Constant Tension Hose Clamps

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Love 'em or hate 'em, constant tension "spring style" hose clamps are here to stay, and here's why we use them.

I'll admit, constant tension hose clamps aren't the most pleasant to work with, and the larger ones under high tension can be even more of a pain. At CruzeKits.com, that's all we use, and I'd like to take a moment to explain why.

1. Simplicity. Doesn't get much simpler than a piece of spring steel wound into the shape of a circle with spring tension. No moving parts, no adjustment necessary; simply tighten it, slide onto the hose, and let it go.
2. No guesswork. You all know that common German unit of measurement for bolts, "gudentite?" Well, it doesn't work too well for hose clamps, especially those carrying fluids. Overtightening those clamps can strip the adjustment screw, damage the hose itself, or even crack the component being tightened inside. Undertighten them can result in leaks. Furthermore, screw-style hose clamps tend to not apply consistent pressure due to the location of the adjustment mechanism. On the other hand, constant tension spring clamps have only one tension. You can't under-tighten or over-tighten them.
3. Practical corrosion resistance. Even if a constant tension spring hose clamp corrodes on the outside, at least it will still work (to a point), but adjustment screws can seize, especially in northern states exposed to road salt.
4. Most importantly: they provide constant tension. An engine bay will typically operate betwen -30F and 200F temperatures, and that means thermal contraction and expansion. This is the biggest reason why OEMs use this style of clamps on just about anything that isn't crimped. Thermal expansion and contraction can cause screw-style hose clamps to loosen over time as they aren't able to take up slack or account for increased pressure, causing them to be too tight when hot and too loose when cold.

For automotive applications, constant tension spring hose clamps simply make the most sense. The reason most people dislike them is that they are a pain to work with in larger sizes, particularly when used in cooling systems. For that, I'd recommend picking up an affordable set of hose clamp pliers, which should be available at your local auto parts store or Amazon. They're designed specifically to tighten these kinds of clamps and hold them open while you work with the clamp and hose.

The constant tension hose clamps included in the PCV fix kits can be easily opened with a pair of multi-purpose (not needle nose) or lineman pliers, and can even be opened and moved by hand using a shop towel to protect your skin. I recommend against replacing those with worm drive hose clamps.

I see ' more expensive' mentioned several times in this thread....
given how important the things these are holding on ... hoses...and how few of them there are on the car.... I would go for the very best design I could find .... to match the quality of the cars themselves......and make for peaceful sleeping at night... the hassle and cost of a single broken radiator fitting.... would pay for all of these for the life of the car... The first step is to make sure the pipe outer surface is very clean and smooth, including the lip around the outside. Second step is putting the hose onto the pipe all the way over the lip, up to the stop if there is one. Final step is putting the clamp right behind the sealing lip as close as you can without being on top of it. The lip is what seals the hose, not the clamp. Therefore, the clamp isn't really important. The only factor I can see is that the worm clamps cut the hose and squeeze it through the slits of the band.

Pick a clamp, follow the above advice, don't over tighten it, you'll be fine. Quote: Originally Posted by shertex I'm sure there's a proper name for these things...but you know the type of hose clamps that you loosen by squeezing with pliers? Do they have any advantage in certain applications over clamps that tighten with a screw drive? The reason I ask the question is that they are the ones used for the hose connections on the W210 duovalve. But they strike me as something of a pain to get on and off in such a tight space....my inclination, if I every replace a duovalve again, is to use screw drive clamps. First off you need the proper tool to remove the "Constant Tension Clamp or Band" aka spring clamp. Pliers are not the best tool for them. There are a few versions of this tool, one that is like a plier, the other is a cable type to allow you reach tight places. They both lock onto the clamp and allow to easy removal and installation.

Second, my understanding from a GM engineer, is the wide use of constant tension clamps is two fold. The ease of installation during production and most importantly, is because of the wide use of plastic cooling parts.

