Ladies and Gentlemen:

I have a 1973 Barth 25 footer built on a P30 with chassis with a big block chevy engine.

I have been eating belts for the past year and I have not been able to work out what is happening. OK maybe I have worked it out but I just do not like the answer.

There are three belts, Air conditioning that also runs over the water pump, the alternator and the power steering pump.


I replaced the alternator and the new alternator is about 200 to 250 thousands inside of the belt path from the water pump. This belt fails all the time, I’ve since put a very heavy belt in place as an in interim fix.

I trashed the air conditioning clutch when I was removing it, OK I took the gear puller and pulled then Jesus clip and a good part of the shaft right off, yes I feel dumb. So the point being there is no new belt here until I get the pump replaced.

Now the power steering belt is also wearing out.


So I guess my question are:

How do I check for alignment and how far out is OK?

If I have to move the alternator out a bit can I move just the pulley and how do I do this?

Do I have to have the belt that runs over the water pump and the air conditioner?

The power steering pump may wobble a bit or I may just have a loose mount, I’ll check.


Help and thanks:

Tim

What we have here is an ongoing example of climbing the learning by experience curve.

My shade tree method of checking alignment starts with a straight edge.

First be sure your crankshaft pulley runs true. Then lay your straight edge along the face of it and see how it aligns with each accessory pulley.

All the pulley faces should be parallel. Rotate each accessory pulley by hand to be sure it also runs true.

If an accessory pulley is not parallel it must be made so by adjusting its mount, or if the pulley itself is bent, by replacing the pulley.

The grooves on the driving & driven pulleys must also align, i.e., the distance between the straight edge and the center of the driving pulley groove must equal the distance between the straight edge and the center of the corresponding driven pulley groove. Here's where a picture would be worth a thousand words, but I'm not computer savvy enough to draw one.

I don't know how far out is OK, but 200 thousandths is too far.

To align your alternator, you're better off jiggering with the mount than messing with the pulley. You're out somewhere around 1/4". That's the thickness of a flange or a bracket. It's likely that something has been installed ahead of, or behind where it should be.

If the belt between the water pump & the a/c compressor only runs the compressor, you probably don't need it. In any event, you must have a belt or belts from the crankshaft pulley to drive the water pump, power steering, & alternator.

If the whole power steering pump wobbles, it's a loose, broken or missing mount. If the pulley wobbles on the shaft, maybe it can be tightened. If the shaft wobbles too, you probably need a new pump. All this presumes the pulley is not bent, & runs true. Power steering pumps are the most common cause of misalignment, & except for the new alternator, is the likeliest cause of your problem.

Also check to be sure the belts are sized to the pulleys. In 1973, before serpentine belts, you had 3/8" & 1/2" V-belts, sometimes mixed in the same installation.

Another possibility, considering the age of your coach, is that one or more pulleys have become pitted. That, too will chew up belts. Your pulleys have to be smooth and shiny.

I'm sure I've forgotten something, & someone else will think of it and bring it up.

Just keep telling yourself how much fun you're having, & be thankful you're having it is sunny SoCal, not chilly & rainy Washington.

I ran into a similiar problem with my SOB (5.7L Chebby engine).

When I got it, it ate belts. On changing the second one, I discovered that a water pump leak had rusted the crankshaft pulley so it was essentially a saw blade. I filed it down, got rid of the shards, and had no more problems.

Later I replaced the pulley, and that problem was solved permanently.

The following year I replaced the A/C compressor, and on my way back from Nebraska, the A/C belt (thinned down considerably) rolled, so I shut off the A/C and ran the gen and house air.

When I got home, I replaced the belt, and after it was tensioned, I noticed it was rubbing on the P/S pulley, so I took the RV back to the shop. 13 compressors later, they finally found the right one - with about .25" more clearance.

quote:

Originally posted by Rusty:
I I noticed it was rubbing on the P/S pulley, so I took the RV back to the shop. 13 compressors later, they finally found the right one - with about .25" more clearance.

There should be some sort of a prize for persistence, huh?

The original compressor was discarded, and the local (Modine) shop reports that they couldn't currently process cross reference numbers (they still can't - I had to take the compressor from the Barth down there today too, as they can only supply by make/model/year - took the manager 2 minutes to locate the right one).

So the manager, after sending several that were wrong, gathered up 7 from his warehouse and took 'em to the shop, and matched up one.

Gentlemen:
Thank you for your thoughtful responses. There were a number of things you discussed and approaches I had not considered.

Well, hi ho, hi ho off to work.

Timothy