SunStar KM-380 BL-B cylinder arm consistently leaking oil

[Esket]

Photos of the leak and lubrication system: https://imgur.com/a/ZIpNo72

Longtime lurker, first time poster. I purchased a new Sunstar KM-380 BL-B cylinder arm machine in January 2020. I learned about the machine on here (thanks!) and it's been great, especially for the price. Synchronized binder works well, thread tension is good, and no issues going through lots of thick nylon materials like Cordura and webbing.

The issue I'm having is that is regularly leaks oil in a few places. The primary leak is at the bottom of the bobbin case onto the foot pedal, the oil usually pooling on the back wall of the head, down the swing-up roller guide and foot, and into the bottom of the bobbin cover and then slowly dripping down from the bobbin case bottom and holes at the bottom of the arm. 

The other leak happens in the area of the body with the upright shaft- there's an oil pan at the base but oil will pool within a few hours and also leak from the rear of the hinge and down to the bottom of the machine base. I stay on top of it but it will literally drain a full oil tank in a week or two and it doesn't matter if I'm sewing or not. I have inspected the wick sysem the best I can, noticed no cracks in the oil resevoir, moved the wicks slightly so they're away from the walls, and still have consistent leaking. I've checked the oil pan regularly while sewing and will still notice it leaking near the rear hinge bolts which leads me to believe at least some oil is going down the back wall of the body toward the base. 

I purchased locally here in Los Angeles and can bring it in for servicing but trying to avoid doing that for a few weeks, unfortunately right after I purchased this machine the pandemic started so that hampered things. Hoping it's an easy fix, I know some people on here are familiar with the machine and this is the best resource for cylinder arm info on the internet. 

Checked the lubrication system against the one in the parts manual and nothing looked off: https://www.jati.su/files/sunstar_detailing/KM-380BL_380BLB_PME.pdf

My next plan was to stuff the machine with cotton fabric overnight, let it soak up any extra oil on the felt pads, and try it again. I might have over-oiled in the beginning (coming from my Juki 1541s which likes oil) but have ran the machine a bunch and let it 'dry out' a bit between oilings but never ran it on an empty resevoir out of fear of damaging the internals. I have always followed the oiling instructions from the manual. None of the manuals have troubleshooting for oil leaks and googling hasn't shown me any working solutions so far. 

Thanks, appreciate any help and insight! 

Edited July 11, 2021 by Esket

[Esket]

Still dealing with this issue, anyone own a Sunstar cylinder arm or work on on? 

[Wizcrafts]

See if you can find a slightly heavier viscosity clear oil. Juki makes a couple different viscosities for different types of machines that run at different speeds. Maybe you were sold the thinnest oil meant for high speed sergers. That stuff finds exits and use them. I used some of it in a COnsew 206 walking foot machine and it pooled out all over the place. But, it stayed inside the Juki serger.

@CowboyBob- Bob Kovar might have the heavier oil you need. Contact him at Toledo Industrial Sewing Machines.

[kgg]

13 hours ago, Esket said:

Still dealing with this issue

I agree with what @Wizcrafts said. Also you might try:

i) Remove the wicks at the oil reserve end from the oil reserve and just oil those wicks manually.

ii) Make up put a absorbent soaker pad (cotton / felt) to put in the pan. My LS-1341 clone didn't come with a catch pan so the oil drops would seep out under the frame onto the table top and leave an oily mess. The soaker pad works as long as I remember to clean / change the pad.

kgg

[CowboyBob]

15 hours ago, Esket said:

Still dealing with this issue, anyone own a Sunstar cylinder arm or work on on? 

I think you might be over oiling it,& just put a couple of drops a day in the reservoir instead of filling it as I almost certain it just wicking out when it's full until it's empty.

[Esket]

11 hours ago, Wizcrafts said:

See if you can find a slightly heavier viscosity clear oil. Juki makes a couple different viscosities for different types of machines that run at different speeds. Maybe you were sold the thinnest oil meant for high speed sergers. 

@CowboyBob- Bob Kovar might have the heavier oil you need. Contact him at Toledo Industrial Sewing Machines.

 I've used a few different oils: the big jug of Juki machine oil, unknown sewing machine oil I got from a (good) industrial machine shop, and lately AlbaChem 'Zoom Lily White' since I ran out of my last large jug.  Unfortunately this Sunstar has had the same behavior with all of them. Thanks for the suggestion of heavier oil, I would have never had thought of that and will try it if just oiling the wicks leads to more leaking.

6 hours ago, kgg said:

I agree with what @Wizcrafts said. Also you might try:

i) Remove the wicks at the oil reserve end from the oil reserve and just oil those wicks manually.

ii) Make up put a absorbent soaker pad (cotton / felt) to put in the pan. My LS-1341 clone didn't come with a catch pan so the oil drops would seep out under the frame onto the table top and leave an oily mess. The soaker pad works as long as I remember to clean / change the pad.

kgg

Thank you, I actually ended up doing some version of this yesterday (removing the wicks at the reserve and manually oiling them) after I emptied the oil reservoir to look for cracks.

