Back in the Mack Pack!

[Vladislav]

12 hours ago, BOBWhite said:

 What year was the RS700s introduced and about how many did they make? 

Sorry, no ready answer handy at the moment. Plety was written on the site on this matter. You may do some relaxing reading during long winter evenings or maybe some one will knock on the door in this thread. 

[mackaholic]

On 4/20/2025 at 10:55 AM, BOBWhite said:

Thank you for all the support and advice! Happy easter as well! 

Still trying to get a coolant gauge back, so we taped the wire we thought it was to the sensor with no luck. Not sure if that center part comes out without dumping the coolant but hopefully I can wire something back up. How do you test the gauge? Should it move when it's grounded or when the circuit is open? 

That looks like a capillary type mechanical gauge. No wire attached. It should have a metal tube that runs from the sensor to the gauge with either a plastic or wound wire protective cover over it. If that metal tube is broken you'll have to replace the gauge. If the gauge has 2 wires attached to it now, that's not the sender. Nice truck!

[BOBWhite]

9 hours ago, mackaholic said:

That looks like a capillary type mechanical gauge. No wire attached. It should have a metal tube that runs from the sensor to the gauge with either a plastic or wound wire protective cover over it. If that metal tube is broken you'll have to replace the gauge. If the gauge has 2 wires attached to it now, that's not the sender. Nice truck!

Yes sir you are right it is the capillary type but I've never seen one that looks like that, I'm used to the metal shrouded ones. I swear I had a couple spares laying around but alas I will have to make a trip to the truck parts store. 

[BOBWhite]

After a rain shower I noticed that I had a puddle of water on the floor. Looks like the Kysor AC roof unit will also need some attention. Don't need AC but If I need to seal it back up may as well get it working again. Parts or anything still available for these? I'm not sure what parts are missing from mine or how it was hooked up. The lines are still hooked up but I'm not sure about the electrics since the tag says it 24 volt. 

[Geoff Weeks]

7 hours ago, BOBWhite said:

After a rain shower I noticed that I had a puddle of water on the floor. Looks like the Kysor AC roof unit will also need some attention. Don't need AC but If I need to seal it back up may as well get it working again. Parts or anything still available for these? I'm not sure what parts are missing from mine or how it was hooked up. The lines are still hooked up but I'm not sure about the electrics since the tag says it 24 volt. 

The blower motors and resistors are really the only thing different between 24 and 12 volt units. Hard to say how a 24 tagged unit ended up on a 12 volt truck. Someone could have replaced a damaged unit with that one and transferred the 12 volt stuff, or someone could have put a 24 volt unit on by mistake, and never fixed it.

[Geoff Weeks]

Probably should have said, most parts are likely available, condenser coil may or may not be, but motors switches resistors should be no problem, anything that is not, there is likely a work a round for it.

[70mackMB]

You get that Kysor AC operating 100% you'll need an ice scraper for the inside of the windows!    .....Hippy

[mowerman]

You know, hippy  the size of those things on the size of the cab. I could see that they would blow you out of there.

[BOBWhite]

1 hour ago, 70mackMB said:

You get that Kysor AC operating 100% you'll need an ice scraper for the inside of the windows!    .....Hippy

That's what the PO said it worked really good but too many leaks to keep it running. I just am not sure where the controls would be, there is no "vents" its just an open hole (I'll take a pic if I remember) I think I'm missing some parts from the inside. 

[Joseph Cummings]

22 hours ago, BOBWhite said:

After a rain shower I noticed that I had a puddle of water on the floor.

That was always my problem with those things. Seemed like they always leaked when it rained. Lots of times they cracked the roof too. Maybe they weren't installed correctly

[terry]

I think the roof was supposed to be beefed up some way for them roof mounted units, but alot of times it never got done.  terry

[70mackMB]

Should be a panel with 3? switches on/off-temp-fan and 2 round vents you can turn.

[BOBWhite]

The AC panel Is just gone so I guess I'll be on the hunt for one of those. Good sized nest up there too which may be why it started leaking

[BOBWhite]

Got in a new temp gauge (175 degree thermostat turns out) and gave the engine a good bath but it's still pretty greasy. Gave the radiator a good clean out too, lots of dust in there. Did Mack use orange/reddish primer or is that the original color of the engine and it got painted grey later? 

Next two items on the list are valve lash + valve cover gaskets and the doors need attention. Not sure what I'm doing with these doors but looking for threads/advice 

Edited 23 hours ago by BOBWhite

[harrybarbon]

On 4/23/2025 at 3:57 PM, terry said:

I think the roof was supposed to be beefed up some way for them roof mounted units, but alot of times it never got done.  terry

A friend had a 2 support brackets made up to beef up the R model cabin roof, roof is now solid especially when opening closing the roof air vent.

[mrsmackpaul]

Yeah, I feel.Mack did use a redish primer

Whats up with the doors?

 

Paul

[Mark T]

Sharing the intake air like that isn't a very good idea.

[Geoff Weeks]

48 minutes ago, Mark T said:

Sharing the intake air like that isn't a very good idea.

In reality it is always shared, just where it comes together (air cleaner or pipe) is different. A differential pressure gauge that looks at the amount of pressure drop in the intake pipe when working the engine hard, will tell if there is a problem or not.

[Geoff Weeks]

9 hours ago, BOBWhite said:

The AC panel Is just gone so I guess I'll be on the hunt for one of those. Good sized nest up there too which may be why it started leaking

Not just the panel, the whole evaporator, Tx and blower is gone.

[Joseph Cummings]

1 hour ago, Mark T said:

Sharing the intake air like that isn't a very good idea.

The correct air cleaner had a separate additional filter in it for the charge air cooling. I don't know for certain the cfm the tip turbo moved, but it was a lot at high boost

[67RModel]

If I'm not mistaken there was like a year or two in the early 80s, maybe 1980/81 when Mack painted the engines red. And I don't think it was exclusive to fire trucks. I have seen several over the years that have a dull red engine paint.

[Joseph Cummings]

19 minutes ago, Joseph Cummings said:

The correct air cleaner had a separate additional filter in it for the charge air cooling. I don't know for certain the cfm the tip turbo moved, but it was a lot at high boost.

Or if it was an early one, it had a scoop on the hood with a totally separate air cleaner

 

[Geoff Weeks]

33 minutes ago, Joseph Cummings said:

The correct air cleaner had a separate additional filter in it for the charge air cooling. I don't know for certain the cfm the tip turbo moved, but it was a lot at high boost

but it still pulled though a common inlet (air cleaner)

What is at issue is: does the intake flow enough at full power load? If it does there is no problem, that filter was to power a much bigger engine when the truck was built.

If it doesn't you'll see a pressure drop in the intake tubing under full load. Easy to check.

Edited 13 hours ago by Geoff Weeks

[70mackMB]

11 hours ago, BOBWhite said:

The AC panel Is just gone so I guess I'll be on the hunt for one of those.

 

2 hours ago, Geoff Weeks said:

Not just the panel, the whole evaporator, Tx and blower is gone.

Looks like all that is left is a fancy box covering a hole in the roof.    .....Hippy

[Mark T]

2 hours ago, Geoff Weeks said:

In reality it is always shared, just where it comes together (air cleaner or pipe) is different. A differential pressure gauge that looks at the amount of pressure drop in the intake pipe when working the engine hard, will tell if there is a problem or not.

Ummm   no it's not.  The tip fan only is spun when there's enough manifold pressure to bleed off to spin it. From the outlet of the intercooler back to the ducting from the air cleaner there's nothing filtering air that can pass in there with the tip fan not being fed.  Could explain why he mentioned it seemed loud.