front idlers

[mikes420c]

Getting ready to start working on the frame where the front idlers and rollers are mounted. The two that came off of the crawler when running were approximately 18.5" dia. With the crawler came some extra parts which included some more front idlers. These are approx. 20.5" dia. The crawler is a 420c. Although the smaller ones appear to be in better condition, in the future with some repairs, the larger ones could be used. My question is which are the correct ones for a 420c?

[Lavoy]

If you have a 4 roller crawler, they both are correct. The smaller idler was standard, the oversize idler was an option. If you have a blade on, the oversize will give you better flotation, and will take some of the stress of the first roller.
Lavoy

[mikes420c]

It is a 5 roller and does have a blade. How well will the smaller idler work because they seem to be in better condition?

[Lavoy]

They will work, just shortens your "wheelbase", and puts more stress on first roller. 5 roller crawlers never had the standard idler, oversize idler was standard equipment.
Lavoy

[mikes420c]

Lavoy,
On the front idlers you have ( 2 ) ribs that stick up and and go all the way around the rim. These ribs are to run in the center of the track. My question is if one of the ribs are worn both down in height, and also thin side to side, Is this critical or can the idler still be run. Another thought can the idler be built back up by welding? Also are 1010 roller axles the same as a 420?
Mike

[Lavoy]

If the front idler is running square, it should only be touching those ribs when turning. If they are real short, this could cause a problem.
Idler is cast steel, it can be built up, or if you have someone in your area that can roll strap, you can rim it.
Axles are different, but the 420 axles had a price reduction believe it or not, they are now $75.
Lavoy