Not Your Typical Sebac Shock - Disassembly and Identification of Specific Application

ArcticMinibike

ArcticMinibike

Member
#1
#1
I picked up a set of Sebacs recently that were not of the usually minibike variety. I'm assuming they might be from a moped. Can anyone confirm? They are the same length as the common minibike variety, about 13" but have a different eye casting design on each end. They are genuine Sebac brand. Was this a newer or older design than the model most of us know?

Secondly, I need help in getting them apart. The lower eye castings are NOT threaded into the tubes like most Sebacs. They are under spring tension and spin freely - NO THREADS. In the picture, you can see I compressed one by hand and exposed the internal shaft and what looks like a washer with a spacer. You also notice what looks like a nut within the cavity of the casting but not accessible. There is also what appears to be a spanner notch. There are no flats that I can see on the internal shaft when I compressed it.

Anyone care to weigh in on either the specific application these were installed on or how to take them apart for cleaning and refurb? Thx.

 
markus

markus

Well-Known Member
#2
#2
Some of the Aermacchi bikes had that style, I got one apart from my buddies Harley shortser I just can't remember how I did it :laugh: I know I modified a large tube caulking gun to do it, everything else was a blurr, I want to say on that version you compress the main spring far enough so you can get a grip on the rod inside the tube and unscrew the lower eyelet. They had another version that had a retaining clip under the lower spring cup too, gotta compress the spring on that one as well. Its been over a year since I futzed with it for him, we just wanted to see if we could get them apart to resto and he is currently just hunting for better stuff than what he has before we get to deep into them.
 
ArcticMinibike

ArcticMinibike

Member
#3
#3
markus said:
I want to say on that version you compress the main spring far enough so you can get a grip on the rod inside the tube and unscrew the lower eyelet.
Click to expand...
Thanks Markus! That was my first thought, but you'd think they would have ground a flat on the rod to grip it. The notch fits my adjustable spanner that I use on Arctic exhaust nuts, which makes sense if it threads off with the embedded nut. They're in great shape. I hate to screw them up on disassembly but I really want to make them nice. Plus, the progressive springs are in great shape and would work nicely on another set of Sebac 12's. I will withhold comment on the quality of Italian mechanical design, for now. :biggrin: If anyone else has any ideas, I'm all ears.
 
ArcticMinibike

ArcticMinibike

Member
#4
#4
Success! Pretty easy actually. I didn't even waste time making a compression tool. Vice Grips to the rescue.

All I did was vice it upside down, pull down the lower tube to expose half an inch of the internal rod and get the vice grips on the shaft. I used an adjustable spanner to hook the notch in the eye casting. They came loose pretty easy. Turns out these things are coil over hydraulic! The shaft slides up into an oil-filled cylinder underneath the springs. There is about 2" of travel and most of the resistance is when pulling it out so it counteracts the spring compression for oil dampening and less bounce.

I was going to refurb and sell them but they are pretty nice shocks compared to the Sebac 12's. Chrome is perfect. I might just need to keep these even though they're not correct for my Arctics. They would be great for my riders since I'm not exactly a 160 pound teenager anymore.

Markus, looks like you were right on the application. I found them on Aermacchi bikes, including the AMF Harley Davidson X-90.





Bagged and ready for refurb
 
1970s-BMX

1970s-BMX

New Member
#6
#6
ArticMinibike and Marcus. So glad I found this post! I have these exact same Sebac shocks. They were used on all production Huffy mono shock bicycles in the mid 1970s. Markus had suggested there might be a clip on the rod at some location. Rigged up a shock compressor and found no clip. So, your Vice Grip trick looks like maybe the only solution! Yesterday, I stood over the setup with Vice Grips in hand, contemplating this move. As a kid, I used Vice Grips on everything! Imagine the carnage of axle nuts, headsets, etc! So, at 61 ... I only use them in extreme circumstances! Going to work up the courage to do this shortly! Side note: Vice Grips were invented by Bill Petersen in Dewitt, Nebraska in 1924. My Dad was an advertising man and Petersen Manufacturing / Vice Grip were one of his biggest client over several decades. I even worked on the account with product photography, brochure layouts, etc. I have several of each size and configuration! Guess it time to put them back to work!
 
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