Repair Procedures — Eleven Walkthroughs That Cover 90% of the Work
These are the procedures you'll perform most often. Each one is structured around a single failure mode, calls out the parts you'll need before you start, and includes the verification step Sumner specifies before returning the lift to service.
Replace the lift cable.
Any visible damage to the cable — fraying, kinking, broken strands, or burn marks from arc strike — requires immediate replacement. Never field-splice a lift cable.
Parts & Tools
- Cable (GH-5T)PN 774206 — 1/8" replacement cable for GH-5T winch
- Cable (MX-equipped)7/32" replacement cable — verify OEM PN with B&B SUMNER for your serial range
- TerminationDrop-forged anchor clip + thimble (sized to cable)
- ToolsWire-rope cutter, torque wrench, gloves
- Time~45 min
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Lower carriage and remove load
Crank the carriage all the way down to the base. Remove all material from the forks. Tag the lift out of service.
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Release tension at the carriage
Continue cranking down past the carriage's resting point until the cable goes slack. Once tension is off, the brake is unloaded and no longer holds the drum — unwind the last few wraps by rotating the drum by hand, not by cranking. Never let the drum spin free under any residual tension.
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Disconnect cable at the carriage
Remove the cable anchor clip from the carriage attachment point. Withdraw the thimble and free end.
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Unspool from the winch drum
Crank the handle in the direction that pays cable off the drum until the cable terminus on the drum is exposed. Sumner specifies a minimum number of cable wraps that must remain on the drum at full carriage extension — 4 wraps for the Series 2100; 3 wraps for the Series 2400. Note your starting point and confirm against your operator's manual.
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Inspect the sheave while access is open
With the cable removed, this is the moment to spin the upper sheave by hand. Replace it now if it's grooved, sharp, or rough — installing a new cable on a worn sheave will destroy the cable in days.
Cable sheavecable-related -
Route the new cable
Feed the new cable up through the internal mast routing (or external guides on older 2000-series lifts), over the sheave, and down to the carriage. Fish-tape trick: before you fully remove the old cable, tie the new cable's leader to the old cable's free end with a smooth taped joint, then pull the old one downward from the winch side — the new cable follows the exact routed path. This is the single thing that separates a 15-minute cable change from a two-hour one. Keep tension on the cable while routing — a single twist becomes a permanent kink under load.
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Terminate at the carriage
Pass the cable through the thimble, double back, and install the anchor clip with the saddle on the live side ("never saddle a dead horse"). Torque per the clip manufacturer's spec (typically stamped on the clip box; Crosby-style clips for 1/8″ and 7/32″ cables use two clips minimum, spaced approximately 6 × the cable diameter apart).
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Wind onto the winch drum & form the swage stop
Crank up while guiding the cable so the wraps lay tightly side by side. Verify the minimum drum wraps remain at full extension (4 for Series 2100; 3 for Series 2400; verify your model's operator's manual). Slide the swage-stop sleeve over the drum-end of the cable, seat it against the drum's cable-terminus pocket, and crimp with the hand swager in one full compression. Never form a swage on a cable you've already pulled taut — the drum end must be dead-end.
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Test under load
Cycle the carriage full up and full down with no load. Then test at 10% of rated capacity, then 50%, then 100%. At the 100% cycle, run the carriage to full extension and hold for 5 minutes — inspect for any measurable drift (a good winch holds ≤ 1/8″ over 5 min at rated load). Re-torque the anchor clip after the first 100% cycle — cables seat into clips under load.
safety-critical -
Sign the maintenance record
Log the cable replacement, date, and your initials on the lift's maintenance record decal.
Service the winch ratchet pawl & brake.
If the winch slips when the operator stops cranking, or the brake doesn't fully hold rated load, the ratchet pawl, brake disc, or both need attention. This is the single most common winch issue Sumner techs see.
Parts & Tools
- Pawl & springSub-component of OEM winch rebuild kit
- Brake discSub-component of OEM winch rebuild kit
- ToolsSnap-ring pliers, light machine oil, fine sandpaper
- Time~30 min
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Remove the cable from the drum
Follow Procedure 01 steps 1–4 to free the cable. Don't fully remove it; just unspool enough to access the drum and reel.
