New aluminium alloy clutch slave cylinder A082Q6031F for Lotus Esprit
The original clutch slave cylinder fitted to the Lotus Esprit S3 onwards is of a cast iron construction with a mild steel electro-plated piston.
Unfortunately this combination results in a component that has inherent design problems.
This type of cylinder may last for a while if the rubber weather seal remains intact and the hydraulic fluid is changed periodically.
Cast iron is prone to rust and it’s heavy plus has poor tensile strength. The recommended hydraulic fluid used in the clutch system is hygroscopic which this means it naturally absorbs moisture from the air. So, if you combine a cast iron cylinder with hydraulic fluid that is contaminated by moisture, it will produce rust.
Rust can be highly abrasive, so if the cylinder bore becomes corroded then it will eventually destroy the hydraulic seal on the piston.
In severe cases the internal piston can be badly corroded to the point where it will no longer move.
The solution to this problem is to design and manufacture a new cylinder that is not prone to rust.
Initial thoughts were to consider the best material to produce a strong and reliable component that would ultimately result in and extended service life.
From experience producing an aluminium casting, heat treatment, and then machining was ruled out because of potential porosity problems.
Porosity is not uncommon where small cavities or voids form within a metal casting.
These voids can vary in size and are often invisible to the naked eye.
However, they can have a significant impact on strength and durability of the finished component.
There are several causes for porosity in aluminium castings.
This includes gas trapped in the casting during solidification and moisture present in the mould material plus poor venting in the mould design.
Subsequently aluminium alloy 6061 was chosen to be CNC machined to produce a quality component that was free of porosity problems and leaking fluid.
This high quality component has been designed using Solidworks 3D CAD software.
Carefully attention has been paid to the recessed stepped bore located at the rear of the slave cylinder.
This recess is a back-stop for the internal piston when it is fully retracted.
In addition to this, the recess has a bleed nipple port and an inlet pressure port that is fed from the clutch master cylinder.
The inlet pressure port has a slightly larger diameter (compared to the bleed nipple port) to ensure unrestricted fluid flow to the stainless steel piston.
Installation
It is essential the clutch slave cylinder be installed with the bleed nipple port orientated in the upward position.
This allows any trapped air to escape when the hydraulic system is bled.
Therefore the hydraulic pressure hose should be connected to the lower port to take advantage of the larger diameter connection.
This clutch slave cylinder provides a high quality solution for the Lotus Esprit S3 up to the later models S4, S4s, Sport 300 etc.
Material – aluminium alloy 6061, CNC machined
7/8 inch bore with stepped recess at rear of piston
7/8 inch high quality internal hydraulic rubber seal
Quality external rubber dust/weather seal
Stainless steel piston that will not rust
Mild steel/zinc plated bleed nipple with dust seal supplied as standard
Optional stainless steel bleed nipple is available at $8.00 extra
Clutch slave cylinder assembly comes with a 12 month warranty
This aluminium alloy clutch slave cylinder comes fully assembled and is ready for immediate installation
The price is AUS $195.00 each (excluding GST)
To complement the clutch slave cylinder installation, Lotus Marques offers a stainless steel braided clutch hose that eliminates “Red hose syndrome” that might be experienced on a hot day.
Clutch hose, master to slave cylinder braided and fittings RHD, part number B082J4088J-braided @ AUS $ 223.75 each (excluding GST)
Pricing information is correct as of 9/5/2025 but may alter with time and currency exchange rate fluctuations.
Lotus Marques supports local industry by manufacturing these clutch slave cylinders in Australia.
Trade inquires are also welcome - please call (03) 9761-1903 to discuss your requirements
Please note carefully, pricing above does not included postage and packing.
Shipping from Australia to UK, USA, New Zealand, anywhere worldwide!
Contact Lotus Marques now for postal or courier shipping costs.
The original clutch slave cylinder fitted to the Lotus Esprit S3 onwards is of a cast iron construction with a mild steel electro-plated piston.
Unfortunately this combination results in a component that has inherent design problems.
This type of cylinder may last for a while if the rubber weather seal remains intact and the hydraulic fluid is changed periodically.
Cast iron is prone to rust and it’s heavy plus has poor tensile strength. The recommended hydraulic fluid used in the clutch system is hygroscopic which this means it naturally absorbs moisture from the air. So, if you combine a cast iron cylinder with hydraulic fluid that is contaminated by moisture, it will produce rust.
Rust can be highly abrasive, so if the cylinder bore becomes corroded then it will eventually destroy the hydraulic seal on the piston.
In severe cases the internal piston can be badly corroded to the point where it will no longer move.
The solution to this problem is to design and manufacture a new cylinder that is not prone to rust.
Initial thoughts were to consider the best material to produce a strong and reliable component that would ultimately result in and extended service life.
From experience producing an aluminium casting, heat treatment, and then machining was ruled out because of potential porosity problems.
Porosity is not uncommon where small cavities or voids form within a metal casting.
These voids can vary in size and are often invisible to the naked eye.
However, they can have a significant impact on strength and durability of the finished component.
There are several causes for porosity in aluminium castings.
This includes gas trapped in the casting during solidification and moisture present in the mould material plus poor venting in the mould design.
Subsequently aluminium alloy 6061 was chosen to be CNC machined to produce a quality component that was free of porosity problems and leaking fluid.
This high quality component has been designed using Solidworks 3D CAD software.
Carefully attention has been paid to the recessed stepped bore located at the rear of the slave cylinder.
This recess is a back-stop for the internal piston when it is fully retracted.
In addition to this, the recess has a bleed nipple port and an inlet pressure port that is fed from the clutch master cylinder.
The inlet pressure port has a slightly larger diameter (compared to the bleed nipple port) to ensure unrestricted fluid flow to the stainless steel piston.
Installation
It is essential the clutch slave cylinder be installed with the bleed nipple port orientated in the upward position.
This allows any trapped air to escape when the hydraulic system is bled.
Therefore the hydraulic pressure hose should be connected to the lower port to take advantage of the larger diameter connection.
This clutch slave cylinder provides a high quality solution for the Lotus Esprit S3 up to the later models S4, S4s, Sport 300 etc.
Material – aluminium alloy 6061, CNC machined
7/8 inch bore with stepped recess at rear of piston
7/8 inch high quality internal hydraulic rubber seal
Quality external rubber dust/weather seal
Stainless steel piston that will not rust
Mild steel/zinc plated bleed nipple with dust seal supplied as standard
Optional stainless steel bleed nipple is available at $8.00 extra
Clutch slave cylinder assembly comes with a 12 month warranty
This aluminium alloy clutch slave cylinder comes fully assembled and is ready for immediate installation
The price is AUS $195.00 each (excluding GST)
To complement the clutch slave cylinder installation, Lotus Marques offers a stainless steel braided clutch hose that eliminates “Red hose syndrome” that might be experienced on a hot day.
Clutch hose, master to slave cylinder braided and fittings RHD, part number B082J4088J-braided @ AUS $ 223.75 each (excluding GST)
Pricing information is correct as of 9/5/2025 but may alter with time and currency exchange rate fluctuations.
Lotus Marques supports local industry by manufacturing these clutch slave cylinders in Australia.
Trade inquires are also welcome - please call (03) 9761-1903 to discuss your requirements
Please note carefully, pricing above does not included postage and packing.
Shipping from Australia to UK, USA, New Zealand, anywhere worldwide!
Contact Lotus Marques now for postal or courier shipping costs.
