JoeH

+1 on the rust, gotta disassemble frame, sandblast and paint before it gets to cracking point. You could probably still take it apart and weld it back together if it's the horizontal flange crack by the trunion. Mack frames want 100,000 pound tensile welding rods, 3/32nds for frame repair. I think 10018 rod? Took my dad and I about a week and a bit to do our 95 rd. Well worth it, but we didn't have any cracks yet.

Because the DOT caught you you might have to show them the truck to be put back on the road, or sign that it's been fixed.  Once it's been welded, bring it so you can't tell it's been welded.

I have several seized anchor pins on my trucks, never get this. When I drive other people's trucks I do sometimes.  Adjusting the "self" adjusting slack adjusters takes it away for me...  

Ratio should be stamped in the carrier housing on the differential housing. Axle ratio is how many times the driveshaft has to spin per wheel rotation. If the ratios are different, youre going to blow up one of the rears. If they're the same, check your driveshaft for bad u-koints or a bad carrier bearing. (Rubber bushing looking thing to hold it over the lift axle) 

Power divider is a switch on the top of your dash. It forces one wheel on each drive axle to have to spin. (If it's unlocked in mud, all it takes is one drive tire to spin and you lose all power through that wheel) Never switch it when a wheel is spinning.  Never drive on blacktop with it locked.

If all else fails get an experienced trucker to ride along with you.

You can get pneumatic cylinders online for cheap, just need to measure the throw and figure out how to attach it to the butterfly valve. 

My 95 RD e7 350 has a "cold start only" switch on the dash, operates some sort of intake plumbing that bypasses the intercooler until things get warmed up... We have never had to work on the engine in the 10 years we have owned it, so not real familiar with it. And we never use the switch b/c it's in a heated garage....

22 hours ago, fjh said:

Jokes on you!  I just work on the junk😣 Oh wait no your right  the Joke is still on me! 😡

Glad it's not you that's in for the never ending repair bills then! My dad and I are picking up a 1988 rd6882 tri axle with a new frame (guessing 5 years old) new camelback (5 years again...) rebuilt rears (5 years...) a rebuilt 300 horse with a T2070! About the only thing wrong with the truck is duct taped hvac, some mold on the dash, and it's the wrong color.  Price? $21k!  Thats how you buy a truck. 😉

Your problem is you bought a new truck! You're supposed to buy em after someone else figured this crap out.

6 hours ago, Yoos Brothers Construction said:

Better look closer. The frame is broke at the rears on the drivers side.

 

I can't see that in the pics, but I'll take your word for it!

Double frame looks in good shape, can't see an oil pan to see if there's even an engine in it. Hood has a nice crack, nothing a 2x4 fiberglassed in can't hold. Doesn't look like there's a rear window in it. Needs a lot of small stuff though... Maybe worth 1500...

The 2001 rd688st I owned for a year had relays in the glove box and a relay/fuse box under the hood, top center on the firewall. It had an etech 400 engine. FJH and co. might be talking about the accessory relay in the dash under the ash tray. On our mechanical Macks,  when you bump your key on it actuates an accessory solenoid in the dash under the ash tray. It powers your gauges, radio, blower, etc. Not sure if the electronic engines use this solenoid too, I expect they do. The last couple I got from Mack are junk, they get hot on our stock truck and stop making contact reliably. Smack it with a screw driver handle usually gets it to engage.

Build sheet says "extra roomy cab interior" 

What are they comparing cab roominess to? A Mini Cooper? 

Never worked on an E9, are they shorter than an E6? Can't imagine them being much shorter, your only 4 1/2 pistons deep instead of 6... Maybe that's the "extra roomy cab interior" - less dogbox.

13 hours ago, Mack Technician said:

Let's not argue. I think we can all agree on this...…

If your in a mid 90's PLN...…... With just the factory Jake, well adjusted...…. you will be able to decel on a mountain pass so long as you are Bobtail and you hit a large elk that is jammed under the steer axle skidding like a big, bloody meat wheel chock and your running against a 30 MPH headwind...… the speed control will be perfect.  

Made me think of Maxwell the Pig.