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Remove the reel from the drive shaft
Pop off the retaining ring on the drive shaft, slide the drive shaft out the side, and lift the reel free.
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Inspect the brake disc
Remove the brake pad. Light wear with shiny spots ("glazing") can be restored by lightly sanding both faces with fine paper. Heavy scoring, cracking, or oil contamination = replace.
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Inspect the ratchet wheel and pawl
Look for chipped or rounded ratchet teeth, and a pawl with a worn engagement tip or weak spring. If teeth are chipped, replace the entire pawl assembly — sharp pawl on rounded teeth will wear through quickly.
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Re-install the ratchet wheel correctly
Critical: the ratchet wheel is directional. Confirm the engagement faces of the teeth point in the direction shown in the operator's manual diagram. Reversed = winch will free-spool under load.
safety-critical -
Engage the pawl into the wheel
Press the pawl down out of the way with your finger and slide the drive shaft back into the bushing. Release the pawl — it should snap into the ratchet teeth. You should hear a sharp click on every tooth as you turn the drive shaft by hand.
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Lubricate
Light machine oil on the pawl pivot and brake-ratchet contact. Avoid getting oil on the brake disc face.
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Reassemble and test
Wind cable back onto the drum. Test at 10%, 50%, 100% of rated capacity. Stop cranking at each level and verify the brake holds without drift for at least 60 seconds.
Replace the upper-mast cable sheave.
A grooved or seized sheave will fray a brand-new cable in days. If you find one during a cable change, swap it before installing the new cable.
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Lower carriage, remove cable
Follow the cable-removal portion of Procedure 01.
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Access the sheave bracket at the top of the inner mast
On Series 2100/2400 with internal cable routing, the sheave bracket is integrated into the mast head. Remove the pulley guard (one or two screws on most models).
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Remove the sheave axle
Some lifts use a clevis pin and cotter; others a shoulder bolt with locknut. Note the order of any spacers or washers as you remove them.
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Inspect the bracket
Look at the bracket bore. If it's worn oval (cable side-loaded the sheave), the bracket itself needs replacement, not just the sheave.
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Install the new sheave
Spin the new sheave by hand before installing — verify smooth rotation and no measurable play. Reassemble in reverse order, including any spacers.
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Reinstall pulley guard, then cable
Confirm the guard fully captures the cable in the sheave groove — a cable that jumps the sheave under load can sever instantly.
safety-critical
Replace mast slide pads.
Symptom: the inner mast wobbles side to side at full extension, or the carriage chatters as you crank up. Both point at worn nylon slide pads between the mast sections.
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Fully retract the mast
Crank the carriage all the way down. Remove the cable per Procedure 01 steps 1–4 to take tension off the inner mast.
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Remove the carriage
Disconnect the cable terminal at the carriage. Lift the carriage off the inner mast.
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Slide the inner mast out — and immediately secure it
Pull the inner mast straight up out of the outer mast. Be ready for the inner mast's weight — get a second tech for the longer-mast lifts (25 ft variants top ~80 lb and are awkwardly balanced once free). The instant the inner is clear, strap it to a bench or stanchion, or block it against a wall — a free inner mast that drops back into the outer can crush a hand at the joint.
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Replace the pads
Pads are typically held by Phillips screws or pop in/out of slots. Remove old pads, clean the seat, and press new pads in. Verify thickness matches your model — the pads are not interchangeable between series.
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Prep the mast surfaces & reassemble
Before re-nesting, lightly mist the new pads and the mating mast surfaces with dry silicone spray (per the Maintenance lubrication spec) — do NOT use grease or WD-40, which will collect grit. Slide the inner mast back into the outer mast. Reinstall carriage, route cable, terminate, and test as in Procedure 01.
Mast slide pad set
Replace carriage rollers.
A flat-spotted or seized carriage roller chatters as the carriage moves and accelerates cable wear at the carriage attachment. Always replace as a set of four.
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Remove carriage from mast
Per Procedure 04 steps 1–3.
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Remove rollers
Each roller is held by a shoulder bolt + locknut, or a clevis pin + cotter, depending on production year. Note the order of any thrust washers.
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Inspect carriage frame
While the rollers are off, inspect the roller seats. Egged or peened seats indicate a previous roller failure under load — replace the carriage if the seat is no longer round.
