Dynafit Tech Binding Heel Unit Breakdown and Assembly
(We had this in our legacy archive; it is now converted to a blog post. Applies to nearly all model Dynafits: TLT, Comfort, Vertical, FT, ST, Radical)
Dynafit Speed Radical with top plate removed. Heel lifter shown with aftermarket B & D Nubbin lift extension. The screws will be carefully re-inserted with a small dab of epoxy on the threads. Be aware we only recommend this procedure for repairs or for re-lubrication after excessive wear or contamination.
This project is not as tricky as rebuilding a vintage automobile carburetor, but similar attention to detail will yield good results. Taking apart a Dynafit heel unit is easiest if the binding is mounted on a ski. Good mechanical skills are required, as well as proper tools. Reasons for doing this could be: 1.) repair swapping broken part, 2.) cleaning and lubrication after several years of heavy use, 3.) cleaning after exposure to road salt or a solvent spill.
Dynafit Vertical ST binding. Radical series are nearly identical as to internals.
Addendum: Note that later “Vertical” series bindings similar to the one pictured above have a tiny metal roll pin attaching the upper heel-lifter-top-plate plastic unit to the lower housing. To remove, push (or carefully “drive”) the roll pin inwards with a pin punch or reversed drill bit. Before re-assembly, entirely remove the roll pin, re-insert as the last step in assembly.
Driving in the roll pin, Dynafit Vertical FT/ST binding. Early version bindings did not have this pin, easy to spot. Use the butt end of a drill bit, drive pin inward then remove by pulling out with needle nose pliers, re-insert as last step of assembly.
Our victim in these photos is primarily an 07/08 Dynafit Vertical ST. Most Dynafit bindings from the last decade or so have similar or in many cases identical internals, so these instructions will work for most models in use (main exception as of 2014 would be the Beast models).
These are all the tools you need for disassembly of the Dynafit heel, but to do the job right you should have each one. From top: screwdriver bit holder, large slot bit, #10 Torx bit, small slot bit and right angled pick. Find the largest flat/slot bit possible for turning the rear spring adjustment barrel.
First step in taking apart the upper mechanism is to back off the vertical release setting. Crank the adjustment screw until DIN setting indicator is at the lowest marked setting, then give it one more full turn. Don’t go past that point. If you neglect this step, the binding will fly apart as you remove parts.
Next, use your Torx screwdriver to remove the fasteners holding the top plate. Lift the top plate off.
The binding will look like this after the top is removed. Just lift the guts out. They’ll tend to come apart as you remove. Don’t stress, they’re really quite easy to re-assemble.
Here is a parts breakdown with official names. German is a cool language for this sort of thing. The green goo is lubricant and probably a corrosion blocker. If you’re cleaning and re-lubricating you can use a light lithium grease, or better, use a specified ski binding grease such as that sold by G3.
Assembly of Upper Heel Unit
If you’re working on high mileage bindings, inspect housing for cracks in areas indicated by arrows. If the housing is cracked it won’t hold the screws securely and must be replaced before mission critical use. Know that with some TLT moldings there may be a tiny gap adjacent to the screw hole; this is not a crack and not a concern. (Screw inserted to illustrate, not as part of assembly sequence.)
This is what the guts look like flipped over after removal. Arrow points to a small nut on a threaded rod (the vertical DIN adjuster). Before re-assembly make sure this nut is at end of rod as shown.
First step to reassembly is to pop in this stripped down version of the parts. Place the rear in first, compress the springs, and press the front yoke down and in. The small nut shown in photos above must seat in its dedicated slot. Check by viewing binding from side.
After you’ve popped in the yoke and springs, insert the pins with their tapered collars. Orientation is obvious — if in doubt compare to your other binding (which is hopefully still together).
Getting the compensation plate inserted is a bit tricky. Video shows it better than this, but basically you insert the lower flanges first as shown, then drop the rear down.
Don’t forget any parts. This small metal plate, the slide liner, is easy to overlook. You can slide it in at any time in the process before running the screws back in. Once everything is in, press all together with your fingers and make sure it feels solid and completely assembled. Replace the top plate and associated small steel reinforcing plate (obvious) and run the screws back in. Gently snug the screws in a cross pattern, then torque down firmly but with much less force than you’d use for most other fasteners.
In the case of high mileage bindings, consider re-inserting the screws with a small amount of one-hour plastic-enabled epoxy smeared on the threads and under the head — to help prevent loosening or shearing due to micro movement and metal fatigue. Warning: the four screws holding the Dynafit top plate are sensitive to stripping as they’re inserted in plastic; tighten with care, and re-check tightness periodically. Do not over tighten!
