Using heat gun to install bearings

[brandonstclair20]

I got a heat gun today. I heated the flywheel side of a huztl ms440 case. I took a socket and tapped out the bearing. I heated the case and went to put the bearing in and it went in half way and I guess the bearing got hot and expanded too. So now i guess, I’ll just have to use a bolt, nut and washers to pull it in. On the clutch side, i assume I heat around the bearing like I did on the flywheel side? Anyone have any more tips on this method? Thanks


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[dahmer]

When installing keep the bearing cold(freezer). DO NOT waste time installing. How we did stuff at work.

 

[PA Dan]

I got a heat gun today. I heated the flywheel side of a huztl ms440 case. I took a socket and tapped out the bearing. I heated the case and went to put the bearing in and it went in half way and I guess the bearing got hot and expanded too. So now i guess, I’ll just have to use a bolt, nut and washers to pull it in. On the clutch side, i assume I heat around the bearing like I did on the flywheel side? Anyone have any more tips on this method? Thanks


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On the clutch side aim the heat gun at the bar pad and find something to do for a while. I then direct the heat around until I think its ready. I then heat for 5 or 10 minutes more! The bearing should then drop right in.

 

[drf256]

A propane torch works better and faster. Just have to keep distance and keep moving see you don’t burn the paint.

If you hold one far corner of the case, the piece in your hand just starts to get warm, and the case starts to smoke a bit, it’s the right temp.

Freezing bearings actually adds very little positive to the entire event.

I tried the heat gun approach this Sunday and found myself pulling the PTO side bearing into case. With a torch, they fall right in. I have an IR thermometer, but in a moment of boneheadness, I didn’t check the temp.

Just what I’ve learned. YMMV

 

[cus_deluxe]

I just dont like all the condensation that appears on the bearing when you keep it in the freezer. Ive had good luck woth the heat gun, as said above just fond somethin to do for a while. Mine on low takes bit to warm up, gotta be careful on hi it gets damn hot. I do bottom ends at a friends house who has a press, if the bearing doesnt drop roght in all the way i just push it in the rest of the way real quick.

 

[Lee H]

Some of the average heat guns don't put out enough heat. Like drf256 mentioned
a propane torch works well. I use a heat gun most of the time but mine gets HOT.
And it takes longer to heat the case. Remember you have to heat almost the whole
case not just around the bearing. The magnesium is like a sponge for heat.

 

[blsnelling]

Skip the freezer. I use a torch as well.

 

[jk14]

A little off topic, but I picked up an old toaster oven for heating cases. Just pop the case in there set it at 325° for 20 minutes and drop the bearing in. Then give it a minute for the bearing to heat soak and drop the crank in the bearing.
Ymmv

 

[Deets066]

Used a heat gun just yesterday. With the crank in the freezer, after 10 minutes of heating/cooling the crank fell right in. I see no reason to skip the freezer, but that's just me

 

[decableguy2000]

Heat gun works okay. I usually pop the cases in the oven, just seems easier to me. Scrubbed clean and degreased before I do and wait to the wife is gone. Bearings and crank in the freezer. I wait a few minutes after the bearings are in and crank will usually drop in for the most part.

 

[Lightning Performance]

BFH

 

[Chainsaw Jim]

Any particular reason why stihl or husqvarna doesn't offer or recommend heat guns with their bearing installation tools?

 

[Al Smith]

As matter of fact Stihl does recommend the use of frozen bearings and heated cases in their service manuals .I have no idea what Husqvarna recommends . My heat gun is a "varitemp" ,1000 degree .Made by Master appliance in Racine Wisc . It doesn't take very long to heat a bearing pocket .

 

[Gary Courtney]

Propane torch and less than one minute they fall right in

 

[Lightning Performance]

I like the torch myself and have done it every way possible including a commercial press when available. Freezing the crank and bearing assembly, often overlooked, sometimes much easier. I did get another heat gun a few years ago. Ill try it that way again next time. Freezing helps with small bearings for dropping in the cases.

 

[beaglebriar]

Toaster oven FTW!!

 

[XP_Slinger]

I tried a heat gun with my 262 and had the same results that Doc got, bearing only went in half way. I heated my case for about 30 minutes so I now know that my heat gun doesn't put out enough heat. I switched back to using a propane torch, simple and fast. And as Doc said, when the portion of the case you're holding onto gets uncomfortably hot she's ready to accept the bearing.

 

[MustangMike]

I used a HF heat gun on several of the Asian 660s I assembled. The bearings are pre installed in the case, just have to insert the crank. The first side always goes well, but the second side, the bearing has a nylon race so I try not to heat it too much. It always starts going on well, but when I make sure the case pins are lined up, it locks.

I just finish it up while it is still warm with a hammer and socket. So far, they are all still running. Often have to replace the seal on the second side, no big deal.

Just thought I would post for those who do not have access to presses, etc. Got the heat gun on sale for $8.-, love it!

 

[Lightning Performance]

Toaster oven FTW!!

No good with seals installed when trying to heat the bearing already installed that has a plastic cage like Stihl oem does. Plus, it cooks paint if you rattle can them. I pass on it now. Too much work to strip the oil lines and such for a simple bearing replacement. Sometimes the torch is just better to pin point the location and freeze the install part.

 

[beaglebriar]

No good with seals installed when trying to heat the bearing already installed that has a plastic cage like Stihl oem does. Plus, it cooks paint if you rattle can them. I pass on it now. Too much work to strip the oil lines and such for a simple bearing replacement. Sometimes the torch is just better to pin point the location and freeze the install part.

I generally only heat a stripped case in the toaster oven. It's my preferred method but there's always a burnzomatic with mapp gas handy as well.

I also have a heat gun but have no patience for that chit.