How to fix a loose bar stud

[decableguy2000]

I have a 288 that keeps spitting out one bar stud. It held for a while with a dab of Motoseal, but has come loose again. Other than a case half what kind of options do I have?

 

[Onan18]

I have a 288 that keeps spitting out one bar stud. It held for a while with a dab of Motoseal, but has come loose again. Other than a case half what kind of options do I have?

Clean everything thoroughly and use some Loctite sleeve retainer.

 

[Homemade]

I assume is spinning in place as if the splines are shot. You could try brazing it.

 

[jacob j.]

You could convert over to screw-in bar studs, ala Stihl-style. There's also some screw-in exhaust studs available at auto parts stores that would be suitable for the conversion.

 

[tree monkey]

can't braze to mag

screw in studs need a shoulder

 

[tree monkey]

there pressed in from the back side with a square head to keep then from turning. if locktite don't work, it can be drilled out and a thin sleeve made to get a press fit

 

[Homemade]

can't braze mag

Good point. Didn’t realize mag was non braze. Has the same heavy oxide layer that aluminum has. Just assumed brazing would be the non welding solution. What about a screw in time-sert device to hold a stud.

 

[tree monkey]

pull the studs and tin them with solder. that should add a few thow to the dia. hard solder like 95/5 would be best

 

[drf256]

Not sure what “spitting out” means.

If it’s held by the square area behind it, is it popping into the oil tank or is it spinning around while you try to tighten it?

There are new high temp aluminum braze rod that is reported to work an any non ferrous metal. I’ve been fearful to try it inside because of Mag being known to ignite, I’m unsure if the alloys used in saw cases will do that, but I’ve seen them burn hot white in a camp fire for sure.

Plan is to try it with Tig instead of AZ92A and see if it can be done DCEN.

Any pics?

 

[qurotro]

Not sure what “spitting out” means.

If it’s held by the square area behind it, is it popping into the oil tank or is it spinning around while you try to tighten it?

There are new high temp aluminum braze rod that is reported to work an any non ferrous metal. I’ve been fearful to try it inside because of Mag being known to ignite, I’m unsure if the alloys used in saw cases will do that, but I’ve seen them burn hot white in a camp fire for sure.

Plan is to try it with Tig instead of AZ92A and see if it can be done DCEN.

Any pics?

My 288 did exactly the same. The bar stud has a square end which fit in the slot inside the oil tank so it won't turn when you tighten the bar. I think its the stud hole of the crank case that hold it only. Once the hole is loose it's gonna dropped in the oil tank and have to be fish out and drop back in. I just use it that way. Just take extra care when loose the nut. It dont even leak bar oil...

 

[qurotro]

pull the studs and tin them with solder. that should add a few thow to the dia. hard solder like 95/5 would be best

I love this idea.. Just weld a few spot with steel rod and grind accordingly and press it back in.

 

[Al Smith]

Loctite makes a product called "press fit " which should work if every thing is clean .The machine repairmen at work used it to hold bearing races in place in blind holes .Fact I used it to hold a spun bearing in the pocket on an 048 Stihl .

 

[mdavlee]

I drilled and tapped a 3120 case out using time sert and then put Stihl Mid Mount studs in.

 

[tree monkey]

I drilled and tapped a 3120 case out using time sert and then put Stihl Mid Mount studs in.

you then needed to use a stihl bar correct?

 

[Al Smith]

An expandable Time Sert would work but the kits to install them are far and above what the average person can afford for a one of repair .An 056 bar stud would work being m10 on one end and m8 on the other except for the collar which would necessitate using two and a Stihl mount bar or a milled out bar because of the collar .Lots of options here .

 

[Al Smith]

BTW one of my Mac 125's has a loose stud which also is just a square headed bolt .I've only dropped the damned bolt inside the tank once and had to fish it out .It doesn't leak I just have to remember to not let it get away from me .

 

[decableguy2000]

Its in the tank, I'll try the locktite first if I can find any around here. I was thinking of trying to stake the case around the stud with a center punch. I was also thinking of trying to knock a spline or two in the stud and then pull it back through.

 

[redline4]

If one had access to a lathe, could the press fit portion of the stud be knurled? Or would that not give it enough to hold it to the case.
Just thinking it would be easier to modify the stud than the case without disassembly.
Or even weld the stud up slightly and grind it down to achieve the interference fit again?

 

[tree monkey]

i'd start by trying locktite, practice kiss

 

[Al Smith]

Red Loctite might hold it but again everything would have to be very clean .Which still means you have to get into the tank .