Use a large flat blade screwdriver for adjustment and removal of rear spring barrel. Getting this out is easy, but it's quite difficult to re-install without stripping the threads. If you strip an old binding it's possible you will not find replacement parts.
To remove lower housing and side/lateral release mechanism please refer to our Dynafit brake installation instructions.
Remember, taking apart the upper part of a Dynafit tech binding rear unit is most often unnecessary and may even void your warranty. But the process might be necessary to maintain or rebuild older bindings hence our publishing these instructions.
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Comments
29 Responses to “Dynafit Tech Binding Heel Unit Breakdown and Assembly”
Hey Lou,
I’ve found that when re-installing the rear spring barrell, if you apply light pressure with your thumb to the barrell from the bottom of the housing in the direction of the heel post, it tends to be guided by the semi-circular molding of the housing to contact the threads in a true manner. I’ve been able to successfully reinstall the barrell on a couple of heel units that had been partially cross-threaded by doing the above very carefully. I always thought this area could use a nice acme thread or similar to avoid being so easy to strip.
thanx for that Lou, what is “plastic enabled epoxy” would 24 slowset work? I have a couple of skinny but high milage friends who never had Vert failures but have pulled those top plate screws out on rads in < a season which makes me think the Rad flippy heel lifters put stresses on the top plate that the Vert towers never did.You seem to be recommending the epoxy dab to help prevent stripping but how well does the epoxy trick work on screws that have stripped ?
Hi Xer, the epoxy won’t help at all on a stripped/pulled screw. The housing is Delrin, the epoxy doesn’t really adhere to it, it’s just a space filler as it adheres to the screw.
The “plastic epoxy” is sold at the hardware store, says “for plastics” on the package, adheres a little better sometimes, I just use it out of hope. 1-hour regular or slowset would I’m sure be fine.
Amazing what a hassle those flip lifters have been compared to the rotation system of the TLT and Vertical series, isn’t it? An engineer once explained to me that in any machine, there is NOTHING you can do that will not have a consequence, frequently unintended…
I know good skiers who much prefer the Vertical ST/FT lifter system. I have to say I find the flippers to be no better, though I don’t mind them and haven’t had any screws pull out.
Lou
Thanks Dave
Thats why we wait a year before buying any Tech binding so the flippers SHOULD have worked, as a recovering HW tech I have seen > my share of HW that should have worked
I have verts and rads, so far they both work fine, in use I can’t say if I like one more than the other, besides the possible problem the verts were on clearout & cheaper while the rads were fullprice … cheap & reliable is better
I do make sure to tread lightly on the rads, I inspect often … fingers crossed!
Once, while tightening bolts on my tractor’s cultivator, an old truck driver pulled up and muttered ‘constant speed and vibration’.
Thanks for the info Lou.
Well, I have only used the flip up levers once, but I have seen and repaired/ replaced a few mangled top plates. I did break one Vertical heel top plate, but it was my fault, not the binding’s. Perhaps I should already be ordering B&D heel top plates?
Canadian Loonie, or larger Toonie dollar coins does a good job of carefully threading the rear spring barrel cap.
I push the nylon piston all the way forward, before I start to thread the aluminum barrel cap back into place.
This post reminded me of your post a while back that detailed how to construct a custom tool for adjusting the rear spring barrel. I can’t seem to find that post anymore? I’ve tried a bunch of iterations through your internal search engine with no success. My question really is: what is the slot width on the spring barrel and have you found a readily available driver that does it well? the one you are using in these pictures looks adequate but still a bit less than ideal since it doesn’t span the width of the slot. thanks.
found it! “search site” didn’t get me there but good old Google did with the search of “custom tool for dynafit”… odd. oh well now i guess i’ll be able to sleep at night.
Just saw this after my email to you requesting this. I just took my verticals apart and I had a hell of a time getting the pin out on the lower top plate. The lowest part of the volcano has a pin that I was able to push out with a dental tool and then pulled out with a needle nose pliers. So you can’t simply remove the four screws on the top sheet and lift off. Maybe different years of the Vertical didn’t have this pin.
Great thread as always Lou
Hi Gregg, thanks for pointing that out. Yes, nearly all Vertical series Dynafit bindings have the roll pin helping hold the top on. The easy way to remove the pin is to drive it _in_with the blunt end of a small drill bit, then yank out out with needle nose pliers, or at least that’s what I recall. I mention that in another thread, forgot to add when I updated this thread with new photos.
About two part epoxies – I’ve found part of the problem of “durability” may often be related to how carefully the two parts are measured and how completely they are mixed. Even with liquid epoxies we use for restoring window sills and wooden boat parts, given exact 50/50 portions, the mixing has a huge influence on how the goop sets up and ultimately performs. Same is true of two part polyurethane marine coatings which we’ve seen get a kind of hazy, not unlike epoxy “blush” if not mixed enough. I’d be interested in links to suppliers Lou and some brand info if your expert can drum it up? I remember trying to epoxy mount Dynafits on Stokes a few years back – in spite of mixology care it sure seemed a short “5 minutes” on those skis!
