64 Hose clamps to large

[Ed P.]

64 365 hp bypass hose clamps and heater hose clamps at expansion tank are to large. Clamps are bottomed out with minimum clamping force. have tried two venders with same results. My have to do with hose thickness. Any source for a smaller clamp. Clamp is stamped with an 11 number.

[Richard G.]

Re: 64 Hose clamps to large

I purchased my clamps from LIC.
They worked, one lower radiator clamp was at the limit of contraction after a leak was identified and the clamp tightened further.
However they are functioning. The bypass hose clamps worked fine, and I didn't have an issue with them.
I will measure the hose diameter so you can determine if that is the issue.
Here is a picture of an original bypass clamp. Possibly it will help.



I know one has to check everything and if you don't have a stock example it's tough to determine where the issue might be.

[Alan D.]

Re: 64 Hose clamps to large

An old car trick (Model T's & A's) - coat the inside of hose and metal connection end with Indian Head Gasket Compound, the brown stuff. It remains flexible and tends to stop those minor leaks. Needed to use on my lower radiator until I found the old clamp, worked fine.
Noticed the repo's are a cheaper metal which does not take much force to run the screw through them (radiator clamps) and into the hose.

[David M.]

Re: 64 Hose clamps to large

I've run into this problem on several restorations of different makes. The new repro hoses are thinner than the old OEM spec'ed hoses and the spec is not adjusted on the repro clamps to compensate. This may or may not be true for the vette repros?

[Richard G.]

Re: 64 Hose clamps to large

Here are a couple pictures with a measurement included. Note, the bypass hose is thick, very thick at almost 1/4" wall thickness.
Sounds like a correct thickness replacement bypass hose will be the likely solution. I wish I could tell you where I got mine.
I can't as I purchased way too long ago. May have even been a GM part?

[Ed P.]

Re: 64 Hose clamps to large

Wow thanks for the info. Repro bypass hose only measures 1.070. I found a thicker piece of heater hose for under the expansion tank and that worked great. So far have not found thicker wall bypass hose.