JoeH

Man that stand is a monster.

When you're working 14 hour days it barely leaves you the steam to take your boots off...

We just bought the harbor freight 2,000# engine stand for a Case A336BD 4 cylinder diesel engine we're rebuilding that dumped all its coolant into the oil... Caught onto its problems before any bearing spun. Had to make some longer brackets to bolt the engine on there, but it holds this engine nicely. I wouldn't put a compete Mack engine in there, but if you're the adventurous sort you might be able to get away with putting the block in there if you support the front end with an engine hoist or car jack... This engine rotates fine with a cheater pipe on the handle.

+1 on 55 mph. If you've ever ridden a motorcycle on the highway then you know this first hand. Wind resistance on your body is negligible up to 55 mph, start getting above that and your arms start getting a workout to keep you in the saddle.

My volumetric concrete trucks get about 3.5mpg annually. We have a 15 mile radius, and a typical delivery is drive 20-40 minutes to a job, sit at the job for an hour or so idling/revved around 1300 rpms, drive back to the yard to reload for next job. Or drive straight to next job from previous. 1979 R686ST with endt676 gets best around 4-4.5mpg but it's the lightest maxing at 50,000 lbs 1995 RD688S with E7-350 and 8LL gets around 3.5mpg but maxes around 73,280 lbs 2003 MR688 AI-350 with Allison HD4560 auto gets worst at sub 3, maxing close to 73,280. That auto is nice but sucks on economy. Note that our trucks are almost never empty, whatever material a customer doesn't use gets lugged on back for the next load. Frequently as much as 8,000 lbs of extra material getting carried around.

I think you need the king pin forward 6 inches or so. Wiser heads will steer you straight. If your 5th wheel is too far back you can do this... https://youtu.be/udE01fKbWCk?si=PhfTDYy6-Snp3YSc

But my 1979 r686st does probably the same hop you're talking about. Endt676 motor with a 2 stick 6 speed. 5th gear, ~45mph. Solution? Just don't drive at 45 mph. Even though it might be a very comfortable speed otherwise.

Rubber bushings probably bad on the engine mount, no big deal to replace. Could have loose bolts threading the rear engine mounts into the bell housing. Bellhousing is probably aluminum, so hopefully they aren't stripped out. How's your 5th wheel positioned? Is it dead center over the tandem or is it forward enough to put some weight on the steer axle? What weight rating springs are on your steer axle? Too light could be too weak to steady out any uneasiness in the chassis. Does it do this around 45-50mph on all roads or just on one particular road at a certain spot? I've got roads around me that certain bends make you feel like the tie rods are about to fall off. Only does it at one pair of bends, everywhere else it does fine. Had another road started making my triaxle buck for a couple hundred yards, always the same exact strip, then they came through and paved the road and the truck goes smooth as glass over it now.

Joey is right, you just weld a bead vertically along the inside of the sleeve and they pop right out when they cool.

This block uses the same oil pan gasket as the E7. I think there are incremental differences in the 673 block casting as more was demanded of it. Pistons and liners should be the same, the displacement never changed. Biggest question will be head gaskets, and replacement heads if these can't be rebuilt.

Replace the whole thing is what I've heard in the past, not sure it's worth the safety risk of fixing, but I don't have much experience with 5th wheels

Says he can apply power to the Jake and it works... What's the vmac III use for brake control? Throttle signal through the pedal and a clutch mounted switch? Maybe it's got nothing to do with pressure washing and the clutch switch is buggered or got tweaked coincidentally.

Has signal coming from the VECU, I'm gonna assume it's a Vmac III.

But at least AI will have this movie to watch to keep itself company: https://youtu.be/iJ4T9CQA0UM?si=o5OK_ZNCiwpVtkp6

Spitballing, but I was thinking the other day that the movie "The Matrix" may not have been that far off. Elon Musk is over there trying to build Neuralink, which is a fascinating hopeful opportunity for people with paralysis or Cerebral Palsy. (which I am convinced my 10 month old has to some degree; we've had her in physical and occupational therapy weekly since she was 3 months old to try and remap her brain to help mitigate some of the consequences of a traumatic birth) If Neuralink takes off, it's not gonna be long before "immortality" becomes a thing. They're already able to grow chicken meat in a lab by putting meat cells in some sort of solution. When they fine-tune Neuralink they'll be able to hook your consciousness up to a network, dump your brain and organs into some solution like the chicken, and let you run around and live your life indefinitely in Dreamworld controlling a robot from your artificial womb bath. Other thought I had was that AI will decide we're the problem, kill us off, which will kill off CO2 production, which will make the plants use up all the CO2 to make oxygen, then the plants will suffocate from lack of CO2 and the AI will be left alone to do God only knows what on a planet devoid of all life. Earth will be a barren wasteland. Though I haven't factored in what happens to all the animals, maybe the EATR robot that eats bio-mass to keep charged will eat all the animals. And whatever's left of plant matter as it rots down. 🤠

Are the midliners the ones that are awful to find parts for? Like $10,000 for the brake treadle valve?

you will want to read this thread start to finish. It'll give you all the part numbers you need I believe.

Can an admin sticky this thread somewhere easy to find? Thanks!

Note that trucks of this era were built when highway speed limits nationally were 55 mph, so that's typically what you can expect any old dog to be built to do. Gearing an old dog to go 75 mph is probably doable, but remember the steering geometry and linkage may or may not be happy going that fast. My '79 R686ST keeps you on your toes to make sure you stay in your lane, albeit it's a top heavy truck with light frame and springs.

Ideal is go to a junk yard and see if they have a rear single axle cutoff with a suspension you like and axle ratio that'll get you the top speeds you're looking for. Take note of outside frame rail measurements, I believe Mack frame rails are a slightly different spacing than other manufacturers. May require shims of some sort to match up another brand suspension to the Mack. My Mack experience doesn't begin until you land in a mid 1970's R model.

That's ESI+.

I post all kinds on all kinds of stuff all the time. Probably just an anti spam feature til you've established yourself. log in every day for a week, it'll get you a badge.

In US, 1-3/4" will fail at a DOT stop. If 3 out of 8 wheels fail then your truck is put "Out Of Service" and has to get towed or repaired on site.

Type 30 brake chambers only have 2 inches of rod travel before they bottom out, unless they're "Long Stroke" versions. If your brakes have 2 inches of travel when cold then the air chambers are bottoming out and not applying full pressure on the slack adjuster. Plus, when your brake drum heats up it will expand, requiring even more brake travel to apply the brakes. If your slack adjusters won't keep the brakes adjusted under 1.5 inches then I'd argue it's time to replace them, they're worn out/failing.

https://maps.app.goo.gl/xg1jTHpCnufV1Wdx7 Have you tried these guys? They're only a few miles from Sun Valley, NV. "Absolute Hose and Fittings"