1080 3pt jumping

[unclemerle]

Having trouble with my 1080 3pt raising very slow and jumping while it comes up. The 3pt is used in position control 100% of the time with a box blade and snowblower. If I play with the draft control lever while it's doing this for about 10 minutes it will come out of it and work normal for about a week or so, then it's back to it's same old games. The pump has less than 300 hrs on a complete rebuild. Anyone else have this problem with a 1080/1085/285 and if so what did you do?
TIA; Merle

 

[Masseynut)Australia)]

Hello Merle,

Were the lift (hitch)cover adjustments carried out, while the tractor was dismantled for the pump rebuild? Sounds like the draft may be out of wack.
With the position control and draft levers in the fully raised position, the implement should reach the top lift position. Now slowly move the draft lever back down the quadrant. When the lever reaches roughly the area of the "sector" marks on the quadrant, the implement should start to lower. This will depend of course, on the weight of the implement being lifted. If the draft lever is not in close proximity to the sector marks,adjustment may be the problem.
To check if the draft is the problem, uncouple the top link from the draft rocker on the rear of the lift cover. Now couple it (with a short length of chain if necessary), to the "grandfather" pin on the rear of the centre (or diff) housing. Try the lift. If it still "performs", the problem is not a draft related one.
The other possibilities may be a sticking draft rod, (from the plunger to the draft link), or a partially seating or "sticking" inlet or exhaust valve in the pump.

 

[gbs]

you said you use a box blade on it,have seen a 230 do about the same ,man was backing up pushing some brush out of the field using a rear blade his lift started acting up, ask an older mf mechanic about it before we tore into it,he said the internal control linkage had gotten bent because the blade suddenly jumped up hard and fast shock loading the top link, he had repaired a couple in the past that had done this,sure enough that's what we found, not saying that's your trouble though

 

[unclemerle]

Thank you for your advice. I'll print your replies out and put them in my service manual and look at them next summer when I tear it down.

Merle