leversole

Hey leversole we have seen pictures of all inner workings of your 615. Where are the pictures of the outside in daylight?

That pesky job (read as monetary support for my new Mack project) of mine keeps me away till almost dark every night...here are a couple though...more to come.

Partial success! Having the RPMS at 2100 before trying to shift made all the difference in the world. I successfully made the shift from 3rd hi to 4th lo, and 4th hi to 5th lo! Still had to stop a couple of times and start over, downshifting was only successful a few times...

It really shows the skills a trucker had to have hauling freight up and down mountains!

hmmmmmmmmm........I could do the art, output a separation, or even better, output a screen, and maybe a trophy shop could produce it!

Anybody want to swap a triplex plate for a quad?

Here is what I have...

Does anyone have any experiance with these? Are they worth the price?

Mack Manuals

Thanks All...Dont know what I would be doing without all of the help...looking forward to the first time I can help answer someone else's questions...

Found it! Right where it is supposed to be!

Can someone point me to the transmission (TRT72) and rear end (38K tandems, I am told) serial numbers?

I will send all these numbers off to the museum with a donation!

What is the welded plate for?

Some kind of heavy duty bumper mount...there is some structure with pivot point around the front axle...It looks like the truck may have had a snow plow at one time...

Nope the serial #no is stamped on the front cover where the fuel pump bolts on! the flat spot on top!

Right where it is supposed to be! Not an ENDT number though, anybody know what I have exactly?

Am I looking in the right place?!? Or is it under that welded plate!

Thanks

Is this the engine model number (first pic) and serial number? Any engine details jump out?

I could probably figure these out eventually! What are they?

Here are my guesses...

First one is relay valve to not allow front brakes (slippery normal switch on dash)

Second is the valve that gives all air to main tank before other air devices?!?

Thanks

Still trying to get the floor out! Looks like a homemade firewall...have to get that out before I can pull the floor...firewall looks homemade, like they had to do it because of the engine change?!? I can't believe the brake pedal is not mounted to something more substational than some thin sheetmetal...

The floor is already cut and damaged, I may just cut out an access for the top of the clutch, and put a nice piece of metal with stiffeners in to replace...

This shifting business don't come easy! After driving 6 loops (2 or 3 miles each on curvy backroads), I am struggling to shift this monster...

Call me a nerd, but I built a spreadsheet with with all of the ratios so I can "guestimate" rpm drops to help me shift...

On this last loop, I suceesfully (for the first time) downshifted the main from 5th to 4th...normally, any attempt to downshift either stick results in a complete stop to start agian!

1700 rpm feels and sounds like it time to shift...I wonder if I am not letting wind up high enough...cruising around at 12-1300 seems about right, maybe I am running the engine too slow...

Also, I have not been able to make a two stick shift, end up stopping and starting again!

Those videos make it look sooooooooo easy!

I guess I shouldnt complain...I only have about 20 miles under my belt...I will get it!

After reading most of the posts on 24v to 12v conversion, alternators, batteries, etc...

My truck has been converted to 12 volt (two batteries) negative ground.

Even with fully charged batteries, the truck cranks about half a trun, then stops, continue to hold the key, and it will turn over and start, but very slow cranking, I am wondering if they left the 24 volt starter in? How would the 24 volt starter act with only 12 volts?

I will get under her tomorrow and find out the voltage if I am able...

Thanks

Just wanting to pull the dash out and get a look at things back there...what must be disconnected before the dash can be pulled out a few inches?

Tach cable? Speedo cable? Do you just have to reach up behind there to get the stuff loose? I took the screws out and could not pull it back at all!

Thanks

Yes it's a push type. The release shaft is below the centerline of the trans, and the rod pulls on the arm, which causes the fork to push on the throwout bearing.

It's definitely a double disc because the mounting bosses where the bolts attach the trans bellhousing to the flywheel housing are about an inch long. On a single disc bellhousing those bosses would be nearly flat.

Also in that pic is the adjusting bolt with jam nut that I was referring to earlier, but yours must have been replaced with a conventional 3/4 hex head bolt at some point..

Looks like I will be trying to get the floor out tomorrow! Dosent look very easy, as there are several smaller plates and EVERYTHING is rusted shut! I just hoper there are lots of shims!

Thanks

In a B model that double disc would be a push type, as opposed to the more modern pull type double disc clutches.

