ASV Undercarriage design 4500/4810

[bz1]

Bison, hope you see this. I did some checking and found some information in ASV annual reports that provides the history of their product line. Here is some of that history from their 2002 report:

MD70, production start 1991 - First rubber tracked crawler/tractor by ASV. Low ground pressure, bi-directional drive and loader capabilities

HD4500, production start 1997 - Larger than MD-70. Maintenance-free suspension. Currently manufactured in limited quantities for select markets

DX4530, production start 1997 - Largest Posi-Track. Used primarily in over-the-snow application

2800, production start 1998 - Size, weight and operating capabilities of the MD-70 plus maintenance-free undercarriage

4810, production start 1999 - Caterpillar engine and other Caterpillar components (replacement to HD 4500 series)

So the 4810 should be a later improved model. My guess is that is why you have different seals, they started using CAT metal face seals at one point, probably on the 4810. Mine has something else but I don't know what until I get them apart. I see in several annual reports that they continued to build the MD70, 4500 and 4810 into at least 2004 time frame at which time they planned on phasing out the 4500 and 4810 while keeping the MD70 in limited production. I don't think it ever happened that way however. I read that the MD70 had grease fittings on all the axles to grease the bearings and the 4500 was the first machine to have a "maintenance free" undercarriage with bearings bathed in oil. I wonder if they should have left well enough alone. Although I will say that in my career as an engineer working military vehicles we always used oil bathed bearings with CAT type seals. That's what the M1 tank and others have and they work pretty well. However the M1 has clear plastic bearing covers on the end of the axle so you can easliy tell if they are low on oil. I'll use this thread to post my progress on working my undercarriage and let you know how your ideas work on my machine.

 

[Bison]

Bz1,interesting post to say the least.

That "maintenance free" phrace must've been a sales pitch
It's maintenance free till it fails and then the engineers must've been thinking,Replace the whole undercarriage at that time.

I have no experience with the 4500 but when you dig into it you'll find that the design is not as rosy as one was made to believe.
It's no diff on the 4810.

I have some spare components and i'll post some pics for ye.

 

[Bison]

Problems,
Here is how the end of the axle shaft look where it supports the bogie after 2300 hrs.
Now, one can flip them over to get a second run out of them but the bogies and lockplates need rebuilding to make it last as the shaft contact surfaces are no longer straight and the shaft can still roll back and forth in the worn out slots.
The bogie side plates are only 3/8" thick,not thick enough where it supports the axle and not beefy enough where it is welded to the torsion shaft IMO,cause they do break loose there.I got several that where rewelded or cracked and a couple broke off ones as you can see in the pic.

 

[bz1]

Bison, interesting, thanks for the pics. I can't quite tell what the third picture is showing. It will be interesting to see what I find when I take things apart on my machine with 1800 hours. I'm glad to have found you here since you are definitely someone who's been there and seen these parts. Not sure when I will tear into the job. Might not be for a week or two yet.

 

[Bison]

Third pic is the axle shaft pocket in the bogie that supports the down pressure on the axle.It wears out of true (look at the shaft pic),when one flips the shaft it tends to support only a fraction of the shaft and it's gonna be shortlived if one does not pay attention to it( weld back up and file/grind flush).

 

[fixatruck]

I have a question to any one that can help me? I have a 2000 4810, The question I have can I pull off the whole trac assembly from the tractor itsself without dismantling it piece by piece?

 

[Bison]

I have a question to any one that can help me? I have a 2000 4810, The question I have can I pull off the whole trac assembly from the tractor itsself without dismantling it piece by piece?

Yes you can i you if you take the bolts out where the torsion bars bolt to the track frame.
Why would you want to do that anyway?
Its much easier to work on this stuff with the frames on the tractor

 

[bz1]

Bison, I'm still just thinking about digging into my undercarriage so my comments are just theorectical at this point. I am thinking that when I do get things apart I'm going to try to find a way to install some standard/readily available shaft seals in place of whatever expensive seals ASV has on the axles. Have you ever tried to find replacements? Help me remember now but it was you who said you had replaced bearings with sealed units and used grease in the axles, correct? I thought that was a good idea but how about also putting more readily available seals in there? Just a thought that I won't be able to check out until I get the axles apart and start measuring things.

 

[Bison]

Here is a couple pics of a original axle seal cut in half.

When i had it cut in half i found all the spaces in and between the seals solid packed with dirt(to put it mildly, a very poor design at best)

It was the reason i put a sealed brg in and packed the cavity between the seal an the brg with grease in the hope to keep the dirt from the bearing as long as possible.

there are 2 common spring loaded double lip oil seals side by side( and a single thin dust seal washer(lip facing the world) in a single steel rubber coated housing.
The seals ride on a steel sleeve with a rubber coating on the inside(the sleeve has an intererence fit on the shaft)
The total seal is 1" thick and acts as a spacer between the brg and the end cap as well.

I have not been able to find an after market seal to take its place.
I dont think a common oil seal(even doubled up) will last very long in the environment it has to work in on these machines.

 

[bz1]

Again thanks Bison more good info that might help me. These pics are interesting. One of the ideas I had was replacing whatever was in my machine with a pair of lip seals. I've done this on other shaft seal designs and they will last more than twice as long as a single seal although I've never done that on something in this type of environment. I would also use your idea of installing a bearing with seal and filling with grease. How many hours did your machine go before the factory seals started going bad? From things I have read I believed that your machine had several design changes influenced by CAT and I thought I read that axle seals was one of those changes. Apparently not. I read somewhere that CAT uses something called Duocone seals that are essentially metal face seals, no rubber parts involved other than static o-ring seals that seal against the housing on the outside and the shaft on the inside. The moving parts are metal against metal face seals. I also read somewhere where someone claimed you could replace some of the ASV seals with Duocone. I'm not sure which machines this might apply to however. I hope to start working on my machine soon and it will help to find out what I have in my machine. Oh, BTW, are there any markings on the seals or outer cartridge that might indicate who made these seals?