Any you guys ever hear of this ?

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pearljam724
430 crawler
430 crawler
Posts: 74
Joined: Mon Dec 12, 2022 12:19 am
Location: Pittsburgh, Pa

Any you guys ever hear of this ?

Post by pearljam724 » Wed Jan 11, 2023 4:39 pm

For you guys that have been following my posts on here. You know my past regarding my machine in the past month. Anyways, a very good friend of mine who is no mechanical dummy said. After pumping grease into the idlers to set track tension. You have to shim them and remove grease fittings to keep the adjustment there. Otherwise you will blow the seals. Is this true ?

B Town
350 crawler
350 crawler
Posts: 752
Joined: Fri Dec 11, 2015 7:04 pm
Location: Western Iowa

Re: Any you guys ever hear of this ?

Post by B Town » Wed Jan 11, 2023 6:24 pm

The Deere 450 crawlers only use shims in the front idler forks for aligning the track in the center of the idler wheel.

The grease is left in the adjuster. This adjuster is attached at the rear to a large spring. The idler floats at the front and if the front is impacted the energy is transferred to the spring. And the energy is absorbed by the spring, limiting the amount of damage to the undercarriage.

Best regards, Bruce

Jim B
350 crawler
350 crawler
Posts: 2080
Joined: Sun Nov 05, 2017 11:36 am
Location: western Maine

Re: Any you guys ever hear of this ?

Post by Jim B » Wed Jan 11, 2023 6:38 pm

Not true for your crawler. The grease fittings stay in place and the grease inside the adjuster cylinder holds the adjustment. The hydraulic adjuster and its seals are designed and built to take the pressures involved. The track sag spec and adjustment info are in the Operator's manual, no shims are involved to adjust track sag (tension).

You pump grease into the hydraulic adjusters, not the idlers, to adjust track sag (tension). The adjuster is a basic hydraulic cylinder. With the proper grease fitting (buttonhead or zerk) in place and the set screw tight on the ball in the release port of the hydraulic adjuster, the grease does not escape or compress, thus holding the idler in the position it was pushed to. The back end of the ram in the adjuster cylinder barrel fits into a spring which absorb shock if the idler comes up hard against something. If grease is leaking out around the ram, the adjuster needs to be resealed/repaired so it will hold pressure. To shim the idler in place on these crawlers would cancel the shock absorbing function of the spring and could lead to other damage. (Some machines do use a system where a jack was used to push the idler out, then shims were used to hold it in place when the jack was removed. I am familiar with that system on some older crawler cranes and older excavators. Those travel slower and did not have any shock absorbing springs.)

pearljam724
430 crawler
430 crawler
Posts: 74
Joined: Mon Dec 12, 2022 12:19 am
Location: Pittsburgh, Pa

Re: Any you guys ever hear of this ?

Post by pearljam724 » Wed Jan 11, 2023 11:22 pm

I thought he was wrong. Made no sense to me what he said. I just wanted to confirm my thoughts that he was wrong. Thanks guys.

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