How much to tighten worm gears? (Hose clamps, jubilee clamps, band clamps)

Post by **FireFox31** » 14 Jul 2022, 21:52

How much should we tighten worm gears around hoses? I replaced many of my coolant hoses with Volvo brand parts and used the OEM Norma worm gear clamps. Yet, I find coolant seeping out at the thermostat. Is there a torque for this clamp and others? I don't want to crank down too hard and hurt the clamp or hose. Thanks.

Post by **scot850** » 14 Jul 2022, 22:56

How clean ids the mating surface? If it is or was crusty and is full of pock marks it may be impossible to seal. You should not have to really crank down o the clamps to make them seal. You should only need to tighten then until you see the rubber starting to indent either side of the clamp. Looking at your thermostat cover it looks pretty poorly.

Other than replacing the cover with a better one, all I can suggest is to remove the pipe again and try to sand down the clamping section to reduce an imperfection on the surface.

Never seen Norma clamps. I always got ABA Swedish clamps from Volvo until about 5 years ago when they started to sell the cheap crap with little cuts in the surface and sharp sides.

Neil.

Post by **abscate** » 15 Jul 2022, 00:38

Snug the clamp right up the ridge on the pipe so that the clamping force is stretching the rubber tight over the ridge to seal. That will help. If it’s really badly pitted , some permatex aviation gasket sealer will help or call me for a replacement

Ive got a replacement order or replacement oetikers from Belmetrics. You can use cheap crimping pliers to close these.

I use them at the radiator top and bottom hose

Clamp first, then push rubber over nipple, line up clamp. Crimp.

Norma and ABA are both quality, closed band hardware. Avoid the box store cheap stuff

Post by **MrAl** » 15 Jul 2022, 05:08

FireFox31 wrote: ↑14 Jul 2022, 21:52 How much should we tighten worm gears around hoses? I replaced many of my coolant hoses with Volvo brand parts and used the OEM Norma worm gear clamps. Yet, I find coolant seeping out at the thermostat. Is there a torque for this clamp and others? I don't want to crank down too hard and hurt the clamp or hose. Thanks.

Hi,

Yeah as Scot850 'Neil' says, the mating surfaces have to be clean and smooth so you get a close, tight fit. From that pic it looks like there could be either a lot of erosion to the connecting pipe or it is very dirty. Either could cause a slow annoying leak.
So i would say take it off and clean the mating pipe to start with, then maybe some sealant as Abscate says if you see any erosion.

454cid · Post by **454cid** » 15 Jul 2022, 05:31

That clamp doesn't look tight to me, although I admit, I've never used one of this specific type before. I've got them on the car of course, but I've not had to remove them.

I have seen specs for worm drive clamps, but I don't recall exactly where, and they may not apply to this specific type any way.

I agree on the need for cleaning. Besides the casting, I'd also scrub inside the hose.

Post by **ZionXIX** » 15 Jul 2022, 07:06

In a perfect world we would be using spring clamp for constant tension but a worm gear will work if used correctly. I domt like the cheap clamps with a sharp edge. They just cut into the hose. The nicer more expensive clamps will have a nice beveled edge.

Post by **FireFox31** » 15 Jul 2022, 14:41

Thanks for the feedback. When I removed the old cooling hose, the thermostat housing was covered in yellow slime. I did my best to scrape it off, but wasn't super careful about it. Before and after pictures are attached. I'll drain the system and try to clean up the housing even better.

Speaking of dirty coolant connectors, the metal pipe which leads to the lower radiator was covered in rust. I don't have picture of after I cleaned it but I'll be checking it for leaks as well.

454cid · Post by **454cid** » 15 Jul 2022, 18:25

I like using a wire wheel to clean up stuff like that. Preferably off the car, but even on the car if necessary... a small wire wheel on a drill, die-grinder, or even a Dremel. The Dremel would not be very aggressive, so I'd try to only use it in low clearance situations.

Post by **MrAl** » 17 Jul 2022, 13:09

Hello,

I thought i posted this but i guess i forgot to hit the button to submit.

Anyway, the way i used to do it was i would clean the mating surface and make sure it was smooth. Then i would put the hose and clamp on and tighten the clamp up snug. Then check for leaks. If any leaks, tighten a little more.
The thing i was trying to avoid was ruining the hose itself because the clamp is metal and it can dig into the hose rubber which can damage it. I think i also used some tape first wrapped around the end of the hose first to protect the rubber from the metal as it squeezed the hose when it was tightened. Dont remember what kind of tape i used though but something that is strong. The hose clamp then grips the tape which grips the hose and all is well.

Ok clicking the 'SUBMIT' button now

Post by **800artfreed** » 18 Jul 2022, 12:03

Has anyone switched over to the "self adjusting" spring hose clamps? These are the kind that need a pair of pliers to grip one tab and the opposite two tabs, squeeze and move the clamp. I ask because a promotional/explanatory video makes the case that these clamps expand and contract as the coolant temperature changes reducing stress and maintaining a tight seal. I attached a sample clamp picture.

: hose clamp.jpg (16.65 KiB) Viewed 3213 times

Thanks.
Jason