A question for those with an MX5400/6000 with cab and A/C or similar tractor.

[mcmxi]

I changed the coolant in the MX this past weekend and noticed that an idler near the A/C compressor belt wasn't making contact with the belt. There's no adjustment to get it into contact, only a bolt on the left side of the engine that is used to adjust the tension in the A/C compressor belt.

If you have an MX with cab and A/C or a similar tractor, can you check and see if you have the idler pulley, if it's in contact with the belt, and what size it is. I'm wondering if the idler pulley is too small, or if it's an artifact from some other feature on the tractor that isn't being used. I have the printed WSM and it says nothing about this idler.

Idler in center of image not in contact with the A/C compressor belt.

Bolt to adjust A/C compressor belt tension (on left side of engine).

 

[mcmxi]

Before anyone suggests that the belt should go around the idler, it would seem unlikely given the shape of the pulley. The shape implies that the back side of the belt would contact the idler. If the belt were intended to go over the pulley, the pulley would be the V-groove variety ... I would think.

 

[edritchey]

Mine has the same thing going on.

 

[mcmxi]

Mine has the same thing going on.

View attachment 126413

Thanks for the quick response. So maybe it's an artifact from the open station MX models. They don't have the A/C option so there's obviously a different belt routing on those models. I'll look through the photos I took when I had the MX6000 open station and report back if I find something interesting.

So now I'd like to expand the question to open station MX owners. Do you have the idler pulley, and if so, is it utilized or just along for the ride as shown in my tractor and @edritchey .

 

[North Idaho Wolfman]

Looking at parts prints it all looks right to me.
I'm pretty sure it's purpose is to keep the belt from hitting hoses or other lines, or parts.
It's a safety.

 

[mcmxi]

Looking at parts prints it all looks right to me.
I'm pretty sure it's purpose is to keep the belt from hitting hoses or other lines, or parts.
It's a safety.

That's interesting. So if the belt gets really loose due to stretching or the adjustment being off and starts flapping around, the pulley would prevent it from getting way out of control?

 

[Matt Ellerbee]

No idler on my rops. Not even the bracket. That large boss just to left of belt is threaded.

 

[mcmxi]

I looked through my MX6000 open station photos but don't have a photo of the engine. I am still curious about the belts on an open station model though. I'll look through the WSM to see if it shows anything.

 

[mcmxi]

View attachment 126414
No idler on my rops. Not even the bracket. That large boss just to left of belt is threaded.

Thanks @Matt Ellerbee . That's very helpful.

 

[North Idaho Wolfman]

I looked through my MX6000 open station photos but don't have a photo of the engine. I am still curious about the belts on an open station model though. I'll look through the WSM to see if it shows anything.

Look one post back. HAHAHA

 

[mcmxi]

The parts diagram on Messicks shows the pulley (# 170) being in contact with the A/C belt but I'm still not sure if there's a way to adjust the bracket to move the pulley closer to the belt. I'll have to look into that.

By the way, #170 is described as a "tension pulley" so it needs to be in contact with the belt to increase tension in the belt. I don't think that the intention of that tension pulley is to sit 1/2" off the belt and make no contact. My concern here is having the A/C run optimally during the hotter months, and insufficient tension in the belt could cause the A/C compressor pulley to slip which isn't good for anything.

 

[Matt Ellerbee]

The parts diagram on Messicks shows the pulley (# 170) being in contact with the A/C belt but I'm still not sure if there's a way to adjust the bracket to move the pulley closer to the belt. I'll have to look into that.

By the way, #170 is described as a "tension pulley" so it needs to be in contact with the belt to increase tension in the belt. I don't think that the intention of that tension pulley is to sit 1/2" off the belt and make no contact. My concern here is having the A/C run optimally during the hotter months, and insufficient tension in the belt could cause the A/C compressor pulley to slip which isn't good for anything.

View attachment 126415

Looks like bolt #180 would be used to get pulley closer to belt. Bracket and all would rotate.

 

[mcmxi]

Looks like bolt #180 would be used to get pulley closer to belt. Bracket and all would rotate.

The drawing does make it look like that's how it'd work, but I think there's another bolt that's not shown. There's a hole in the middle of the bracket that has a bolt (I think). I'm taking the MX, bucket and the EA land leveler over to my neighbor's house to spread gravel since a big truck just dumped a load outside their house. I'll have to look at the pulley later.

 

[edritchey]

The drawing does make it look like that's how it'd work, but I think there's another bolt that's not shown. There's a hole in the middle of the bracket that has a bolt (I think). I'm taking the MX, bucket and the EA land leveler over to my neighbor's house to spread gravel since a big truck just dumped a load outside their house. I'll have to look at the pulley later.

There is 2 bolts holding that bracket to the engine the belt is adjusted from the other side with a slotted bracket and a tension through bolt.

I think Wolfman is correct in thinking it's there for protection and I think it's protecting the rubber hose going into the top of the oil filter base.

If that belt gets real loose or jumps off or breaks off it would be likely to catch that hose without that pulley there and it wouldn't take much to cut through or damage that small hose.

 

[BAP]

Check and see if the hole that the pulley bolts through the bracket is slotted. Could be you loosen the pulley and slide it in the bracket.

 

[ruger1980]

That's interesting. So if the belt gets really loose due to stretching or the adjustment being off and starts flapping around, the pulley would prevent it from getting way out of control?

Yes that is the purpose of that idler. My L4310 is the same way. It is on the slack or return side of the configuration and a belt that long can really get to flapping around.

 

[mcmxi]

I had to chance to look more closely at the "tension pulley" and bracket and there's no provision to rotate it. The schematic above is missing a bolt, and the boss that @Matt Ellerbee mentioned is solid and not threaded.

I took a look at the M6060 engine compartment and the unsupported belt distances are much shorter so there's no need for such a gizmo on that model.

At this point I think that @North Idaho Wolfman nailed it and someone else misnamed the part. It's not a tension pulley since it doesn't appear to be able to apply any pressure to the belt. As @ruger1980 confirmed, it's there to prevent the belt from flapping around and doing damage.

This is such a good forum and I learn something from it just about every day. I now feel better about the gap between the pulley and the belt and no longer feel that I've been remiss in terms of maintenance. I also won't worry about the belt slipping on the A/C compressor pulley during those hot months pulling a cutter around a field. I will of course check belt tension and adjust if necessary, using the bolt on the left side of the engine.

Thanks to everyone for such thoughtful and helpful photos and responses. Case closed!

 

[mcmxi]

Check and see if the hole that the pulley bolts through the bracket is slotted. Could be you loosen the pulley and slide it in the bracket.

For the record that was the first thing I tried since it made the most sense. It's a 14mm bolt, and after loosening it I realized that there was no slot to allow the pulley to move inwards. Good suggestion though.

 

[chim]

My L4240 isn't too similar and the pic isn't great. Mine has the belt barely kissing the pulley.

 

[Flintknapper]

It's not a 'tensioner' pulley, else it would have obvious provision for adjustment. It is an 'idler' pulley and in this case is most likely there to prevent deflection.

Same exact thing on 80 series Land Cruiser's. The belt does not touch the pulley. BUT because there is such a long 'unsupported' run of the belt, it can flex/wobble under certain conditions and thus be susceptible to coming off a pulley. You don't want a thrown belt on your tractor.