Track Roller Frame Alignment{0653, 4151} Caterpillar

If more than normal wear of undercarriage components is found, visually check the idlers, track rollers, sprockets and track links. Since most tractors do not work on level ground at all times, the wear rate for the inner and outer track roller flanges is often different. This can be the result even if all the undercarriage components are in alignment and wear of the track roller flanges is within the correct limits. If other than normal wear is found on any of these components, use the following procedures to find the cause of the problem.

Roller Frame Alignment

(1) Condition: A roller frame toe-in and/or toe-out condition exists: From a top view of the tractor, either/or both of the roller frames are not parallel to the tractor centerline.

Problem: Variable wear between inside/outside roller flanges and idler flanges and rail sides. Roller flange wear increases from the rear to the front.

Cause: Worn mounting bearings and/or bent diagonal brace or roller frame.

Correction: Make diagonal braces and/or roller frame straight and make repair to mounting bearings.

(2) Condition: Tilt: From front or rear view, the roller frame tilts toward or away from the tractor.

Problem: Different wear between inside/outside roller flanges, idler flanges and link wear surfaces - same differences from front to rear on rollers.

Cause: Bent diagonal brace, broken mountings or bearings.

Correction: Straighten diagonal brace and make repair to mounting bearings.

(3) Condition: Similar to toe-in and toe-out, but roller frame is bent and turns in or out from centerline of tractor.

Problem: Similar to toe-in and toe-out, except rear rollers are not worn.

Cause: Bent roller frame.

Correction: Make roller frame straight.

(4) Condition: Twist in roller frame - similar to tilt, but twist in roller frame causes a tilt at the front end of the roller frame only.

Problem: Similar to effect of tilt, except that rear rollers are not worn.

Cause: Roller frame has twist around a horizontal axis parallel to the tractor.

Correction: Make roller frame straight.

(5) Condition: Idler toe-in or toe-out: From the top view, idler is not parallel to centerline of roller frame.

Problem: Wear on inner rail sides and idler flanges - possible effect on wear of front roller flange.

Cause: Bent idler support box sections or bent idler yoke.

Correction: Make idler support box sections or yoke straight.

(6) Condition: Lateral (parallel to side of tractor) idler location: From top view idler is parallel to, but is either in toward or away from the tractor, within the roller frame.

Problem: Wear on inner or outer idler flanges and either side of the rails. Also, may wear front idlers.

Cause: Shims not correct.

Correction: Install correct amount of shims.

(7) Condition: Twist-tilt: From front view of the tractor, the idler tilts out of vertical position.

Problem: Same as idler toe-in or toe-out.

Cause: Bent idler support box frame (inner and/or outer side is up and/or down in relation with the other).

Correction: Same as idler toe-in or toe-out.

NOTE: If no problems are found during the above visual checks, it is necessary to measure the alignment of the undercarriage components.

Undercarriage Alignment Check (On-Tractor)

(1) Operate the tractor forward on a level surface and let it come to a stop without the use of the brakes. Fabricate a set of tools as given on pages 21, 22, 23 and 24. These tools can be used for on-tractor undercarriage checks on most track-type tractors. Make a record of all measurements on a data sheet. A sample data sheet is shown on page 20.

(2) With the dial indicator tool, check reference bars (1) to make sure they are straight. Install the bar in test block (2); as the tool is turned around the reference bar, the total indicator movement should be less than .0508 (.002").

(3) When necessary for the procedure, install reference bar (1) and check the accuracy of alignment of the reference bar with the roller shaft as follows:

a) Remove all dirt and rust from the end of the roller shaft. The reference bars are installed in the roller shafts in place of the lubrication plugs or pressure fittings.

b) Tighten the bar by hand with a 7.9 (.312"Ø) rod.

c) Slide the tool over the reference bar until the end of the tool makes contact with the roller shaft. Tighten the thumbscrew.

d) Adjust the dial indicator so the contact point is against the end of the reference bar as shown.

e) Turn the tool around the bar and check the dial indicator movement. The total indicator movement should be less than .0508 (.002").

f) If the movement is more than .0508 (.002"), the bar is not in alignment because of paint or rust. Loosen and tighten the bar several times to remove the foreign material.

Procedures

(4)

NOTE: For each of the following procedures, use the tools as given in the procedures or use straight edges and a tape measure. Fabricated tool drawings are given on pages 21, 22, 23 and 24.

