Wednesday, February 21, 2007

Decoupler

Since I had taken the VC out, I had to have a way to disconnect the front differential. The driveline will bind up quickly on dry paved roads and it becomes really hard to make a turn.
After some research on the web, I found out that there is a choice of two systems, one is like the original system used by VW and it is manufactured in South Africa, it looks like the strongest of the two. The other is made in the USA and uses the original splined sleeve that is in every Syncro, they added a bearing onto the sleeve which is moved by a shift fork.
It looked like I could make either one of them myself, the SA one would be the hardest to make,but I really liked the design.
So I gave it a try, I got a piece of 4340 bar stock, machined it and put splines on it in the milling machine. I ended up making two of them, the first one I screwed up trying to heat treat it myself. Some things are best left to an expert.
The hardest part for me to make myself was the internal spline of the gear hub, I ended up using an old fashioned shaper with an index.

The sliding collar (the part that I thought would be the hardest to make) came from a Chev S10 front differential, it just fitted in the housing. I made a shift fork out of a slice of bronze bar stock, drilled the housing for the shift rod and electrical switch and made a bracket for the vacuum actuator.
I had the shaft and gear heat treated, pressed a needle bearing into the shaft and fitted it all together.

4 comments:

jayzoid said...

So how does your decoupler work? Are you selling any?

Herman said...

Hi, I don't have the van on the road yet, but I am sure that it will work OK.
It takes too much time for me to machine one and sell it, if I had access to a CNC machining center then it would be way easier to make a whole bunch of them at the same time, but I have not.
Sorry. Herman

Robert Wilson said...

Hi I'm a cnc machinist in Red Deer if you have drawings I could make a few . I'am going to the coast in a couple week to look at a syncro out there for sale i would love to stop in to see yours.

joshho said...

Hi Herman, great work, Is it possible to flip the ring and pinion in front differential to achieve the opposite rotation..? Also does your brake set up fit inside 16" rims?..

Regards
josho