JoeH

My MR688 tripped the 4-1 code a few times. We changed the crankshaft sensor when we changed the flywheel housing last week. If your flywheel housing says "Renault" on the top then I'd check it real close for cracks. Ours was cracked from the starter motor area over the top, and halfway down the passenger side.  Apparently it's common for the Renault housings to crack.  Ours was also leaving pretty hefty puddles of oil that would dribble out of the flywheel housing whenever the truck parked. Been running the truck on the road a week and a half no issues now, no leaks.

1 hour ago, Joey Mack said:

Diesel is still $5.49-$5.69,  here today..  Gas, $4.39 ish......   

5.49 sounds like a dream, PA is $6.50+

My repaired R model frame has sleeves centered on the outside of where the welds are. It's not just about making the crack go away, it's also about making sure the frame holds up.  Mack has a book with "how to repair frames" properly. If you're going to do it, follow Mack's instructions...

We have a steel frame truck that's had both rails welded, been running it for years. But no aluminum frames...

Leaky fuel tanks can cause bad fuel mileage....

How are the king pins? I assume these use a tie rod from left to right? How are the tie rod ends?

I drove an oil delivery truck that had a nasty wobble, the trucks usual driver just put up with it.  When I drove the truck I went straight to the tie rod ends and the one was horribly worn out, about ready to fall apart.  Boss had the truck fixed the next day.

Do you have a VIN? A Mack dealership would be your best resource. They'll ask for the "last six" of the vin, but you'll want to have them run the full vin as it will likely have a different country code or something weird.

All reassembled and operable.  Tomorrow is "Sink or Swim".

12 hours ago, theakerstwo said:

I may be wrong but i dont remember that.I have never seen one on any mack that was off center unless the block was line bored but then it would be very little off center.When we did dial them and found one off it was always a bad housing or distorded or broken.In later years on a E6 and E7 i got were i would not put a dial on one if it was a replacement.You want to see from top to bottom same and from one side to the other same and i think the reading can be as much as .010 off center.

.010 is if you're using a Machined Dowel type runout gauge that fits into the engine in place of the crankshaft.  .020 is if you're bolting a runout gauge to the crankshaft.  The difference in runout tolerance is because of any wobble in the crankshaft/bearings.

According to the book.

No idea. Depends on how big your hills are and how heavy your foot is.

19 minutes ago, terry said:

I believe the earlier Mack’s, after the flywheel housing was dialed in, you reamed the holes for a oversized dowel then tapped them in.  Terry

That makes sense.

Allison Auto & torque converter bolted to the flex plate. Not sure how much "slop" the Allison input shaft can tolerate.

Inline pumps can be computer controlled from ~1991 on. It's called econovance or something.  Drive hub for the fuel pump is electronically controlled via VMAC I and VMAC II computers.  About 1998 is when it went full computer with the EUP fuel pumps.  I have 2001 in my head as the best year for the ETECH motors.

The E7 can be full mechanical or partial computer controlled. You have to look closely at the fuel pump assembly to figure it out.

Mechanical E7s are probably the best Mack motor ever for durability. Personal opinion.  Computer E7s... Good engines but electronics fail...

My dad cut out around 7, I put in another 4 hours trying to get dumb stuff done that doesn't need 2 people.

Remaining:

Trans mount bolts

Battery cables to new starter, tie up wiring

PTO shaft & drive shaft

Rear oil pan bolts/readjust gasket

Reinstall the water tank for the mixer body

If I have to take this apart again it's to drop a reman engine into this truck. Will run it til it says otherwise...

Currently scraping the last of our bottle clean to torque up the bellhousing/flywheel housing bolts.

I would have much rather had the Mack brand flywheel housing, but Mack has yet to get back to me on an ETA.

First Motion part number from online matched the Mack number, but noted that it wants 7/16 bolts for the flywheel to bellhousing, not the metric ones that Mack had. New flywheel housing is within 1/16th overall depth of the old one. Overall I hope I'm not screwed.

Trans is bolted up, torque converter is bolted to flywheel.  Time to torque up some things and keep working.... Late night...

Left dowel is a solid round pin.  Right dowel is a flat blade.

Top left. Top right.

Bottom left. Bottom right.

On 5/5/2022 at 4:39 PM, Joey Mack said:

I had another thought...  check the bell housing flange for wear that could causes the bell housing bolts to loosen, and therefore cause the tranny to move, and crack the flywheel housing.. I had an '01 RD that had loose bell housing bolts, and I would remove them and put lock tight on them, put'em back in, and next service they were loose again..  I knew it was the bell housing, but because it was a T-2070 tranny, and I handled all maintenance intervals, I just kept tightening them whenever I saw the truck, until it was time for a clutch, then I Sent it to "Overdrive rebuilders" to get the case replaced..  and a re-build..  jojo

Broken lower right flywheel housing to block bolt.

How do we adjust flywheel housing runout? 

0.022, 0.000

0.028, 0.013

Those are the runout readings on the four corners.

Macks don't respond well to deletes.

https://www.firstmotionproducts.com/mack-flywheel-housing-634gc5337m2/

Found one here.  Getting started on replacing it tomorrow morning.