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Shield Gate Repair

Swing gate operator

FAAC 400 Hydraulic Operator Repair in Dallas–Fort Worth

Shield Gate Repair works on the FAAC 400 hydraulic ram — CBC, CBAC, SB and the long-stroke EG versions. The call we get on this operator is a leaf that has turned slow or stops short, and on a 400 that is usually the bypass valves, the release knob or the oil before it is ever the motor.

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Is this a FAAC 400?

The 400 is a long cylindrical hydraulic ram pinned between a bracket on your post and a bracket on the gate leaf, with a slotted protective cover over the piston rod. It is the largest of FAAC's surface-mounted swing rams: FAAC's manual gives an overall length of 40½ inches for the standard body and 50½ inches for the EG long-stroke body.

The letters after the number matter more than the number. FAAC's manual covers the 400 CBC, CBAC, SB, SBS, CBACR, CBAC EG and SB EG. Per its specification table, the CBC locks hydraulically in closing, the CBAC, CBACR and CBAC EG lock in both opening and closing, and the SB, SBS and SB EG have no hydraulic lock at all and depend on an electric lock to hold the leaf. Knowing which one is on your gate tells us whether a leaf you can push by hand is a fault or simply an SB doing what it was built to do.

The common mix-up is with FAAC's compact 402 and 422 rams. Those are roughly three feet long and slimmer. On the 400 the release is inside a keyed cover with a knob beneath it, rather than a triangular key turned on the underside as on the 402.

  • A long round ram — about 40½ in overall (standard) or 50½ in (EG) — pinned between post and leaf
  • The version letters after "400" on the operator label: CBC, CBAC, SB, SBS, CBACR or EG
  • A keyed cap and cover; beneath it a release knob and two force screws with green OPEN and red CLOSE wording
  • A vent (breather) screw with its own label on the body
  • A separate control enclosure — FAAC pairs the 400 with the 455 D board, which has a two-digit display and F, + and – buttons

Also labelled: 400 CBC, 400 CBAC, 400 SB, 400 SBS, 400 CBACR, 400 CBAC EG, 400 SB EG

400 at a glance

Drive
Electric pump and hydraulic piston
Versions (FAAC manual)
400 CBC, CBAC, SB, SBS, CBACR, CBAC EG, SB EG
Hydraulic locking
CBC: closing · CBAC, CBACR, CBAC EG: opening and closing · SB, SBS, SB EG: none (electric lock required)
Effective rod stroke
10¼ in (standard) · 15 in (EG)
Overall length
40½ in (standard) · 50½ in (EG)
Power supply
115 VAC ±10% or 230 VAC +6% −10%, 50/60 Hz
Electric motor
1400 rpm, 4-pole
Winding thermal protection
248°F
Ambient operating temperature
−4°F to +131°F
Protection class
IP55
Oil
FAAC HP OIL
Opening time, 400 CBAC
17 seconds (FAAC troubleshooting table)
Control board (FAAC manual)
455 D — force programmed to 50 for hydraulic operators
Position sensing
Gatecoder only; limit switches cannot be used on the 400
UL 325 classes (FAAC 2003 class table)
Class I, II and III

From FAAC’s published documentation. Your unit’s label and manual take precedence.

What your 400 is doing, and what usually causes it

  • The gate got slower over the months and now stops before it is fully open

    Usually: Oil level down through seal wear or a breather leak; bypass screws backed off or set for the wrong opening direction; learned run time now shorter than the leaf needs; board force below 50.

    What we do: We check the oil with the ram vertical and rear flange up, confirm force is at 50, then raise bypass pressure in small quarter-turn steps as FAAC's troubleshooting table advises. Once the leaf reaches its stop with force to spare, we re-learn the times.

  • The motor hums or runs but the leaf does not move

    Usually: Release knob not fully turned back clockwise; motor turning the wrong way after rewiring; bypass set far too low; a failed thrust capacitor.

    What we do: We re-seat the release knob, check motor direction on the 455 D terminals, test the capacitor and only then look at valve settings.

  • It jerks or shudders instead of moving smoothly

    Usually: Vent screw never removed at installation — FAAC warns this causes erratic operation; air trapped in the piston; binding hinges; a gate leaf that flexes under the ram.

