Rebuild Service for Full Set of 12 Convertible Hydraulic Cylinders - send in your cylinders first UB92044 UB92045 UB92029 UB9202
  • Rebuild Service for Full Set of 12 Convertible Hydraulic Cylinders - send in your cylinders first UB92044 UB92045 UB92029 UB9202
  • UB92045 UB92044 UT13581PA UT13582PA UB92029 UB92028 UB92048 UB92047 UB90262 UV20837PA UD75668

Rebuild Service for Full Set of 12 Convertible Hydraulic Cylinders - send in your cylinders first


Rebuild service for the full set of twelve actuators. Please send locking cylinders mounted inside their latches - this minimizes risk of mechanical damage to the shafts.

Includes pairs of Front Lock Cylinders, Tonneau Cover Lock Cylinders, Tonneau Cover Lift Cylinders, Bow Extension Cylinders, Rear Lock Cylinders, and Main Lift Cylinders.

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No sales tax for orders in the USA


We provide world class technical support


3-year standard warranty (should last decades)

Bentley Azure Top hydraulic cylinder rebuild and upgrade



Rebuild service to "better than new" condition with 3-year warranty on parts only (assuming parts arrive without blemishes on the polished shafts). Using the best seals available, far surpassing OEM quality. All cylinders should be rebuilt in pairs, and preferentially as complete sets.


Includes the following Bentley/Rolls-Royce part numbers:

Locks with cylinders:
UB 92044   aka UB92044:  RH front lock "Front Header Latch"
UB 92045   aka UB92045:  LH front lock "Front Header Latch"
UB 92029   aka UB92029:  LH tonneau cover lock  "Hood Cover Latch"
UB 92028   aka UB92028:  RH tonneau cover lock  "Hood Cover Latch"
UT 13582PA aka UT13582PA: RH rear lock  "Rear Bow Latch"
UT 13581PA  aka UT13581PA: LH rear lock  "Rear Bow Latch"

UV 20837PA  aka UV20837PA:  main lift cylinder (2x)  "Main Lifting Ram"
UB 92048 aka UB92048:   LH bow extension  "Bow Cylinder LH" (has switch attached)
UB 92047  aka UB92047:  RH bow extension "Bow Cylinder RH"
UB 90262  aka UB90262:  tonneau cover lift cylinder (2x)  "Power Piston - Tonneau Cover"


Top Hydraulics manufactures stainless steel replacement shafts for all cylinders listed above and can replace your shafts (at an additional charge), should they have become damaged during removal from the vehicle. The metal parts on these cylinders do not get damaged by regular use.

Bentley Azures use some Mercedes "R129" cylinders, with two of them modified. Rebuilding these cylinders is NOT a matter of changing o-rings. Every R129 cylinder has one o-ring, and those rarely ever fail. What fails most frequently, are the other seals, which have special shapes for proper function. Top Hydraulics replaces and upgrades ALL seals in the cylinders with superior material:

1) Rod seals. They are cup-shaped and seal the piston rod from the rest of the cylinder. When they fail, you will see fluid coming out next to the chromed shaft (rod). These are usually the first seals to fail in the cylinders.
2) Piston seals. They seal the input and output sections from each other, as the piston slides through the cylinder. The piston seals have been made of different materials and sizes even in the same p/n cylinders throughout the years. Failing piston seals will cause internal leaks, which result in a pressure drop in your hydraulic system. Early model years have the added problem that the piston seals swell up and make it very hard to move the piston inside the cylinder. Crumbling piston seals can block valves or pinholes inside the hydraulic system, and it can be difficult to diagnose a piston seal failure without testing several cylinders once you find that your top is moving slowly or not at all.
3) Cap seals. These are just o-rings that seal the top cap of the cylinder from the housing. They are usually the last seals to fail, but these o-rings are penny items.
4) Port seals. They seal the hydraulic lines where they are pushed into the cylinders. Port seal failure is becoming more and more common as the R129s age. It also applies to the front distributor p/n 1298000022. Port seals have a special shape that makes them seal under pressure. O-rings wouldn't do the trick. They are secured by precisely machined brass rings (accuracy about 1/100 mm). DIY removal of the brass rings will almost certainly destroy the brass rings. Top Hydraulics installs port seals that are tighter than the originals, just in case the hydraulic line fittings have been scratched.


Azure Full Set Rebuild

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