JoeH

Bad grounds

Why did you dig up a 9 year old thread to tell us your email?

Wonder if "per set" comes with 6 sets....

Longer hood, you're further from the steer axle I'd bet. I like the new R hood partly because the R was such a long running model, and the hood bought it another 10+ years before switching to the granite, which is also a sharp looking truck. I wonder if Mack would still be using the R model if they didn't sell out to Volvo.

That's a lot of horsepower for a truck rated at 44,500 gvwr.

Read what he recommended. If it doesn't make sense read it again. He told you what he thinks you should do.

Refer to your post in antique trucks. You need to provide more information.

Is the 87 a 2 valve or 4 valve?

More info than just "I have a vibration" is needed to point you in the right direction.

Or you just had tires put on spoke hubs and you didn't true them up. Or if it's in the steering then it could be worn out tie rod ends. Or if it's a slower rhythmic vibration that is related to vehicle speed not engine speed then you could have a bubble in the tread of one of your tires, in which case you'll find out pretty soon when the tire blows up what the vibration was.

Carrier bearing.

Good fleet; I'm partial to the green Mack's hood.

I have a 1988 RD690S with an em6-300L

Maxi brake Chambers have 2 sides, each side can act on the brake rod. If you are flooring the brakes and you pop the park knob, you're trying to use both sides of the brake chamber to hold the truck. You may not hear a hissy from the park brake engaging because of this. Have you had situations when trying to set the brakes where they didn't actually set and the truck started rolling?

My 79 does it, we figure it's just a driveline balance thing or just how the truck is loaded. Started life with a 5tg wheel, but we have a concrete mixer on it with most of the weight sitting on the Camelback. On a full load I probably have 12.5k on the steer (rated at 11k) and 40k on the Camelback (rated at 38k). My guess if it's not a driveline balance issue is just soft springs on the front with a top heavy load. Come to think of it, there's a 100 yard section of road near me that would make my 95 rd688s triaxle do it at like 42mph itd get that same hop going. If I went through slower or faster it wouldn't do it. But they repaved the road last year so it doesn't do it any more.

Not sure what you mean by bounce the throttle; my 79 gets a hop in the chassis around 45 mph or so, it has the shackle style steering springs. Gotta plant your heel.

With that motor in that truck I doubt it could handle a 7.5 foot plow. But it's possible, no holes for plow lights on the fenders because the engine can't handle anything bigger than a pickup truck plow which would ride below the factory headlights anyways, or would have its own light bar. That'd make a decent yard truck for someone that just needs to putt putt around moving dirt on their acreage. That's what we use our U685T for. Run it like once every 5 years for projects on our property. It's days plowing snow are long gone unless I replace the whole cab and redo all the airlines brakes and tires and hydraulics.

Yes the engine is factory, no idea about the bumper.

That hood cracks me up. It's fiberglass, but is set up with the foldup sides you see on steel hoods. You flip those sides up and the motor is 4 feet down below the hood! Lol that hood is useless like that.

Probably also around the time they added 3 inches to the back of the R cab too.

My 1980 DM is a slipper style rated at 20k, 12 leaf.

Nice toys by the way! We never get pictures from new members.

Go to a yard near you, snap tons of photos of a set forward axle truck, and note every difference you see, make your list off that. Make sure you take a peak at the oil pan to make sure yours doesn't have the sump in the front whereas a set forward might have it in the back.

That's a more accurate phrasing of what you're trying to find out. My 79 is shackled. I have an old U model and a steel dash R Ill look at today and see how they're set up.