Pfaff 438 timing belt replacement

[Josacraw]

I've looked at the available repair manuals and timing belt replacement doesn't seem to be covered. Has anyone done this? Are there initial timing marks to the three gears to?

It looks like it's gonna be a real pain in the ass.

[Josacraw]

I marked everything with a grease pencil and nail polish to be double safe. So far it really isn't that bad. Of course the timing is gonna be way off but that was a given with the broken belt

[Gregg From Keystone Sewing]

Pfaff 438 and 418 Service Book Download PDF

Too large to attached, click link to download, this should help a lot in this case here.

Edited, uploaded PDF here in case the link goes away sometime in the future.

Pfaff418_438Service.pdf

Edited February 2, 2021 by Northmount
Uploaded PDF

[Josacraw]

5 hours ago, Gregg From Keystone Sewing said:

Pfaff 438 and 418 Service Book Download PDF

Too large to attached, click link to download, this should help a lot in this case here.

 

Thank you! I found the 538 only service book but this one is much better especially in the description of the bobbin case opener timing. Belt should arrive in a week. I'll keep the forum posted. It is recommended in the service manual to replace oil pan foam. Is there something I can get locally for this? And what oil should I use? 

 

 

[Josacraw]

Another thought about the oil, from the way the timing belt had broken down it was clear that the oil had an adverse effect on the rubber. It was broken down into tiny chunks. Is there a macine oil that plays well with rubber? Or is this just what's going to happen with time?

[Josacraw]

Belt arrived from gold star(the only place I could find it). Unfortunately it is a 15mm belt which is too wide for bobbin hook pulley and I swear it is at least 2 teeth too short. I now know that it is a T5 belt at least.

Update:

Spoke to the good people at Premium Industrial Machine and they informed me the 438 has two different lower belts mine was apparently the older of the two. Part number 91-168275-05. I've now ordered the right one. 

Edited February 1, 2021 by Josacraw

[Josacraw]

Well the machine is more or less back together and sewing pretty well. The trick that I could not see in the diagrams was the belt need to go on the other side of the oil tube. As soon as I did that it became very obvious. Of course I had to reset most of the lower end, feed , bobbin hook and bobbin opener. I'm thinking it might be worth my time to make a series of narrow metric probes to set the various distances specified in the manual. Now that it is working I'm going to switch it over to a servo motor. I live off grid and my lights dim when I turn on that clutch motor. 

 

Thanks you all for this forum it is a great resource.

[DonInReno]

Good job - that looks like quite the project!

[Tymefixer]

A question for Josacraw, if he is still monitoring the thread. I have a Pfaff with the same problem. How do I remove the main bearing to get the timing belt in?

[Northmount]

23 hours ago, Tymefixer said:

A question for Josacraw, if he is still monitoring the thread. I have a Pfaff with the same problem. How do I remove the main bearing to get the timing belt in?

Tag him like this so he gets a notification:

@Josacraw Tymefixer has a question for you.

[Dragonara]

Hi Josacraw,

I just tried to put my Pfaff 438-6 back to work only to find that the bobbin timing belt had turned to mush and wire! Are you still watching this thread? And can you or someone answer a few questions I have?

thanks in advance. 
Danny

[Northmount]

4 hours ago, Dragonara said:

Hi Josacraw,

I just tried to put my Pfaff 438-6 back to work only to find that the bobbin timing belt had turned to mush and wire! Are you still watching this thread? And can you or someone answer a few questions I have?

thanks in advance. 
Danny

Tag him as illustrated in the post just above yours.