1979 Western R Model

[h67st]

On BigIron auctions, in Nebraska. Looks like a nice truck (with the exception of wedge brakes). Two weeks left on the auction.

https://www.bigiron.com/Lots/1979MackRS686LSTTATruckTractor

[storkmack]

I couldn’t believe the wedge brakeS!

[mackaholic]

This had to be some corporate fleet truck. No gauges, tachograph, wedge brakes. Seems like a strange spec.

[mackaholic]

And what's with the offset opening in the grill? Never seen that before.

[70mackMB]

I'm thinking the off set grill is for the air intake. The exhaust looks like it had an exhaust powered product blower on it. And it looks like it had an air starter at one time. With the large tank, tire valve filler, 2"-2.25" line and hand valve that's been disconnected, and a new looking electric starter. Even has an after market hill climbing helper on the right side of the cab.  Wedge brakes are fine so long as they are maintained. My sons 6 pcs of CFWY antiques work fine. He carries the repair manual for wedge brakes with him should the DOT ask about them. lol     .....Hippy  

[storkmack]

Looks like aluminum carriers and crossmembers also.  Would love to see the light weight on her. 

[terry]

That under slung rear suspension is not a good set up, would not use it for a working truck.    terry

[h67st]

15 hours ago, 70mackMB said:

Even has an after market hill climbing helper on the right side of the cab. 

I was working at a Cat dealer in 1981, we had a brand new 3208 come in that would make a sound like valves hitting the pistons every time you started it. We checked a lot of things over before the lead mechanic noticed the spaghetti line feeding into the intake. Come to find out it had an electric solenoid that put a shot of ether in there every time you started it, no thermostat to cancel it when the engine was warm.

[Mike Harbison]

Thats an old Herman bros.truck. They pulled alot of different style tankers,im betting its been very weii used.

[Whiskymack]

Looks very clean for its age. I've never seen an offset Western Grill like that before. Is it factory? If so you'd have thought they would have offset it both sides and blanked out behind it on the right hand side. Looks like it's got a dual air cleaner set up with the external one feeding the tip turbine and the one under the hood routed to the turbo. I think there used to be a similar set up with a rear facing scoop on the hood but I thought it was only the Super-liner with a grill intake.

Forgive my ignorance but what exactly is a hill climbing helper?

[Whiskymack]

Oh yes, and no insignia at all except for the Mack letters under the passenger seat!

[70mackMB]

3 hours ago, Whiskymack said:

Forgive my ignorance but what exactly is a hill climbing helper?

Go to picture 66. Driver operated ether canister. "Puppy dogs' little helper!"    .....Hippy

[navypoppop]

It has a direction plare for an exhaust turbo conveyor but the turbo conveyor is missing from the exhaust stack. This would indicate that it was used to unload dry bulk tanker loads thus also the reason for the underslung rear springs. They rode smoother than camelback but didn't last nearly as long. My father had this set up on R685 years ago and had the main leaf break while under load and caused a rollover on I80 near Hazelton, Pa. about 1968.

[Rob]

Inverted Camelback is what it was called and used to see it a lot in the early 80's. Can't put a number on how many fleet tractors the company I was working for converted to tandem dumps and swapped this suspension to a regular 38K Camelback setup. Most was well worn when it came into the shop, but I'd never seen an accident attributed to it's breakage myself. The suspension itself did ride very good, but didn't render long service life before requiring repairs in end dump work. Standard Camelback went much longer between service intervals.  

[Rob]

On 3/15/2021 at 6:06 PM, 70mackMB said:

Go to picture 66. Driver operated ether canister. "Puppy dogs' little helper!"    .....Hippy

Sure wore engines out fast when used that way too.....

[Rob]

On 3/9/2021 at 4:23 PM, 70mackMB said:

I'm thinking the off set grill is for the air intake. The exhaust looks like it had an exhaust powered product blower on it. And it looks like it had an air starter at one time. With the large tank, tire valve filler, 2"-2.25" line and hand valve that's been disconnected, and a new looking electric starter. Even has an after market hill climbing helper on the right side of the cab.  Wedge brakes are fine so long as they are maintained. My sons 6 pcs of CFWY antiques work fine. He carries the repair manual for wedge brakes with him should the DOT ask about them. lol     .....Hippy  

I have wedge brakes on a 74 RL797 and they will stick you in the glass if applied hard, but do require maintenance which most did not get rendering their bad reputation. Hard to get parts easily for any longer too as not much available over the counter.

[Rob]

On 3/9/2021 at 3:34 PM, mackaholic said:

And what's with the offset opening in the grill? Never seen that before.

I've only seen that type offset grille on one other truck and it was also an ENDT-676 powered RS-686. It was either a 78, or 79 model year truck.

[doubleclutchinweasel]

My '70 had the inverted camelback springs.  Fairly light spec...34K I think.

It always amazes me how the guys on here can spot so many details looking at a picture!  Serious knowledge housed in the members of this forum!

 

[Lmackattack]

that offset Grill looks horrible. like it was a mistake.

[Lmackattack]

Lots of odd ball stuff the more i look at it. the engine bay looks crowded how it was layed out with the tip turbine filter and intake set up. way more troublesome to work around that engine.

The passenger side air tanks and battery box are missing and the air tanks were moved to the other side.

The passenger side fuel tank is much larger than the driver side and its moved forward.

The driver side fuel tank is smaller and has some sort of filter between the batt box and fuel tank.

Extra short rear frame

the under cab exhaust routing and muffler mounting is not cab mounted but I read its for turbo bulk unloader

 

and it has the all to common broken/welded rear cab mount.

These RS/RL trucks with hard mount cabs were all bucking broncos. worse than East coast R's. almost every one I see with cab rubber mount had this cracking issue. Greco had 2 RS700Ls that both had their rear cab floor structure bent upwards because of the violent shake these trucks had. 

I put a superliner cab airide under my 700 and you would swear I had square tires on it before

[doubleclutchinweasel]

Anybody got a picture of an "exhaust turbocharger conveyor" system in-use?  That's a new one on me.

[storkmack]

Trent, the tank on the drivers side is the air tank for the air start.   Diffidently  a very specific spec’d truck.