relpace alt on 78 L6

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cnova78

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my alt light is going off on my 78 and i want to swap out my alt on the orginal 250 l6 engine .when i press the gas the light dims and when i release it the light brightens back up.so i looked for the tensioner and cant find it from it looks like the altenator is on the center of the engine and i may have to take the radiator out . from the service manual i purchased says how to test the alt but not remove it. it looks like the alt is held on by two bolts and the pos lead on the back. any suggestions
 
Doesn your alternator have a bracket with a slot in it which is used to adjust the tension on the belt? Never heard of having to remove a radiator to replace the alternator. Did you go through the whole manual and still cannt find the removal procedure. Usually you loosen and remove the adjustment bolt. Swing the alternator so the belt comes off and then unbolt it from the mounting bracket.
 
The manual did have the but it didn't say how to put the belt back on. So the tensioner is the top bolt I'm not looking at the engine now.
 
Yes, the top bolt acts as the tensioner along with the slotted bracket it goes through
 
OK so to reinstall attach the belt lower bolt first them the upper one and as it tightens so does the tension on the belt
 
Correct, you use a long screwdriver and use it as a pry to estalish the tension then tighten the bolt on the slotted bracket. Just dont overtighten the belt, you want about a 1/2" play towards the center of the belt.
 
An easy check for proper belt tension, if you can turn the alternator pulley by hand it is too loose or the belt is worn. When tightening the belt after replacement the 1/2" deflection Zora stated is important to keep excessive loads off the alternator bearings. After a few hours of running time with a new belt the tension should be checked and readjusted if necessary.
 
OK the belt tension must be correct because I can't turn the alt pulley by hand so the alt has to be bad
 
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Most times when a v belt has been slipping due to age or improper adjustment it will need to be replaced. The surface glazes and can no longer grip the pulley well. Also look for signs of the pulley wearing. It should have a smooth flat surface.
 
Well in know the belts are bad because they have that greyish look and who knows when they was last swapped the guy i Purchased the car from didn't do much to it but leave it in the sun
 
Belts. plugs, cap, rotor, plug wires should all be inspected when purchasing a used car and changed as needed. Fluid levels and condition should also be looked at. If unknown mileage on the engine and auto trans fluids change both and use a quality filter like a WIX, not the well advertised orange ones.
 
Yes I know and all of it is going to get swapped out. I got the car based on it was a project car so its needs cosmetic and a basic engine overhall. Good part it doesn't leak anything
 
You are ahead of where I started. Mine had half the engine in the trunk, just the block still bolted in place.
 
True the worstnoartnofnmine was he spray painted the interior black over the factory yellow and the muffler is rusted out on the bottom but over all the car is complete .o and the ebrake is broke in the open position but that's a project for another day
 
I feel your pain, the previous owner of mine spray painted the interior red, without masking anything off and used some sort of blanket material for carpeting. Some people should not be allowed to own tools :D
 
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