Kav

Hi everybody - If the radiator tubes are badly blocked , detergent cant always get down them so you have to unbolt the top tank and carefully push a dip stick down to the bottom tank. Another cause for overheating can be the impeller in the water pump breaking away from the hub, especially the early pressed stainless steel Mack impellers. Best regards - Michael.

Hi Tony, as Rob and all have said, The first thing is to give it more fuel but if you want to go a different way you can get more boost by upgrading the existing turbo to the 350 turbo, or by machining out the original compressor housing in the turbo and fitting the larger compressor wheel.I have done this in the past and at the same time I made up a short funnel shaped adapter to take the 4 inch outlet on the turbo out to 5 inches so that there is a 5 inch pipe right to within an inch of the turbo. This makes a big difference to the acceleration as the turbo spins up quicker. I also put lagging on the exhaust from the turbo back and fitted the 5 inch muffler to keep the noise down. With this system it goes better then the original straight through system without the muffler. Either way you must keep a close eye on the Pyrometer on the long hard pulls. The other thing is - do you have the big air cleaners fitted? The original cleaners restricted the air to the turbo and shortened the turbo service life. An air ram on the top of the air cleaners also helps with the boost, especially at higher speeds. Best regards - Michael

yeah bad dog, im really a firm believer in their grease,,,randy

Hi everybody, I have been using it for about 15 years. The main thing I use it on is Planetaries and Hub reductions. They run about 10 to 20 degrees cooler compared to oil. The seals don't leak anywhere as much as it seems to stick to them and keeps them flexible. In the Hubs on the loaders and tractors I use 100% Lucas with no other oil. In the Mack diffs when I am changing the oil I put a 4 litre container in each diff first then top it up with oil. I have had very good results with it. Best regards - Michael.

Hi everybody, Years ago I had the same trouble - I could not get two of the bolts out of the starter. A couple of months before,I was turning and the truck was hit from behind so hard that it broke the fifth wheel king pin and tipped the trailer right over and back onto its wheels . Some time after this happened, two of the bolts that hold the clutch housing to the block broke off and were loose in the clutch housing and they completely wrecked the end of the thread on the starter bolts that protruded into the housing and mushroomed them over. I could only undo them about half a turn and they would go dead tight. I cut the heads off the starter bolts with the oxy to remove the starter, and then ground the bolts off up against the housing and screwed them inwards into the the clutch housing to remove them. The starter was damaged but repairable. Your story reminded me of this. Regards- Michael.

Are your cab mounts good. I once had trouble with the cab sometimes putting pressure on the gear lever in 4th and 5th Gears. -regards - Michael.

just taking the cover off the top of the pump and "giving 'er a couple of rounds" (turning the fuel up) will make a 237 go like a scalded dog. Little dab'l do ya'. Used to be a sure fire way to get fired, breaking the seal on a pump. If it's your own truck you'll have to fire yourself if you turn it up.

I agree but what he was originally referring to is the early maxidyne pistons that we had here used to burn up and fail if you gave it too much fuel. When the Econodyne series with the front intercooler was released they fitted better pistons to them with a better insert around the top to stop them burning. At the same time they fitted heavier Con Rods as some of the earlier maxidyne rods failed. We used to set the 237 pumps up to the specs of the 285 and fitted 285 turbos, but you have to watch the Pyrometer on a long hard pull to keep the heat under control. As Rob said you need a 10 or 12 speed transmission to get the best out of them.If you increase the torque screw, the extra fuel at low revs puts a lot more strain on the bottom end of the motor and the early blocks were not as heavy as the later E6 blocks. Best regards - Michael.

Hi everybody. I have a Modine Radiator with an attached Intercooler which has the numbers N-109162 and 1A16898 and the date 18/5/94. It is unused and it is exactly the same height as an R Model Radiator, but a bit narrower. Can anybody identify what it was built for or how big a motor it was designed for. I am looking to use it on a rigid truck so it should be adequate. Thanks best regards - Michael

This problem can be solved with a Mack rear mounted PTO. You do not need to have the Main in gear to run the PTO.

Hi David - Where do you attach the PTO to the rear of the 6/10/12 speed boxes? I have never seen one here in Australia only the side mounted ones. Joe is right about spreading. This is the way I have done it for the last 30 years but it is not as convenient as the 5 speed where you can throw it in and out of gear easier when spreading.Best regards - Michael

Hi Jason - Don't forget that you have to put the 6 or 10 or 12 speed into a gear and the hi-lo-rev lever into neutral to use your PTO to lift your dump. It's no bother if you are always dumping in a single tip but if you are trying to spread the load, it can be a nuisance as you have to keep dropping into neutral to lift the hoist. For spreading, the system on the 5 speed or the old 6 speed O.D box is simpler where you don't have to put the main box into a gear, only when you want to move forward. Best Regards - Michael.

Hi Al and everybody, Does your Air Compressor intake come from the manifold? I had an E6 that had a split in that little intake hose and it used to open up under pressure when it got hot, and send the pyro up. Regards - Michael.

