Tilton 32XX Hydraulic Release Bearing (98-1128) - Manual

Description
Tilton’s 60-32xx Hydraulic Release Bearing (also known as a concentric slave cylinder) is designed to
be mounted either to the front of the gearbox or adapted to the bellhousing, depending on your
application’s design. This hydraulic bearing assembly uses a radius-faced bearing with a 44mm
contact diameter that is intended to work with Tilton 7.25" racing clutches.
If you are using something other than a Tilton 7.25" clutch you must verify that your clutch is
designed for a 44mm bearing.
The hydraulic release bearing assembly is self-adjusting in that the bearing stays close to the clutch
spring at all times. Although the spring changes position with clutch wear, there is no extra return
spring that pulls the piston back all the way to the bottomed position. In this respect, the piston in
the hydraulic bearing assembly works like the piston in a disc brake caliper, returning only as far as
forced. For this reason, with a Tilton hydraulic release bearing the feel of the clutch does not change
with clutch wear allowing the driver to make more consistent shifts.
prior to installation
1. Both ports of the hydraulic release bearing are threaded 3/8-24 UNF x .28" deep with a 37º
tapered seat and are suitable for use with standard AN-3 or JIC 37º fittings. Alternatively, the top
of the port is machined flat for use with a crush washer (banjo fitting installations). Two AN-3 to
AN-3 union fittings are supplied with the slave cylinder. If you choose to use banjo bolts instead,
be sure that the bolt does not stick out past the bottom crush washer by more than .28".
2. Hydraulic hose is not included with this hydraulic release bearing. It is up to you to source
high quality hose and a bleed fitting assembly. We recommend the use of PTFE lined stainless
braided hose for the entire length of both the feed and bleed lines.
3. For most standard clutch pedal ratios, this hydraulic release bearing and a Tilton 7.25" clutch will
work best with a 3/4" bore master cylinder.
installation
Bearing clearance and mounting
1. Some applications may require you to cut the pilot tube off the gearbox input shaft bearing
retainer. You may need to remove the bearing retainer from the gearbox to do this.
2. As received in the box, the bearing piston may not be fully retracted. You will need to compress
it before taking any measurements. The small lip on the outside diameter of the piston is
intended to bottom against the orange wiper seal.
3. Position the bearing assembly on the surface you wish to mount it so one port points directly
up. This will be the port to which you attach the bleed line. Both ports are identical, so either
one can be placed in the upward position. The other port will be attached to the supply line.
Its orientation is not critical. Position the lines so they are clear of the clutch and flywheel.
4. Prepare the mounting surface to which the assembly will be attached. Three bolts (1/4" or 6 mm)
hold the assembly in place. Accurate positioning should be done with a register on the I.D.
or the O.D. of the three legs. This register should be on center with the input shaft within
.010" (.25 mm).
5. Check the bearing clearance. A clutch assembly with worn friction discs will not provide
accurate results, so make sure new friction discs are used when taking measurements. The
bearing clearance must be in the range of .170"-.230" (see Diagram 1). If the clearance is less
than this range, there will not be enough room to allow for the full wear range of the clutch
since clearance reduces with clutch wear.
6. If the assembly is too short or too long, Tilton has pistons available in a range of lengths (see
drawing). Also, note that the plastic shim under the bearing (.050" thick) may be removed for
additional clearance if needed). If the shortest piston and removal of the shim still makes the
assembly too long, the three legs of the hydraulic base can be accurately trimmed on a lathe.
Block all ports to prevent chip entry if any machining is to be performed.
60-32XX Hydraulic Release Bearing
Diagram 1
Bearing Fulcrum Spring Contact Point
.170"- .230"
Bearing Clearance
(New Clutch)
INSTALLATION INSTRUCTIONS
98
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