    What we do: We check the vent screw, run complete cycles to purge air as FAAC recommends, and test the hinges with the ram released. If the leaf itself flexes, we tell you — FAAC’s answer is to stiffen the gate or use a slower operator.

  • There is oil on the ram or dripping near the breather screw

    Usually: FAAC says a small initial leak at the breather is normal, and that a larger one can occur if the ram is not mounted perfectly horizontal. A leak that continues or grows points to seals.

    What we do: We check the ram is level on its brackets, clean it and look for the true source. A persistent leak gets the 400 seal kit and fresh FAAC HP OIL.

  • The leaf slows down near the end and then just stops there

    Usually: FAAC's table lists anti-crushing (bypass) adjustment as the cause when leaves stop at slowdown.

    What we do: We raise bypass force carefully in the direction that stalls, confirm the leaf still stops on a firm obstruction, and re-learn slowdown points.

  • The speed changes through the swing — fast at one end, crawling at the other

    Usually: FAAC attributes inconsistent speed to incorrect installation dimensions. A moved post or re-welded bracket changes the a and b dimensions.

    What we do: We measure the bracket geometry against FAAC's standard or EG table and correct the mount rather than adjusting pressure to mask it.

  • When the gate is closed I can push it open by hand

    Usually: An SB, SBS or SB EG version with a failed electric lock; a CBC that only locks in closing being pushed the other way; release knob partly open.

    What we do: We identify the version first. On a no-lock version we repair the electric lock; on a locking version we check the release and the lock valve.

400 down? Tell us what it is doing — we will tell you what it needs.

(214) 735-4314

How the 400 works — and what that means for repair

An electric pump and a piston — no gears, no clutch plate

FAAC describes the 400 as an electric pump and a hydraulic piston that transmits drive to the gate leaf. A 1400 rpm motor turns a pump inside the oil tank, and oil pressure pushes the rod out or draws it back. There is no gearbox to strip and no chain to stretch, which is why a 400 that has lost force so rarely needs a motor.

Force is not set on the board the way it is on a screw-drive operator. The 400 has two bypass screws: the OPEN screw (green wording) limits thrust while opening and the CLOSE screw (red wording) limits thrust while closing. Clockwise raises force, counter-clockwise lowers it. On a gate that opens outward with the ram mounted inside, FAAC swaps the roles — the OPEN screw governs closing and the CLOSE screw governs opening — and that single detail explains a lot of 400s that were "adjusted" in the wrong direction.

The 455 D has to be told it is driving hydraulics

On FAAC's 455 D board, force is adjustable over 50 levels for each motor. FAAC's instruction for hydraulic operators such as the 400 is to program force at the maximum of 50, so the board delivers full power and the bypass valves do the limiting. If that value has been turned down, a healthy ram will feel weak and no amount of valve adjustment will fix it.

FAAC's manual is also explicit that the 400 cannot use limit switches — only Gatecoders, which read the leaf's angle to set slowdown and stop points. Without a Gatecoder the board runs on learned times. That means a change in oil level or valve setting can change where the leaf stops, because the learned time runs out before the leaf reaches its stop.

Hydraulic locking, the release knob and why an SB feels loose

Versions with hydraulic locking hold the leaf when the motor stops, so FAAC says they need no electric lock. Versions without it require an electric lock to keep the leaf mechanically locked. On an SB whose lock has failed, the leaf drifts in wind — a lock repair, not a ram repair.

The release is part of the same valve circuit. Turning the release knob counter-clockwise about two full turns lets the leaf move by hand; turning it clockwise until it stops re-locks the hydraulics. FAAC lists a release that has not fully re-engaged as a cause of a motor that runs while the gate does not move.

Standard and EG bodies are not interchangeable

Effective rod stroke is 10¼ inches on the standard 400 and 15 inches on the EG models, and FAAC publishes separate mounting-dimension tables for each. The geometry is sensitive: FAAC notes that smaller a and b dimensions give a faster leaf, and that letting a and b differ by more than about 1½ inches considerably varies speed through the swing.

FAAC also requires the rod to stop short of its internal end, so the effective stroke is less than the maximum stroke, and it requires mechanical travel stops at the gate. A 400 that is mounted off its dimensions, or on a post that has moved, shows up as uneven speed long before anything inside it fails.

400 parts we repair, adjust or replace

A failed part is not a failed operator. These are the components that actually wear or fail on the 400, and what we do about each.

