Stihl 034 AV Super oil leak

mttritle

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I've got an 034 AV Super which I bought new about 35 years ago, and the thing still runs like a top. Not long ago, I noticed it was leaking a substantial amount of oil while not running, and as I checked it out I noticed the bar wasn't getting any oil. I took it to the dealer for a complete replacement of the oil pump and lines, but they said they wouldn't work on it because Stihl didn't make the oil pumps anymore and they couldn't use after market parts due to liability issues.

So, I got an after market pump from China through Farmer Tec, and new pickup and discharge lines from Stihl. This type of saw repair was all new to me so I watched a lot of good you-tube videos from a lot of really decent mechanics. It was a bear getting the discharge line/grommet in, but after a couple of failures, I finally got it seated. One of the videos said that at that point, to check the oil flow with the saw running to see if oil was coming through the grommet, and it was flowing very well. I put the bar and chain back on, and while the saw was running oil was dripping off the saw and virtually nothing was getting on the chain. Taking the cover, bar and chain off, it appeared that the entirety of the oil that leaked was between the inner side plate and sprocket cover. The only thing I can figure at this point is that maybe the "inner side plate" is bent and not providing a good seal between the grommet channel and bar, or perhaps the bar is warped slightly and not allowing for a good seal, I should add that I've clean the ports on the bar, so there should be no obstruction there. Any helpful thoughts would be appreciated.
 

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ajshoe

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only way oil would drip is wrong bar for 034. I have 2 of these saws (034 super is best saw I've owned out of 20 different saw types) and I do get a little oil drip when saw is not used. When saw is full bore - you should see oil coming off bar tip. I would check hole in bar - makes sure it lines up with oil outlet as previous post stated. Another thing to check is actual oil flow with no bar on - you may have seen oil coming out of oil port but that may have been from saw vibration. Oil pressure may be not there so when bar is put on - no oil gets to bar.
 

mttritle

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only way oil would drip is wrong bar for 034. I have 2 of these saws (034 super is best saw I've owned out of 20 different saw types) and I do get a little oil drip when saw is not used. When saw is full bore - you should see oil coming off bar tip. I would check hole in bar - makes sure it lines up with oil outlet as previous post stated. Another thing to check is actual oil flow with no bar on - you may have seen oil coming out of oil port but that may have been from saw vibration. Oil pressure may be not there so when bar is put on - no oil gets to bar.
This same bar worked well on this saw for many years. Not sure why it wouldn't line-up correctly now. I checked the oil pump with the bar off and oil was pumping out of the supply line/grommet. I then thought it was fixed. I ran it with the bar and chain on and oil started dripping out of of the saw with just a microscopic amount coming off bar tip (chain basically dry). It is a fairly old bar, but cleaned-up, I'm not sure how age itself would negatively effect alignment/oil flow. I'll re-check the alignment and flows tomorrow to re-verify what's happening.
 

mttritle

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only way oil would drip is wrong bar for 034. I have 2 of these saws (034 super is best saw I've owned out of 20 different saw types) and I do get a little oil drip when saw is not used. When saw is full bore - you should see oil coming off bar tip. I would check hole in bar - makes sure it lines up with oil outlet as previous post stated. Another thing to check is actual oil flow with no bar on - you may have seen oil coming out of oil port but that may have been from saw vibration. Oil pressure may be not there so when bar is put on - no oil gets to bar.
Ajshoe and Steve, Thanks for your thoughts. I have taken some pictures and attached them below. I'm thinking that perhaps the guide plate/inner side plate may be bent a bit, so as to not allow a good seal between the housing with the oil discharge and the bar. Oil flows out of the discharge at a fairly decent flow when running, whether I'm holding the saw to cushion vibration, or it setting on the ground with vibration. I don't know what the flows supposed to look like, but it seem like it's enough to lubricate the chain. I've posted a short video here that shows the oil flow (sorry it's so short but my camera kept shutting down. Oil comes through the slot in the plate ok, but it could be leaking down on both sides of the plate if it's not flush anymore, causing the chain to end up basically dry. Also, the bar holes are clean. I'm thinking I'm going to try a new plate, and perhaps a new bar, as this one pretty old. What do you think about the flow in the video? Other thoughts?
 

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SteveSr

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Ajshoe and Steve, Thanks for your thoughts. I have taken some pictures and attached them below. I'm thinking that perhaps the guide plate/inner side plate may be bent a bit, so as to not allow a good seal between the housing with the oil discharge and the bar. Oil flows out of the discharge at a fairly decent flow when running, whether I'm holding the saw to cushion vibration, or it setting on the ground with vibration. I don't know what the flows supposed to look like, but it seem like it's enough to lubricate the chain. I've posted a short video here that shows the oil flow (sorry it's so short but my camera kept shutting down. Oil comes through the slot in the plate ok, but it could be leaking down on both sides of the plate if it's not flush anymore, causing the chain to end up basically dry. Also, the bar holes are clean. I'm thinking I'm going to try a new plate, and perhaps a new bar, as this one pretty old. What do you think about the flow in the video? Other thoughts?
Did you use a Stihl OEM oil hose and brass ferrule? The hose/ferrule MUST press fit into the crankcase to seal properly. This should be step 1 in the installation. I believe that there should also be a spring inside the hose to keep it from collapsing in the bend radius. A hair dryer / controlled heatgun makes it MUCH easier to install on the pump end.

