JoeH

Door and window interior handles have a spring loaded collar against the door panel that needs to be pried away that hides a pin that gets tapped out. Exterior handle I forget exactly, but it has a screw in the door jam that held hold it in. Shouldnt have to take the exterior door handle off to get window out. You probably have to undo linkage from the interior door latch handle to release the window assembly from the door latch.

Crank the window down all the way, undo all the screws on the inside of the door, and the whole assembly lifts out of the door. Takes some patience to get it out. If it's a real old R model, there's a round plate with a "shelf" inside, below the window assembly that needs to come out first. Newer R models just have a round stamp pattern below the window assembly, and you don't have to do anything with it. Change happened sometime in the mid 70s I assume because my 1972 has the round shelf thing and my 1979 just has the stamp pattern.

Most of the ones I've done on our trucks the bolts have been seized to the nut so we have to torch them off. Be careful you don't cook airlines and wires.

Do you know what the access is to this air cylinder?

My '95 does something similar, won't work above ~1500 r if the engine is hot unless I've been using it a lot before the engine is up to temperature. Guys here will likely point you in the direction of low oil pressure at the cylinder heads due to worn camshaft bearings? Supposedly there's an external oil gallery routing that can be done to compensate but I havent read a good write up on it to understand what exactly it's for/fixes.

That's be fun trying to convert a DM to RHD.... Not!

Where's the rod/door located?

http://www.truckpaper.com/ListingsDetail/Detail.aspx?lp=TRK&OHID=23834703 That is a good logging truck. 6x6 Mack DM. Mack solid beam tandem. It's a bit long, but could be shortened and you'd have a tough time getting it stuck!

Talk to other loggers you know and find out what they recommend. Probably a double frame RD6**S if you can find one with little or no rust jacking in the frame.

Air ride suspension is terrible for off-road work. Nothing is better than Camelback springs.

Check your "new" solenoid by jumping across. I've had them bad right out of the box. Or fail within a month of being out of the box.

1995 RD688S won't switch from cab heat to defrost. What should I look for?

Probably, with the right flywheel housing.

Great read! Thanks for taking the time to post it!

The R cab is primarily unchanged, with the exception of adding 3 inches to the back side of the cab in the early 70s. Might be minor roofline changes, but that should be about it.

Triaxles tend to have a good amount of twist/flex to them going down the road, simply because of how long they are.

Looks like the weeds are going to be prohibiting that trucks freedom soon...

What size are you looking for (gallon capacity) and are you opposed to buying new? My '95 has aluminum tanks, if you use my vin at the dealer it should get you a set of ~50 gallon tanks....

Your local Mack dealer. A good parts guy should have no problem looking up the book for your motor.

Bump

The last 6 digits is all they need. If it doesn't work they're dysfunctional. And the last 6 are numbers.

Here's a 3 knob setup.

Australians really know how to doll up a superliner right!

I believe on the Eisenhower interstate system, the roads are designed to federal weight limits unless the state had even heavier weight limits, i.e. in Mass with the 77k permits. In such a situation the federal highway system is built to state standards. In PA a triaxle is good for 73,280, and a standard tractor trailer 80k. On bridge laws in PA a short tractor trailer with 5 total axles cannot gross as much as a triaxle can, which is irrational because you're longer than the triaxle and you have an extra axle. That 98k DM686 is safe so long as you have the heavier brakes and you maintain the truck in good working order. I have a retired dm686sx with 58k rears and 20k front, had a lift axle. It was always able to stop faster than our other triaxle with 44k rears, with a load on, even with the lift axle up. Bigger circumference on the brake drums means more surface area and better mechanical advantage to slow down. If your lift axle has the bigger brakes as well as the drive axles then you should have no problems stopping 98k. Getting it moving with an endt676 on the other hand is another matter. It'd go but not in a hurry!