What's this valve for? 72 mci

[bronson]

A friend of mine picked up a 72 mci challenger it is leaking air out of the  vent of the valve below the regulator in the picture. It leaks whether valve is off or on. The valve knob is wired in one position. It is located on rear drivers side of engine. What is this valve for and can they be rebuilt?

[Van]

Belt tension release valve maybe?

[richard5933]

Follow the tubing and see where it goes?

[luvrbus]

Alternator belt tension preset regulator and valve there is air cylinder on the left side

[buswarrior]

Alternator belt tensioner.

It will be wired as further assurance that it doesn't move by itself.

Re-build or re-place. They leak a lot of air when they fail.

Happy coaching!
Buswarrior

[bronson]

Could we modify it and put a turn buckle or something in its place for consistant tension?  My apologies for being too lazy to crawl up inside and trace the hoses. I could see one hose that disappeared overhead but was too slack to follow it further . The air lines and fittings in the engine compartment all need replaced. What type of hose and fittings are these? No smart comments needed. Bus is not near me but i would like to order a roll of hose and fittings.

[edvanland]

I have a mci 7 and got the parts from Luke at US Coach so will be installing those tomorrow my are for the alternator tensioner ands is up on the bulk head, wish I was smaller and more limber to do that.

[buswarrior]

Yes, you may replace the air piston with a fixed link.

However, a properly working air tensioner, both tensions the belts, and drives the alternator the other way, in order to put the belts on. 

A really big deal, cuz heaving that 85lb monster by hand to get the 4 belts onto it has a bit of physicality to it.

If the tensioner is airtight, I'd do the control valve. If the tensioner also needs rebuilt, the decision gets easier to go with a fixed link.

Call Luke and see what the options cost?

I like the air tensioner, however...

Your bus, your money, your choice!

happy coaching!
buswarrior

[bevans6]

I have a fixed turnbuckle on my alternator to tension the four belts.  The setup is the same idea as the air tensioner for the cooling blower belt, a valve and a regulator.  The same regulator is used in a number of applications on the bus, set to different pressures, so a spare is cheap and easy - I got one from my local truck store.  The valve is simple, with one o-ring inside.  I changed the o-ring and fixed a leak.