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Adjusting hydraulic rooms

The cylinder moves a hydraulic room, but stops, nuts, brackets and sync hardware decide where it ends up. Get height and sync right, then set the in and out stops, then check the seal.

The short version

Work from the bottom up

A room that's racked or sitting low will never seal right no matter how you set the stops, so look at height and side alignment before you touch the stops. Make small changes and run the room after each one, the way Lippert's procedures are written.

Lippert says all slide-out room adjustments are to be done by certified service technicians. Retighten every jam nut and bolt you loosen before the room travels.

In and out stops (Lippert through-frame hydraulic)

The cylinder's threaded shaft mounts to the drive bracket with three nuts, and they are the stops. For the in seal, hold jam nut A with a wrench and turn the nylock nut C toward the bracket if the room doesn't seal, or away from it if the room is too tight and damaging the fascia. Run the room in after each small change.

For the out position, extend fully and check the fascia and seals, retract a little, back jam nut A off nut B, then turn B away from the bracket if the room goes out too far and damages the inside fascia, or toward it if the room doesn't seal. Retighten A. Lippert calls 2 to 3 in of free travel normal.

Height and side to side (Lippert)

For horizontal position, loosen the carriage bolts on each bracket at the end of the guide tubes and move the room by pushing on the sidewall or with a pry bar, taking care not to tear the seals. For height, loosen the carriage bolts and the jam nut, turn the vertical adjustment bolt, then retighten the bolts and jam nut.

Synchronizing the two sides

Lippert: extend the room about halfway and measure from the T-molding on the room to the outside wall on the active (cylinder) side, then the passive side the same way. Loosen the bolts on top of the passive tube's synchronizing bracket, push or pull the passive side to match, retighten, then retract and run it.

Equalizer shaft-timed rooms are timed at the center timing coupler, with gears riding racks on the inner rails. A gear that skips or binds points to bearing preload that's too loose or too tight. When you reseat a gear, pull the shaft down gently; Equalizer warns that pulling too hard binds the gear in the rack.

HWH four-cylinder rooms sync hydraulically. The valves in the sync cylinder's pistons open about 1 in before the room is fully out or in, so a room that's out of step catches up when you hold the switch at the end of travel. If the sync cylinder's stroke is too short the valves open too soon; too long and they never open. HWH sync cylinders aren't serviceable in the field.

Cylinder stroke and mounting (Equalizer)

The cylinder's stroke has to match the room's travel. Set the rod-end jam nuts so the rod is straight at full extension, then set the rear of the cylinder so it's fully extended when the room is fully out and fully retracted when the room is fully in. A bowed rod at full extension means the stroke doesn't match; damaged flanges mean the room over-retracted after a stroke change.

Room height: B must be equal to or greater than A, typically B equals A plus 1/8 in, minus 0. If the inner rail lifts as the room closes, B is less than A. A rod that rubs the timing shaft bends the shaft and breaks gears, and a rod that hits a hard surface ends up leaking, so fix the mounting or fit Equalizer's rod guard on center-drive flat-floor rooms.

When the room needs re-squaring

Re-square when the side measurements at half travel don't match, the seal compresses on one side only, or the room leads and then binds. Find the cause first: loose sync bracket bolts, a slipped timing coupler, a bent tube or shaft, or a replacement cylinder with the wrong stroke. HWH warns that two cylinders that look the same may not have the same stroke.

Squaring a room around a bent part only lasts until the next trip. Once the cause is fixed and the sides match, reset the in and out stops, run the room full out and full in, and check the seals all the way around.

On the job

  1. Run the room out and in and watch both sides; note where it leads, binds or gaps.
  2. Check height and side-to-side position before anything else.
  3. At half travel, measure both sides and sync per that system.
  4. Set the in stop for seal, then the out stop, in small steps.
  5. Confirm cylinder stroke matches room travel: rod straight, nothing bottoming.
  6. Retighten every jam nut and bolt you loosened.
  7. Cycle full out and in and inspect the seals all the way around.

Numbers

Shop tip

Write your side measurements on the room frame with a paint pen before you loosen anything. If the adjustment goes wrong, you can get back to where you started.

Where this comes from