(A) Measurement of Roller Frame Toe-in or Toe-out

MEASURING BETWEEN ROLLER SHAFTS WITH AN ADJUSTABLE BAR AND COLLAR. AN ENLARGED VIEW OF THE COLLAR IS SHOWN.

(1) Each roller frame must be in parallel alignment with the tractor centerline and within a specific tolerance. A difference from parallel is called "toe-in" or "toe-out" as shown above. Find the distance between the inside ends of the rear roller shafts at location (A) and the distance between the front roller shafts at location (B). If the difference between the two measurements is more than 8 (.31") there is too much toe-in or toe-out. If the front (B) and rear (A) dimensions are the same, the roller frames are parallel.

(2) Even if the roller frames are parallel to each other, they may not be in alignment with the tractor centerline. To check if the roller frames are parallel with the tractor centerline, measure diagonally (across) from the front roller shaft on one roller frame to the rear roller shaft of the opposite roller frame; see distances (X) and (XX) shown above. If these measurements are different by more than 10 (.38"), the roller frames are not parallel to the tractor centerline.

After the toe-in or toe-out of the roller frame has been found, it is necessary to install reference bars so that frame straightness and the position of the rollers, idler and frame can be measured in relation to each other. Install one reference bar in the front roller shaft and the other reference bar in a roller shaft toward the rear of the tractor. The location will be different from tractor to tractor, but the squaring tool should extend between the front and rear reference shafts.

(3) If the roller frames are not parallel with each other, the roller frame can be bent, or the diagonal brace can be damaged or bent. To check for a bent roller frame, install reference bars as given (in item 2a) on one roller frame. Install the squaring tool on either roller reference bar and tighten the thumbscrew.

NOTE: Make sure that both blades of the squaring tool are in parallel alignment. The distance between the end of the roller shaft and the inside edge of the squaring tool blade will be 76 (3.0"), if the squaring tool is against the shoulder on the reference bar. At each roller position, check the distance between the edge of the squaring tool blade and the end of the roller shaft. If the distance is variable by more than 3 (.12"), the roller frame is bent. If neither roller frame is bent, and the frames are not parallel to the tractor centerline, then one or both diagonal braces are probably bent or broken.

Before removal of the roller frame from the tractor, make several more checks to the roller frame to be sure that it is bent or broken.

(B) Measurement of Roller Frame Tilt

(1) A severe (sudden) load on the rear or side of the tractor can bend the sprocket shaft, diagonal brace or outside box section of the roller frame. If any one of these is bent, the roller frame will tilt either in or out from the frame. The amount of tilt can be measured with Starrett No. 98 [152 (6.0")] adjustable level as shown above. The knurled thumbnuts can be turned to center the bubble, even though the bore is on a slanted (not level) surface. One mark on the level gives indication of a slope (angle) of .13 (.005") every 305 (12.0"). One turn of a thumbnut will change the slope 2.2 (.086") every 305 (12.0"). When this level is used, make sure the reference surface is smooth and free of all foreign material. Also, make sure the level is in the same position each time for consistent (same) readings and make sure the same end of the level is always toward the tractor centerline. To measure the roller frame tilt, put the adjustable level on a machined surface of the bevel gear compartment or similar surface as shown, and adjust the bubble to the center. Move the level to the reference bar in the front roller shaft. Count the number of turns of the thumbnut needed to adjust the bubble to center. If more than one turn of the nut is necessary to move the bubble to center, the frame has too much tilt. Make a record of the number of thumbnut turns on the data sheet.

(C) Measurement of Roller Frame Twist

(1) Put the level in position on the reference bar in the front roller shaft and adjust the bubble to center. Move the level to the reference bar on the rear roller shaft. Count the number of thumbnut turns that are necessary to move the bubble to center. Make a record of the number of turns on the data sheet. The two roller shafts should be in alignment within one-half turn of the adjustment thumbnut. If the thumbnut is turned more than one turn, the frame has too much twist and must be straightened. To find the location of the twist, make this check on each roller shaft.

(D) Measurement of Idler Tilt

(1) The idler shaft should be parallel with the roller shafts, but a bent box section in the support can cause a vertical tilt. If the idler is tilted, the track will be moved to one side and cause increased wear on the flanges of the front rollers. Remove the reference bar from the front roller shaft and install it in the idler shaft. Put the adjustable level on the reference bar and count the number of thumbnut turns necessary to adjust the bubble to center. Make a record on the data sheet of the number of turns. A maximum of one and one half turns of the thumbnut 3 (.129") per 305 (12.0") is permitted. If beyond the given tolerance, it is possible that the roller frame has a bent idler support box section.

