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Cat 311B sproket/final drive removal

RobMonk

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Joined
Nov 28, 2012
Messages
55
Location
Halifax, NS
Today I was trying to remove the sprocket off my machine so that I could then get a lighter final drive out. After I was unsuccessful at getting the sprocket off I tried going after the final drive and then worrying about the sprocket later. I ended up giving up after getting all the bolts removed and trying to hammer on anything to get it to move and I was unsuccessful.

I am now at the state of every fastener removed but it seems to be hard rusted on and will not come off. I was wondering if anyone knew off a way to get the thing to come off? The final drive itself is completely ruined and does not turn so anything involving turning will not work.

look forward to hearing any advice.
 

hJeffro

New Member
Joined
Dec 2, 2012
Messages
3
Location
washington
Occupation
Mechanic/ logger
double check all fasteners are removed it should not be that seized on have you remove cover to make sure final drive has failed
 

Lee-online

Senior Member
Joined
Jan 16, 2010
Messages
1,023
Location
In a van, down by the river
There are usually two threaded holes in the frame where the mount bolts are. You can use these for forcing bolts to get the final unstuck. It is designed to be a tight fit and after years it seizes in there and can be a PITA to get out. If it doesnt have forcing bolts use a jack on the outer edge to get it to move up and down. Use a BFH to shock it.

Same with the sprocket, remove all bolts and it should come off with some persuasion from the BFH.

The final and motor are 350 pounds.
 

RobMonk

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Joined
Nov 28, 2012
Messages
55
Location
Halifax, NS
Definitely all removed. The cover removed itself, that is how I know it is broke. The casing broke and the outside gears got a bit chewed up. Trying to get it off to rebuild but here I am.
 

Nige

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Jun 22, 2011
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G..G..G..Granville.........!! Fetch your cloth.
Even with the sprocket removed the final drive and travel motor together weight 350 pounds. The sprocket is held on to the final drive with 15 bolts. I'm sure that you've already removed these bolts but if the sprocket is still rusted to the flange of the final drive (it appears to be quite a tight fit from the Parts Manual illustration) then as Lee says look for 2 threaded holes in the sprocket - if it has them. If it does have these 2 holes then you may have to run a tap into them to to clean them out before using 2 of the sprocket bolts as forcing bolts. If not then my favourite tool is a 3ft long 6"x6" hardwood block used as a battering ram to shock the sprocket loose. A bit of heat if you have access to a gas axe might also help.

A similar process would apply to the final drive but 16 bolts in that one, just make sure you remove the travel motor before beating the living daylights out of the inside end of the final drive (make sure you protect the inside face where the motor mounts) and it should eventually fall right out.
 

RobMonk

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Joined
Nov 28, 2012
Messages
55
Location
Halifax, NS
I went at the sprocket with a 10lbs hammer and it didn't seem to "shock" it at all. I don't recall seeing any extra threaded holes and I did try to use my bucket to turn the sprocket off the holes to be able to use the sprocket bolts as forcing bolts. I have also doused the whole mess in penetrating fluid and it is still badly stuck. I am starting to lean towards heat as the way to get it off.

Is there a reason you use a 6x6 rather than a hammer?
 

Nige

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Jun 22, 2011
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G..G..G..Granville.........!! Fetch your cloth.
Is there a reason you use a 6x6 rather than a hammer?
Believe it or not you can get more impact on a piece of good hard 6"x6" timber (or a length of 8"x8" if you're feeling really strong) than you can with a sledge, and it has the advantage of not needing to protect what you're beating on at the time ...... this disadvantage is that it's not quite as user friendly working in tight corners.

If your sprocket has been on for a while it will likely be rusted to the final drive flange. The combination of a bit of heat and plenty of brute force should get it off. Let's face it, your final is toast anyway so what do you have to lose..? Best of luck.
 

RobMonk

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Joined
Nov 28, 2012
Messages
55
Location
Halifax, NS
Just to set tell how everything made out, I let the penetrating fluid do it's thing over night and then I came on to the sprocket with a BFH and off it came after about a dozen hits. Then I got rummaging around the final drive bolts and found 2 forcing bolt holes that were filled flush with grime (why I couldn't see them at initial glance) and 20 mins later (had to plug and cap hydraulics) I was hoisting it onto my trailer for transport to the workshop. So far it looks like the rebuild will cost me approx $4k which is still $2500 - $3000 cheaper than getting a used one. I wish I could find an aftermarket housing to get the price down but I don't think that is going to happen.

Thank you for all the advice.
 

RobMonk

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Joined
Nov 28, 2012
Messages
55
Location
Halifax, NS
Yeah I have a question, why is Cat so ridiculous? They have everything locked up in random sizes that only they make... went to the bearing place I go when i am rebuilding anything and they couldn't match a single bearing and the place I get gears from said they can't match the gears... everything is approx 4-5 times more expensive from cat for comparable parts!

Another question is, what is the torque spec for the final -> undercarriage and sprocket -> final?
 