+1 on the engine brake. It'll make a big difference. 1) cuts shift time to less than half, and 2) Jake keeps the turbo spooled up a bit.  I would try that before swapping transmissions. Makes the maxidyne & maxitorque a real heal climber. 3) when you use Jake to slow down through your curve it can keep your turbo at 10psi boost if your RPMs are kept at1800+ for long enough.

Note his problem isn't low end, it's 40+ mph.

Those are sweet dimensions. Do you have those drawings for a 1995 rd688s? 228" wheelbase? Does Canadian spread tandem have the same turning radius as the closer set American tandem with same wheelbase?

I haven't done one on an e7, but I always put the copper heat sink on the "hot" side. It needs to heat up to cause it to open. I also always make sure that there's a small hole in it to allow the water jacket to purge air out of the block before startup. If it doesn't have one, I drill one.

I have three 2 valve endt676 engines that we have pulled the engine brakes off of. Everything on those engines are American sized wrenches. Not sure if it fits the em6, dad would probably kill me for giving them away, but I doubt we will ever put them back on a truck.

Took one set off because it was on a DM686sx and never worked, another set was on a spare motor we needed a camshaft out of, and the third engine has a weak valve spring and the Jake brake spacer plate on top of one exhaust valve slipped out a few times, so we pulled it off rather than keep messing with it.

Mack wanted $80 per jake style valve lash adjuster, several of ours were worn out one motor. Having a spare motor pays.

I think the only differences between an e6 237 and a 285 are turbo, exhaust, fuel pumps and intercooler. Block, heads, crank, pistons, all the same. My dad ran into some different timing covers over the years but that's about it. 

My dodge pickup would do this. Low trans fluid, sump was just barely in the oil, enough to pickup air and go in neutral, then back in gear, then neutral. Once it warmed up it'd be ok (fluid expansion). It was an idiot behind the wheel problem. Read the dipstick and check it how it says! Ford's say check in park or neutral, dodge says check in neutral. (NOT IN PARK)

Previous owner also used a  filter from his hemi baracuda.  Almost the same trans as my 47re, but the Cummins auto used a deeper pan and filter.

http://www.discountdrivetrainsupply.com/rebuilt-mack-transmission.html

Listed here as a 10 speed.  No idea on ratios.  If it's out on the floor put it in gear and count. Use a degree wheel to get your fractions. 

Ewww dug up an old post. 

I remember watching my dad do split rims once in a while 20 years ago when I was a kid. They are dangerous. We still have the tools and whatnot, but I'm happy with tubeless. Never get in front of that lock ring when airing up, if it lets loose it'll cut you in half. And on disassembly don't bend the lock ring, it'll be far more dangerous when it goes back together, as it won't want to fit in it's groove.

It should say on the engine plate on top of the valve cover. E7 probably. Post a couple pictures of the engine and the plate.

Someone else might chime in, with a computer you should be able to individually shut down one EUP at a time to find which injector nozzle/eup might be faulty.  I've never had a need to hook one up to a computer but the book says you can. See if your local non Mack Dealer shop can accommodate you on doing that.

One truck I just looked at for potential buy had a miss when I cold started it, but once the truck warmed up I shut it off/restarted and the miss went away.

Looking at a 1999 rd688s with an etech motor turned up to 475 hp at the rear wheels. (Heavy hauler triaxle tractor) and an 18 speed.

It has the exhaust side computer.  Is this vmac III? What concerns should I have about the computer being mounted under the turbo? Truck is in great shape, only 300+k miles. I don't need 475 rwhp, but I sure as hell won't let the dealer touch that eecu if I buy it.

Thanks! Joe

They would stop me from being able to do 50% of my work lol. Half the day I'm driving, other half I'm mixing and wheelbarrowing/raking concrete. When I'm not doing that I'm welding or an a roof. Boots every day, sun up to sun down.

Just looked at it again, yours appears to be bolted together, ours are crimped together. 

My dad's 1980 DM uses one of those valves. Not sure if our R and RD trucks have them too, I assume they do.  It's on the firewall under the hood, near the steering column. It prevents the air from going to driver seat and other cab features until truck hits 60 psi. They're cheap, he has had some fail after a year or so I believe. Keep a couple on hand, I think he had one blow apart where it is "crimped" together. I believe it's probably an emergence feature to protect air brake system from auxiliary system leaks. Starting your truck after sitting for a month is a luxury, stopping on a downgrade with an air leak is a necessity.