"startem Up Movem Out"

[Mike]

It's 3:40p.m. here and I'm getting ready to go home and put both batteries back into the Mack. I installed a new s/p switch last night and have all cables that were marked attached. Keep those fingers crossed and I'll let you know how it went.

mike

[Mike]

Well,

It didn't go as planned. I know every cable was marked, I connected everything as the first switch. As I connected the last battery ,I put the positive side to it's terminal and I noticed a spark, then looked toward the front of the truck and smoke was coming out from the inside. I disconnected it at once. The other battery did not spark when connected. I believe the cables may need to be swapped at the battery. I've read the instructions before installation many times but this has me stumped as of this time.

mike

[Rob]

Well,

It didn't go as planned. I know every cable was marked, I connected everything as the first switch. As I connected the last battery ,I put the positive side to it's terminal and I noticed a spark, then looked toward the front of the truck and smoke was coming out from the inside. I disconnected it at once. The other battery did not spark when connected. I believe the cables may need to be swapped at the battery. I've read the instructions before installation many times but this has me stumped as of this time.

mike

Hope you didn't fry the new switch internally.

Rob

[Mike]

Hey Rob,

I'm sitting around licking my wounds, Puzzled......... I can expect anything at this point. I only know that I have all connections the same as the switch before. I'm going to the house to get some sleep. And check it tomorrow after work. I marked every cable with masking tape, also put on them what it was for.

mike

[Freightrain]

Ouch! Did the switch come with a wiring diagram?

I hated when I screwed with mine as I knew it would be a bad day when I smoked it by hooking something up wrong.

Seems like you might need to reconfirm each cable and see where it got switched. Sounds like you got something grounded out or two batteries hooked directly together?

[Rob]

Hey Rob,

I'm sitting around licking my wounds, Puzzled......... I can expect anything at this point. I only know that I have all connections the same as the switch before. I'm going to the house to get some sleep. And check it tomorrow after work. I marked every cable with masking tape, also put on them what it was for.

mike

It is possible the original switch was miswired and burnt up internally as a result. Then unknown to you, the new switch was wired as the original. I certainly hope this is not the case.

I would look at the electrical print, and then follow the battery cables to ensure their correct routing.

Rob

[Mike]

Well tryed a second time. The starter sounds like its running backwards, gets hot and starts to smoke. As much oil and grease is around, i'm surprised it hasn't caught fire. Have had to change the terminals around they were crossed up. Sounds like a job for SuperMan. I haven't gave up yet, I feel like something else is not right. Yea I know what you are thinking, and you are probably right. Here is the diagram. You can see where I have followed it to the letter. How do I know the s/p switch is not faulty?

mike

[Rob]

Well tryed a second time. The starter sounds like its running backwards, gets hot and starts to smoke. As much oil and grease is around, i'm surprised it hasn't caught fire. Have had to change the terminals around they were crossed up. Sounds like a job for SuperMan. I haven't gave up yet, I feel like something else is not right. Yea I know what you are thinking, and you are probably right. Here is the diagram. You can see where I have followed it to the letter. How do I know the s/p switch is not faulty?

mike

Your diagram appears to be for a negative ground system which I doubt you have. I will try to locate one for a positive ground system and post it for you tomorrow.

As you can see from the diagram there are two discs inside of the switch. When the switch is not engaged to start truck, the batteries are in parallel. When engaged, the batteries are removed from a parallel condition and placed in series for the 24VDC starting voltage.

The switch is shown engaged to start the truck in the diagram.

Rob

[Mike]

The other diagram shows segmented lines from battery "B". I'm not sure as to what this is trying to tell me. Also the cable from the side of the starter is showing a lighter cable to the top of the s/p switch. No luck at this point.

mike

[Rob]

The other diagram shows segmented lines from battery "B". I'm not sure as to what this is trying to tell me. Also the cable from the side of the starter is showing a lighter cable to the top of the s/p switch. No luck at this point.

mike

I've got a diagram stored on an old computer. I can't find the original paper copy I'd thought had been retained.