I was just wondering, I bought some Radical STs and I am going to try and install them myself but I have a question. On the bottom of the heel unit is a very thing metal plate, it has 4 screw holes in it. It is only attached to the plastci bottom of the unit by the 4 screws, almost looks like it’s just there to hold the screws in place for shipping. That being said, there is quite a bit of lubricant on the back side of this thin plate and I am wondering if it is supposed to be installed to act as a buffer between the moving parts and the ski. It is a very thing and flimsy metal sheet, do I need to install it? Thanks so much for your advice.
Yes, install the plate. Lou
Dear Lou,
I broke the metallic part of my Vertical ST which makes the rear binding to move forward/backwards along the plastic base. How can it be removed from the heel unit? It kept moving clockwise +and anti) I can see a tiny hole next to that. Maybe there is another way to unscrew it?
Gaspar, apologies, but I don’t understand your question. Send a photo to the “Contact” link in menu above. Lou
Hi Lou, do you happen to know what type of plastic the vertical top plate is? I picked up a pair of used skis that had some verticals on them. Everything looked good but I failed to see one of the top plates was tweaked slightly and the post on the top plate that engages with the housing was popped out (from an impact I guess). Basically the top plate is bent…I’m really surprised the screws didn’t strip out. Anyways, if the plastic is a thermoplastic then I might be able to get it back into shape with a vise, well placed heat gun, and some muscle. If that doesn’t work I can always get some B&D top plates and volcanoes. Thanks!
Hi Joe, it’s injection molded Delrin, not sure how repairable it would be. I’d worry about cracks in the housing hidden under the plate. Lou
I may have partially cross-threaded the barrel when trying to re-install the rear spring barrel. Wondering if Lou or Dave Field might be able to help me understand how to get it back on. Read Dave’s post above but am a little confused… Did you have to take the whole unit off the ski to apply pressure to the bottom of the housing? Any help would be greatly appreciated.
I’ve found that when re-installing the rear spring barrell, if you apply light pressure with your thumb to the barrell from the bottom of the housing in the direction of the heel post, it tends to be guided by the semi-circular molding of the housing to contact the threads in a true manner. I’ve been able to successfully reinstall the barrell on a couple of heel units that had been partially cross-threaded by doing the above very carefully. I always thought this area could use a nice acme thread or similar to avoid being so easy to strip.
If you try to use the barrel to chase the threads back to normal you risk damaging them even more, it’s a tough situation. If you can see the original threads, try using something like a right angled sharp pick to scrape the correct grooves so the barrel starts threading. Also, while fooling around do it without the spring in there so you don’t have any resistance. Lou
Thanks Lou! I had cross-threaded one of the barrels, luckily your tip with a right angled sharp pick worked like magic. That plastic is really easy to cross-thread if you’re not careful. Thank you for saving my binding!
Lou, is Extreme Weapons Grease by The Professionals Choice a reasonable choice for bindings? I remounted some Dynafit Tri-Steps that are about 13-15 years old–almost bone dry inside.
Mark, the only grease I’d recommend is G3’s, as it’s compatible with binding plastic, otherwise you never know what additives are in the grease that could influence plastic. Though your question makes me think of what grease we use here on firearms, lots of such tools have plenty of plastic, so I’m wondering if weapon grease might be ok? Perhaps they talk about plastic in their specs? Binding plastic is usually Delrin, a form of nylon, but sometimes ABS, to the best of my knowledge. Lou
Thanks so much for this God! I needed to remove just the top plate from my 2010 dynafit St bindings. This was just what I needed to make sure I didn’t screw it up.
” I remounted some Dynafit Tri-Steps that are about 13-15 years old–almost bone dry inside.”
you know those Tri step toes suck right?
Thanks for mentioning that Xer, I’m slacking on my job! Yeah, Mark, those are not acceptable bindings. Lou
Yeah I know what its like getting old
https://www.wildsnow.com/backcountry-skiing-history/binding-museum-backcountry-skiing/dynafit-tri-step-binding-faq/
Hi, I cross-threaded too. It’s unexpectedly easy as you expect some resistance from the spring. Sharp pick, Dave’s comment and patience saved my binding eventually.
If you’re lucky enough and you didn’t screw up your binding yet, I would recommend to try reinstalling the barrel without the spring to get the feel of how should it fit together. Furthermore for Radical remember to set release force as low as possible before reinstalling the barrel.