I've been thinking about adding fender flares to my '75 Ford shorty, but I haven't been able to find a source for sliding door extension hardware to create the necessary clearance. Anyone have a source ?

Old stock. Ebay, craigslist, junkyard, swap meet. However, if you are handy with a welder or know someone who is, you can build your own from two standard door extensions. Then you have to find a way to extend the stop in the slider track to get the slider arm to stop sliding at the right point in time.

They never worked properly anyway,

I had one on my old 84 E150. It actually worked OK, most of the time. Getting the stop adjustment set properly was critical.

Been checking ebay,craigslist. Nothing that fits '75. I knew lots of guys who had them "back then", most worked just fine.

If a person that lives near a Bone Yard that could collect all the slider arms..... make a jig & welding fixture. The 1st run could be 50 extensions. They could make a fortune.... well a vanner fortune ...lol

I've been keeping my eyes open for 6 months and haven't found anything for my 84 just yet. I wish someone with the know how would make them again. I'd throw money at them.

Get two stock slider extensions. Cut one end off each. Weld them together. Done.

I welded two together for my 76 Ford and it worked perfect. I see them on Ebay but the cost is up there. If you need it you have to pay.

As I stated some one that can weld can make a small fortune !

Come on some one make a dozen & see .....

I'm doing one for my Dodge and planning to just section in a piece of 3/4" round steel (solid) that I got from the local Tractor Supply store. No need to sacrifice two factory ones, in my opinion. Fingers crossed, it works out well for me! I don't see why it wouldn't. Then, just gotta carefully reset the stop tab to make sure it lines up properly and doesn't hurt my paint.

It can't be hard to make. My problem is I've never actually seen one in person to know exactly what has to be done to make everything function properly.

Exactly. How long do you make it so it works properly and not TOO long ? And different for Ford, Dodge, Chevy ?

Well, I took a stab at it and added 2 1/2" length. It opens a lot farther now but still not all the way. I wouldn't go any longer because it's too much leverage on the mechanism. Still gotta do some more tweaking and final welding.
Here's a link to some photos I took:
https://photos.app.goo.gl/fUq5iwTJR2w4P9Gp1

Can people, that have the extension already, measure so we can get a Chevy length, a Dodge & a Ford length......if they are all different.

Thanks Doug, I applaud the bold move. Keep us posted as you get it figured out. I noticed that the Dodge has a U-shaped bar while my Ford has an S-shaped bar in the middle of the door. Might be why some worked better than others.

Not too oversimplify, but the amount you extend should be the same as the amount you need the door to move outward to clear the flare/tire.....

I have a spare arm I may play around with, I'm toying with the idea of just making a complete arm out of 3/4" round stock.

With my Ford's mechanism being in the middle of the door, you're probably correct. But MobileCustom's Dodge has the mechanism at the top of the door and you can see in his photo that the added length is tweaking the door, probably not getting the equal extension. And as Doug mentioned, putting excessive leverage on the mechanism.

They all do that.

If you grab the bottom of a Dodge or Chevy slider door, you can move the door a few inches. Any extension is going to increase the load on the mechanism, that's just physics. There was no 'magic design' to the slider extensions in the 70's, they were just a few inches longer- about 4" if I remember.

That said, the track and mechanism can handle the load ok as long as the area isn't rusted out.

I finished my home made slider extension and it's working great! I had to make a new hard nylon glider piece because the old one was worn pretty bad and causing some binding. Once i got everything tweaked and adjusted, it's working really well. I cleaned all of the old hardened grease & grime out of the top and bottom tracks and that REALLY made a huge improvement in the way it all works...Easily operates with one hand & a gentle pull.

Here's a link to some pics:
https://photos.app.goo.gl/uV7kbg3azJS9tgqE2

Nice job Doug. Looks like a clean job. (I apologize for the late response, my computer quit and just found time to get off the island to replace it.)

Hi All

The stock Chevy extender is 5 1/4 inches. I found one at the junkyard off a conversion van. It's exactly twice as long at 10 1/2 inches. I found it by chance. I was at the junkyard for something unrelated.

After I thought about it, it made sense. A lot of these conversion vans were sold off the lot with flairs. Some with running boards. If they had a sliding door, it had a longer extender.

Great info, Tom. Now find me an extension for a '75 Ford.

My Vanagon came with the longer extension and it is broken. I have a spare one but it is smaller, is there a way to move the track or something to allow the smaller extension to fit?

I have a 1975 Chevy G10 and my extension is 10 1/8" center line to center line. However, mine is not functioning correctly. It delivers the door to the rear locking pin about 1/2" to low. Can't seem to adjust it to correct this problem. May be the nylon block (although it looks good) or the arm is a bit bent. Any ideas. I'm getting frustrated with this issue.

Welcome to the site Bill ....

I have a 1975 Chevy Van and mine is 10 1/8" center line to center line.
This is a response to Slider Extension Lengths on page 2 of this post.

Gullwing it!

I extended my stock arm by welding in 6" of round stock. Door actually works smoother now than it did stock. On Chevy, you also need to make the linkage about 1/4" longer for the bottom latch so it will latch open.