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Discussion Topic:
fan belt adjustment
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dawsrobe |
07-10-2024 @ 7:00 PM
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Member
Posts: 1
Joined: Jul 2024
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Hi: New to the forum. I'm rebuilding my 1949 Mercury M47 pick-up, and sure enough, I'm having trouble putting tension on the belts to the generator. I would love to get a copy of this article that you're referring to. I'm more of a visual learner, and can't quite follow the directions you've given. Fingers crossed!
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supereal |
03-16-2017 @ 12:52 PM
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Senior
Posts: 6819
Joined: Oct 2009
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I have been using an old tire iron for years to tension both belts. Be aware that old Fords require a difference width and pitch than modern vee belts. They are best sourced from a reputable dealer in vintage parts. It is important to observe the correct "give" when the belts are tightened, or the generator and water pump bushings will be damaged, as will the fan with the builtin oil reservoir. Ford used belts that gain traction from the sides of the belt so they didn't have to be overtightened to prevent slippage. If you have belts that must ride at the bottom of the pulley groove, you have the wrong type.
This message was edited by supereal on 3-16-17 @ 12:55 PM
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TomO |
03-14-2017 @ 9:03 AM
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Senior
Posts: 7256
Joined: Oct 2009
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Drbrown, I did not realize that there was a change from 1940 to 1942 and later. The 1940 Mercury Reference Book, (owners manual) states "permits 1 inch inward or outward movement of the belt" and the 1946 Service manual staets a 1/2 inch movement in each direction, as you said. This change was probably made due to the smaller generator pulley and the higher amperage generators used in the later cars.
Tom
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Drbrown |
03-13-2017 @ 8:38 PM
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Senior
Posts: 570
Joined: Nov 2013
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TomO, len47merc, 6lucky13 .... regarding belt tightness adjustment: I should have described my adjustment of my belt deflection in a more detailed manner. I tighten both belts as stated in the Ford "Service Manual" for 1946-1948 Fords, Chapter VI, Section 365, page 174 P365.a.(2) which says for gen and fan have approximately 1/2 inch movement EACH WAY (fig.113)". The Operators Manual I have is silent on the issue. So I have been using the 1/2 inch deflection, from the belt's static position, according to the Ford Service Manual which results in a total deflection of 1 inch. This appears to be a common spec. I have the wide belt and so far have not had any problems with pump bushings and bearings.
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6lucky13 |
03-13-2017 @ 2:47 PM
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Member
Posts: 57
Joined: Jun 2011
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I agree with Tom and Steve's recommendations. I damaged the front bearing on the generator by overtightening the fan belt. After replacing the generator eventualy one of the water pumps froze up. After installing new water pumps, I tightened to 1" deflection. Runs fine now.
Kerry
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len47merc |
03-13-2017 @ 11:04 AM
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Senior
Posts: 1165
Joined: Oct 2013
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Same as Old Henry - just with a screwdriver for me. Regarding the belt deflection specification/tightness, I too always adjust mine as TomO states and have never had a problem or prematurely worn belt; however, Fig. 11 on Page P-4 of the 1942-1948 SHOP MANUAL shows 1/2" FREE MOVEMENT as the tightness setting. I typically tighten just to the point there is no excess belt movement at rpm which equates to approximately 1" deflection. You be the judge of what works best for you.
Steve
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Old Henry |
03-13-2017 @ 7:43 AM
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Senior
Posts: 738
Joined: Apr 2010
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I use the handle of my large crescent wrench under the generator right against the front generator bracket on top of the manifold. See picture.
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TomO |
03-13-2017 @ 7:07 AM
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Senior
Posts: 7256
Joined: Oct 2009
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Drbrown, you are adjusting your belt too tight, and it may damage the generator bearing or the water pump bushings. The correct adjustment is 1" of deflection half way between the water pump and generator. See your Operator's Manual.
Tom
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len47merc |
03-13-2017 @ 5:50 AM
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Senior
Posts: 1165
Joined: Oct 2013
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It should be the same Drbrown. These custom tools are 'nice to haves' but an extension or pry bar is all you really need as you say. I use a 12 1/4" long heavy shaft Craftsman screwdriver and it works fine, using the top front of the manifold under the generator as the fulcrum.
Steve
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Drbrown |
03-12-2017 @ 9:12 PM
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Posts: 570
Joined: Nov 2013
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Maybe my '47 is different ..... From the passenger side, I stick my socket extension shaft underneath, nest the end of it on the coil bracket that's bolted to the top of the driver's side head, and lift until the gen/water pump belt can only be depressed about a 1/2 inch. Next I use a pry bar on the water pump housing to tighten the fan belt.
This message was edited by Drbrown on 3-12-17 @ 9:17 PM
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