LOL that sounds like a good workout! I wonder how long it would take to fill a 60gallon tank to 100+ psi

Hi everybody, over the years I have always carried and used an air hose to pump up the start tank. I have found that you always have to use two tyres with about 100psi in them to get enough pressure in the tank to start the truck. The problem is not always getting enough air to work the starter but enough pressure to open the dump valve on the start tank. There are at least 4 different types of dump valves, and some dump valves will open at 70 psi whereas most of them need closer to 90 psi to activate them. Years ago I tried unsuccessfully to pump up the tanks with the 12 volt compressors that were around then. After about 15 minutes they used to melt - never to go again. The modern 4wd compressors should be much better- the only way is to try them. Supercheap and Repco both have 12 volt compressors which they claim will do the job, but the duty-cycle beats a lot of them once they get to about 50psi, and this is not enough to start them. Certainly the small petrol powered compressor mounted in a tool-box is the ideal thing if you remember to carry petrol all the time. It is essential to have a guage on the start tank as you can top up the tank if the pressure is a bit low, rather than waste that pressure that is already there. We were fortunate over the years as we mostly left the trucks at the Quarry and used the End loader to pump them up if they ran out of air, but if they were left at the other end, we used the tyres. Best regards - Michael.

Hi all - The first Superliners in Australia had the 3408 Cat. They were a bit heavier on fuel but they were great pullers on road train and heavy float work. Best regards - Michael.

Mike, I agree with you on this point. When the "C" Motor and Maxidyne motors were fitted to the early R Models here in Australia, the air tanks seem to have been cut down in size to about half of what the 711 motors had. There is not a great deal of difference in the weights of the tanks as the heaviest part was the ends, however if you are short of space the shorter tank can sometimes help. On one truck I put a small Mack air start tank on it and converted the old big air tank to hold the hoist oil for the tipping trailer, without even moving it from where it was mounted. Best regards Michael.

Hi Rob and all. Before bulk distribution of fuel was introduced here in the 1960's, the oil companies here were very fussy about not putting diesel fuel in galvanized drums. There were still a lot of old heavy Galvanized Drums in circulation from WW2, but they were very particular to put only Petrol or Kerosene in them. Their story was that the Sulfur in the Diesel reacted with the Galvanizing and with a little moisture from condensation, formed Sulfuric Acid which, among other things, corroded the Barrels and delivery Valves in the Injector Pumps over a period of use. Apparently the Oil Companies had to compensate some users who had bought diesel fuel which had been stored in the Galvanized drums and caused damage to injection systems. Best regards Michael.

Hi Fellas.

Just wanted to ask all you smart and knowledgeable blokes what is the best way of flushing and cleaning the coolant/water out of the radiator and engine block.

I have been told to get it hot flush the old water out, fill it up again with some radiator cleaner get it hot again then flush it out and fill it up with the mack premix lime cordial, i can get the Mack cordial at cost so that healps with the $$ also i would think that it would also be a good idea to put in a new water filter

-Monty

Hi Monty and all. This is the way that I have always flushed the Block/Radiator on all the trucks and machines. First of all take the radiator cap off, then take out the drain tap on the side of the block or the tap on the Brass pipe on the lower Mack hose and replace it with a quick release hose fitting. Then you can put your garden hose onto that fitting and flush it out the top. After you have flushed it for a while, pull the water hose off and plug an air pressure hose in place of it for a quick blast. It will lift a lot of rubbish out. Keep alternating the hoses until it is clear. This method is good if you have oil in the radiator as it pushes it out the top. The old treatment we used to use was a handful of washing soda in the radiator and run it hot for an hour, flush it out till it is clear, then change the filter. Best regards - Michael.

Hi M5040, The numbers on the blocks which were produced in the early 1980's don't necessarily mean much as Mack in Brisbane were retro-fitting intercooler kits to the ESI 237 motors to take them up to the 285 motor. They fitted the tip turbine/intercooler unit, the larger Turbocharger and changed the delivery valves and barrels in the injector pumps to take them up to around 300hp. These were done as a paid job for the customers after the intercooler units were released. It made a big difference for road-Train work. These trucks would still have all their original numbers and markings of 675 instead of 676 which the were then. There is no reason why this conversion could have been done anywhere else also. If you bought a new block from Mack they did not always have any engine numbers at all so you could stamp the original 237 number to simplify registration. Best Regards - Michael

I have a cab that used to have a walk-in sleeper fitted - now I want to revert back to a normal cab. How hard is it to change the rear cab panels and where do I cut them - or do I just fill in the missing piece from the rear window down. I have a donor cab shell. Regards - Michael.

Hi Grant I would be fairly certain that what you have is the C Motor which was 250 HP. It was the most common in the Flintstones and F models before the Maxidynes were released, in conjunction with the Maxitorque gearboxes. If the block had been replaced with a new one from Mack , it would not necessarily have an engine number , nor would it have been painted any colour at all. I have a Maxidyne motor which was never painted until I got it and it has no engine number. best Regards - Michael.

