

It is highly recommended to upgrade the bow tension cylinders in pairs. You send in your cylinder(s) first.
No sales tax for orders in the USA
We provide world class technical support
3-year standard warranty (should last decades)
See removal instructions https://www.tophydraulics.com/e46bowcylinders.pdf in our DIY section. You remove your cylinders you would like to have rebuilt, and send them to us. Core exchange (from our stock) is available ONLY for full sets of BMW cylinders. See removal instructions in our DIY section.
NOTE: There was a change in cylinder design in 2002 or 2003, depending on country. Earlier model years have the detachable aluminum piece on the left side bow tension cylinder, which has the hydraulic lines permanently attached to it. This version is shown in the above picture. Newer model years have the hydraulic lines individually detachable from the left bow tension cylinder. In newer versions, lines 31 and 34 going to the valve block can be removed individually. Older and newer version bow tension cylinders (aka tension bar cylinders) are fully interchangeable as pairs, but not individually.
The right side cylinder always has the lines permanently attached, and the lines can be removed from the left side cylinder (clip on old version and T10 Torx bolt on new version).
P/N 54347025599
International shipping: One or two of these cylinders can be return shipped in an International Priority Mail or Express Mail Envelope (we box them up inside the envelope).
54347025599 |
Rebuild/Upgrade Service for Left Main Lift Cylinder for BMW E88 1-Series.
Send in your part(s) first, or select "Order now with core exchange" to order from our inventory. Core exchange orders are subject to a $50 inventory surcharge as well as a $120 refundable core deposit.
Replaced and improved rod seals, piston seals, cap seals, gland seals, wipers, and port seals make these parts better than brand new ones, with an expected service life of 30-50 years under normal circumstances.
P/N: 54347190665
You send us your pump to be rebuilt and upgraded. Includes replacement of electric motor if needed, overhaul of valves and internal parts of the pump assembly to exceed manufacturer's specs, a full bench test for flow, pressure, and thermal behavior. Ships filled with fluid for plug and play installation.
Expedited core exchange option is available and includes a $30 inventory surcharge + $150 core deposit.
BMW p/n 54348410305
840722402
HB70095-002
Top Hydraulics upgrades the seals in these cylinders with far superior material. It is highly recommended to upgrade the tonneau/case cover cylinders in pairs. You send in your cylinder(s) first, or order from our stock with the core exchange option below.
BMW P/N: 54348236956
This is a special Core exchange option only.
We ship you a pair of E46 Bow Tension Cylinders from our inventory, and you send us back your old parts for a refund of your $300 deposit.
NOTE: If you have a 2003 model, we will need to know if your left bow tension cylinder has a detachable (clip-on) aluminum line fitting before you place your order
Slightly extended version of the OEM hose, which is not available from BMW. Only available from Top Hydraulics. This line is for the newer version bow tension cylinder on the left side, top fitting, where the lines are attached via a screwed on clamp.
You send in your malfunctioning E63/E64 6-Series hydraulic pump unit, and Top Hydraulics rebuilds it. The rebuild includes electric motor replacement or rewinding if necessary, service of hydraulic and solenoid valves, service of moving parts and replacement as necessary, upgrade of internal seals in the pump to eliminate current or future pressure loss or internal bypass, and extensive testing to ensure the pump exceeds factory specs. Three years warranty.
p/n: 54347154648
Core exchange option is available (we ship the part first from our inventory) for $50 surcharge plus $250 deposit. Core exchange pumps ship filled with fluid, for plug-and-play installation.
Early model years (cut-off somewhere in 2003) have bow tension cylinders aka clamping bar cylinders with hydraulic lines that cannot be removed from the cylinder. Send in your left side cylinder, and Top Hydraulics will replace the line with OEM material.
Rebuild/Upgrade Service for the full set of BMW F23 2-Series.
Send in your cylinders first, or select "Order now with core exchange" to order a set from our inventory. Core exchange orders are subject to a $200 inventory surcharge as well as a $600 refundable core deposit.
Replaced and improved rod seals, piston seals, cap seals, gland seals, wipers, and port seals make these parts better than brand new ones, with an expected service life of 30-50 years under normal circumstances.
Rebuild/Upgrade Service for Left Soft Top Lid Cylinder for BMW E88 1-Series.
Send in your part(s) first, or select "Order now with core exchange" to order from our inventory. Core exchange orders are subject to a $50 inventory surcharge as well as a $120 refundable core deposit.
Replaced and improved rod seals, piston seals, cap seals, gland seals, wipers, and port seals make these parts better than brand new ones, with an expected service life of 30-50 years under normal circumstances.
P/N: 54347190669
This special core exchange option includes a $300 refundable core deposit, i. e., you pay $650 plus $300 deposit. These pumps have been rebuilt and upgraded. The electric motor has been replaced or rewound if necessary. Two new high-current relay have been installed, and all hydraulic valves and solenoids serviced. The internal seals in the pumps have been upgraded to eliminate current or future pressure loss or internal leak.
BMW 1-Series (E88 chassis) hydro unit/convertible top pump
Rebuild/Upgrade Service for Right Soft Top Lid Cylinder for BMW E88 1-Series.
Send in your part(s) first, or select "Order now with core exchange" to order from our inventory. Core exchange orders are subject to a $50 inventory surcharge as well as a $120 refundable core deposit.
Replaced and improved rod seals, piston seals, cap seals, gland seals, wipers, and port seals make these parts better than brand new ones, with an expected service life of 30-50 years under normal circumstances.
P/N: 54347190669
You send in your malfunctioning BMW F12 6-Series hydraulic pump unit, and Top Hydraulics rebuilds it. The rebuild includes electric motor replacement or rewinding if necessary, service of hydraulic and solenoid valves, service of moving parts and replacement as necessary, upgrade of internal seals in the pump to eliminate current or future pressure loss or internal bypass, and extensive testing to ensure the pump exceeds factory specs. Three years warranty.
Core exchange option is available (we ship the part first from our inventory) for $50 surcharge plus $250 deposit. Core exchange pumps ship filled with fluid, for plug-and-play installation.
p/n: 54347299838
Price listed is for rebuild/upgrade service for an individual hydraulic hinge cylinder.
Expedited Core Exchange Option includes a $250 Refundable Core Charge plus a $75 surcharge for inventory management.
It is highly recommended to upgrade them in pairs. These hydraulic cylinders always fail almost simultaneously.
To order a pair of hinges instead, click here.
You send in your malfunctioning E46-Series hydro unit, and Top Hydraulics rebuilds it. The rebuild includes electric motor replacement or rewinding if necessary, service and check of all internal pump components, upgrade of internal seals in the pump, and full bench test to assure that factory specs are exceeded. Three years warranty.
p/n 8 234 530 or 54347025595 or HB70346-002
Send in your part for for rebuild/upgrade service, or get immediate shipment from our inveentory if you choose optional core exchange.
Rebuild/Upgrade Service for Left Tension Rod Cylinder for BMW F23 2-Series.
Send in your part(s) first, or select "Order now with core exchange" to order from our inventory. Core exchange orders are subject to a $50 inventory surcharge as well as a $120 refundable core deposit.
Replaced and improved rod seals, piston seals, cap seals, gland seals, wipers, and port seals make these parts better than brand new ones, with an expected service life of 30-50 years under normal circumstances.
P/N: 54347421759