br549

Put a test light in cab of truck and run long wire and unhook one of the jake wire at the valve covers and hook it to it. Test drive see if the light goes off at 1600 rpm, if the light stays on but the jake quits its problem with Jakes internal or oil pressure problems, might need a tune up kit or soleniods. If the light goes off at 1600 it is in electrical but I don't remember a place to set cut off in settings in computer.

Low oil pressure could be cause, all of the 2000 models had jakes cut out early especially on a hot day when the oil really heats up, not enought oil pressure to the jakes . We put a higher speed oil pump on ours, it helps out but they did make a kit to feed oil from the main oil galley on the block to the jake spacers and feed direct oil to Jakes. If yours have been changed you will have external oil lines on the drivers side going to the jake spacers. I have seen several of the freeze plugs in the end of the rocker arm come out and loose oil pressure, but most of the time that head quits working. See how much oil pressure it has when it cuts off, I think it takes 35 lbs for jake to work so you need to have around 50 lbs on the gauge in truck to work.

How many batteries do you have? For test purposes disconnect and just use 1 or 2 of the new batteries, it should start in warm weather with 1 battery, just 2 make sure old one not bad or giving problems. Check all connections good. check ground cable from starter and block to frame. If starting before battery removal it sounds like connection or short in battery cable rubbing somewhere. When started if both red and yellow light comes on when running it can be low water, high water temp or low oil pressure sensors. We had a few of that model where the harness comes under the intake manifold and above the starter on the driver side where it rubs on the block and tie down clamps would rub and short out causing same problems. You can blink out the code for the yellow ck engine lite with the cruise buttons and narrow down the problem if you can get it started again. Some times the connections at the injection pump can cause starting problems too, take apart and spray and clean connections.

Check the turbo relief valve. Look at the exhaust pipe behind the turbo and you will see a small pipe about 1" that goes back up to the intake manifold pipe, there is a short rubber hose with 2 clamps on it. Remove the valve I think it takes a 1 1/16 wrench. I just put a pipe plug in it and by pass it and test drive the truck and see if it does better and the noise goes away. I have heard them make funny noise and loose a lot of turbo pressure there when they are bad.

If no other clutch problem, replace clutch brake with a 2 piece one old 1 can be cut out with a air chiesel or a cutting torch, not easy working in tight spot but we do it if there is no other clutch problem. They usually don last as long as a factory clutch brake but if it go bad again it can easily be replaced again.

That spring is in the valve on the bottom left in the last picture. It is below #1 injector line the valve that has a braided hose and a 1/4 plastic line going to it. I think it takes a 3/4 wrench and a 7/8 to remove it, be careful don't loose the ball and hat. WE take a #6 fitting and drill a 1/8 pipe thread in it and put a line and guage on it and put it where the line going into the pump for checking fuel pressure.

If the spring is broke you will have most all of the fuel returning to the tank and truck cant build pressure, simple to ck.

ck the fuel pressure over flow valve, its at the front side of the pump where the line hooks and returns fuel to the tank, remove the nut and there is a spring, a ball, and a little hat for the ball, have seen several times the spring breaks and the truck can't hold fuel pressure.

It could be the oil pan gasket. Our 2000 CX model seeped oil on the passenger side between the block and flywheel housing from about half way from the top down. We lived with it for about 5 years finally at a million 3 we pull the transmission to replace the clutch ( a solo clutch, the most I have every had a clutch go, but also only 1 driver on the truck since new) we pulled the flywheel housing and put new rubber sealant on it,there is no gasket just rubber sealant, also replaced the rear cam plug it was just about rusted out. If it is the cam plug you can see a small hole about 3/4 of the way up between the flywheel housing and the block, I think it would leak bad if it was leaking there. Good luck

Does the right turn signal work? If it does check the turn signal switch, the brake lights go through the signal switch.

Bad eyes, now I see the other stick behind the steering wheel.

I only see 1 gear stick, probably a 5 speed maxidyne.

Where is it leaking, there is a pin hole in the little cylinder for air to exhaust out of, if it is there you have oil in the air system, if it where it screws in the little housing, remove it and put some rubber sealant around the shims. If it is leaking around the housing it screws into there is a oring around it but you have to pull the pump to change it, there is no oil pressure on it and I have seen some people clean it up real good and put rubber sealant on the outside of it and sometimes it will stop it there.

If the fuel is leaking where the line hooks on and that is the only problem, you can remove the pump nut with a 1-1/4 12 point socket and there are orings in there that can cause it to leak. There is a oring around the top nut and one around the part the line screws on and seals on the inside of the big nut.