Rob

[Mike]

At this point, I feel like i've made a mountain out of a mole hill. I know this is not hard, just something i've either overlooked or ignorant on the subject. As we know now i've been using the negaitve diagram. The s/p switch I bought from Tracy has come with 2 diagrams. The top one I used and put on this site is the neg. diagram. The positive i'm not sure as how it hooks up since I said battery B shows pos. & neg. cables have segmented lines going to the s/p switch.

Bewildered

mike

[Rob]

At this point, I feel like i've made a mountain out of a mole hill. I know this is not hard, just something i've either overlooked or ignorant on the subject. As we know now i've been using the negaitve diagram. The s/p switch I bought from Tracy has come with 2 diagrams. The top one I used and put on this site is the neg. diagram. The positive i'm not sure as how it hooks up since I said battery B shows pos. & neg. cables have segmented lines going to the s/p switch.

Bewildered

mike

I would get under the truck and trace/follow, then label the battery cables to ensure your known starting point. If you are attaching cables incorrectly; Problems will arise.

Without known reference, you are quite likely "shooting in the dark". I believe your problem is minor, and the solution is near.

Just don't give up.

Rob

[Rob]

At this point, I feel like i've made a mountain out of a mole hill. I know this is not hard, just something i've either overlooked or ignorant on the subject. As we know now i've been using the negaitve diagram. The s/p switch I bought from Tracy has come with 2 diagrams. The top one I used and put on this site is the neg. diagram. The positive i'm not sure as how it hooks up since I said battery B shows pos. & neg. cables have segmented lines going to the s/p switch.

Bewildered

mike

Mike, attached may be the same print you have, and it has always worked for me. The larger switch located to the right of the new switch is long discontinued, and was referred to as the "845" switch, as the last three numbers in the part number corresponded with this.

If you change the diagram to reflect a positive ground system by marking the battery posts opposite of what they are on the print and then wire accordingly, your problem will be solved unless the switch is damaged internally.

The upper diagram shows the switch in an engaged position with the batteries in a series state, supplying 24VDC to start the truck. The lower diagram shows the switch in a disengaged position with the batteries in a parallel state supplying 12VDC for normal electrical operation of the truck. One can see this by the position of the contact disc(s) internal to the switch assy. The broken lines are circuit electrical flow, and internal connections of the switch.

I would replace those battery cables with new if affordable. They are at the end of their useful service life going by the physical condition that I see. I use plenty of dry grease on my electrical terminals to seal out contaminants also.

If you have the guts to tackle this, you have the smarts to fix it.

Rob

[Freightrain]

I'm thinking you just need to turn the battery polarity around, basically. The diagram was ok, you need it for POS. ground.

[theakerstwo]

When you get it running there is another test you need to do and that is when engine is dead turn on all kights and heater and the unhooh both sets of battiers. Now light go out. Now hook mone set up now battiers should burn. If ok unhook them and hook other set up and lighy should burn. This proves the new switch is not ok.

this proves if you can discharge from your battiers you can charge into them if your generator is ok.

[Rob]

What's the latest on Mikes' plight? Did he get it starting on it's own?

Rob

[Mike]

Hey Rob,

No cigar, been having to set it aside. Have been trying to get my dad on Medicade, dealing with Elder Care Lawers, also the Nursing Home people. My plate is running over, but I don't go a day without coming in late night at do something to the Mack. I never realized how much this truck could get into my blood. I promise to let ya'll know when I get it started.

Thanks for the concern!!

mike

[Rob]

I never realized how much this truck could get into my blood. I promise to let ya'll know when I get it started.

mike

Oh yeah, I have to keep five of my "precious jewels" inside the shop at all times so they don't get cold, wet, or otherwise uncomfortable.

Had to get a rise out of my wife the other day; Told her I had an offer on the 51 Mack, (Sheila). Threatened to de ball me, (her EXACT words) should I do that. Then said the rest could go to the junkyard for all she cares.

I guess that means she has accepted at least one.

Good luck on the medical issues. Been through a bit of that myself with family.

