Pioneer P51 bar stud

[backwoodsdave]

So on my newly acquired p51 the rear bar stud is about stripped, looking into the fuel tank it appears to be threaded into a boss, I’m assuming the rear is the same just inside the crankcase, I’m thinking just screw it out and find a replacement, is there something I’m missing thinking this thing is going to come out without destroying something or do I need to go another route ?

 

[CamMann]

I got a P41 carcus & the part #431696 for the studs is the same as for the P51. Just briefly tried a pair of vise grips on the smooth part & heat gun to see if it'd just screw out like many do. no luck... i'll try later w/ more heat & penetrant, but IDK. Could always re-thread for one size down if they're too much of a pain to get out.

Also pulled up a pic of inside the crank case half, and it doesn't look to me like they'd knock through into the case like some do. The one closer to the crank looks clearer to be part of the casting, as opposed to a free-end that could be knocked backward into the case.

 

[backwoodsdave]

I got a P41 carcus & the part #431696 for the studs is the same as for the P51. Just briefly tried a pair of vice grips on the smooth part & heat gun to see if it'd just screw out like many do. no luck... i'll try later w/ more heat & penetrant, but IDK. Could always re-thread for one size down if they're too much of a pain to get out.

Also pulled up a pic of inside the crank case half, and it doesn't look to me like they'd knock through into the case like some do. The one closer to the crank looks clearer to be part of the casting, as opposed to a free-end that could be knocked backward into the case.

@CamMann I appreciate the photo, that’s exactly what I’m seeing looking into the fuel tank, my concern is the stud is either bonded in the case from the factory or just from time, though I would think that the factory would make these to be serviceable, when I get a chance I’ll give this one a twist with caution and see how it feels, it’s such a good running saw and I’ve become attached to it so I definitely don’t want to damage anything if possible.

 

[CamMann]

I'm kinda stumped. I tried vise grips, tried the double-nut method of tightening two nuts against each other to lock them in place & unscrew with that... even tried putting one stud directly into a bench vise & using the whole crankcase as leverage to unscrew it... hasn't budged.

Maybe someone here has the service manual for these

 

[pioneerguy600]

I have not smashed a side case apart to see but our old Pioneer dealer told me the studs are not replaceable, the head of the stud is supposed to have a square head just like a bolt, the head is embedded in the casting and will not come out. I have had several members argue with me that they could remove and replace the studs but they never came back afterward with a post or pic they actually accomplished the task. I have also never seen a replacement stud on any IPL for these saws and I do have most every IPL that Pioneer issued. For stripped threads Pioneer offered a nut kit that was an extension that reached in through the clutch cover to engage the stud threads that did not get stripped by the regular nuts, the clutch cover holes needed to be drilled out to a bigger diameter to accommodate the retaining nut extension. Re threading the stud was easier and it would work for a while but eventually strip out again.

 

[Old2stroke]

I have not smashed a side case apart to see but our old Pioneer dealer told me the studs are not replaceable, the head of the stud is supposed to have a square head just like a bolt, the head is embedded in the casting and will not come out. I have had several members argue with me that they could remove and replace the studs but they never came back afterward with a post or pic they actually accomplished the task. I have also never seen a replacement stud on any IPL for these saws and I do have most every IPL that Pioneer issued. For stripped threads Pioneer offered a nut kit that was an extension that reached in through the clutch cover to engage the stud threads that did not get stripped by the regular nuts, the clutch cover holes needed to be drilled out to a bigger diameter to accommodate the retaining nut extension. Re threading the stud was easier and it would work for a while but eventually strip out again.

Years ago I got a free P-20 because the owner had stripped the threads. My memory is fuzzy but I know I had to separate the cases and get to the inside end of the studs and I think I had to drill the squared ends off but I can't remember if the remainder of the studs was pressed in or threaded. I still have the saw somewhere so I could check to see what size bolts I replaced them with.
I see so many light duty homeowner saws with the bar nuts so tight, they were close to stripping. No-nothing owners think the chain is getting loose because the bar is slipping, just need a bigger wrench.

 

[pioneerguy600]

On the bigger P series saws from the P40 on up I have not seen the head of the bar stud showing through to the inside of the crankcase , I still believe the square head is fully embedded into the crankcase /bar pad area and cannot be removed. I am open as always to be proven otherwise. This problem came up after a chap brought his P52 to me in the early 90`s, he had stripped the threads of both studs using a 20" long X1/2" power bar for removing and re tightening his bar nuts, I bet he easily applied 50 lbs of torque using that strongarm.

 

[CamMann]

I do suspect they are non-serviceable. There does however appear to be a part number for the studs in the IPL (circled in red). Though, I've never seen one anywhere, and in the IPL, they're not shown independently. Maybe that number is for something else.

The Poulan versions of these saws (PP405, PP455, PP525, etc) showed their studs independently in the IPL. Maybe the design had been updated by that point.

 

[pioneerguy600]

That IPL shows a separate pin, called a groove pin that was available, not the bar studs on saws like the P40, 41,50 ETC.

 

[pioneerguy600]

Does anyone have the Service Bulletin, #1800 from Dec 1979? Stamped "OBSOLETE" in my service manual. I have covered over 200 pages of manuals starting back in the IEL days, late 50`s on up to late1981 with no mention of servicing bar studs.

 

[backwoodsdave]

Well this got interesting, now I’m a little gun shy of twisting too much on that stud, the bar adjustment screw and tab were missing when I got the saw so I imagine the previous owner was wrenching on it pretty good to keep the chain tightened , on a side note I talked to the owner when he drove up to drop the saw off for scrap, I just happened to be there at that moment, he said he purchased the saw second hand from a now long gone local saw shop back in the 80s, used it around his place, he said probably run if you put gas in it, and it sure did.

 

[CamMann]

Maybe you could improvise to mimic the manufacturer's nut-kit Pioneerguy600 mentioned. Possibly widen the side-cover's hole & use an extended nut to get to the deeper, previously unused threads that are hopefully still good. Add a washer on the nut's neck, and it's probably a solid solution.