I keep a pad where the oil pan is and definitely leaks through there and if I don't change the pad it'll go through the base. The vast majority of the leaking seems to be coming from the head, dropping down into the foot or roller seam guide, into the hook, then down onto the pedal which has a rag or paper towels on it to catch the oil. I seemed to have lowered some of the leaking by tying up a wick that had gotten loose and making it so another wasn't bottoming out in the bottom of the head (against the ground and wall).

3 hours ago, CowboyBob said:

I think you might be over oiling it,& just put a couple of drops a day in the reservoir instead of filling it as I almost certain it just wicking out when it's full until it's empty.

This sounds like the problem, thanks for the suggestion and I will be doing this going forward. Even when I fill the reservoir 25-50% (100% being at the red line) it will still leak, and the slow speed of the leaking and it fully emptying the reservoir sounds like what you're suggesting. At this point I've gone into this machine enough times to know where all of the internal oiling spots and wicks are, lol.

 

Which leads me to my new problem: when I turn the handwheel on the Sunstar it gets stiffer when the needle is getting to it's highest position then smooths out again for the downstroke. It's a very noticeable stiffness at its highest point and while the machine was never as smooth as my Juki 1541 this is definitely a new issue.

I did as much troubleshooting as I could: removed the belt and needle (setup for size 21 and that's all I use), oiled EVERYTHING as it's been sitting for a few months which smoothed it up some but didn't completely remove the stiffness, checked as many of the nuts/bolts/screws as I could and everything is tight. I've torn the machine down pretty well for someone who (barely, sorta) understands timing but because I can't find a Sunstar manual showing timing info I haven't started loosening things up. Everything is clean inside, no thread or other foreign objects in the bobbin area, can't find any metal with obvious wear marks, can't hear loud friction coming from any parts. I was going to undo a gear to figure out if it's the top or bottom half of the machine but again, can't find timing info so didn't want to add another problem to my pile. Gears are clean with no burrs or debris, for what it's worth. Timing seems good or at least isn't off in any obvious way I've found. I spent a good 6+ hours going through the machine yesterday. 

It doesn't make any additional noise during the stiff movement but it definitely ramps up stiffness until the needle reaches it's highest point then gets smooth again. I have not ran the servo motor yet as I'm worried about doing damage.

I relocated a few months ago and both of my industrial machines rode in a U-Haul. I did all of the preparations I could find to safely transport them and they both arrived a few hundred highway miles later with no visible damage. I live in the SW (LA, now Vegas) and there is no rust on either machine. My Juki is fine and I've been using it in the meantime. 

Sorry for this tome of a reply and thank you to everyone who responded: I really appreciate all of the help! I'd like to learn how to do all of the work on this machine, especially now that I live in Vegas which has far fewer industrial techs than Los Angeles.

I'd also like to fix it soonish as I just started streaming on Twitch where I teach people how to sew/pattern softgoods (I'll eventually upload these to YouTube). It's all totally free, I'm not selling anything just trying to help people learn because there isn't a ton of info online for this stuff, and am working on a patterning course to help folks go from design to pattern to mockup to prototype. If anyone is interested it's at: https://twitch.tv/frat_house/

Photo is my streaming setup + shop manager making an appearance!

Edited March 31, 2023 by Esket

[Wizcrafts]

I wonder out loud if those wicks can be replaced with tighter woven wicks?

As for the stiffness on the upstroke, I have had that happen on my walking foot machines when I increased the alternating height of the feet to handle an extra thick job. It turned out that there is a point at which the mechanism that joins the two feet can actually make hard contact with the presser bar during a portion of the cycle. When I detected this issue, I lowered the lift slightly so the crank shafts just miss the presser bar. Things got a lot smoother at that setting.

So, unthread and remove the needle, remove the left faceplate, place a stack of three 8 ounce thick pieces of hard leather under the feet, lower the lifter, then rotate the hand wheel. See if the cranks hit the presser foot bar. If not, add another layer and test again. Some of my walking foot machines can only clear 3/8", or 7/16", while one clears 1/2 inch before making hard contact.

Another setting that affects the maximum lift before contact is the lifting height ratio. This is usually adjusted on the back of the head where a crank comes out of the head and connects to a sliding block in a curved slot connected to a shaft that connects to the cranks controlling the parts in the left side of the head. The position of the block determines the alternating feet lift. You can reset the ratio to the lowest lift setting that still jumps over a typical new layer, but allows you to sew a thicker stack before the foot crank hit the presser bar.