First off, does the pedal have 1 to 2" of free travel at the beginning before you feel resistance? If not, then adjust the linkage at the clutch release shaft on the side of the bellhousing. It will have a 3/4 hex jam nut and a square head adjusting bolt. Loosen the jam nut and back off the adj. bolt til you have the proper free travel in the pedal, then tighten the jam nut.

If the pedal already has free travel and the clutch is slipping, then you can take out the shims between the pressure plate & flywheel to get some more life out of a worn clutch. Take out the floorboard, take off the inspection cover on top of the bellhousing, and remove the pressure plate attaching bolts one at a time and take the shim out (the shims are washers with a tab that has a hole in it where you can hook a piece of mechanics wire while removing, so you don't drop a shim into the clutch or bellhousing), then replace the bolt Do not fully tighten any of the bolts until you have rotated the flywheel 360 degrees and removed all the shims, then go around one more time and tighten all the pressure plate attaching bolts.

After removing the shims you will have to re adjust the clutch as I described previously.

If you find that the shims have already been removed and the clutch is properly adjusted and still slipping, or, you cannot get a good adjustment, then the clutch is history and needs to be replaced.

.

I know the motor is a later model, and the transmission is not the original, can you tell from this photo if it is a puch type for sure?

Thanks

I was told that I have a dual disk clutch. Is there a way to "tighten" it up? It slips pretty good in high gear...The pedal linkage is not holding it off so I think the adjustment there is okay.

Is there a way to increase the pressure?

Thanks

Yes, there is supposed to be an external return spring.

Usually there is an "eye" for it to attach to that rod that hooks to the throttle arm, ans a bracket that sticks up from the top of the compressor with a hole in it where the other end of the spring attaches.

Any generic throttle spring will work. Use the lightest spring tension possible which will pull the throttle back to idle. A too heavy throttle spring makes it crappy to drive and puts a lot of extra strain on the linkage..

Sho nuff! I found a picture I took when I looked at the truck before buying and there it is! Now off to get a spring! I dodged another bullet! You sure are a Know-it-all! (and I am glad!)

Thanks AGAIN!

Dumb question...

Is there supposed to be an exteral return spring? It looks like there is a place for one...

I took the governer cap off (I assume that what that is, and if I pull the pedal linkage forward (closed) the assembly inside moves. I am wondering if I just lost the external return spring?!?

Thanks

Bad Dawg!

On the second shakedown run, I hit a bump and jammed the throttle all the way down and it stuck! Luckily I had sense enough to pull the fuel shutoff and get her whoa'd up. Looked for obvious issues, could not find anything, the actuator going into the injector moves and the shaft turns, but there is no resistance, dont know if it pushes against something that may be hung up, or how it works...thought I was goin to have to call a wrecker ($$$)...but I got it home modulating the fuel cut off...kept it right around 1600rpm! Had to make a few hills working the cutoff, so suffice to say, I was out of breath when I got it home!

Anyway, is it terminal, or is there something I can dissasemble and "unjam"

Thanks

I'd say the bottom end of the stick is worn to the point that it can jump out of one rail and get caught in between the rails when not shifted carefully. Back in the good ol days we used to carry a small pry bar in the truck for just such occasions. You have to stick the pry bar thru those 2 clevises that connect the compound shifter rails to the compound box and pry them into neutral, then the stick will be "unjammed"

To cure the problem, we used to build up the bottom of the stick with a welder, then grind it off to the approximate original shape & dimensions so it cannot jump out of the rails.

Until then you can also prevent it from jamming by shifting it "square", slide the stick straight out of gear, then across, then straight into the next slot. Don't push sideways on the stick when coming out of or going into gear.

Hope this helps.

Thanks! THat must of been it. I just moved one of the rails slightly and all is well. I was porbabably going fron lo to direct in a circular motion instead of up and over...lesson learned!

I searched the forum and found nothing, but I read about this somewhere?!?

Anyway, on the first drive I got the compound shifter hung up...dont know what gear it is in, but I cannot change it. How do I "unjam"?

Other than that, I realize I got lucky last night, shifting this thing at speed is going to take some serious practice!

Thanks

Neat post! glad you are having fun with it! not many things in life (in my opinion) that are much more fun than driving a two stick mack! once you get the hang of it,it kinda comes naturally. I learned to drive a truck on a B-model,some of the best times of my life were spent in that truck! where ya' at around milton? i get through there quite a bit,just stayed at what used to be the petro just last week. If you ever see the vision in my avatar,give me a holler!....Mark

I am just down the road about a mile from the truck stop!