Allis-Chalmers — Belt Replacement and Tension Adjustment (Series 433, 649 and 670)
Adjustments · Alternator/water pump drive belt
From a Allis-Chalmers owner's manual covering: Series 606, Series 633, Series 649, Series 685. Check it applies to your exact model before use.
Before you start
- Do not check or adjust belts when engine is running.
- Do not place head, body, limbs, feet, fingers or hands near a rotating fan or belt.
- Where sets of 2 or 3 belts are used, replace all belts if one needs replacement.
Procedure
- Stop engine and remove belt guard.
- Loosen alternator adjusting brace capscrew and mounting bolt or capscrew.
- Install new belt(s) in pulley grooves.
- Move alternator away from engine until specified belt tension is achieved.
- Tighten brace capscrew and mounting bolt or capscrew.
- Reinstall belt guard.
Tools required
- Belt tension gauge Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 1/2 in (12.70 mm) belt: new 107-114 lb, used 90-95 FridayParts $105.00 lb
- 11/16 in (17.46 mm) belt: new 123-130 lb, used 102-107 lb
- 3/4 in (19.05 mm) belt: new 143-150 lb, used 118-124 lb
- 7/8 in (22.23 mm) belt: new 143-150 lb, used 118-124 lb
- Hand check: 1/2 in belt depresses 3/16 in to 1/2 in; 11/16, 3/4 and 7/8 in belts 1/2 to 3/4 in
Source: Allis-Chalmers owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.