(E) Measurement of Idler Position (Parallel Relation of Idler to Side of Tractor)

(1) The procedure gives the location of the centerline of the idler shaft with relation to the centerline of the roller shafts. If the idler is not parallel within the roller frame and with the rollers, too much idler and roller flange wear will be the result. Install the squaring tool on the rear reference shaft and tighten the thumbscrew. Distance (C) will be 76 (3.0") if the squaring tool is against the shoulder on the reference bar. Distance (C) is the dimension between the end of the roller shaft and the inside edge of the squaring tool. Loosen the thumbscrew on the squaring tool and adjust distance (D) to 76 (3.0"); this is the distance between the end of the front roller shaft and the inside edge of the squaring tool. Tighten the thumbscrew. Lift the squaring tool up against the reference bar and measure distance (E). Distance (E) is the dimension between the end of the idler shaft and the squaring tool. Make a comparison of dimension (E) with the dimension given in the following chart. If the measurement is different by more than 5 (.18") from the value in the following chart, then the cause for the difference should be found and the necessary correction made.

Lubricated For Life Track Roller Assemblies

(F) Measurement of Idler Toe

Dimension (F) is the distance from the reference roller shaft to the blade of the squaring tool. The reference bar in the roller shaft is not used to obtain dimension (F).

(1) Check to see if the idler is at an angle within the roller frame, from the top view. At zero idler toe, the centerline of the idler is exactly 90° from the centerline of the roller frame. Too much idler toe can cause increased wear on the inside of the track links, idler flanges and front roller flanges. Install the squaring tool on the idler reference bar against the flange and tighten the thumbscrew. NOTE: Make sure that both blades of the squaring tool are in a parallel alignment. Find dimension (F); dimension (F) is the distance from the inside edge of the squaring tool to the end of a rear roller shaft. Measurement (F) should be within 13 (.50") of the dimension given in the chart on page 8.

(G) Service of Idlers and Rollers

Remove all reference bars from the idlers and rollers. If any lubricant was lost when the measurements were checked, again fill the rollers and idlers and install the plugs.

Measurement Of Roller Frame Alignment (Off-Tractor)

TOOLS FOR MEASURING ROLLER FRAME ALIGNMENT OFF THE TRACTOR.

(A) Tools For Measuring Roller Frame Alignment Off The Tractor

Tools shown above must be fabricated (see page 21) and are necessary for measuring alignment of roller frames off the tractor. Straight-edges, 610 (24") and 2133 (84.0") in length, are used with the level to find a reference point on the roller mounting pads and to measure the position of different surfaces of the roller frame respective to that reference surface. These straight-edges are either fabricated from 19 x 25 (.75" x 1.0") steel bars or 25 (1.0") square tubing. Check to make sure they are straight; use the adjustable level shown above. The total difference from straightness should not be more than 0.127 per 304 (.005" per 12.0"), or one mark on the level. If necessary, these bars can be made straight with a small press. The centering fixture is used to find the centerline of the sprocket shaft. The fixture fits all current and most earlier roller frames. Make a record on the Roller Frame Data Sheet, Components Removed, of all measurements taken on the roller frame; see sample data sheet, page 19.

(B) Location of Reference Surface for Measurement of Position of Outside Bearing Bore, Toe (in or out) and Idler Support Box Section

(1) Put the roller frame in position on its side, about 254 (10.0") above the floor. Install bolts (1) in the front and rear roller mounting pads and put 2133 (84.0") straight-edge (2) on the bolts as shown. Put adjustable level (3) in the middle of the straight-edge, and adjust the bubble to the center of the level. All the following measurements (with the frame in the vertical position) are taken with respect to this reference surface.

(C) Measurement of Outside Bearing Bore Alignment

(1) The surface of the outside bearing bore should be parallel with the reference surface that was found earlier. To check this condition, put short straight-edge (4) across the bore with level (3) as shown. If straight edge (4) is not on machined surfaces, use spacers of equal thickness under the straight-edge. The bore should be parallel with the reference surface within one-half turn of the knurled nut or 3.6mm per m (.043" per 12.0"). Make a record of the measurement on the data sheet.