Hi Rob, I'm having trouble getting reverse in the truck I just purchased, I've only managed to select rev once, and that took alot of flipping in/out. When I'm in neutral on the button with lever in gear, I cant get neutral, so its in the shift knob or the airshift I spose. I spent 1/2 hr nudged up against the front gate then managed to get rev. With mine it is very quiet, can hardly hear the shifter. This is the 1st time I've had anything to do with airshift. Jeffro

Hi Rob and Jeffro , I find that if you are using the truck every day they shift easier. Before I changed the regulators on the ten speed I had trouble getting it into reverse and also if it hasn't been used for a while you sometimes have to flick the little lever a few times. Sometimes it helps if you put a kit in the switch. You used to be able to get a Spicer kit with just the rubbers that you need. Buntines in the Northern Territory who had hundreds of Macks, apparently used to run higher pressure in them (maybe full supply pressure) but I once saw one of their twelve speeds with a broken reverse selector when it was traded in to Mack. Another thing - do you have anything that builds nests in the exhaust hose in the changer. We have wasps who seal the pipes with mud nests and that doesn't help the change. Best regards - Michael.

Thanks HK, I was told it was a 6 spd but got confused by the extra case and no airshift to the rear. Also no shift pattern lable and no engine. Thanx Jeffro

Hi Jeffro - I also had a 1969/70 R model with a Maxidyne and the 6 speed Overdrive. They took the place of the double Overdrive Quad Boxes when the Maxidynes were fitted as we were told that the Quads would not stand up to the higher torque. They still used the Quads with the 250 HP C Motor. By using that box with the .6 overdrive, you could use the old slow diff ratios. The one I have , has 7.49 diffs in it and that used to do about 58 MPH. The original diffs were about 8.25 and Western Transport changed them when the truck started doing the Toowoomba to Perth run in about 1971. Best regards - Michael.

I have a 10 speed that was sometimes hard to get into reverse. What I eventually found was that it had either two or three air pressure regulators on the gearbox, and one of these was faulty and the pressure was not balanced so it would not go into reverse. I replaced the regulator and reset the pressure and it fixed the problem. The airline to the piston at the end of the rack on the fuel pump used to pressurise when the gearbox was in low or reverse gears to limit the torque of the motor. This used to leak air sometimes and after I put a rivet in this line it made it easier to get into reverse and low gears, so it must have been upsetting the pressure also. Best regards - Michael.

I agree with Glenn.

Most times it's a problem with the double check valve that causes this.

Hi everybody, When I was working My 1969 R Model I had a similar problem. It turned out to be the seals between the Service and Maxi brake chambers were leaking and the air was coming back through the vent on the treadle valve. That model had a very simple arrangement where the Parking brakes discharged through the service system so that when you put your foot on the service brakes, it released the pressure from the spring brakes. I don't know whether this was only on the Australian models, but it was much simpler than having the double check valve. I change the Maxi -brake units and stopped the leak. I too had already changed the foot valve but it made no difference. Best regards Michael.

I agree with Glenn.

Most times it's a problem with the double check valve that causes this.

Hi everybody, When I was working My 1969 R Model I had a similar problem. It turned out to be the seals between the Service and Maxi brake chambers were leaking and the air was coming back through the vent on the treadle valve. That model had a very simple arrangement where the Parking brakes discharged through the service system so that when you put your foot on the service brakes, it released the pressure from the spring brakes. I don't know whether this was only on the Australian models, but it was much simpler than having the double check valve. I change the Maxi -brake units and stopped the leak. I too had already changed the foot valve but it made no difference. Best regards Michael.

I alway's thought the FR was the set back axle model

Hi Werkhorse, The FR model was fitted with an F model type cab, either Day-cab or Sleeper Cab in either Steel or Fibreglass, that was a designated Right hand drive, mounted on the standard Australian R Model Chassis. All the plumbing on the FR was the same as an R Model with extension hoses and wiring etc. to fit to the F cab. The FR cab did not have the cross-over steering arrangement that the older F Models had. The F Models had a wider chassis than the FR Models so they had different (wider)rear engine mounts. The set back front axle was only introduced near the end of the production of FR Models, just before the Cruiseliner was released. Best regards-Michael.

the person that did my heads said that it showed very little engine wear so i thought it must mean rings should be good. the truck has close to 500,000 KM. on it.

Hi jook24 - Have you ever changed the rocker shafts on the heads. We had trouble with two different motors where there was oil dripping out of the breather pipe even after the motor had a new piston and sleeve kit. We found excessive clearance under the rockers as they had grooves worn into the shafts. When we changed the shafts the oil dripping stopped. We found that worn rings and sleeves usually caused excessive fumes and blow-by down the breather. One motor that had blow-by past the rings as well as the worn rocker shaft was loosing half a gallon of oil down the pipe in a big day. Don't forget that with the Mack sleeves you can still have original honing marks in the bore at those sort of miles and at the same time have stuffed or broken piston rings. Best regards- Michael.