Yuchai dozer do I repair this or just leave it

[timbatrader]

Greasing my Yuchai YCT306S-S dozer the other day I noticed the rubber block on one side of the machine that the undercarriage frame sits on missing. So a new rubber block and buffer cap have been fitted. Also damaged are some lightweight ribbons of steel wielded over the slots in the undercarriage frame. I cannot see a purpose to these steel ribbons so why repair them?

When the rubber block is in place the frame cannot move far enough for the ribbons to do anything and if the rubber block disappears (I don't understand how but it happened to mine) the ribbon is nowhere strong enough to hold the frame and it snaps. Can anyone shed any light on their purpose?
The parts diagram shows the frame without the ribbons wielded on

 

[Bob Rooks]

What year is the dozer?

 

[timbatrader]

I bought it "new" in 2012 but it had been on the dealer floor for a long time maybe three or four years

 

[timbatrader]

Here is photo of the other side the steel ribbon has been crushed when the blade frame comes down at the same time as the undercarriage come up on that side

 

[Bob Rooks]

Okay, this is a later model. I can't see the "ribbon" you're referring to in that pic, but if it's what I think it is, it's supposed to keep the equalizer bar in (if it goes over the top of the retaining pin). Seems to me that there should be a retainer for the rubber cushion also. Yes, it is necessary, although it should not be contacting the wishbone.

 

[Bob Rooks]

If the rubber cushion came out and the retaining strap was not in place the equalizer bar would come out and potentially cause a lot of damage to the swing frame pivot shaft and possibly break the transmission housing.