[68ragtop]

As I recall the top part of the seal is so close to the bottom as it passes in that there is no room. I had also tried one of those spring clamps simular to whats used on the oem fuel lines & it either didn't fit or rubbed. I did send some time putting small washers as shims & adjusting things so the rods pass through as centered as possible.

Don't feel bad Greg, I just put mine together 6 months ago & I am forgetting details....

[68ragtop]

Digging through my 7000 pictures & I found some that may help.

I did the the O-ring idea as you can see in the pictures & for some reason it failed. I don't recall if it rubbed, or why it didn't work. maybe a little "right stuff" and the o-ring would hold it, but if it doesn't, it will be a mess...

you can see my orignal seal in place & how much tighter it fits the shaft. No comparison in quality. the oem seal fits tight & seats into the grove on the shaft perfectly. Not sure why I left orange paint on it I think for the nostalgia of another orignal part & its hidden under the dust boot.

Now the the pictures refreshed my memory I recall the dust bellows sliding on the shaft. So that might be were some confusion is.

[dataway]

Yep ... you can see how those OEM pieces fit the shaft like a ... well like a condom. Much tighter, thinner and more flexible than those re-pops. Re-pops look way too thick and stiff.

[68ragtop]

The other thing I thought I would mention is, in the pictures it looks like there is room for some sort of clamp, but in reality the shaft kind of moves side to side as it goes up & down, so even if its centered the way I have mine in the pictures, it doesn't stay in the middle when its operating. I guess that makes sense too because when you think about it, there nothing to keep the rod centered. just the diaphragm & it is turning inside out as it moves too. Just my thoughts for the day

[68ragtop]

Originally Posted by dataway

Yep ... you can see how those OEM pieces fit the shaft like a ... well like a condom. Much tighter, thinner and more flexible than those re-pops. Re-pops look way too thick and stiff.

Thicker, but yet too stretchy. When you slide the oem seal in place, you can feel the lip lock into the grove on the shaft, where on the aftermarket one it slides right past. If it was just a better grade rubber it probably would work.

The O-ring idea like I have pictured did work at first, but it didn't stay. The shrink wrap I think would have worked. I slid it down past the edge in the same position as the o-ring was but the heat that it took to shrink it, ruined the already crappy rubber. That's when I put the original ones on & realized they are soooo much better

[slowride66]

Originally Posted by 68ragtop

Thicker, but yet too stretchy. When you slide the oem seal in place, you can feel the lip lock into the grove on the shaft, where on the aftermarket one it slides right past. If it was just a better grade rubber it probably would work.

The O-ring idea like I have pictured did work at first, but it didn't stay. The shrink wrap I think would have worked. I slid it down past the edge in the same position as the o-ring was but the heat that it took to shrink it, ruined the already crappy rubber. That's when I put the original ones on & realized they are soooo much better

What did you use to shrink the tube? I have a craft sized heat gun I use only for shrink tube.

[dataway]

Yep, I was thinking that careful use of a heat gun might not damage the rubber ... probably depends on the heat shrink ... I've seen two types .. the shiny stuff and the dull stuff ... forget which shrinks easier ... I think the dull stuff.

I just bought three cans off ebay ... one is probably a re-pop, the other two look like pretty nice originals ... says none of them hold vacuum ... I bet the problem with all of them is that seal. The OEM units probably have rust somewhere under them.


https://www.ebay.com/itm/183244499481

[Greg Reid]

Thanks for those pics, really refreshes my memory now.
I'm sure mine are not original...they are way too clean and with a bright finish. They work perfectly. I guess that's why I don't recall accurately how they functioned...I never have to look at them.
I've only had two issues with them, one was an adjustment issue where I had to add a lock washer so the adjustment would stay more than a month and the other was having to glue the seal on to the lip of the one of the cans because it kept pulling up.
Maybe they are 20~25 year old repops when they were still made in USA?

