Pfaff 145 H4 upper tension won't loosen, too tight

[seamsperfect]

I was trying to adjust the tension of this new-to-me machine but it seems like there is no movement in the upper tension disc when the pressure foot is lowered and raised. Doing research on this site I found a video post by UWE showing the tension disc movement (open and close) on his Pfaff 1295. I was wondering if my 145 should work the same way? Mine doesn't open and close .....it stays closed ,when I loosen the screw in the front (to the point of of the screw almost falling out) it still seems too tight.

The machine briefly sewed with good tension on very thick fabric test run when I first bought it a few days ago...but now I'm trying it on different thicknesses and running into this issue.

 

see 7:58 mark in this video.   http://leatherworker.net/forum/topic/75297-pfaff-545-thread-tension-problems/?tab=comments#comment-496087

What could be the reason for my tension discs not opening and closing...and won't   loosen! How to fix??

Thank you in advance

[seamsperfect]

More research has led me to discover two pins in the back of tension plate cover...one pin pops out controlled by presser foot lifter. ...the other pin SHOULD pop in and out between the tension disc to open and close them

it seems one of the offending parts is the back  plate that is in contact with the pins on opposing sides. When the pressure foot lift pushes out the one pin....that pin doesn't push on the plate which should then push the other pin on the other end to the tension disc....are the pins not long enough or strong enough to really push on the plate?? I can move the plate manually

the pins pop in and out when I MANUALLY move them but the plate doesn't have that see-saw action,that moves the pins back and forth to open and close the tension disc....

does this back plate need to be tightened?  cleaned? Could it be rusted stiff

I haven't taken the front tension cover plate off to get a better look at the plate that sits behind the tension cover that's in contact with the pins.....waiting for some expect advice....

 

thanks

[Uwe]

If you can manually press on the backplate of the tension unit to separate the thread tension discs, then the thread tension release bits on the tension unit itself are fine.

If the pin that pushes through the body of the machine from the back to press against the backplate on the front is not making contact or is not pushing far enough,  three possible causes come to mind:

1: The big tension release pin itself is missing altogether or worn and not long enough (unlikely)

2. The thread tension release mechanism on the back of the machine is worn, incomplete, or broken (more likely, lots of parts involved)

3. The manual foot lift lever is worn or incorrect, thus not lifting the feet high enough to fully actuate the tension release mechanism on the back (also likely, wrong lever is hard to spot)

The Pfaff 145 H4 versions have special manual foot lift levers that lift the feet higher than the standard foot lift levers, because, H4! Check to make sure you have the right manual foot lift lever installed on your machine. My Pfaff 545 H4 actually had no manual foot lift lever when I got it, so I had to order one. The Pfaff 545 is essentially a Pfaff 145 with a large hook. My part Pfaff 145/545 parts manual ( PFAFF-145-545.pdf) does NOT have a 145 H4 listed. I had ordered the 545 H4 version of the manual foot lift lever, and it works fine for lifting feet and releasing thread tension on my Pfaff 545 H4. The manual foot lift lever may be interchangeable between Pfaff 145 H4 and Pfaff 545 H4 versions, but I've not verified this.

This is the Pfaff 545 H4 manual foot lift lever (part No. 91-010 736-15 for the google bots)

If you have the big lever across the back for knee-operated foot lift installed, check if you can use it to lift the feet all the way and see if the thread tension release works that way.

I made a video to better show how my Pfaff 145 H4 does thread tension release during foot lift. You can compare the video to your machine and see if anything is different on yours.

 

 

[Miguel t]

Are the tension discs only supposed to separate when the manual foot lever is used, or when the foot lifts during normal sewing as well?

[CowboyBob]

Yes,they should open either by hand or foot lift,that way the tension is released & you can pull the material out.

[Uwe]

...and the thread tension discs should NOT open during normal sewing. If they do, something is not right. Normal walking foot movement during sewing should not actuate the tension release mechanism.

[raymiemack]

I know this is an old thread and not sure if it was solved or not. I had a similar problem with my Pfaff 145 where the tension discs were staying loose  after the foot had been lowered....ie the pin that pushes onto the plate wasn't returning.  I traced it back to a tiny broken spring at the back of the machine which solved the problem for me.....not sure what to call the part but can take a photo if it helps. 

Regards

Ray