Stihl trimmer bearing

[russ57]

Went to tidy up the grass Saturday, now spring is here.
Trimmer started easily, remarkably as it's been a while.
Revved it up and the head barely rotated.

It seems the bottom bearing, a bronze sleeve type is really tight.
It seems as though it's not designed to be disassembled, and replacements difficult to find and expensive.

So, obviously I have to fix it.
Anybody ever played with one?
It's a stihl fs45 or similar.

I've tried wd40, to no effect.
The hex collar turns but isn't threaded.
I've tried squeezing in the vice but no sign of movement.
All hints welcome..

Regards Russell

-russ

[awemawson]

It's probably a sintered / porous bush. Warm it and leave it soaking in diesel for a day or two and it'll probably free up. When it does rinse out the diesel with a solvent and when that's evaporated cook it in a light oil to re-fill the pores.

 

[russ57]

Thank you
Hmm, don't have diesel.
Acetone? Degreaser? Shellite? Carby cleaner? Petrol (2 stroke)

[John Rudd]

Red diesel is bout 85p a litre....no local farmers nearby?

[russ57]

Well actually it is about $1.50/l here in the suburbs of Melbourne...
But there is a servo (aka petrol station, gas station, garage?) just around the corner.

Don't know what colour it is. 😂

[John Rudd]

Ah...didnt know you were near Ramsey Street.....😂
Just get a litre of regular diesel then for $1-50, soak the bits in it as Andrew said...
 A few cycles of heating-soaking-heating -soaking should get it free....then clean in a good solvent...

[John Rudd]

Well actually it is about $1.50/l here in the suburbs of Melbourne...

I have a niece that lives in Moorabbin....
Back in 2016, we toured the East coast from Melbourne up to Cairns....took us a month...great place.

[russ57]

At the moment, moorabbin is 4 times my permitted distance from home, And a $1600 fine..

We have supposedly 2 weeks of stage 4  lock down to go, and if the numbers keep dropping, next week we'll find out what stage 3 may look like.




-russ

[John Rudd]

Wow! Didnt think things were that bad for you all....
Hope things get better soon..

[awemawson]

Central heating oil is very similar to diesel

[awemawson]

Small tin with a bit of cooking oil just to submerge the part, and heat it but beware of the flash point of the oil, best done outside rather than in the best parlor 

[John Rudd]

Put it in the chip frier....

[Bee]

Diesel, cooking oil, all quite 'thick' oils. if you want to dissove out existing oil just use paint thinner as in white spirit in the UK.
Seems a bit odd that this bearing has gone tight as one would expect it to wear loose. Maybe grass sap has penetrated as a sort of glue.

[russ57]

Diesel, cooking oil, all quite 'thick' oils. if you want to dissove out existing oil just use paint thinner as in white spirit in the UK.
Seems a bit odd that this bearing has gone tight as one would expect it to wear loose. Maybe grass sap has penetrated as a sort of glue.

Yeah, most of the references to this bearing are that it wears. Maybe grass sap is a possibility.

Perhaps I should give it a rub down after use and not put it away wet....



-russ

[russ57]

Wow! Didnt think things were that bad for you all....
Hope things get better soon..

Matter of opinion I guess. National deaths around 500 {population around 25m) so pretty low by some standards, but the new infection rate was getting really low then took off in melbourne.
Lots of finger pointing as to the cause, but the government elected for a very tight lock down to control. Numbers back to double digits after 4 weeks, was up to 700 I think (for Victoria only, population 10m)

-russ

[vtsteam]

The problem with vegetable oils is they oxidize -- they are the original basis for oil paint (as in fine art) and can clog sintered bushings. Use any mineral based oil (it doesn't oxidize. Paint thinner, kerosene (parrafin Br.), lighter fluid, or, if you're careful, and outdoors gasoline (petrol). I wouldn't use brake cleaner, toluene, acetone, or any of the whole alcohol group. Keep it in the mineral oil family. Then when it's time to re-lube the bearing (if you're going to save it) soak in a light automotive oil. Heat helps.

[russ57]

Success
After soaking in petrol for a week with no success, I eventually took the plunge and heated it gently, dropped it into a tin of (petroleum based solvent which I won't name but something with a higher flashpoint would have been better) which resulted in a little bit of bubbling and a lot of black. After that treatment it was quite free.
I then warmed it again, dropped into motor oil. It again went black.

After that I don't think it was quite as free but I reassembled and tidied up the lawn/grass/weeds/jungle.

(I was reluctant to heat too much as the housing is diecast, and I'm suspicious there is some sort of seal inside that hex collar which potentially is a plastic).

Russ

-russ

[awemawson]

Excellent 

A bit a heat often helps.  I was struggling yesterday to unscrew the left hand threaded nut on my Pedrazzoli cold saw to change the blade, but tickling it with a propane torch quickly had it undone.