The plastic necks tend to expand and contract ever so slightly during normal engine operations. With a fixed clamping worm drive clamp, the plastic neck cannot expand or contract, and this will lead to stress and fatigue in the plastic.

With the constant tension clamp, it will allow for this expansion and contraction while providing enough clamping force for the hose. Constant tension clamps hardly wear out and can be reused many times, unless damage from the removal process.

The biggest mistake that most people make is to replace these clamps on plastic necks with a worm drive clamp.

I really do think the use of worm drive clamps is the reason we saw many neck failures in the past on our w123s. This is reason I switched over to constant tension bands on the radiator side.

Attached Thumbnails __________________
123.133 California
- GreaseCar Veg System


Last edited by DeliveryValve; 05-13- at 03:57 PM. I grew up with US made Vehicles form the s-s and all had worm gear type Hose Clamps on them somewhere.

I can say that it is not the Clamp that fails. It is the Hose.

As the other member said about torquing the Clamps. Over tightening them shortens the life of the Hose especially or the Rubber is squeezing out of the slots in the Clamp.

But, even that is not an issue if you get under the Hood of your car and check things once in a while.

For myself I would not like to be on the Road with a clamp like the EZ Clamp and have to remove the clamp and change a Hose on the Road. It might be difficult to remove or damaged during removal and re-installation.

If you get a decent quality stainless steel oned the typical worm Gear Hose Clamps are extremely reliable and can be reused over and over and over without loss of reliability. __________________
84 300D, 82 Volvo 244Gl Diesel Just thought I would include these pics of other types of clamps.

The fist pic is a type of clamp that was used on some US Cars. They worked OK but the Nuts and Screws on the ones I have see were not stainless steel and would often rust up to the extent that the screw would snap off.

Single Wire Spring Clamp. Also seen on older US Cars. The work and are quick to install but when it is time to change yout Hose you find that the Clamp has cut like 1/2 way into the Hose.
There is also a double Wire version that while not as agresses in cutting the Hose still does that.

The click type Clamp may be the one that the OP was speaking of. Looks like i is only good for a specific size.

Another Spring type Clamp. Usually seen on Fuel Lines but they make them larter like up to 2.5 inches. They are usually not stainless and I don't like them as the ears occasionally snap off when you try to remove them also not being stainless the ears or other parts of the Clamp can rust through.

That is all of the adjustable ones I have pictures of in My notes. __________________
84 300D, 82 Volvo 244Gl Diesel I scanned the thread quickly but I don't think I saw mention of the "official" name of those type clamps. It is an "Oetiker" clamp. Oetiker - Connecting Technology The ones you see are called ear clamps. Volvos use them a lot. I'm not going to opine on the relative betterness of one type over another, but I thought I'd post anyway for info.

Rgds,
Chris W.
'95 E300D 441K __________________
Objects in closer are mirror than they appear. Quote: Originally Posted by renaissanceman Where'd you get the spring clamp for the upper radiator hose? I'm not a fan of the worm clamps and would like to replace with an alternative. Constant Tension Bands are usually an application specific item and are not easily available. You can get them from a new car dealer, but you have to match them up. I have also seen them on Amazon and on eBay.

I myself have salvaged them from my local wrecking yard by matching them up.

On my w123, the radiator's OD neck measures about 35mm. Which is the same on your w124 603 radiator.

If you are looking to salvage these clamps from a parts yard, the size is stamped on the tab or ears.

I found a 44mm clamp fits the best. I also found 43mm clamps can work, but it is a little tight going on over the hose at the neck lip. Both are odd ball sizes and can be hard to come by. You will see 42mm and 46mm all the time.

I believe the clamps I salvaged are made by Roto Clip, who is a major supplier of clamps to the automotive industry.

Here is a .pdf of their clamp offerings.
https://www.rotorclip.com/cat_pdfs/ctb.pdf __________________
123.133 California
- GreaseCar Veg System


Last edited by DeliveryValve; 05-13- at 04:15 PM.