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Install the new rollers
Spin each new roller by hand before installing. Torque mounting hardware to spec — 3/8-16 Grade 5 shoulder bolt = 30 ft-lb dry (see Tools & Torque). Use a drop of medium (blue) thread-locker; don't overtighten or you'll bind the roller against the frame.
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Reinstall the carriage
Slide the carriage onto the inner mast. Verify smooth travel by hand, with no rocking. Reattach cable and test.
Carriage roller set (×4)
Replace the winch assembly.
When Procedure 02 has not restored brake or pawl function — or the worm gear inside the winch is damaged — Sumner's sealed current-production MX winch is intended to be replaced as a complete assembly rather than rebuilt. This procedure swaps the winch as a unit. Older GH-5T winches may be field-rebuildable using the OEM rebuild kit.
Parts & Tools
- MX winch (current)PN 783590 — complete assembly
- GH-5T winch (legacy)PN 785912 — complete assembly
- HardwareReplacement Grade 5 mounting bolts (verify OEM PN)
- TerminationNew anchor clip + thimble sized to cable
- ToolsTorque wrench, 7/16 in socket, wire-rope cutter
- Time~35 min
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Remove the cable
Follow Procedure 01 steps 1–4 to disconnect the cable from both ends. Coil and label as “reuse” or “scrap.”
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Disconnect the crank handle
Pull the spring pin and slide the handle off the input shaft. Stow it; you'll re-fit it on the new winch.
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Mark and remove the mounting bolts
Snap a photo of the winch's orientation before you remove anything. The MX mounts with four bolts through the winch flange into the mast weldment — identify the actual fastener size on your unit before selecting a socket (commonly 5/16-18 or 3/8-16 Grade 8 on current production; older units may use 1/4-20). Loosen all four before fully removing any one.
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Lift the old winch off the mount
Support the winch with one hand as the last bolt comes free — it weighs ~6 lb. Set aside.
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Inspect the mounting bracket & mast weldment
Check the bracket bore for elongated holes (sign of a previous overload event). Clean any corrosion off the mating surface. Also inspect the mast web where the mount attaches for hairline cracks radiating from the bolt holes — a hidden crack there is often the real cause of a “bad winch” complaint. The new winch must seat flat or it will load the mounting bolts in shear.
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Install the new winch
Hand-thread all four bolts before tightening any. Cross-pattern torque to the spec for the actual fastener size and grade — see the Tools & Torque chart (e.g., 5/16-18 Grade 8 dry = 24 ft-lb; 3/8-16 Grade 8 dry = 45 ft-lb). Do NOT torque a 5/16 or 3/8 mount to a 1/4-20 value — you'll leave the winch loose.
safety-critical -
Re-fit the crank handle, then the cable
Re-install the handle and verify smooth rotation through the full range with no load. Then route a new cable per Procedure 01 from step 5 onward.
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Test under progressive load
10% → 50% → 100% of rated capacity, with a 60-second hold at each step to verify no brake drift. At 100%, run the carriage to full extension and hold for 5 minutes — confirm no measurable drift. Re-torque the cable anchor clip after the 100% cycle.
Service the outrigger latch.
A loose or non-engaging outrigger latch is one of the highest-risk failures on the lift — the leg can swing free under load and the lift becomes top-heavy. The latch and spring kit is inexpensive; replace at any sign of weakness.
Parts & Tools
- PartOutrigger latch + spring kit (verify OEM PN with B&B SUMNER for your serial range)
- Part (opt.)Rubber outrigger foot pad
- ToolsSnap-ring pliers, white lithium grease, safety glasses
- Time~20 min per leg
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Deploy the leg fully and block it
Fold the outrigger leg out to its locked position. Place a wood block under the leg so it can't swing as you remove the latch hardware.
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Disengage the existing latch
Safety glasses on. Compress the spring with your thumb (gloved) and slide the latch cam out of engagement. Contain the spring in a rag or a magnetic parts tray as you release it — it will launch. If you lose it, you'll be back-ordering an OEM kit before the outrigger goes back into service.
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Remove the latch retaining clip
Use snap-ring pliers to remove the e-clip or c-clip securing the latch pin. Slide the pin out, capturing any thrust washers.
