Stuck Sprocket

[dieselsamurai]

Decided the weekend to do a bit of undercarriage maintenance on the mini digger tracks off the main idler was sloppy thats another story but i have a drip from the left track motor output. Looks like its a parallel shaft at least a 1 1/2 diameter with a keyway . Damn thing wont budge got a hydraulic puller on it nothing , not sure what they are rated at but im tempted to put a short 10ton ram in its place as I have one for my porta power .



Looks in photos worse than it is but its been there happily for nearly 30 years so i expected a fight , whats the best course of action now ?

Im a bit worried to put too much heat into it as if i fudge the seal and still cant get it off then im really screwed
I can put a 10ton ram in that puller frame but not 100% it will take it
Last resort i can FAB up a puller that will be strong enough but its a lot of work .

there are 2 13mm tapped holes but i doubt they would exert enough pressure before shearing

unfortunately the sprocket traps the motor in the track frame so i cant even get it out to put in the big press

any ideas welcome

 

[Agroshield]

Add something that pulls on the tapped holes at the same time as the hydraulic puller.

If you neck down the bolts that are screwed in there, they will fail in a place you can unscrew the stub with mole grips.

To me, having the puller on the outside is trying to turn the sprocket inside out, so might not be directing the force along the shaft.

 

[mr haynes]

A little shock and awe with a persuader, whilst under load, might be enough to get it moving

 

[Kram]

Do you have a photo without the puller of the shaft and pulley?

The light brown rusty peice looks to me like a nut that could be securing the sprocket? Taperlock? What are the two threaded holes for? Thread somethjng in them to use as a pusher.

Possibly cracked at the red circle?
Looks like 3 seperate peices pulley, nut, shaft and your spacer.

 

[dieselsamurai]

Add something that pulls on the tapped holes at the same time as the hydraulic puller.

If you neck down the bolts that are screwed in there, they will fail in a place you can unscrew the stub with mole grips.

To me, having the puller on the outside is trying to turn the sprocket inside out, so might not be directing the force along the shaft.

Its pretty thick metal probably 20mm where im pulling its possible it could deform i guess , ill add some studs to those holes later and try that with a thick bar across will add some extra pressure

 

[dieselsamurai]

A little shock and awe with a persuader, whilst under load, might be enough to get it moving

I did try a bit of persuasion too !

 

[dieselsamurai]

Do you have a photo without the puller of the shaft and pulley?

The light brown rusty peice looks to me like a nut that could be securing the sprocket? Taperlock? What are the two threaded holes for? Thread somethjng in them to use as a pusher.

Possibly cracked at the red circle?
Looks like 3 seperate peices pulley, nut, shaft and your spacer.
View attachment 536561

Ill take a better photo in a bit looks really rusty here but its actually not terrible , theres a m16 bolt that screws into the end of the shaft with a flat bit of metal welded to it and thats bolted on using the 13mm bolts to stop the sprocket falling off

 

[Blobber]

I don't think a little bit of heat would do any harm, you dont want it glowing red

 

[tom2207]

oxy acet and a bit of sympathetic tapping will get you there .

 

[addjunkie]

oxy acet and a bit of sympathetic tapping will get you there .

Sympathetic tapping….is that a posh way of saying BFH

 

[dave h 2]

Usually when you see two threaded holes like that they can be used to push off by bottoming longer bolts and applying equal pressure, in this case the sprocket just like those found on steering wheel bosses.

 

[Erie Fred]

10 tons on 1 1/2" dia. is not enough IMHO

When I have a puller tool to design, the rough rule
is 10 tons to the inch of diameter.

I add some more when it's rusted (as yours appears to be)
So I would go with 20 tons.

But not thru those arms, nor the outer rim of the sprocket.

 

[atomant48]

What’s under that spacer you have on the end of the puller? Are you sure it’s perfectly centred and not pushing against you? I ask from experience trying to remove some bearings off a hub a few years back…. Bent my puller and then realised….

Now that i have zoomed in on the iPad i wonder too if bottoming out a couple bolts in those threads will push it off.

 

[Bullet2012]

just take the sprockety thing off, file the hole in the centre a tiny bit, put it back together with some grease
Now when you take it apart it will be easy
I have lots of useful tips like this if you ever need any

 

[dieselsamurai]

Do you have a photo without the puller of the shaft and pulley?

The light brown rusty peice looks to me like a nut that could be securing the sprocket? Taperlock? What are the two threaded holes for? Thread somethjng in them to use as a pusher.

Possibly cracked at the red circle?
Looks like 3 seperate peices pulley, nut, shaft and your spacer.
View attachment 536561

heres a better view , keyed shaft no idea if parallel 99.9% sure it will be

 

[dieselsamurai]

Usually when you see two threaded holes like that they can be used to push off by bottoming longer bolts and applying equal pressure, in this case the sprocket just like those found on steering wheel bosses.

they are threaded but some numptey couldnt even drill them straight !



here what locks it on the shaft

 

[dieselsamurai]

10 tons on 1 1/2" dia. is not enough IMHO

When I have a puller tool to design, the rough rule
is 10 tons to the inch of diameter.

I add some more when it's rusted (as yours appears to be)
So I would go with 20 tons.

But not thru those arms, nor the outer rim of the sprocket.

Im really hoping 10 will budge it but suspect it wont be enough like you say

i have hydralic jacks up to 50ton but not sure yet if they will work on there side


If I cant use the outer rim of the sprocket how do you suggest i proceed ? i can drill and tap the m8 holes out to m10 or m12 but doesnt give me enough room to get a jack in there

i was going to cut a U shaped bit of plate to fit behind it then have 4 m12 studs with another plate for the jack to press against

 

[Dozzer]

Had same issue on 500kg tracked hi-tip dumper,
in the end it was out with Oxcy torch, large 10 tonne puller and lots of love taps with 10lb tickling stick.
took and afternoon of strong language.
Oh and gave it plenty of penetrating oil in-between each heat session = https://www.lsengineers.co.uk/freeway-penetrating-oil-500ml.html not an advert but have found it to be one of the better ones on old rusty crap.

 

[Erie Fred]

Im really hoping 10 will budge it but suspect it wont be enough like you say

i have hydralic jacks up to 50ton but not sure yet if they will work on there side


If I cant use the outer rim of the sprocket how do you suggest i proceed ? i can drill and tap the m8 holes out to m10 or m12 but doesnt give me enough room to get a jack in there

i was going to cut a U shaped bit of plate to fit behind it then have 4 m12 studs with another plate for the jack to press against

I like the plate behind method at this point as I can't see all the details.

What's you thoughts on explosives ?