Make sure that there is no "crud" between the crankcase and the cover plate.

You can also bolt the bar less chain to the saw using washers in place of the clutch cover. Start the saw and watch where the oil goes. It should fill up the bar slot. If not you should see where it is leaking from.

BTW, your original oil pump is probably good and can be disassembled, cleaned, and reused.
 

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set the bar on a glass table, mirror, granite counter top or other very flat surface to check flatness using a feeler gauge, if the chain drivers, the bar groove or both are worn they will not carry the oil efficiently to the tip resulting in drips.
 

mttritle

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Did you use a Stihl OEM oil hose and brass ferrule? The hose/ferrule MUST press fit into the crankcase to seal properly. This should be step 1 in the installation. I believe that there should also be a spring inside the hose to keep it from collapsing in the bend radius. A hair dryer / controlled heatgun makes it MUCH easier to install on the pump end.

Make sure that there is no "crud" between the crankcase and the cover plate.

You can also bolt the bar less chain to the saw using washers in place of the clutch cover. Start the saw and watch where the oil goes. It should fill up the bar slot. If not you should see where it is leaking from.

BTW, your original oil pump is probably good and can be disassembled, cleaned, and reused.
I went through a couple of the Stihl oil hose kits before I finally got everything together and the ferrule seated properly. Those hose lines are quite fickle when it comes to "heat", and it seems there's a fine line between getting it warm enough to be pliable, and melting it into uselessness. Your idea about using the chainless bar is a good one and I'll try it tomorrow. Any thoughts on the adequacy of the amount of oil being ejected through the ferrule in the short video I provided?
 

mttritle

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set the bar on a glass table, mirror, granite counter top or other very flat surface to check flatness using a feeler gauge, if the chain drivers, the bar groove or both are worn they will not carry the oil efficiently to the tip resulting in drips.
Thanks. I'll try that tomorrow. Any thoughts on the adequacy of the amount of oil being ejected through the ferrule on the short video I provided?
 
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The amount of oil in the vid looks fine, to be honest, I would have kept the original stihl pump on it, and just replaced the oil lines if they actually needed it.

saws will leak oil when not being used, its just what they do.
The one way breather valve allows for air to come into the oil reservoir as the oil is used and since its a one way valve, when the saw is not being used, the atmospheric changes from day to day caused oil to pump out of the oil res, it just happens.

Anyway, a few things to check, yes the bar mount area can over time become convex, and a check with a straight edge over it when the steel plate is removed can confirm that.

But, if its sealing up well and the bar and bar mount area are ok etc, sometimes it takes a while for the oiler to fill the bar rail and lube the chain, and when I fit chains to bars, I put a bit of bar oil in the bar rail, then fit the chain, and rotate the chain a few times to evenly distribute the oil along both sides of the bar, and to the chain.
Then when running, its oiled, and the saw oiler can then just oil what it needs to as well.

when running a saw, but not cutting, there can be a build up of oil and it goes everywhere as its flung back off the chain onto the chip/ bar cover and leaks down and you may think that the bar is not being oiled as its leaking down under the clutch cover area, but its usually from excess oil.

Again, check bar mount for sq, check bar, but that would be my first step, and make sure you dont leap frog over something simple before adding bits to it that it may not need.

I would not expect the bar to be the issue at this point, as it was fine before, and you have not said you got the saw jammed, or pinched when used last.

my guess is that there was an air pocket in the oiler, and you replaced stuff when you may not have needed to, and you didnt give it time to clear the air, and get enough oil to the bar to wet the chain.
 

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I went through a couple of the Stihl oil hose kits before I finally got everything together and the ferrule seated properly. Those hose lines are quite fickle when it comes to "heat", and it seems there's a fine line between getting it warm enough to be pliable, and melting it into uselessness.
I usually put the ferrule in the end of the hose and then press it into the crankcase. If it doesn't go willingly a little heat should make it cooperate.
 

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Saws will leak oil when not being used, its just what they do.
The one way breather valve allows for air to come into the oil reservoir as the oil is used and since its a one way valve, when the saw is not being used, the atmospheric changes from day to day caused oil to pump out of the oil res, it just happens.
They will also leak a LOT more if the oil pump is clogged with sawdust that makes it way through the screen (not really a filter) in the tank. The sawdust in the pump will also reduce the stroke of the pump piston and decrease the oil output to the bar.
 