(D) Measurement of Toe (in or out) of the Frame

(1) Install centering tool (5) in the bore of the frame as shown. Tighten thumbscrew (6) to remove all end clearance. Tighten thumbscrew (7). Put the level in position on the reference surface and adjust the bubble to center. Then put level (3) on the machined surface of centering tool (5) so that it is parallel to the reference surface. Turn the knurled nut until the bubble in the level is centered. Make a record of the number of turns of the nut or the number of graduations on the vial needed to adjust the bubble to center. Each mark on the level is 0.4 mm per m (.005" per ft) of toe-in/toe-out of the frame length.

(2) Measure the distance from the centerline of the sprocket shaft to the centerline of the front roller shaft. To find the actual amount of toe-in/toe-out, multiply the reading taken from the level by the distance measured on the roller frame. Maximum allowed toe-in/toe-out for all frames is 6.4 mm (.25"); if this measurement exceeds this amount the frame must be straightened. See example below.

EXAMPLE:

1) Level reading; 4 marks = 1.6 mm per m (.020" per ft).

2) Length of frame between sprocket shaft and front roller centerline; 3 m (10 ft).

3) Actual amount of toe-in/toe-out equals:

1.6 mm X 3.0 m = 5.00 mm

(.02" X 10 ft = .20")

This frame is within allowable tolerance.

(E) Measurement of Idler Support Box Sections - Parallel Alignment

(1) Adjust the bubble to center with the level on the reference surface found earlier. Put short straight-edge (4) on the idler supports as shown. Put level (3) on the straight-edge and turn the knurled nut until the bubble is again at center. Each box section should not be out of alignment more than three quarters of a turn of the knurled nut, or approximately 5.0 mm/m (.060" per 12.0"). Make a record of the measurements on a data sheet.

(F) Location of Reference Surface for Measurement of Roller Frame Twist, Diagonal Brace Vertical Alignment, Twist in Diagonal Brace Bearing Bore, Vertical Alignment of Idler Support Box Sections and Measurement of the Frame Straightness.

(1) Put the frame in an upside down position and as near level as possible. Put short straight-edge (4) on the rear roller mounting pads as shown and adjust the bubble in level (3) to center. This procedure gives the reference surface of the rear roller mounting pads and all following measurements are respective to that surface.

(G) Measurement of Roller Frame Twist

(1) Put short straight-edge (4) on each roller mounting pad as shown. Measure the alignment of each pad, respective to the rear roller mounting pad. The location and amount of twist in a roller frame can be found with this procedure. The maximum difference of each roller mounting from the reference surface should not be more than one turn of the knurled nut. Make a record of the measurements on a data sheet.

(H) Measurement of Diagonal Brace Vertical Alignment

(1) Install centering tool (5) in the roller frame as shown. Put level (3) on the shaft of the centering tool and measure the out of alignment dimension, respective to the roller mounting. The diagonal brace should not be out of alignment more than one-half turn of the knurled nut, or 3.6 mm/m (.043" per 12.0"). If the dimension is more than permissible, it is probable that the diagonal brace is bent. However, it is possible that the outer box section is bent down; check for this condition with the 2133 (84") straight-edge.

(J) Measurement of Twist in Bearing Bore of Diagonal Brace

(1) Put short straight-edge (4) through the bearing bore. Put level (3) on the straight-edge and measure the amount of twist in the diagonal brace bearing bore, respective to the shaft of the centering tool shown in item (H). The bearing bore should not be out of alignment more than one-quarter turn of the knurled nut, or 1.8 mm/m (.022" per 12.0").

(K) Measurement of Idler Support Box Section - Vertical Alignment

(1) Put short straight-edge (4) on the lower surface of the support as shown. Put level (3) on the straight-edge to measure the alignment of the idler support surface, respective to the rear roller mounting. The parallel alignment of the idler supports should be within one turn of the knurled nut, or 7.2 mm/m (.086" per 12.0"), respective to the reference surface. Make a record of the measurements on a data sheet.

(L) Measurement of Roller Frame for Straightness

(1) Put straight-edge (2) on the surface of the roller mountings as shown. Check to see if all surfaces are flat and in line. If they are not, measure the difference and make a record of the measurement on a data sheet. The maximum difference in straightness should be no more than 6.4 (.25").

(2) Install bolts in all roller mounting pads. Put straight-edge (2) on the bolts as shown to check the centerline of the bolt holes. The centerline of the bolt holes should be in alignment within 1.5 (.060"). If the tolerance is above this dimension, the roller frame is bent either in or out. Make a record of the measurements on a data sheet.

