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Hydraulic Clutch Slave Retrofit Kit
for
AMC Bellhousings
Hydraulic clutch release systems have gained wide acceptance in the aftermarket as a keen solution to both engine conversion and stock clutch linkage replacement scenarios.
Novak's Hydraulic Clutch Slave Retrofit has evolved into its best rendition, as our #HCRA. It bolts to the popular AMC I6 & V8 style bellhousings on 232, 258, 4.0L, 304, 360 & 401 engines. This kit will work with conversion or factory transmissions.
Our #HCRA clutch kit has been engineered to bolt to most AMC style bellhousings and to work with their associated pressure plates.
All included components work as a system to insure a straightforward installation. The arm provides the proper ratio for the great majority of pressure plates and the T6 hardened and hard anodized billet aluminum slave cylinder and piston are absolutely durable, yet rebuildable or replaceable down the road, if necessary.
3/4" Slave Version
- Our most popular - if you are in doubt which to choose for your Jeep, start here
- e.g., Jeep CJ, XJ, YJ, TJ vehicles with factory 3/4" hydraulic master cylinders
- Other types of factory or custom vehicles
- Note that the Novak 3/4" slave is usually compatible with many 7/8" master cylinders, but will increase required pedal pressure and may give a slightly less precise feel
7/8" Slave Version
- e.g., Jeep CJ vehicles with factory hydraulic release though our usual recommendation is to use the 3/4" version for adequate throw. The 7/8" slave with stock CJ master cylinder will have to be adjusted and set up to exact minimum clearance specifications to function properly
- Other types of factory or custom vehicles
Applications & Compatibility
Hydraulic clutch release systems are typically engineered to have a 1:1, master-to-slave ratio, where the leverage is not obtained through differential hydraulics. The force is obtained through the leverage provided by the clutch pedal and then the release arm / fork at the throwout bearing, like a conventional mechanical clutch - the method of transmitting the force is the only difference. These principles are discussed here.
As such, the installer will generally choose between our 3/4" bore version or our 7/8" bore version to best match the diameter of their master cylinder.
- Choosing a larger slave for a smaller master may create a situation where the pedal pressure is reduced, but the lessened travel may not fully release a clutch.
- Choosing a smaller slave for a larger master may create a situation where there is excessive pedal pressure. However, the Novak 3/4" bore slave has more travel than OEM units and typically work with 7/8" master cylinders without blowing out. This is helpful if the throwout bearing needs more travel for release, but note that this is not a substitute for not choosing the right length throwout bearing.
- Keep in mind these ratios are based on the area of the bores, not the diameter so, πr2 to calculate either master or slave area. Small changes in the bore size can yield a large change in distance or force. 3/4" bore yields .442 sq. in. whereas the 7/8" is .601 sq. in. Travel is a linear function of the area x the distance equals volume. The volume of fluid moved is the key and the same on either end no matter what changes are made so long as the system is sealed and no air is present.
For your best benefit, read and understand the principles of working with hydraulic clutch release systems and determine the applicability for your vehicle.
* Note that Full Size Jeeps (Wagoneer, Cherokee, J Truck) vehicles do not accommodate conventional, firewall mounted master cylinders due to the brake booster and the electrical bulkhead connector. If converting one of these Jeeps to hydraulic clutch release, the installer will need to custom configure a master cylinder accordingly.
Bellhousing Compatibilities
The HCRA has been proven to work on all known clutches for AMC I6 & AMC V8 engines.
All known bellhousings made from 1976 through 1986 are compatible, including those adjoined to these factory transmissions:
This kit also works with AMC bellhousing to transmission conversion scenarios, such as:
Incompatible Bellhousings
Some AMC bellhousings feature bosses to mount a factory style slave cylinder. These cylinders are limited to the 7/8" bores and additionally, we've seen their prices rise and availability fall.
The Novak kit will work across the variety of bellhousings, and allow for use with the more popular 3/4" master cylinders, provide adjustability and ongoing availability and support.
The 2.5L Iron Duke bellhousing features a Chevy bolt pattern and is not compatible
Driveshaft Clearance on Wranglers
Since this slave cylinder assembly mounts on the driver's side, it may be in proximity to the front driveshaft on Wrangler. If your Wrangler has factory springs that have sagged some, a risk of interference exists here. We have seen good clearance on Jeeps with good factory and, of course, lifted spring sets.
Shown below is the Chevy version of this kit. The AMC version is very similar in appearance and specs.
Related Products
Installation Requirements
Installation instructions are included. If you have an existing hydraulic master cylinder, installation is very straightforward. If retrofitting the master things can get more challenging. Later CJ models are marked with the correct location on your firewall (at least the 80s era).
Older versions, especially if you have floor mount pedals will need to get more creative. Wilwood and other manufactures have some very nice options available. Make sure that the master cylinder travel will be about 1-1/2". It is popular to retrofit the pedal assembly from a later Jeep (1987-1990 YJ models would be a prime candidate if you choose to go that way and work well with the YJ master cylinder, in Related Products, above.
The clutch article listed below is extensive and highly recommended reading.