Recent Posts

21

Technical Support / Re: Cat 3126 shredding serpentine belts

« Last post by Carl Boger on October 24, 2025, 11:40:49 PM »

To follow up, Went out to where I have the coach for a couple of weeks and found the hidden zerk over the fan pulley.  Well yes it was hidden!  It also is at a location that a standard grease gun end will not fit.  I had to grind down 2 opposite sides of the grease fitting to get it into the recess and onto the zerk fitting.

While the bearing still feels good it did need greasing, so that task is now done.   Fred I cut down a piece of thin aluminum that still had a factory straight edge and lined it up with the pulleys.  They appear to me very well aligned.   I fired up the engine and watched the belt track again and there doesn't seem to be any issue and it tracks straight.  The idler barely moves as it is running. 

I do appreciate everyone's help.  I will be carrying a few extra belts and I will be prepared to change them if necessary.  I will try to get this to may mechanic after this next trip in November and have him go over everything, and look at some oil leaks.  He has a lift and can get access to that area better than I can at home.

22

Technical Support / Re: Cat 3126 shredding serpentine belts

« Last post by Carl Boger on October 21, 2025, 11:30:57 PM »

Thanks for everyone's responses!

I took the belt off today and made sure that all the pulleys felt smooth.  I have not used a straight edge like Fred suggested, but will.  I did watch the belt running and it appeared to track straight, but that doesn't mean it actually does.

As for the zerk, well I will have to look for that one.  Not a problem.

I actually just relocated the MH today to a friends property since I am having some concrete work done here.  So now instead of being right here to work on its 30 miles away.  I drove it down there today with no issues.

I will double check the pulley's grooves, but I believe they are correct.  Since I have owned it I have replaced the AC compressor, the Alternator, and the Water pump.  Thankfully the water pump has its own separate belt.

Thanks for the ideas, I will see if I can get things lined up better.  Worse case maybe I can get another 7K before another belt lets go.

23

Technical Support / Re: Headlights not working??

« Last post by RogerMilne on October 21, 2025, 08:05:51 PM »

Roger,
I suggest you break this problem down and focus on getting the system back to OEM status and then worry about the added wires etc. As I requested in my previous post, please take the following steps and report the  results.

 1. Did you pull F69 and jumper from the cold side of the fuse to the pin 30 slot of R11?
 2. Did you have a short between F69 and VCB-11 with low beam selected on the dimmer switch?
 3. If so, what was the resistance to ground with low beam selected on the dimmer switch?
 4. Did you have a short between F69 and VCB-12 with high beam selected on the dimmer switch?
 5. If so, what was the resistance to ground with high beam selected on the dimmer switch?

Once you have and provide the answers to the above you can focus on getting the 2 circuits to read identical. Strongly suggest you not cut or remove any more wires or components until you establish status of above.
Steve

Thanks Steve,

yeah I'm back at the RV for a couple days and will attempt to do the troubleshooting you listed and I'll post results when I accomplish them.
I definitely won't be taking any more wires out until I can get back to OEM condition.

thanks for the inputs and will post once done.

24

Technical Support / Re: Headlights not working??

« Last post by Steve Huber on October 21, 2025, 06:42:51 PM »

Roger,
I suggest you break this problem down and focus on getting the system back to OEM status and then worry about the added wires etc. As I requested in my previous post, please take the following steps and report the  results.

 1. Did you pull F69 and jumper from the cold side of the fuse to the pin 30 slot of R11?
 2. Did you have a short between F69 and VCB-11 with low beam selected on the dimmer switch?
 3. If so, what was the resistance to ground with low beam selected on the dimmer switch?
 4. Did you have a short between F69 and VCB-12 with high beam selected on the dimmer switch?
 5. If so, what was the resistance to ground with high beam selected on the dimmer switch?

Once you have and provide the answers to the above you can focus on getting the 2 circuits to read identical. Strongly suggest you not cut or remove any more wires or components until you establish status of above.
Steve

25

Technical Support / Re: Headlights not working??

« Last post by RogerMilne on October 21, 2025, 05:41:06 PM »

Ok folks, between work schedule and this crazy webpage issue everyone is having, I can finally try and attach some pics to show where my problem is and try and figure out why I'm blowing dimmer fuse #69

So a quick synopsis, of what I have at the moment.
Removed wiring directly from light bar and relays and from what I can see, one splice in at the steering column, for what was a LO Beam power source. PO then spliced the Lo Beam from smart wheel to the Lo Beam on the connector plug at the headlight unit. There was a power source that he ran from the battery to power the relays and then came back into the dash and had a main power switch and a Hi & Lo beam switch that PO installed and then went back to light bar. No apparent splice into the Hi Beam circuit. So when I inadvertently removed what I was guessing was just a overkill for a light bar appears may have removed all the wiring for the Headlight Dim Mod'.
So the problem is I have no clue where the VCB 11 & 12 splice is in my wiring. I'm guessing the VCL 5 splice was the battery feed I still have out on the firewall, but it was disconnected at the Fuse adapter he had installed.
So my understanding is I should be able to just go back to normal by tying VCB 11 back together at the smart wheel splice BUT no clue where he spliced VCL 12.
So not knowing where VCL 12 spice is and connecting VCL 11, I blow fuse #69. If I disconnect the Lo Beam t the smart wheel splice I can have Hi Beam only, no Low beam and no blown dimmer fuse.