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Inspect the cam pocket on the leg
Look at the cam-engagement pocket on the leg itself. Egged or peened pockets indicate the leg has been operated with a worn latch — a fresh latch in a worn pocket won't hold for long.
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Install the new latch
Reverse the disassembly. Lubricate the pin and cam contact face with white lithium grease before assembly. Capture the spring under the cam before installing the retaining clip.
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Verify positive engagement
Stow and re-deploy the leg ten times. Each cycle should produce an audible snap as the latch cams home, and the leg should require deliberate force on the release lever to disengage.
safety-critical
Replace the reversible-fork pivot pin.
A worn pivot pin lets the fork shift under load, increasing tipping moment and accelerating wear at the carriage. The pin is among the cheapest parts on the lift and also among the most overlooked.
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Lower carriage and remove load
Forks empty, carriage all the way down.
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Remove the R-clip
Pull the R-clip from the end of the pin. Capture in a magnetic tray — these get lost on jobsites.
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Drive out the pin
Using a brass drift to protect the pin, tap the pin out from the side opposite the R-clip. Note the order of any thrust washers as you pull the fork off.
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Inspect the carriage bore
The bore in the carriage that the pin rides in is what wears second — if it's egged, you need a carriage, not just a pin.
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Install the new pin
Slide the new pivot pin through the carriage and fork. Reinstall any thrust washers in the same order. Install a new R-clip; do not reuse the old one.
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Verify fork articulation
Reverse the fork through its full travel. The motion should be tight without binding. A fork that swings under its own weight has an undersized pin or overworn carriage bore.
Service the tilt-head detent pin.
The 2300's tilt-head is called out as a top service item on every 2300 sold. When the detent won't lock the cradle at a discrete angle — flops between 0° and 65°, or the drywall sheet won't stay flat — the root cause is almost always the spring behind the pin fatiguing and losing preload. Replace all three — pin, spring, and E-clip — at once. The spring is the cheap one.
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Empty the cradle and level the head
No sheets, no ceiling grid, nothing on the head. Tilt to horizontal (0°). Set the parking brake and lower the mast to fully retracted.
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Locate the detent assembly
On the back of the tilt-head casting, the detent pin sits in a 3/16″ bore below the pivot boss, held by a small E-clip.
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Trap the spring, remove the E-clip
Cup one hand over the pin head. Pry the E-clip off with a small flat screwdriver. Never remove the clip without covering the assembly — the ball and spring will fly.
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Extract the old parts
Slide the pin out. Catch the spring and the pilot ball. Inspect the pin: flats worn asymmetric = replace. Inspect the bushing bore for ovalization — if the bore has worn from round to oval, the whole head casting needs replacement (rare).
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Clean and lubricate
Wipe penetrating oil into the bore, then a thin film of white lithium grease. Do NOT use anti-seize — it attracts drywall dust and turns to a paste that binds the pin.
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Install: ball, spring, pin, clip
Ball first, spring next, pin last. Compress with your thumb while you seat the new E-clip into its groove. Clip must snap flush against the pin shoulder; if it stands proud, it's not seated.
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Function-check through the range
Tilt from 0° to 65° and back, twice. Verify a positive detent click at 0°, 15°, 30°, 45°, and 65°. The cradle must not free-fall past a detent when released.
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Load-check with a scrap sheet
Load a scrap 4×8, tilt to 30°, release. The cradle must hold. If it drifts, the spring is under-preloaded — recheck the clip seating.
Replace a mast section.
When the troubleshooter lands on "bent or damaged mast section," this is the walk-through. Mast sections are NOT field-repairable and must NOT be straightened, welded, or heated — the aluminum extrusion loses temper and the safety margin evaporates. Order the model-specific replacement and swap it as an assembly.
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Full LOTO
Winch fully released (see P01, step 1), cable disconnected from the carriage anchor, unit tagged out. Remove any load from the carriage.
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Support the mast in the retracted position
Retract fully stowed. Place a shop stand under each side of the top of the mast. Strap the mast to an overhead beam if available. Verify the mast cannot fall in either direction before the next step.
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Remove the carriage
Slide the carriage down to the base. Remove the carriage-to-cable anchor pin. Remove the four carriage-roller bolts. Set the carriage aside.
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Remove the top sheave & pulley guard
Two bolts hold the guard; four bolts hold the sheave bracket. Set aside — these transfer to the new inner mast.
