Removing Stuborn Bearing

[sport hydro]

I have been heating my MAC45 case in the oven at 250 for 20 minutes and the large rear bearing won't budge. The front fell out with a little tap an the table. What elase can I try?

 

[TimothyJones]

325ºF for 10 min and rap the case square on wood

 

[sport hydro]

Thanks, I turned up the heat to 300 and it came out with a couple taps on the wood board.

 

[Jim Allen]

The aging temperatures of the aluminum casting alloys (A-356, A357) which are most commonly used in our toy engines is in the 300 to 340 deg F range. Great care should be excersized when heating the entire crankcase for bearing removal. A prefered method is to heat only the bearing retaining area with a propane tourch.

Jim Allen

 

[Dan Hutchinson]

i agree i always use a propane torch that way you can heat the bearing area to what ever it takes to get it to come free. use a pair of vise grips to hold it and keep the torch moving around the whole case and the bearing should fall out. if it doesnt fall out then tap it on a cutting board. this method has worked for me for years.

 

[Kez]

I, too, use a torch when I replace the bearings. I use a small tip and play it over the bearing area as though I was spray painting.

Instead of using a pair of vice grips, I put on a pair of leather work gloves and hold the case by the cylinder with my left hand. When I can feel the warmth, I smack it on a 2X4. Holding the case with my hand will ensure that I do not melt it in the process.