[68ragtop]

Also, could there are more than one company making these? Maybe there are more than one seal mfg too? Hard to believe the market is big enough for more than one aftermarket mfg though.

[dataway]

I looked for industrial sources for the cans .... I assume GM had them produced by someone, unlikely they made them in house. Back in the day vacuum actuators were very common ... and these cans a very simple design. Heck a person with a good shop could almost make one from scratch.

Lots of vacuum actuators out there, but nothing this size.

I have no idea why the electric systems are so expensive ... a couple of small linear actuators and four limit switches seems like all it would take to me. Adapter to bolt them in place of the cans and some basic electronics that were triggered by power to the headlights. There are a bazillion small linear actuators for very cheap, some probably have adjustable limit switches built right in.

[Charlie Brengun]

I have no experience with this kit but its half the price of the other one Ive seen...
https://www.ebay.com/itm/68-69-GTO-h...4236634?_ul=NL

[dataway]

Yep ... that's the sort of thing I was thinking of. Very simple. That guy is a couple of steps ahead of my idea ... only a single linear actuator, and probably has the linkage setup so no limit switch is needed ... full stroke is full up to full down.

That actuator can be bought for around $60, looks like a simple 12v, 4" stroke piece.

Considering the price of parts and fabrication labor ... pretty reasonable price.

[dataway]

Just got the ebay actuators in the mail ... one re-pop ... no shaft seal so that is easy enough to diagnose. One OEM with rust on the seal, one OEM with a dry-rotted and/or seal has slipped on the shaft.
So I think I can end up with two working units for $25 using the extra OEM seal I have.
I'll examine it closer the next couple of days, but the re-pop unit seems to be a pretty well built piece of kit with the exception of the seal.

All the diaphragms seem to be fine, all of them hold vacuum on the back side.

Someone could make a few dollars if they could re-pop decent seals.

[68ragtop]

Originally Posted by dataway

Just got the ebay actuators in the mail ... one re-pop ... no shaft seal so that is easy enough to diagnose. One OEM with rust on the seal, one OEM with a dry-rotted and/or seal has slipped on the shaft.
So I think I can end up with two working units for $25 using the extra OEM seal I have.
I'll examine it closer the next couple of days, but the re-pop unit seems to be a pretty well built piece of kit with the exception of the seal.

All the diaphragms seem to be fine, all of them hold vacuum on the back side.

Someone could make a few dollars if they could re-pop decent seals.

I agree 100%

[dataway]

So far the only difference worth mentioning I see between the repops and the originals is that the shaft where it enters the can is tapered metal on the repops and on the originals there is some some kind of tapered phenolic resin bonded to the shaft. It was probably far more expensive to taper a metal shaft 50 years ago than it is now.

One of my ebay cans is trash ... rusted out under the seal, but the seal might be salvageable. The repop unit just needs an OEM seal, and the other OEM can had a hole in the seal .... so at most I might need to buy one more decent OEM can with a usable seal.

[68ragtop]

I have an extra oem, but it has a broken stud. Lower diaphragm is good, but typical original 50 yr old finish with light rust & paint overspray.
Oh, and I a took the upper seal for my re-pops.

Not sure if a stud could be welded back on. I assume its a spot welded bolt installed from inside the can. So probably not serviceable.

[dataway]

The studs actually go through the flange ... they are a flat headed bolt spot welded on to the flange from the head side. ... So actually probably not that bad to fix.

Anyway ... appears I have two good cans ... and one good OEM seal for sure, maybe two ... so at worst I have to buy an OEM can with a good seal in it. I see a ton of them on ebay for $35 that say "works" .

[Charlie Brengun]

Originally Posted by Charlie Brengun

I have no experience with this kit but its half the price of the other one Ive seen...
https://www.ebay.com/itm/68-69-GTO-h...4236634?_ul=NL

Well I just bought one of these.. it will take a little longer to get to me but I will in due course post up about the install

[dataway]

Definitely post the build ... that system looks so simple I can't imagine much going wrong with it. If it works it will probably work forever.