Note, this adjustment doesn't seem to work the same if the feet are manually lifted with the hand lift lever on the back, or a knee lever, or a foot pedal lifter. It needs to be done with the foot lifter down in the sewing position and the feet up on a thick stack of non-compressible hard leather, or plywood.

[Esket]

59 minutes ago, Wizcrafts said:

As for the stiffness on the upstroke, I have had that happen on my walking foot machines when I increased the alternating height of the feet to handle an extra thick job. It turned out that there is a point at which the mechanism that joins the two feet can actually make hard contact with the presser bar during a portion of the cycle. When I detected this issue, I lowered the lift slightly so the crank shafts just miss the presser bar. Things got a lot smoother at that setting.

So, unthread and remove the needle, remove the left faceplate, place a stack of three 8 ounce thick pieces of hard leather under the feet, lower the lifter, then rotate the hand wheel. See if the cranks hit the presser foot bar. If not, add another layer and test again. Some of my walking foot machines can only clear 3/8", or 7/16", while one clears 1/2 inch before making hard contact.

Another setting that affects the maximum lift before contact is the lifting height ratio. This is usually adjusted on the back of the head where a crank comes out of the head and connects to a sliding block in a curved slot connected to a shaft that connects to the cranks controlling the parts in the left side of the head. The position of the block determines the alternating feet lift. You can reset the ratio to the lowest lift setting that still jumps over a typical new layer, but allows you to sew a thicker stack before the foot crank hit the presser bar.

Note, this adjustment doesn't seem to work the same if the feet are manually lifted with the hand lift lever on the back, or a knee lever, or a foot pedal lifter. It needs to be done with the foot lifter down in the sewing position and the feet up on a thick stack of non-compressible hard leather, or plywood.

Thank you so much for the help (really!) but this is where my limited knowledge, especially with this Sunstar machine, and my inability to find a full manual for my variant (KM-380BL-B) makes for a bunch of confusion on my part. I didn't have heavy leather or wood so I used a stuff piece of hard plastic that is 3/8" thick and just need to know where the adjustment points are. My confusion comes from different manuals showing different things and having no exploded diagram or anything that would help my novice brain.

I took photos of my machine head from the side and back: https://imgur.com/a/jEp01eg and I'm using this parts guide (https://www.supsew.com/download/Sunstar/Sunstar%20KM-380BL,%20-380BLB.pdf) to try and find the adjustment points you listed but am coming up blank. I'm not used to a dual screw presser bar adjustment and trying to find certain parts you referenced (lifting height ratio especially) in the linked parts guide has come up blank. Other manuals for their 380B/390 have better descriptions and diagrams but different parts and adjustment points. The only manual I found showing my setup and adjustment was page 10 of this manual: https://www.manualslib.com/manual/925151/Sunstar-Km-380.html which says the projection of presser foot adjustment screw should be around 10mm and it is currently screwed down as shown here: https://imgur.com/a/xuf8oco but I've never adjusted it and it worked prior, so I don't know if I should start unscrewing that.

Sorry for the reply full of confusion, I'm trying to walk the fine line between trying to repair it and not doing something that will make the timing off which will just bury me with more issues in a city where I may not be able to get assistance. I tried to request a specific repair guide or other dense manual for my specific machine but my calls and emails went unanswered in 2020/21, perhaps due to the pandemic. A huge thank you again for the help, I've read your reply multiple times and am still trying to sort it out, sorry I'm still learning this stuff and there isn't a ton of info online for cylinder arm machines, especially my specific unit.

 

[Wizcrafts]

At this point, I recommend taking the head to a qualified dealer who can troubleshoot both the oil leaks and the binding, and fix them. Anything else would be speculation. My knowledge is pretty much restricted to Singer walking foot machines. If it turns out that your machine is a clone of a Singer, then there are manuals and videos that show the parts to adjust. But, I suspect your machine is a clone of a Pfaff 335 synchronized binder machine. It's probably a whole 'nuther thing. Maybe somebody with a Pfaff machine can help you.

[kgg]

8 hours ago, Esket said:

The only manual I found showing my setup and adjustment was page 10 of this manual: https://www.manualslib.com/manual/925151/Sunstar-Km-380.html which

A couple of more manuals for your machine:

i) https://www.manualslib.com/products/Sunstar-Km-380bl-3906793.html

ii) https://www.manualslib.com/manual/970676/Sunstar-Km-380bl.html

kgg

[flashman1207]

Hi there, I have the non-synchronized Binder version of this machine and have exactly the same issue with leaking oil (i think it may just be a crappy design) so now i just use a spray occasionally in the red holes. I also get the binding issue, however mine is when the needle is approaching the lowest position. i also have a problem where the main foot does not contact the fabric, regardless of thickness, when i put the foot down manually but then when the machine is going it seems to adjust somehow and grip the fabric....