Is there a torque spec for these things? I have just spent some time replacing a lot of the rubber hoses on the cooling system. I just kind of tighten them till it scares me to go any more. It would be nice to know if there is a right way.
Thanks for any advice!
I'm sure there are specs but I've never used them. A good rule of thumb is to tighten until the hose can't be moved by hand on the connection. However, some connections are so tight that they can't be moved even without a clamp so that doesn't always work.
I go by what I'm tightening over. Sometimes the hose may be on plastic or thin Alor brass which calls for a delicate tightening. Most bus connections are pretty tough though so probably won't be a problem. Some are even cast steel, plenty tough.
One thing to remember is that they need to be retightened after a short time in use because the rubber will give (set) and loosen the clamp. This may not be true for silicone hoses which I've never used, but is true for rubber.
Charles, I use what the plumbers call a no hub torque wrench it is pre set and can be purchased at any large plumbing supply like Ferguson for around $20.00 has 90 degree and a straight head will not strip a clamp good luck
Gus, thanks for the thoughts. I was not worried about hurting the fittings, they are brass castings about 3/16 thick. I just wanted to get them as tight as possible without stripping the clamp.
Just change to the spring loaded constant torq..on the bus and on my turboed toad...
Thanks luvrbus, I will look into that, there is a Ferguson's about a mile or so from me.
Charles, a good rule of thumb is to tighten the clamp until the clamp sinks into the hose about a depth equal to the thickness of the clamp band material. A light coat of 3M weather strip adhesive in the inside of the hose also promotes long leak free hose connections. Do not use the adhesive on fuel or oil lines. If you have to tighten the clamp until the hose bulges to effect a leak free joint You should check the condition of the metal surface that mates to the hose. My two cents. John
Charles don't hold me to the $20.00 I checked and mine 4 years old now
good luck
What is a spring loaded constant torque clamp?
A $10.00 clamp that keeps the same amount of tension hot or cold and recommened for slicone hoses
good luck
Gus, I think that is the type of clamp that is generally used on turbo system hose connections. There is a nut that tightens against a spring, and the spring holds the pressure on the clamp. They are very well made and cost several times what a regular hose clamp is.
Hope that makes since.
Its not a big deal on a truck, if you have a leak you can smell it. Different with a coach. I like to double clamp everything that has enough room for two clamps.
Here is what a Constant-Tension T-Bolt Hose Clamp looks like.
McMaster Carr has them
http://www.mcmaster.com/
At Freightliner, we use Gates Blue Stripe hoses, that are a good alternative to silicone. While silicone hoses are supposed to last a lifetime, they need to be retightened several time and can cold weather leak more then others. I replaced my 5/8" heater hoses on my truck a few years ago with Gates Blue Stripe, installed them once and yet to have to retighten them. On buses, some of the hoses are in such wonderful places, you don't want to have to retighten them down the road. Good Luck, TomC
I use these clamps sometimes.......http://www.oetiker.com/content.asp?l=4&idNavig=88
Helpful hints loosly related to this thread.
This is of my own "design": When I have fittings that are rusted/oxidized, I clean them well with emery strip cloth that comes in a roll. 80 grit or something rough. I then have a pitted fitting that may be OK with a lot of pressure on the clamp. I mix up some JB Weld and liberally smear the epoxy on the fitting AND coat the inside of the rubber hose. It slips on like it was greased. "loosly" snug the hose clamp and retighten after 12 hours. It never leaks and the hose can be easily removed as the JB doesn't stick to rubber. Silicone weeps on anything except a fresh new fitting but if you do it this way even silicone is weep free.
FWIW,
John
I went to Ferguson's today and checked out the hubless thing. The packaging said it was factory set to 60 inch lbs, so now I have a torque spec to start at. I will see how that works. I ran the bus awhile today also and did not have any leaks. I was just wanting to know the right way to do it.
Thanks for all the input!
Double clamp gives you extra insurance.
With some time to kill today i set up a little bench test to destruction. I had some old clamps laying around so I tested them. What I found out was that they could take the 60 inch lbs well but would start deforming at about 12 ft lbs. Hope this helps.
Great test Charles I never knew a clamp could be tighten to 12 lbs without stripping all the info I have shows around 5 lbs or 60 in lbs the limit for worm type clamps Ideal clamp will have the torque for all clamps they manufacture on their site fwiw. If using spring clamps depending on the color of the spring most are around 20 inch lbs and the torque is critical for sealing on silicone hoses have a great day
Thanks to all.
At my age I still learn something every day, I've never seen one of those things before!!
Quote from: makemineatwostroke on November 28, 2008, 05:27:59 AM
Great test Charles I never knew a clamp could be tighten to 12 lbs without stripping all the info I have shows around 5 lbs or 60 in lbs the limit for worm type clamps Ideal clamp will have the torque for all clamps they manufacture on their site fwiw. If using spring clamps depending on the color of the spring most are around 20 inch lbs and the torque is critical for sealing on silicone hoses have a great day
Be aware that my torque wrench that gives ft lbs is not a real accurate piece. It is a beam type and the reading is not precise. Your milage may vary, due to clamp brand, type etc.
Good luck!
You'll find the style of clamp you want to use on this page...
http://www.aapsa.com.au/norma.html (http://www.aapsa.com.au/norma.html)
The high torque worm clamp will likely cover most of our applications.
HTH
Jay
87 SaftLiner