -- how's the hydraulics working??

The hydraulics kinda got put on hold for a bit while doing rear brakes.  I did get a new "cab tilt" pump. Just haven't had a chance to install it though.  Just about everybody I have talked with has said that the two way pump I was using should work.  It does work the ram both directions when just hooked up but not dealing with the weight of the cab when the cab goes over center and and finishes its travel with just the weight of the cab.

I did notice in reading the spec sheet that came with the pump that a certain hydraulic fluid MUST be used or issues with the system could arise.  MIL H-5606  What I used was a hydraulic jack oil.  In researching what this specific oil to be used was and why it might be different it appears that it is a bit thinner than regular jack oil being what is used in aircraft due to the colder temps that those hydraulics encounter.   As we all know, hydraulics don't like the cold as I am reminded every morning I run the packer on my truck up canyon all winter.  in my thinking of trying to remember when my issue became an issue it was early winter here and even though it wasn't the bitter cold I get up canyon, it was colder than back when I can recall the system was working with the old ram before I thought that ram had just worn out.  So I did pickup some aviation MIL H-5606 spec fluid to refill system after I flush it out of the old.  My thinking, if that is the case, the fluids being thicker may of been causing the safety valves in the ram to close. My weekends are tuesday-wednesday so next week I guess I will find out if my new plan of attack is going to work.

1 hour ago, Geoff Weeks said:

Problem is, the blue goo can be forced up the stud when the flange is tightened and "glue" the cones in place. I know it happens, but the correct way is a paper gasket. If you ever have to pull one that someone used a whole tube of RTV on, you'll never install with goo again, and always use a gasket.

 I know one that took 3 hrs of digging to get the cones out so the axle would come out. Paper also saves you from having to clean the old blue goo off the parts.

This was grey gasket maker and I used very little being it was a metal to metal seal.  Like I mentioned earlier, I will watch to see if it leaks and if necessary pull back off and and make a gasket.

23 minutes ago, mechohaulic said:

unsure at this age ; I thought the cone axles always had gaskets? neverseize was used on the cones by me==light film. . don't recall goop and neverseize on same axle which would indicate a gasket was there. hub studs kept gasket in place -if needed a small amount of sealant on hub to gasket area .

I was pretty much just going on the previous axle removal and replace where there was just evidence of silicone and no gasket.  I did make sure that the cones were clean.  I do know that the last time the axle was pulled was 30+ years ago due to a pinion gear break.  This truck sees ALOT of salt in the winter being it works up canyon at the local ski resorts.  I had no problem getting axle out.  Two quick hits with a hammer and the axle popped right out. If the axle ends up showing signs of leaking I will just op it back out and make a gasket.

Previous heavy work was all done by my dad who is no longer with us.  I have been keeping up on the lighter pm maintenance work.  But as far as the more intense work I am pretty much a newbie to heavy trucks, as those of you that followed me on my engine breakdown last summer will attest to.  I asked ALOT of questions.  I am a light truck/automotive mechanic so I do understand the basics of mechanic work.

Shop manuals are great for alot of things, but I highly value real world experience. Particularly on older trucks

14 hours ago, mechohaulic said:

that explains things better. . couldn't find  torque. in todays world of  high tech EVERY fastener has a recommended torque. simple fact is most are unnecessary;; common sense takes priority. axle flange nuts (5/8  fine thread --15/16 socket ). with gasket or without ?? even torque with air gun in staggered opposite location around hub. 

there wasn't a gasket when I took it apart so I didn't use one putting back together.  I went with what the nut and bolt industry google search for grade "C" nuts using a mid range torque of 100 ftlbs.  The studs do have the tapered cone on them anyway.

1 hour ago, mechohaulic said:

possibly you can't find  a torque  number based on there might not be one written in "stone". I never torque a wheel hub nut. it was more based on feel (experience )? had one  ole martin flat bed (grease bearings) which took a while to figure. inner nut brought to "spec" the bearing way too tight after install/ tightening outer nut. the inner nut had to be so loose , wheel set wobbled. install outer nut and tighten ; wheel set perfect. oil or grease bearings make a difference. bearings are lubed / center hub filled to max without making a mess light lube on seal  -depending on seal type. C/R seals spin within themselves , I always put small amount of oil on the two mating parts of seal and manually spin the seal before install. ; install outer bearing and all nuts/ locks = bring to a reasonable tight then spin the wheel based on wheel set  was on  a wheel dolly not just hub. if the wheel stops spinning and rolls back - it's a tad to loose. stops to sudden = it's too tight. 

