95 Suburban rear heater hose questions

steveed

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Where are you getting the Gates PowerGrip hose clamps? I saw some on Amazon way marked up but everywhere else seems to be out of stock. I order some from speedway motors but they keep moving the backorder date.
 
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(previous post continued)

I removed the front wheelwell to gain access. This is almost mandatory, IMHO.

Pictures here illustrate how the coolant lines' compression fittings can be split using a cutoff wheel, and it and the hose removed from the pipe.

Quick-connect fitting was removed at the intake manifold and replaced with a conventional fitting suitable for 3/4" hose (not illustrated). A Gates 28480 hose and Gates clamp then connected to it; this was mentioned earlier.

In the engine bay, at the head of the rear coolant lines, new 3/4" hoses are shown installed and secured with Gates PowerGrip p/n 32929 clamps.
 

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Where are you getting the Gates PowerGrip hose clamps? I saw some on Amazon way marked up but everywhere else seems to be out of stock. I order some from speedway motors but they keep moving the backorder date.

I bought the Gates PowerGrip hose clamps from RockAuto in boxes (qty 10 clamps per box) for a decent price... but sometimes RockAuto has them and sometimes they don't. My local NAPA has them too, although the pricing isn't good.

In this project I used Gates PowerGrip p/n 32929 and 32925. The 32929 is typically used for 3/4" hose and p/n 32925 for (smaller) 5/8" hose.

But, Gates p/n 32925 can also be used on some 3/4" hose when fitted upon non-flared pipe, which occurred on two mid-frame connections and two connections in the rear (see the pictures in my other posts in this thread); these clamps were tighter fit, but they fit, and I used them because the pipe wasn't flared and I wanted all the gripping force possible.
 

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(previous post continued)

Here's more detail on how to fabricate the hoses for the rear.

The pictures show the Gates molded hose w/ part number; I've marked where to cut, in Gold Sharpie, shown in the image. Note there are two cuts shown; this is done to remove the short segment of hose between the two cuts so as to shorten the resulting assembly.

Install the brass PEX connector between the two halves, as illustrated (in the picture only the shoulder of the PEX connector is visible). The PEX connectors were obtained from Home Depot. Any suitable connector will suffice, of course.

Both rear hoses (one each, for the supply and the return line) are fabricated the same way; however, the "twist" required at the splice is a bit different once installed for the supply and return. WHAT TO DO: Cut and fabricate both hose assemblies, but do not clamp them yet at the joint (where the PEX connector resides). Install each hose assembly (i.e., from the supply and return lines to the rear heater core) while adjusting the "twist" at the joint as necessary to get good fitment. THEN, secure the hoses at the joint (where the PEX connector resides) using one Gates PowerGrip p/n 32925 clamp (bridging the joint) or two regular hose clamps (one on each side of the joint). The brass PEX connector within has fairly sharp barbs and grips the hoses well under the force of the Gates clamp.
 

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(continued from my previous post)

Regarding clamps, I would NOT use worm clamps, particularly on the plastic joints in the engine bay.

Either reuse the OEM, or buy new, constant force clamps (the type used by the factory), or use the Gates PowerGrip clamps (which are effectively a constant force clamp).

Worm clamps can be easily under or over tightened. Over tightened, and the plastic joints used by GM in the engine bay may fail if too much clamp force is applied. Under tightened, and you'll wind up with a leak that needs attention later.

Stick with constant force clamps, they ARE the clamp to use. Period. And, yes, for maybe 40yrs I thought worm drive clamps were the thing to use... but not anymore.
 
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Schurkey

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Regarding clamps, I would NOT use worm clamps, particularly on the plastic joints in the engine bay.

Either reuse the OEM, or buy new, constant force clamps (the type used by the factory), or use the Gates PowerGrip clamps (which are effectively a constant force clamp).
Worm-gear clamps have two problems, both easily solved but the improvements cost more.
1. The rubber hose extrudes (cold-flows) through the little slots in the band. This can be solved by buying "shielded" clamps that have a solid--non-perforated--piece of metal on the inside so that the rubber never sees the slotted band.

Worm gear vs. "Fuel Injection" hose clamps.
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2. You're absolutely right about the superiority of constant-force/constant torque clamps that have some springiness to them, so they can self-adjust tension based on temperature and other factors.

The Bus Company used to use a couple of kinds of constant-force clamps; shielded "Breeze" clamps using a stack of Belleville washers as a "spring"; and Oetiker clamps having a coil spring on the end. The Oetikers are a biiitch to use properly--very limited range of adjustment; we had problems with silicone elbows that had varying wall thickness from item to item. We'd need larger or smaller clamps depending on how thick the elbow was made.

Samples:
www.amazon.com/Breeze-Constant-Stainless-Effective-Diameter/dp/B003NR7X20/ref=sr_1_4?crid=3DXOZL5DXY35B&

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www.amazon.com/dp/B008L482KC/?coliid=IDMCJK2RATMQX&colid=2VLYZKC3HBBDO&psc=0&ref_=lv_ov_lig_dp_it
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Stick with constant force clamps, they ARE the clamp to use. Period. And, yes, for maybe 40yrs I thought worm drive clamps were the thing to use... but not anymore.
Cheap, unshielded worm-gear clamps are a crime against nature...and for years I thought they were wonderful. I was wrong.
 
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GoToGuy

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The new standard of hose clamp GM and others use is a "SAE Constant Tension Clamp" that is the name. Worm drive clamps work perfectly for what they are designed for. Like anything else someobe finds a away to screw things up. The Breeze and Aeroseal and others have tge inner liner on worm drive clamps to prevent tearing, shaving of the outer hose skin. New synthetic hose materials high temp, low temp, burst strength but can be damaged from sharp contacts. Inner liner solved that problem and improved clamping torque. You said you used a "pex barbed union " for your connection. Notice the factory tube ends have beaded ends not barbs. Barbs are actually designed to hold the hose with barbed ends, no clamp. Beaded end tube is designed for a clamp. Clamp grips hose onto tube, beaded end prevents hose from trying to slide off. I know race teams use the Gates heat shrink hose clamps, but I'm not sold on them being placed or used in a " out of sight out of mind" area just yet. There are alot of different types of " Constant Tension" clamps that use a multitude of tension applications. Under all the industry names. Breeze, Aeroseal, Marmon, AirResearch, Aveco, Triton, and on and on.
It's not difficult to raise a Bead in aluminum tube for a hose connection.
Get a tubing flare kit.
Fit the tubing as your going to flare the end.
Fit the driving end on start the flaring process as the tubing starts to bulge widen a little like 1/16 of an inch.
It's not exactly SAE perfect, but it has worked for me for since 1974.
And I'm not gonna spend another $ 400.00 on Parker beading tools. Once is plenty. And if your not happy with this well the truth can be brutal. Good luck.
 

Erik the Awful

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I was a fan of worm clamps for about 5 minutes, then my leak returned. As soon as I became a dealership technician, I became a fan of the shielded worm clamps (fuel injection clamps) and the spring-style radiator hose clamps. Unless the clamp was visibly damaged or bent, I've never had a problem with either style. That Gates heat-shrink stuff looks like an interesting solution to a problem I don't have. As it's plastic, I wonder about the long-term durability. It looks like it takes longer to install and remove, but if I had a hose that was difficult to seal, it'd definitely be a consideration. Otherwise, why would I bother with it?
 
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