Coolant System Leaks

[davidbrady]

Due to some leaks, I recently had to tighten the Breeze heavy duty constant torque (HD CT) clamps used on my H3's coolant system, chassis year 2003. Breeze is very clear that the HD CT clamps require 90 in-lbs. That's actually quite a bit on the clamps 3/8" stainless screw. It's quite a bit more than you'd normally apply with a 1/4" drive ratchet. Get a good quality in-lb torque wrench. I use a snap-on rated for 0 to 200 in-lbs dialed in at 90 in-lbs, and I apply a drop of lube to the clamp before tightening. Also, it sometimes helps to fist loosen a quarter turn or so before torquing to final spec. My favorite lube for this purpose is Corrosion-X. On the H3 it's pretty easy to get to all the clamps used in the cooling system. The top most forward radiator clamps (Hot Coolant In) requires some disassembly of the radiator shroud at the exterior radiator door. The shroud is simple to remove and replace.

[Hisham Amaral]

(04-24-2017 18:13)davidbrady Wrote:  Do to some leaks, I recently had to tighten the Breeze heavy duty constant torque (HD CT) clamps used on my H3's coolant system, chassis year 2003. Breeze is very clear that the HD CT clamps require 90 in-lbs. That's actually quite a bit on the clamps 3/8" stainless screw. It's quite a bit more than you'd normally apply with a 1/4" drive ratchet. Get a good quality in-lb torque wrench. I use a snap-on rated for 0 to 200 in-lbs dialed in at 90 in-lbs, and I apply a drop of lube to the clamp before tightening. Also, it sometimes helps to fist loosen a quarter turn or so before torquing to final spec. My favorite lube for this purpose is Corrosion-X. On the H3 it's pretty easy to get to all the clamps used in the cooling system. The top most forward radiator clamps (Hot Coolant In) requires some disassembly of the radiator shroud at the exterior radiator door. The shroud is simple to remove and replace.

David
There is 1/4" measurement on the screw, the 1/4 " is taken from the clamp housing to the end of the screw. If you open the Prevost service manual it describes the way to torque and measure that distance.

[travelite]

Thanks Hish, I appreciate the added info. You're absolutely correct, the Breeze clamps have that visual clamping reference which you describe. Thanks for reminding me!

[Hisham Amaral]

(04-24-2017 18:42)travelite Wrote:  Thanks Hish, I appreciate the added info. You're absolutely correct, the Breeze clamps have that visual clamping reference which you describe. Thanks for reminding me!

Installation
A torque wrench should be used for proper
installation. The recommended torque is 90 to
100 lbf•in. (10 to 11 N•m). The Belleville spring
washer stacks should be nearly collapsed flat
and the screw tip should extend ¼" (6 mm)
beyond the housing (Fig. 3).
FIGURE 3: CONSTANT-TORQUE CLAMP 05037
Caution: The hose clamps will break if overtorqued.
Do not over-tighten, especially duri

[davidbrady]

Thanks Hish,

It pays to read the manuals! LOL!

Here's more Breeze clamp torque figures I've collected over the years. Ideally, I'd double clamp everything, including the coolant hoses:

V-band clamp: 60 in-lbs
9400 series: 30-45 in-lbs
T-bolt (standard duty): 60 in-lbs
T-bolt (heavy duty): 60 in-lbs
Constant Torque: 30-45 (5/16 hex screw)
Constant Torque: 90 in-lbs (3/8 hex screw)
Constant Torque (Aero-Seal): 45 in-lbs