I was able to find wheel bearing nut torques on a previous thread here on this site.  Followed that recommendation and I felt comfortable with it.  My question actually deals with the axle flange nuts where the axle is bolted back to the drive hub

Ok guys, this one is totally off topic here, but didn't want to start a whole new thread.  Doing rear brakes on this truck and unfortunately this truck requires the drive hub to be removed to replace shoes.  Can't find anywhere in my factory service manual as to what the axle flange nuts need to be torqued to when putting axle back in. Any help as to what I should be torquing them to.

On 3/9/2024 at 5:10 PM, mechohaulic said:

1- does the pump have a breather  cab weight is pushing oil back too fast with clogged breather ??  2- pump pushes cab up to center point and cab will tilt fully over with its own weight ?? thinking of older F-models .. 3- cab fully tilts forward and pump brings it back to center with weight bringing cab back to drive mode ?? opposite of raising cab..  4- even if not a specific cab pump , should still pump if it's a two way pump.

Yes. the cab raises to a center point then fully tilts under its own weight.  To lower, the pump tilts cab back to its center point and then it lowers under its own weight.  That was my thinking when I bought the pump.  It was alot cheaper than a true "cab tilt" pump.  But I did get the new pump today so in the next day or so I will get a chance to see it it works.

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

44 minutes ago, mechohaulic said:

this hopefully will be a situation where once issue is solved you will scratch your head and say "why didn't I think of that " ! a simple problem will break b=lls on occasion.is there a screw top on that cyl .. spanner wrench =2 pins holes ?? sure would like to see an internal diagram showing check valve. 

This ram has a c clip type on the end

2 hours ago, mechohaulic said:

when you state " hyd guy wasn't able to do anything " ;; do anything or FIND  anything is my question.  seems awkward that system has same problem after two main components replaced. that puts my thought back to POSSIBLE internal line failure/ problem. days of old ,your correct on bleed procedure with crack respective line; can't say same today with internal checks, reason I asked regarding piston ram disconnected from truck and work up/ down piston operation. 

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?

On 3/3/2024 at 5:26 PM, mechohaulic said:

rewrite =logged me out 

is this system a single cyl  or two ; can't remember that far back. ?  are the hyd lines aero-quipt or premade plastic style ?? did you try disconnecting the lines from cyl attaching a soda bottle  to each line and work the pump ?? 

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.

On 2/26/2024 at 5:07 PM, Geoff Weeks said:

Air in the system can cause the safety check to lock. Basically, the cyl is double sided, fluid on both side of the piston, so for the ram to move oil has to go in one port and come out the other. So if there is no pressure (air) coming out, it slams the ports shut, preventing the ram from moving either way.

 There should be a bleed procedure somewhere in the 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.

On 2/12/2024 at 2:56 PM, mechohaulic said:

bolt on wheel studs have 3/4 right hand thread on INSIDE , with dam good eyes you can on occasion sneak in between drum/ shoes to access  the 15/16 or  1 1/8 ? nut holding double sided threaded wheel stud. if left hand press in wheel studs are no longer available ;; then go to jelly roll song and Hail Mary ; I need a Prayer. instead of trying to cut corners; pull the drum better access to nuts holding wheel studs. be really helpful to know why == 1 stud or all need replace?? only one stud broke/ need repair then say f== k it and put shorter inner nut on outer rim and tighten with outer nut. for safety it's not an issue. for law enforcement every thing looks Kosher. Jewish wife .

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

On 2/9/2024 at 4:09 PM, Joey Mack said:

do you have budd wheels? 

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

On 1/27/2024 at 11:15 AM, JoeH said:

I.dpnt think so, but just make sure any thermostat you put in has about a 1/8th inch bleeder hole in it to allow it to burp on initial warmup.

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?

20 hours ago, Joey Mack said:

Maybe you relieved an air pocket, and it improved the cooling.. there are Mack engines without coolant filters.  Anyway, that's good..

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

17 hours ago, Joey Mack said:

It's All Good Bud...  Jojo

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.