  • Bypass valves (OPEN green / CLOSE red)

    Adjusted

    Set the maximum thrust in each direction and act as the anti-crushing limit.

    Signs it has failed: Leaf too weak to finish travel, or too forceful to stop on an obstruction.

  • Release knob and keyed locking cap

    Part replaced

    Opens the oil path so the leaf moves by hand; the keyed cover protects the release and bypass screws.

    Signs it has failed: Motor runs but leaf will not move; key or knob seized; cover will not lock.

  • Oil and tank

    Serviced

    The tank holds the FAAC HP OIL the pump draws from; level is checked with the ram vertical.

    Signs it has failed: Weak or slowing travel, air noise, drift in speed between cold and hot runs.

  • Piston seals (400 seal kit)

    Repaired

    Keep pressure inside the cylinder and oil off the rod.

    Signs it has failed: Oil trail down the rod or cover, falling level, progressive loss of force.

  • Vent (breather) screw

    Adjusted

    Lets the tank breathe; FAAC requires it removed after installation.

    Signs it has failed: Erratic, jerky movement if left in; oil at the vent if the ram is not level.

  • Thrust capacitor

    Part replaced

    Starts and runs the single-phase motor — 25 µF on 115 V or 8 µF on 230 V per FAAC.

    Signs it has failed: Motor hums without turning, or starts only when the leaf is nudged.

  • 455 D control board

    Part replaced

    Logic, run times, Gatecoder inputs, safety inputs and force output (set to 50 for hydraulics).

    Signs it has failed: Dead display, blown F1 or F2 fuse, STOP or FSW LEDs out with no device tripped.

  • Gatecoder (where fitted)

    Part replaced

    Reports leaf angle so the board can slow and stop accurately and sense obstacles.

    Signs it has failed: FCA/FCC LEDs not flashing while the leaf moves; stops in the wrong place.

Repair or replace your 400? The honest answer

A 400 is built to be serviced. Oil, seals, the release assembly, bypass valves, capacitor and board are all separate parts in FAAC’s parts lists. Replacing the whole ram is justified when the cylinder or rod is physically damaged, or when the version on the gate was never right for the leaf.

Repair it when

  • Loss of force with an intact rod — oil, seals and bypass adjustment first.
  • Motor runs but the leaf will not move — release knob, capacitor and valve settings are all serviceable.
  • Uneven speed — correct the mounting dimensions; the ram itself is usually fine.
  • Board fault after a storm — the 455 D is replaced separately from the ram.

Replace or upgrade when

  • Scored or bent piston rod, cracked tank or damaged cylinder.
  • Wrong version for the gate — for example a no-lock SB on a leaf that needs to hold position without an electric lock, or a standard body where the geometry calls for the 15-inch EG stroke.
  • A second ram on a double gate fails of age and the pair are mismatched; keeping both leaves on the same version keeps timing predictable.
Call Now — (214) 735-4314Request a Free Estimate for FAAC 400 repair

Case studies

FAAC repairs we have documented

Other FAAC operators, written up in full — the same diagnose-first approach we take on a 400.

All case studies

Our FAAC work

Photographs from our own FAAC jobs — a mix of models, not all of them the 400. None of it is stock.

  • A FAAC sliding gate operator mounted at the base of a dark aluminium slide gate, with the drive rack visible along the gate frame
  • Close view of a FAAC operator housing opened for service, showing the hydraulic pump and control board inside
  • A FAAC swing gate operator arm connected to a metal driveway gate post
  • A dark metal estate driveway gate closed between stone pillars, fitted with a concealed gate operator

How we diagnose and repair a 400

  1. Identify the exact 400 version

    CBC, CBAC, SB, SBS, CBACR or EG decides whether the leaf should lock hydraulically, which mounting table applies and what "normal" looks like.

  2. Release the ram and swing the leaf by hand

    Knob counter-clockwise about two turns, then we check hinges, stops and free movement before any electrical testing. A binding gate makes a healthy ram look weak.

  3. Check oil, vent screw and seals

    Ram vertical, rear flange up, level checked as FAAC specifies. We look for the source of any oil before topping up.

  4. Read the 455 D

    Force at 50, STOP and both FSW LEDs lit at rest, OP_A lighting on command. A short across the open terminals separates a remote or keypad fault from an operator fault.