Procedure For Straightening Roller Frames

Two different procedures are given in the following instruction for straightening the roller frame. The heat and cool procedure can be used for straightening frames in the field or in small repair shops. The hydraulic press procedure is practical for use in large undercarriage rebuild shops where a high volume of rebuild work is done.

During the straightening operation, check the alignment of the roller frame from time to time with the tools given earlier in this instruction. Additional tools needed to check the amount of beam deflection with the heat and cool procedure are given below.

1) 7H1948 Snug

2) 9.5Ø (.38"Ø) Rod (heat, make flat and drill as shown)

3) 9M9268 Dial Indicator

4) 7H1943 Clamp

A) 8.7Ø (.344"Ø) hole

B) 19 (.75")

C) 457 (18.0")

Heat and Cool Procedures

(1) Heat the convex (outside radius) side of the beam to a dull (not shiny) red color. Limit the heat to the length of the bent area. Heat in a short area causes a sharp bend in a small area; heat in a larger area gives a longer, more gradual bend. Cool the area with air or water. Heat causes expansion of steel, and contraction (size reduction) takes place when it becomes cool. When one side of a beam is heated and the other side is cool, the heated area is kept from expansion in length, so there is expansion in the cross section area. This expansion is enough to cause a permanent increase in the cross section area after the beam becomes cool. Since the beam is larger in the cross section area, it becomes shorter in length on the convex side and the inside stresses cause the beam to bend toward the side that was heated.

(2) Heat to a dull red color the sides that are vertical to the convex side. Make sure to heat both sides evenly. Keep the heat at the center of each side. Cool the area that was heated with air or water. Heating the sides of the beam will cause a dimension change similar to the changes given above. However, the inside stresses are in reverse.

(3) Beams can be bent any amount by use of step 1 and step 2 in sequence, as many times as necessary. The use of either step without the other will cause the beam to bend very little; however, the step 1 to step 2 sequence gives the maximum rate of bend.

Hydraulic Press Procedure

(1) A large hydraulic press as shown above can be used to make a roller frame straight. This press is most practical for use in an undercarriage rebuild shop where a high volume of rebuild work is done. The press is a 1524 x 4267 (60" x 168") platform and two 136 metric ton (150 ton) capacity frames which roll on the platform. There is a large hold down screw on one frame and a 1335 kilonewton (150 ton) ram on the other. The 1335 kilonewton (150 ton) ram is used along with the hold down screw, blocks and supports to straighten roller frames. Frames can be straightened cold with this press but heat can be used, if necessary, to cause the frame to bend in the desired location.

NOTE: Miscellaneous Facility Drawing Numbers 3025, 3026 and 3027 are available from your Division Service Manager for fabrication of the above press.

Dimensions For Welding Diagonal Braces

Roller Frame Data Sheet - Components Removed (Sample)

Alignment Data Sheet - Components Installed (Sample)

Tool Fabrication Drawings

1) Locknut, 1/4"-28 (NF); socket head setscrew, 1/4"-28 (NF), 9.5 (.375") in length (four each needed).

2) 5.4"Ø (.2130"Ø) drilled hole, 1/4"-28 (UNF) tapped through hole [for 13 (.50") in length thumbscrew].

3) 1Ø (.38"Ø) drilled through hole in movable blade, 5.4Ø (.2130"Ø) drilled through hole in fixed blade, 1/4"-28 (UNF) tapped hole [for 19 (.75") in length thumbscrew and 1/4" flat steel washer].

4) 8Ø (.31"Ø) drilled through hole in both blades, use 8 x 25 (.31" x 1.0") bolt with two nuts.

Adjust the squaring tool as follows to make the fixed blade square with respect to the reference bar:

1. Put the test block in a vise (see diagram).

2. Tighten a reference bar in the test block.

3. Slide the squaring tool on the reference bar and tighten the thumbscrew in hole (2).

4. Measure from the fixed blade to a point on the work bench.

5. Turn the squaring tool upside down and again do step 4.

6. Adjust setscrews (1) until the distances measured in steps 4 and 5 are equal.

LARGE CENTERING FIXTURE

CENTERING FIXTURE SHAFT AND SMALL CENTERING FIXTURE. SHAFT MAY HAVE MAXIMUM VARIATION IN SLOPE OF 42 mm/m (.005"/FT.)

Clamp each centering fixture on a 25.4 ± .025 (1.000" ± .001") arbor and machine the conical surfaces concentric with the arbor within .050 (.002") Total Indicator Runout. While the fixture is on the arbor face both ends of each fixture. Face the large circular end plate within .025 (.001").