Odd Failure Of Constant Tension Spring Clamp

[George7941]

The clamp ends. where the ears are, rusted and seized on the hose and thus could not move to accomodate the shrinking of the plastic hose barb in cold temperatures.

I had a bit of coolant loss last winter and I posted about it

Inexplicable Coolant Loss

Last winter, in the dead of winter in February, the coolant level is the surge tank started going down. I had to put in a half litre of coolant every 500 kms. This only lasted for less than a month and the truck stopped using coolant after that. I carefully checked all the hoses for leaks...

bobistheoilguy.com

Spring clamp goes on the lower rad hose at the rad on my Sierra. I had taken this clamp off twice before for coolant replacement, once in 2011 and once in 2019. Rad has no drain, so this is how I drain the coolant. I always put them back on in the exact same position it was when it left the factory.

I could not figure out where the leak was last winter and the leak stopped once temps warmed up a bit. Last Friday, when it was really cold at -20C, I came out of Costco with my groceries and there was puddle of coolant under the front of my truck. Opened the hood and saw the leak from the bottom rad hose. Nothing I could do in the parking lot, so I just loosened the surge tank cap so the the cooling system was not under pressure, verified that there was enough coolant for operating the engine and went about my day.

On Sunday I used my OTC tool to expand the clamp. I had to use wood clamps to get enough leverage to open up the spring clamp fully and engage the built in catch on the spring clamp and thus stay expanded. Access was limited and I had to reach in from the top. When I tried to move the clamp, I noticed it was seized on to the hose where the clamp ears are. After struggling to move it for a bit, I gave up because I did not want to risk cracking the plastic hose nipple on the rad. Got my Dremel and cut the clamp off. I used two clamps this time, a Mikalor wide band T-bolt and a constant tension Belleville washer clamp.

 

[Wrenchturner44]

I have recently seen some T bolt clamps used on connections like these. My initial thought was that neck or outlet damage could occur due to overtightening. I was told that T bolt style clamps are easier to tighten vs worm gear style clamps and that is easier to judge when they are secure and snug enough to prevent a leak, but not excessively so as to damage the connection neck.

Anyone else use T Bolt clamps in this kind of application?

 

[wpod]

I have seen that failure before.

 

[fozzdesy2001]

This is one of the best spring clamp tools I have found. they make a larger one too definitely worth having.

https://www.amazon.com/Lisle-44500-...=1677236077&sprefix=hose+vice,aps,234&sr=8-17

 

[George7941]

I have that tool and, agreed, it is a useful one. Its small size, compared to pliers, keeps it out of the way while you work on the hose. Didn't know there was a larger one.
It was the first tool I tried on my rad hose but, due to the orientation of the clamp ears, would not fit. The cable driven pliers was the only one which fit into the tight space.

 

[The Critic]

I have seen this issue before on some Nissan products. The radiator hose material “shrinks” so the clamp is unable to apply enough tension.

Ideal solution is a new hose and new clamp, but usually a Gates Thermo Clamp (or what you did) will work.

 

[George7941]

I have seen this issue before on some Nissan products. The radiator hose material “shrinks” so the clamp is unable to apply enough tension.

Ideal solution is a new hose and new clamp, but usually a Gates Thermo Clamp (or what you did) will work.

I love the Gates Thermo Clamps and will use them if I have the correct size in stock and I do not have to remove the hose in the near future.

 

[Soft Cars]

Those constant tension clamps will fail if they're over sprung. What you need is a ratcheting hose clamp tool like the Mayhew 28680.
That will allow you to expand the clamp just far enough to get it moving without over expanding it.

 

[kschachn]

Those constant tension clamps will fail if they're over sprung. What you need is a ratcheting hose clamp tool like the Mayhew 28680.
That will allow you to expand the clamp just far enough to get it moving without over expanding it.

Every one of those clamps I've installed cannot be opened more than when the tabs are compressed together. How would you open it any farther? I've always had to open them all the way just to get them on.

 

[Soft Cars]

Every one of those clamps I've installed cannot be opened more than when the tabs are compressed together. How would you open it any farther?

When they lock open, that's too far.

 

[George7941]

When they lock open, that's too far.

The engineers built the lock into the clamp so that it stays open while the hose is being worked on. I find it hard to believe that the clamp is being opened too far when all you are doing is using the clamp the way the engineers meant it to be used.

 

[Soft Cars]

The engineers built the lock into the clamp so that it stays open while the hose is being worked on. I find it hard to believe that the clamp is being opened too far when all you are doing is using the clamp the way the engineers meant it to be used.

They may have engineered it that way, but it shortens the life of the clamp when expanded that far. Maybe the engineers expect you to replace it after removal.

 

[kschachn]

When they lock open, that's too far.

That's the way they come new.

 

[Soft Cars]

That's the way they come new.

When the solid square tab goes through the window square tab and gets held open by that tang on the window tab, it's now locked open.

 

[kschachn]

When the solid square tab goes through the window square tab and gets held open by that tang on the window tab, it's now locked open.

Yes just like you said, locked open.

 

[John105]

When they lock open, that's too far.

The oddity is when I did my wife's water pump, I had the clamp open. Might have been 5 hours. I put it back exactly as I took it off of the hose, into the same identation on the hose. IT LEAKED! I moved said clamp further up to virgin rubber, and it did not leak. If you said it's meant to be replaced once opened, I'd believe you....