Can anyone please advise best approach. This is a car seat, the inner seam is leather, the outer (right) is vinyl. I'm having issues with the leather side.
I can insert the needle tip in one hole of the leather and out the adjacent hole, but as soon as the much larger eyelet passes through it splits open all the leather between the two holes. The needle feels like it is hitting a welting cord or something behind these holes, but I see no piping, just a foam coating on the back of the leather. Since the eyelet can't push inward at all it's forced to push outward and breaks open the leather - screwed. The vinyl side is no problem, stretches, flexes.
I'm using a 3" curved needle and T135 bonded nylon. I had to bend the tip slightly to help get needle out the adjacent holes, and takes tremendous force with pliers to get the needle through the two holes. I test soaked a couple inches of this seam in leather conditioner for 3 days, that didn't help.
On the backside of the seam I noticed the gray thread that is visible on the seat, but there is also white thread. I'm not sure what this is holding down - maybe it is piping of some sort. The only thing I can think to do is use the outer seems. See Plan B below. The leather is 22 years old.
Click thumbnails for larger view:
Driver seat view. It's the outer bolster.
This shows the existing holes,
I thought it would be easy to sew together - NOT.
The old thread broke/failed as some point.
This is the backside of the leather.
Seam holes breaking through here:
Plan B? Should just I use the outer threads, like the image below.