I have attached some pics with description, so hopefully this makes sense to someone.

26

Technical Support / Re: Cat 3126 shredding serpentine belts

« Last post by Richard Davis on October 21, 2025, 01:29:20 AM »

I agree with the things that Fred  and Eric have said.  The only other thing I would check is the grease zerk behind the fan pully on the 3126.  Most people do not even know it is there and it does not get greased.  It is hard to see.  You have to be looking straight down on the back of the engine to see it.  Because it got overlooked, CAT changed the design when they went to the C7 and used a permanently greased bearing.  Anyway, if that bearing is starting to seize because of lack of grease, that could cause your belt problem.  Good luck.
Richard   

27

Technical Support / Re: Cat 3126 shredding serpentine belts

« Last post by Eric Maclean Co-Admin on October 20, 2025, 02:09:10 PM »

Carl
As Fred described check the pulley alignment first if you replaced both the alternator and the A/C compressor make sure they both have the proper pulley on then ( count the groves on the pulley ) if they ore too narrow or not aligned properly you will have belt issues.
Next with a rear rad I assume you have a belt driven cooling fan check it for bearing slop and rumble a belt issue if the bearings are going bad..
Next check the belt tensioner and any idler pulleys for bearing issues.
And finally take a real good look at the spring loaded belt tensioner if it has one, they tend to fail in a couple of ways  they will get seized or sticky and not move through their full travel second the center pivot will get worn allowing the tension arm to deflect which tilts the pulley which in turn allows the belt to misalign and or roll the belt off the other pulleys which will cause the shedding you describe and of course a weak spring in the tensioner will also cause issues with belt chatter and slipping .
Anything that can cause the serpentine belt to misalign or slip will be catastrophic to the bell considering the fan assembly can require upwards of 45 horsepower to drive at highway speeds..

Hope this helps
Eric

28

Technical Support / Re: Cat 3126 shredding serpentine belts

« Last post by Fred Brooks on October 20, 2025, 01:14:52 AM »

   Carl,

I ran into that on my summer vacation in 2024. I replaced the a/c compressor and it looked fine when I installed it. After shredding 2 belts, I decided to do an in-depth alignment check of all the belt pulleys. On my coach, the serpentine belt keys off of the bottom crank pulley. I went to HD and purchased a flat stock steel 1" x 1/8 x 4'. Holding it on the crank pully I aligned it with the Idler, alternator, tensioner pulley, and then the a/c compressor clutch pulley. Everything was ok except the a/c clutch pulley. It was off 3/16". Turns out when I installed it, I put the spacer washers on the wrong side of the cradle mount. I relocated the compressor correctly and all is good. Hope you find it, Fred

29

Technical Support / Cat 3126 shredding serpentine belts

« Last post by Carl Boger on October 20, 2025, 12:54:18 AM »

My 1998 Beaver Patriot with a Cat 3126 and a rear radiator has shredded 2 serpentine belts in about 7000 miles.
The first time I had just reached a campground just south of New Orleans, about 750 miles from home.  Had run fine until reaching the campground then suddenly ran hot.  I had a used belt with me so I replaced the belt and I was back on the road.   The Belt was totally gone leaving just shredded material behind. Bought a new belt outside of Atlanta and then installed it.

That lasted right at 7000 miles and a little over a year until yesterday.  Coming home on I85 about 10 miles from the SC line and having just fueled up, the coach suddenly ran hot and derated.  I pulled over on a exit, and checked.  The belt was gone,but shredded pieces of the belt were around the pulleys or laying in the engine compartment.   Having spare belts I replaced it, before the engine had cooled, but I was in a hurry.  I first had to pull all the shreds of the old belt out and then putting the new one on was the easy part. 

So my question is does anyone have any idea why this is happening?  Belt was a NAPA 25 080710HD.  Pulleys and grooves appear good.  Belt seems to run true.  Has anyone run into this in the past?  Alternator is new as is the AC compressor. 

I did run through a debris field of shredded tire from a Tractor trailer that was maybe 1/2 mile in front of me when his LF blew and he ended up on the rim.  I didn't think that I had hit anything, but who knows.  That could at least explain this.

I hope to get it in a local shop soon as I really can not get to the area to do a proper inspection and evaluation, or I'd just rather pay then do all the work involved in removing the rear radiator. 

I would appreciate any insights before I leave for a 1000 mile trip in Nov.

                                                               Thanks Carl



 

30

Technical Support / Re: cleaning walls and ceiling

« Last post by Carl Boger on October 20, 2025, 12:18:51 AM »

Rick,

I would cover everything up with plastic that I wanted protected and then use the folex on a mop head and lightly scrub it a few times a day for a few days.  Let it dry between treatments and hope for the best. 

My ceilings are in decent shape, but I have used the folex to spot clean.  My walls were not so nice, so I ripped them out and added vinyl clad aluminum panels on the top half, and used bead board panels as wainscotting on the bottom.  I don't have a Marque but it turned out fairly nice.