Full Floater

Interesting....is that a Mack thing or just specific to the CL series? I have a couple R models that have a little slop there.

Thank you guys. I just ordered that one from HD pros. We'll see how she goes!

I'm new to the air wiper world, or at least; new to servicing them. Never really had much trouble with them before. The air wiper switch on this 75 R600 is leaking air in the OFF position. What is my best way of resolving this? Is there an o ring or a kit or something that I can replace? And as for the air motor itself, although it works fine, it's probably never been touched in 48 years, is there anything I should do to it in regards to maintenance? Cleaning? oiling? Many thanks!

That seems to make the most sense, doesn't it.

Re-visiting this topic. Im now at the heater box, putting together 1 heater box out of two. Same boxes, same dimensions, different heater cores. One appears to be a 3 row and much bigger. I'm assuming this one would give off more heat? Your thoughts?

39MT. I have and have had several in service.....they've been pretty reliable. And way easier/lighter to fandangle into place

Here in BC canada, 36 keeps at an annual inspection level instead of semi annually, which would be great of course. So that's what it will be then. Thank you

Great insight, thank you. And it's a rollback tow truck just fyi. Should be well spec'd for it's application.

I have converted a tandem R600 to a s/a The blown 38,000 Mack rears were replaced with a Mack RAD529 24,000lbs rear axle with the Mack 23,000lbs springs that came with it. The truck has an 18,000lbs front axle. 22.5 rubber I need (should) to determine a new lower GVW for the truck. I have not scaled it yet to determine it's new net weight. The door tag is blank and always has been and I see there are a few outfits online that are duplicating door tags on old truck. Not trying to do anything funny here, just would like a legible and accurate door tag with current and relevant weight numbers on it that apply to the truck now that it's a single. Any insight as to how I would best determine a "new" GVW for this unit? The old GVW was 53,xxxlbs. Im thinking the new GVW should be in and around the 36,000lbs range.

Got er done. Removed this and that, the valve is gone, more space to see what's going on behind the dash....the yellow and red still work as they are supposed to. Replaced a few air lines. Nothing's leaking. Im happy. Thanks folks.

Yes the blue one is independent of the yellow and red valves. There is a line from the yellow, going to the blue....not sure what it is, but im going to try to delete it. Simple is good.

I have a 237 that has had a fan clutch installed in place of a fixed fan. And they used a pile of washers as a hub spacer (which seemed to work but it looks sloppy). Im hoping to buy this spacer....anyone know if they are available anywhere? Also, say one wanted to buy a new fan clutch, just because.... is this what im after? https://www.woodlineparts.com/en-ca/products/pai-efc-1640b-mack-38mh416-fan-clutch-e6-21-00-26-00-fan-183125

Very interesting guys. Ya the one I have is a mechanical shift PTO. I have not engaged the PTO on that truck yet as it's just getting back together....but I will play with it both ways, main in N and aux in N. Im always a less confident with that aux box being in N position as they seem/feel less assuring as there isn't much wiggle room on the stick....so I always release the clutch real slow JUST IN CASE it's not actually in N

I'm new to the rear mount PTO on a 6 speed. Can I get any operating tips before I try to figure it out for myself? Does the main trans need to be in gear for engagement? Where should the aux box stick be positioned?

Im in the process of tiding up a bunch of hack job air line repairs and routing on a 75 R model. What are you thoughts on removing/bypassing the blue tractor parking brake valve, leaving only the yellow and red, as in more modern applications. The tractor is a straight truck and will never be pulling a trailer, so no real need to keep the trailer charged and the tractor brakes set for any reason, thus not needing the blue valve....unless it has a use that I'm not familiar with.... Just wanting to simplify things and keep the "what is the blue knob for" conversations to min with future drivers. Thanks folks.

For sure. I had to switch voltmeters, but everything else worked in regards to gauges and interior lights. Heater motor needed the wires reversed. Not sure about low air buzzer yet, but will probably need the wires reversed. I would have left it + ground, but I installed Jacobs 675 jake heads on it and they are grounded through the casing so I figured this is my calling to convert. Really wasn't a probably, just stumped on this signal issue. But it could very well be another issue

So far, everything has been trouble free in converting from positive to negative ground. I have only the signal lights left to get working. Im getting nothing from them, nor any power from the rectangular plug that hangs down and plugs into the signal-stat pigtail. The relay and all other relays on the relay board, are functioning. Changed flashers, to no avail. I'm suspect of this unit, mounted above the drivers side kick panel area. (this is a picture of 2 separate ones, one off of a parts truck). Anyone know if they have anything to do with the signal lights? Im at a loss as to where to look next, the harness is in tact and im hoping to leave it that way so I figured i'd ask here before I pull that harness all apart and make a mess, whilst trying to solve this problem. HOWEVER, I do not know if the signal lights were working in this truck, before biting the bullet and converting to negative ground and replacing LOTS of wiring, grounds and various things along the way in part of the restoration. So I may have had a problem to begin with, that I do not know about.

Ooooohhhhh!!! Sounds like something I can do away with?!?!? In exchange for using common sense and not compounding the brakes!

I did, sorry for the lack of responses, been tied up with other clutch problems on a different truck. I got both the front service brakes and rear air supply to a relay valve plumbed into the delivery ports, which were on the bottom if I recall correctly. (Im not in front of it at the moment). there is a small line from the foot valve that is connected to the parking brake knob for some reason, that I plumbed into the foot valve wrong as the parking brake valve won't apply the maxi's now when pulled out. I think that line has to "dump" air somewhere and I have it plumbed into a supply port I think. Not sure on whats up with that but I got the service brakes to function so I could get that truck home. So for now, mission accomplished. Thank you

A reply that exceeded all expectations, again! THANKS

I am in the process of converting a tandem R600 into a single axle for a re-purpose of the truck. The overall length of the driveshaft has extended by a little over 2ft. I had the driveshaft professionally lengthened and balanced. All new u-joints and steady bearing. The location of the steady bearing is further back and I am moving a crossmember to accommodate the bracket. AND I have to use or make another steady bearing bracket as I didn't get the bracket back with the driveshaft and the driveline shop is 5hrs drive away. Can someone school me on driveshaft angles a bit? It's my understanding that the angle of all the joints should be 3 degrees or less.... what else am I missing here?

You're pyro probe is in the downpipe after the turbo and not in the manifold, correct? Ya don't hold it at those temps for too long.

Ah good to know!

I just bought another parts truck, with a 6 speed and a side mount with a driveshaft pump. Never actually seen a side mount on a 6 speed. Haven't got the number off of it, just something I noticed

Thanks. Curious as to what is better about the rear mount? Is it a stronger or more reliable location to mount the PTO, rather then the side?