  5. Set bypass force and re-learn

    OPEN and CLOSE screws set for the actual swing direction, leaf tested against an obstruction, then run times or Gatecoder learning repeated. You get the diagnosis and a quote before parts are fitted.

FAAC warranty on the 400

FAAC International's 400 installation manual states a limited warranty of 24 months from the date of invoice on FAAC gate operator systems it distributes. The same statement says the warranty extends only to wholesale customers buying through FAAC International's distribution channels and that FAAC International does not warrant its products to end consumers — owners are told to ask their selling dealer about that dealer's own warranty.

  • Hydraulic oil is named in the warranty as a maintenance part that is not covered.
  • Damage from lightning, electrical power surge, hail, flood, wind storm and improper installation is excluded.
  • Warranty terms change over time; the manual that shipped with your unit and your installer’s invoice are what apply to your gate.

Our warranty on the repair

Every repair is backed by a clear written warranty. No hidden terms and no confusing fine print: what is covered is explained before we begin, and it is separate from whatever FAAC covers on the operator itself.

What our warranty covers

The 400 in Dallas–Fort Worth conditions

Summer heat and a 248°F winding cut-out

FAAC rates the 400 for ambient temperatures up to 131°F and protects the motor winding with a thermal cut-out at 248°F. On a busy estate or community entrance, a ram sitting in afternoon sun and cycling back to back can reach its thermal limit and pause — which looks like a dead operator and recovers once it cools.

Heat also thins the oil. A 400 that is borderline on level or bypass setting often runs normally in the morning and falls short of its stop by late afternoon. That pattern points us at oil and valves, not at the board.

Clay soil moves posts, and the 400 is geometry-sensitive

North Texas clay swells when wet and shrinks in drought, and a post that leans even slightly changes the 400's a and b dimensions. FAAC's own troubleshooting ties inconsistent speed to incorrect installation dimensions, and it requires travel stops at the gate — a moved post also moves where the leaf meets its stop.

Lightning and the 455 D

FAAC's 400 manual tells installers to ground the operator, use a grounding rod if necessary and add a surge suppressor, because power surges and lightning damage the electronics. FAAC's warranty excludes surge and lightning damage, so after a spring storm the board is often the part at fault and the ram is untouched.

FAAC 400 repair across DFW & Surrounding Areas

Customer testimonials

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Real Shield Gate Repair customers describing the job in their own words, FAAC jobs first.

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FAAC 400 repair questions

How do I release a FAAC 400 to move the gate by hand?

Per FAAC's manual: lift the protective plug, insert the key and turn it 90° clockwise to open the cover, then turn the release knob counter-clockwise about two full turns. To restore operation, cut power first, turn the knob clockwise until it stops, close the cover and turn the key back 90°.

Why does the board need to be set to force 50 on a 400?

FAAC's instruction for hydraulic operators on the 455 D is to program force at the maximum of 50. The bypass valves on the ram limit thrust; a reduced board setting just starves a healthy ram of power.

What oil goes in a FAAC 400?

The 400 manual specifies FAAC HP OIL and lists it in the 400 parts list. We do not top up with an unknown fluid, because mixed oils make the next diagnosis harder.

Is a little oil around the breather screw a problem?

FAAC says a small initial leak at the breather is normal and that a larger leak can come from a ram that is not perfectly horizontal. If it keeps going or gets worse, it needs looking at — usually seals.

My 400 is an SB. Why can the gate be pushed when it is shut?

SB versions have no hydraulic lock; FAAC requires an electric lock to hold the leaf. If that lock has failed or lost power, the leaf will move. The repair is the lock, not the ram.

Do you carry parts for the FAAC 400?

We carry seal kits, hydraulic fluid and the common control boards. Less common 400 parts, such as a release assembly or a Gatecoder, are ordered — and we tell you that upfront before booking the repair.

Request a free estimate for your 400

Leave your name and number, and tell us what the gate is doing. A technician will call you back. If the gate is stuck open or shut, calling is faster — someone always answers.

We'll call you back on this number — we don't sell your details to anyone.

Or call (214) 735-4314 — someone always answers.

Gate Not Working Right Now?

We answer the phone 24/7. If you are stuck, call and we will talk you through the manual release before anyone arrives. See what counts as a gate emergency.

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