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Extract the inner mast
Lift straight up out of the middle section. Weight is 40 lb (Series 2100) to 80 lb (Roust-A-Bout). Use a second technician or a hoist. Do NOT tip the section as you extract — the slide pads will scrape.
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For middle-mast replacement, repeat step 5
Lift the middle section out of the outer. For outer-mast replacement, additionally unbolt the base weldment (typically 4 × 3/8-16 Grade 8, 30 ft-lb dry).
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Transfer slide pads
Move the yellow pads from the old section to the new. Pads are matched pairs — do not mix new and worn pads on the same section. Replace any pad that has visible thinning or metal-to-mast contact.
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Install the new section
Reverse of steps 3–6. Torque all fasteners to spec (see the tools & torque reference).
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Verify plumb
Place a level on each face of the mast at three heights (base, mid, top of outer). All three readings must agree within 0.25° of vertical. If they don't, the base weldment is bent — that's a separate repair.
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Reconnect cable and load-test
Follow the consolidated load-test procedure (P11): 10% → 50% → 100% for 5 minutes at full extension, then a 125% proof load for the first extension after a structural repair.
Load test after any structural repair.
Run this after any cable, winch, brake, sheave, mast, carriage, or base-weldment repair. After any weld or crack repair on the base. After a lift that has been dropped, tipped, or exposed to a shock load. As part of the annual periodic inspection. The customer's asset-management group typically requires the test-record log as documentation of return-to-service.
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Pre-test inspection
Cable seated in all sheaves. Winch handle turns freely; ratchet engages positively. Outriggers deployed and latched. Casters locked. Test area clear — the exclusion zone is a 45° cone from the load extending to the floor.
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10% test load
Load 10% of the model's rated capacity (65 lb for a 2100/2124 rated at 650). Extend to full mast height. Verify no cable slap, no mast bind, no drift when the winch is released.
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50% test load
Add weight to 50% of rating. Extend to full mast height. Hold 1 minute. Note any drift at the carriage — should be zero.
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100% test load — 5-minute hold
Add weight to 100% of rating. Extend to full mast height. Hold 5 minutes with a dial indicator or graduated tape at the carriage. Pass = drift under 1/8″. Fail = drift over 1/8″ = brake or winch service required before return to service.
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Proof load (post-weld or post-crack-repair only)
Add weight to 125% of rating. Extend to 50% of full mast height (not full — reduces the consequence if the repair fails). Hold 5 minutes. Pass = no drift, no visible deflection at any weld. Fail = the repair is not sound; do not return to service.
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Retract under load
Lower from full extension to fully stowed under 100% rating. Verify smooth descent, no cable jump on the sheave, positive ratchet click at each pawl engagement.
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Log and sign
Fill the return-to-service log: date, tech name, unit serial, cable PN, brake condition, sheave condition, drift measurement at 100%, drift measurement at 125% (if applicable), pass/fail. File one copy in the customer's records and one in the shop's warranty binder.
Repair index.
| # | Procedure | Symptom | Time | Skill | Safety-Critical? |
|---|---|---|---|---|---|
| 01 | Replace lift cable | Frayed / kinked / broken-strand cable | 45 min | Intermediate | Yes |
| 02 | Winch ratchet & brake service | Slips under load / drifts when released | 30 min | Intermediate | Yes |
| 03 | Replace cable sheave | Grooved sheave / cable wear at top | 20 min | Basic | Yes |
| 04 | Replace mast slide pads | Mast wobbles at full extension | 40 min | Intermediate | No |
| 05 | Replace carriage rollers | Carriage chatters during raise/lower | 25 min | Basic | No |
| 06 | Replace winch assembly | Brake won't hold after pawl service | 35 min | Intermediate | Yes |
| 07 | Service outrigger latch | Outrigger leg loose or won't latch | 20 min | Basic | Yes |
| 08 | Replace fork pivot pin | Fork shifts under load | 15 min | Basic | No |
| 09 | Tilt-head detent pin (2300) | Cradle won't lock at angle | 20 min | Basic | No |
| 10 | Replace mast section | Bent / dented / bowed mast | 90–180 min | Advanced | Yes |
| 11 | Load test (return to service) | Post-repair verification | 45 min | Basic | Yes |