Rob

[Mike]

Well guys,

I bit the bullit, sent the Mack to A&B Inc. for electrical help. Its a long story and i'll try to be brief. The p/s switch was fried, alternator fried, voltage regulator fried, wiring fried, because only a small wire acted as a ground for the whole system this was all fixed and is new now. The start switch was ok and the ignition switch was ok, so no need to replace. They checked the starting system and fixed as needed and charging system. They encourged me to replace the old cables and to buy group 31 batteries as Rob said earlier. I have to tell you the drive home all 19 miles, on the interstate 65 was a concern. My girl friend followed me in her car with flashers on, and clocked me going warp speed of 48 miles per hour at 2000 rpm. I felt tied to a post. I hope you all can imagine this event and get a real laugh from it. Now I can consider myself as a REAL, SOUTHERN, DUMB, REDNECK!!!!!!!!!!!!

Stay Tuned Until next time

mike

[Rob]

Well guys,

I bit the bullit, sent the Mack to A&B Inc. for electrical help. Its a long story and i'll try to be brief. The p/s switch was fried, alternator fried, voltage regulator fried, wiring fried, because only a small wire acted as a ground for the whole system this was all fixed and is new now. The start switch was ok and the ignition switch was ok, so no need to replace. They checked the starting system and fixed as needed and charging system. They encourged me to replace the old cables and to buy group 31 batteries as Rob said earlier. I have to tell you the drive home all 19 miles, on the interstate 65 was a concern. My girl friend followed me in her car with flashers on, and clocked me going warp speed of 48 miles per hour at 2000 rpm. I felt tied to a post. I hope you all can imagine this event and get a real laugh from it. Now I can consider myself as a REAL, SOUTHERN, DUMB, REDNECK!!!!!!!!!!!!

Stay Tuned Until next time

mike

Not till you use a white cob after a brown one to see if you need another brown one are you a redneck; (just kidding).

Electrical problems can be a bitch to trace out but grounds, and conductors are normally the first place to start. A 40 year old truck will have it's own idiosyncracies but from what I gathered from your explanation(s), your problems were multiple but can only be fixxed one at at time without a visual inspection.

If you are going to drive much you will need to address the final drive ratio, or spend lots of time and money getting to your destination. Only 48mph @ 2000 engine rpm is a bit low geared; probably in the 5.XX ratios.

Glad to hear it is repaired and thanks for the update!

Rob

[Freightrain]

Yup, glad to hear it moves/starts under it's own power. Electrical can be a real bear, especially with so many problems in one.

You need to find some 4.10 gears for that ol dawg now. Get'r up to highway speed.

[Mike]

Thanks guys for the compliment. Rob those cobbs still work just fine down here. Ben nedun ta git tha Sears an Roebuck catalog back out of tha outhouse check ta see if I can git more of em. A big LOL!!!!!! I agree that I will be keeping the oil hot in the mack, so i'll also be ckecking on rear ratio's but now I'm playing local. I failed to mention on my recent interstate trip the air pump gage showed above 120 psi while driving, but when using brakes the gage would show 90 psi until I let off the brakes. I know the system needs evacuateing of oil and repair. That will be my next project. And yes Larry I do agree with you, looks like the rears need higher ratios 4:11 or 4:56, i'll look to see what I have now. It sure is nice to turn the switch, push the button and she'll fire right up. Question ? Do I recall the Macks having a buzzer sound off when the switch key was turned on before pushing the start button?

mike

[Freightrain]

Low air buzzer?

The govenor might be stickin? Does the pressure go way over if it just idles?

If I could come up with my air ride, you could have my 4.62's. It gets you 65 in OD.

[Mike]

Larry,

Been out of town since friday a.m. gave Mom a weekend away from the problems facing us at this time. Don't think she even knew how to relax, neither did I. I was only curious, not having any buzzing but, maybe I was thinking about an air starter before the start up. I'm not having low air pressure problems. It maintains 90 when braking then, pumps up to 120 and alittle above when on the highway but, i'm getting fuel oil mix when I drain from tank when I get back to the house. Thanks for the offer on the rears and hang on to it for I may need to call you. Can I ask why you changed rear ratios if it's a high gear setup?

Thanks

mike

[Freightrain]

Sounds like you need to get your compressor rebuilt. I did mine as it had bad oiling issues in the air tank. Not a cheap fix, but now it's dry as a bone. It always made good pressure, but just worn out.

I'm wanting an air ride, and if I get one, I want something in the 4.1 or 4.3 ratio which will give me a few more MPH/drop my cruising rpm. I'll then part with my complete rear axle assembly.