A man i know bought a used truck that had just been inframed, the oil pressure drop a few months later. Pulled the pan and a piece of grit was in the oil pump valve, simple fix, but #5 & 6 clyinders there was gobs of rubber glue around the bottom of the sleeves. I always wonder why You would spend the money to overhaul and than get rid of it. Like some one said be sure you get warranty and was done by a reputable place.

Most of the time it is usually the oil cooler, your can remove it and pressure ck it. We made fittings for the oil side and put air pressure on it while in a tube of water and ck for air bubbles.

The wear ring is replaceable just make sure you get the right one for the type of seal. For a hobby truck I would just put a new seal ring and new bearings in it, Years ago we had a knurler you could use on spindles, I would pack the bearing in semi fluid synthetic grease like a lot of the new trailers use to make sure seal don't leak for a hobby truck and see what happens, not sure but I have seen bearings that were extremely tight and would cause the inside of the bearing spin on the spindle and cause wear like that.

Air compressor is on passenger side behind the fuel injection pump, has 3 bolts, should be a tag you can see to get model, bendix or midland. power steering should be mounted on the back with 2 bolts. truckpro is in Johnson city, Tn about 30 miles from u. FleetPride is in Kingsport, Tn about 40 miles both deliver down that way. Did the a/c throw a rod. some times the fiber coupling slips on the drive and one way to tell is if you loose your power steering too. that being said a lot of times it just the unloader valves or governor bad, or a air leak on the main line or else where, a couple of times I have seen the hose to the intake air swell up inside and close of air and it will not build air.

The Big Line on the Air Compressor goes to the Air Tank or the air dryer, there in no line to a quick release valve or foot valve. I the air governor bolts directly to the a/c, you have a feed line from the air tank and if air dryer on truck one line goes to the bottom of it to tell it to spit off. If the air governor is bolted on the fire wall it has one line to the compressor to the unloader valves. I don't understand the quick release valve you are saying from the air compressor? Could it be a air dryer or air governor?

Dad bought a used b61 with integral sleeper in the 6o's his first mack, he had a hot load of lumber that had to be in Pa the next morning,so he turned the fuel up on the pump, and took another driver with him, telling him not to hold the pedal down all the time. dad was in the sleeper when the truck quit running, motor was locked up. Got out look under the hood and said u could see through the exhaust manifold, he said they sat there for 2 hours let it cool down and it started back up and finished up the trip, but turned the fuel back down. The other driver went off a mountain in NC and turned the truck over with a load of lumber a year later, he still has the newpaper article he was there about 4 hours before being found and was pinned in the truck, they got him out and he was ok, them trucks could take a beating, and driver's too.

Had one do the same thing, replaced unit pumper orings, supply pump, still fuel in oil, it ended up being the plug leaking at the front of block at the fuel gallery. Our never did show leaking under pressure, but when engine is running the heat, vibrations caused it to leak more. Good luck

Mackpro68 We replaced the bolts when they broke when the truck was about a year old, and also about 2 or 3 years ago when they changed bolts again, also the fan hub broke off at about 60,000 miles both under warranty but I think Mack handle all of this stuff bad they should have had a recall on these thing, they knew they were bad, we broke down on the road both times, warranty covered it but not load delivered late plus loss of other loads because we could not pick up on time plus driver motels and pay. Another guy bought a truck at same time and got rid of his at 80,000 miles because of so many breakdowns on a new truck, It was his first New Mack, he traded for a Peterbilt. We have been running Macks since the 60's, but after the first couple of years it has done a pretty good job, but I still don't understand why when they know problems like that they don't recall before you break down a thousand miles from home. Enough venting I guess, but thanks for advice on the bolts.

Thanks Staxx, I replaced the O-rings on the engine brake solenoids and its ran 4500 miles since and no problems.

Check the fuel linkage for slack in it, also take the rod loose that hooks to the fuel pump shaft, and see if the spring in the lever is broke or has slack in it, it need to be tight with no slack in it but should be able to give as you push hard on it. Other than that it probably be in the governor and be repair at a pump shop. Is it American Bosch or Robert Bosch pump?

Years ago when they would leak and right new we would pull them apart and put NAPA exhaust sealant around the joint and slide them in, be careful not to get excessive amounts in the manifold, but the last 4 or 5 we put on that came from Mack we just put them on dry but before we tighten the nuts up we knock the manifolds together tight and we not had any leaks.