71 heater hoses and clamps

[Ralph A.]

Need a clearification.
1971 350/270hp auto A/C

I have purchased 2 replacement heater hoses but when I look at the installation there seams to be a short hose between heater control valve and heater box. Is this a separate item or do I cut the replacement hose at that control? Also what hose clamps are proper and if not all tower which location is the worm (I assume)located.
I assume this model has a heater control valve (can not find reference to it) as there is a gold cad control of some sort between the box and the pump that has a vacume line attached.
Thanks in advance.
Ralph

[Harmon C.]

Re: 71 heater hoses and clamps

Ralph The hoses are all sold in one length and if your Corvette requires the valve you need to cut the hose to fit. Lyle

[Ralph A.]

Thanks Lyle, what about clamps *NM*

[Chuck S.]

Re: 71 heater hoses and clamps

Ralph, the heater control valve is screwed to the outside of the fiberglass evaporator housing between the housing and the fender. You gain access to the valve by removing the passenger side fender grille. Clamps are tower clamps, galvanized finish, and are dated month/year. TIM&JG has additional detail.

[Ralph A.]

Re: 71 heater hoses and clamps

Thanks Chuck,
I have gained access to the valve from the bottom of the car. The clamps were worm type, not original. I think you are saying all cmps on the heater hoses are tower. Then I would need 6 clamps, correct?
If they are dated then do you know if a source.
Ralph

[Harmon C.]

Re: 71 heater hoses and clamps

Ralph The clamps at the heater core on A/C cars are hard to get at and are worm clamps on most years so you may only need four tower clamps.Lyle

[Ralph A.]

Re: 71 heater hoses and clamps

I can get to the 2 worm clamps and will replace. Are the tower clampsdated for a late 71?
Thanks
Ralph

[Harmon C.]

Re: 71 heater hoses and clamps

The tower clamps were all dated and need to be prior to the build date. As for a sorce I usally find them used as they were not Corvette only parts. Lyle

[Ralph A.]

Thanks again *NM*

[Chuck S.]

Re: 71 heater hoses and clamps

Ralph, Lyle is correct on the side screw clamps at the heater core. If you have a AIM (Assembly Instruction Manual), you can verify this in UPC C60. In my 70 AIM, a different part number (2467789) is shown at the heater core pipe connections than at the heater control valve and engine connections (9423574).

Earlier, I thought I remembered a side screw clamp on least one of my core pipes, but thought it could be a replacement, and gave the answer according to the TIM&JG. The TIM&JG makes no mention of side screw clamps, but I suppose that there was no expectation that anyone would ever see the core pipe clamps, let alone judge them. TIM&JG also says that some of the tower clamps have the Wittek logo but no date; my recollection is that all of my clamps were dated, but I don't recall them all having the Wittek logo.

You will have to beat the bushes for dated clamps. In fact, the original Wittek clamps are now very hard to find, since Wittek is out of business. Several years back, there were vendors that could date original Wittek clamps, but I don't know the present situation. The best source for original Wittek clamps may be junk yards, as Lyle says, but the pre-existing dates are going to be problematic unless you get lucky. If you can find dates in the 12 months preceding the car build date, you should be OK for judging. I would put the "best" dates at the engine connections, since they are the only ones likely to be seen.

[Patrick H.]

Re: 71 heater hoses and clamps

In addition,

for the hose that attaches to the hot water valve on the outer side of the AC unit, I just cut the hose at the appropriate location, and put one end on each side of the valve. The hose isn't sold as two hoses, but rather one in need of a cut.

I also used side screw clamps in this location. It, too, is impossible to see, and much easier to service using a screw clamp rather than a tower clamp. The only tower clamps I then used were the ones attaching the heater hoses to the water pump and the intake.

Patrick

[Ralph A.]

Thanks Chuck and Patrick

The side clamps are going on all but the engine side.