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Almost looks like a rub hole in the top of the bar plate below where the chain has been hitting it, not sure the chain should be rubbing it that much. plate looks bent where it meets the case near the sprocket holding it out away from the case causing your leak.
 

mttritle

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set the bar on a glass table, mirror, granite counter top or other very flat surface to check flatness using a feeler gauge, if the chain drivers, the bar groove or both are worn they will not carry the oil efficiently to the tip resulting in drips.
I put the bar on the counter top and there was a slight wobble from end to end on opposing sides. 1 - 2 mm at most. That, along with a bent plate are the likely cause in my mind,
 

mttritle

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The amount of oil in the vid looks fine, to be honest, I would have kept the original stihl pump on it, and just replaced the oil lines if they actually needed it.

saws will leak oil when not being used, its just what they do.
The one way breather valve allows for air to come into the oil reservoir as the oil is used and since its a one way valve, when the saw is not being used, the atmospheric changes from day to day caused oil to pump out of the oil res, it just happens.

Anyway, a few things to check, yes the bar mount area can over time become convex, and a check with a straight edge over it when the steel plate is removed can confirm that.

But, if its sealing up well and the bar and bar mount area are ok etc, sometimes it takes a while for the oiler to fill the bar rail and lube the chain, and when I fit chains to bars, I put a bit of bar oil in the bar rail, then fit the chain, and rotate the chain a few times to evenly distribute the oil along both sides of the bar, and to the chain.
Then when running, its oiled, and the saw oiler can then just oil what it needs to as well.

when running a saw, but not cutting, there can be a build up of oil and it goes everywhere as its flung back off the chain onto the chip/ bar cover and leaks down and you may think that the bar is not being oiled as its leaking down under the clutch cover area, but its usually from excess oil.

Again, check bar mount for sq, check bar, but that would be my first step, and make sure you dont leap frog over something simple before adding bits to it that it may not need.

I would not expect the bar to be the issue at this point, as it was fine before, and you have not said you got the saw jammed, or pinched when used last.

my guess is that there was an air pocket in the oiler, and you replaced stuff when you may not have needed to, and you didnt give it time to clear the air, and get enough oil to the bar to wet the chain.
The dripping of oil while sitting silent is not my main problem as the saw has done that for the entire 35 or so years I've had it. The main problem is that all of a sudden, oil was fast-dripping out of the bottom of the saw while in use, with the chain staying basically dry no mater how long I waited.

I took your advice and checked the housing mount with a flat edge and it was straight. I then checked the bar on the kitchen counter and found that there was a slight wobble from end to end and on opposing sides. No more than 1 - 2 mm. Please note, that occasionally getting the saw pinched or jammed when I'm using it is not out of the question, and I cannot remember if that happened the last time I used it, which has been a little while now. Since a decent amount of oil is flowing (off the bottom of the saw) and virtually nothing getting on the chain, all I'm left with is that a slightly off-kilter bar, combined with a potentially bent plate, is causing all my problems.
 

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The dripping of oil while sitting silent is not my main problem as the saw has done that for the entire 35 or so years I've had it. The main problem is that all of a sudden, oil was fast-dripping out of the bottom of the saw while in use, with the chain staying basically dry no mater how long I waited.

I took your advice and checked the housing mount with a flat edge and it was straight. I then checked the bar on the kitchen counter and found that there was a slight wobble from end to end and on opposing sides. No more than 1 - 2 mm. Please note, that occasionally getting the saw pinched or jammed when I'm using it is not out of the question, and I cannot remember if that happened the last time I used it, which has been a little while now. Since a decent amount of oil is flowing (off the bottom of the saw) and virtually nothing getting on the chain, all I'm left with is that a slightly off-kilter bar, combined with a potentially bent plate, is causing all my problems.
You can also try removing the plate and mounting the bar and seeing if there is a gap where the oil hole in the bar meets the crankcase. Also make sure the bar is tight when using clutch cover. As I recall some clutch covers had a recess for the ends of the studs near the crankcase to fit into. Early ones did not and may be sensitive to newer/different studs if they were ever changed.
 

mttritle

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New bar plate and new bar might fix it. Might want to try it and see.
Are your bar studs like they are supposed to be? Clutch cover tightening up flush with everything underneath?
I've got the bar now, waiting on the plate. Other than those items, everything else seems to fit tight and proper. After closer inspection of the plate, I found that there was a fairly significant groove worn into it by the chain.

I'm now thinking that the reason oil pooled under the saw after the last time I used it was simply due to the bar and plate not seating properly, and the oil that was supposed to go into the bar and onto the chain leaked all over on the inside of the housing, and over time, drained-out via gravity. If that was indeed the case, it would explain everything: Substantial oil under the parked saw after use, and the substantial amount of oil dripping out of the bottom of the saw while running, along with the dry bar and chain. I will follow-up on this thread when the plate gets here, and after I get things put back together.
 

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