Lee-online

Senior Member
Joined
Jan 16, 2010
Messages
1,023
Location
In a van, down by the river
Put a thin coat of 9S-3263 Thread Lock (loctite blue) on the threads of fifteen bolts that hold the sprocket to the final drive. Tighten the bolts to a torque of 270 ± 40 N·m (200 ± 30 lb ft).

final specs.png


Crossover relief valve pressure setting ... 36 800 ± 1470 kPa (5336 ± 140 psi)

(1) Torque for two plugs ... 50 ± 3 N·m (37 ± 2 lb ft)

(2) 7I-1041 Spring:

Free length ... 53.00 mm (2.087 in)

Outside diameter ... 10.50 mm (.413 in)

(3) Torque for five orifices ... 2 ± 1 N·m (2 ± 1 lb ft)

(4) Torque for eight plugs ... 10 N·m ± 1 N·m (7 ± 1 lb ft)

(5) Torque for two valves ... 373 ± 20 N·m (276 ± 15 lb ft)

(6) Torque for four plugs ... 29 ± 3 N·m (22 ± 2 lb.ft)

(7) 099-7077 Spring:

Free length ... 37.70 mm (1.484 in)

Outside diameter ... 23.50 mm (.925 in)

(8) O-rings of floating seal and all surfaces in contact with them must be clean and dry at assembly. Put a thin layer of oil on the contacting surfaces of the metal seals just before installation.

(9) 7I-1077 Spring:

Free length ... 24.00 mm (.945 in)

Outside diameter ... 17.10 mm (.673 in)

(10) Torque for four plugs ... 10 ± 1 N·m (7 ± 1 lb ft)

(12) Torque for four screws ... 44 ± 5 N·m (32 ± 4 lb ft)

Apply 262 Locktite on threads of four screws.

(13) Torque for 16 bolts ... 29 ± 2 N·m (22 ± 1 lb ft)

(14) Use an appropriate thickness plate to get a clearance (A) of ... 0.30 to 1.20 mm (.011 to .047 in).

Plate thickness:

6I-6516 ... 2.30 mm (.090 in)

6I-6482 ... 2.80 mm (.110 in)

6I-6483 ... 3.20 mm (.126 in)

(15) Torque for eight bolts ... 59 ± 5 N·m (44 ± 4 lb ft)

(16) Torque for two orifices ... 2 ± 1 N·m (2 ± 1 lb ft)

(17) Torque for two plugs ... 74 ± 5 N·m (54 ± 4 lb ft)

(18) Torque for nine bolts ... 294 ± 20 N·m (220 ± 15 lb ft)

(19) 099-7079 Spring:

Free length ... 51.70 mm (2.035 in)

Outside diameter ... 34.50 mm (1.358 in)

(20) Torque for two plugs ... 110 ± 10 N·m (81 ± 7 lb ft)

(21) 099-7145 Spring:

Free length ... 52.20 mm (2.055 in)

Outside diameter ... 51.00 mm (2.008 in)

(22) Make a preload adjustment of the bearing as follows:

a. Tighten nut (11) to a torque of approximately 10 N·m (1 lb ft).

b. Rotate housing (24) and measure its rotational torque.

c. Tighten nut (11) for a rotational torque of housing (24) of ... 21 N·m (16 lb ft).

(23) Torque for four plugs ... 39 ± 5 N·m (29 ± 4 lb ft)

(25) Apply 1U-8846 Gasket Maker on the mating surfaces of cover and housing.
 

Lee-online

Senior Member
Joined
Jan 16, 2010
Messages
1,023
Location
In a van, down by the river
Cats standard metric torque specs.

Thread Size mm Torque
M6 ... 12 ± 3 N·m (105 ± 27 lb in)
M8 ... 28 ± 7 N·m (250 ± 62 lb in)
M10 ... 55 ± 10 N·m (41 ± 7 lb ft)
M12 ... 100 ± 20 N·m (75 ± 15 lb ft)
M14 ... 160 ± 30 N·m (120 ± 22 lb ft)
M16 ... 240 ± 40 N·m (175 ± 30 lb ft)
M20 ... 460 ± 60 N·m (340 ± 44 lb ft)
M24 ... 800 ± 100 N·m (590 ± 75 lb ft)
M30 ... 1600 ± 200 N·m (1180 ± 150 lb ft)
M36 ... 2800 ± 350 N·m (2060 ± 260 lb ft)
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
30,199
Location
G..G..G..Granville.........!! Fetch your cloth.
Yeah I have a question, why is Cat so ridiculous? They have everything locked up in random sizes that only they make... went to the bearing place I go when i am rebuilding anything and they couldn't match a single bearing and the place I get gears from said they can't match the gears... everything is approx 4-5 times more expensive from cat for comparable parts!
It's not just limited to Cat. All manufacturers do it. And the auto parts stores don't quite go big enough for what you want. Welcome to the world of heavy equipment, although TBH in my particular world a 311 would be classed under the heading of "Lawns & Gardens" ............... :tong:tong
 

RobMonk

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Joined
Nov 28, 2012
Messages
55
Location
Halifax, NS
TBH in my particular world a 311 would be classed under the heading of "Lawns & Gardens" ............... :tong:tong

I know exactly what you are saying, if I were an operator I would not be interested in that machine at all. Luckily I am just a lowly small time developer that realized that buying an excavator is cheaper than paying to get driveways and digging/back filling foundations ... by a long shot. All things being equal I could have gone as big as a 15t but that would still be on the large size for the biggest of my plans. Its probably like anything, you have beginners machines and expert machines... I sat in an excavator for the first time a couple weeks ago :)
 

RobMonk

Well-Known Member
Joined
Nov 28, 2012
Messages
55
Location
Halifax, NS
Out of curiosity, how much does a machine like that cost? I think each scoop would do a home foundation ;)
 
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