DS 19 OPERATION No. DS 334-0 Checking and adjustments on the change speed control. Op. DS 334-0 222
PARTICULAR POINTS
Important remark.
Before carrying out any work on the gearbox or its controls, check the following adjustments:
(a)The adjustment of the slow running, of the clutch clearance, clutch drag, and clutch engagement control.
(b) The setting of the hydraulic gear selector.
(c) If it is not possible to engage 2nd gear by passing from 1st to 2nd gear, check the assembly of the gear lever washers.
(d ) Check the distribution of the pressure by observing the operation of the clutch fork (car raised at the front). If not proceed to check the following:
To check the pressure (test bench 2290-T).
Insert the pipe assembly (P) or (P1) between the feed pipe assembly (5 pipes) and the front pipe assembly of the gearbox. Fit the pipe (W) successively
in each of the openings of the pipe assembly (P) or (P1), the other openings being closed, the other end of the pipe (W) connected to the pressure
gauge (M
2
) or (M’) using the pipes (A).
Operate the gear lever successively through each gear. One should read a pressure between 1,920 p.s.i. and 2,490 p.s.i. (135 to 170 kg/cm
2
) The
needle will pause for a short period at 570 p.s.i. (40 kg ‘cm
2
) (on the synchronised gears). If not, check the hydraulic gear selector.
To check the hydraulic gear selector (test bench 2290-T).
Connect the pipe assembly (P or P1) to the feed pipe assembly (5 pipes) and blank off the pipe assembly (P or P1) using the blank flange (D).
Proceed as indicated above. One should read a pressure between 1,920 p.s.i. and 2,490 p.s.i. (135 to 170 kg/cm
2
). The needle will pause for a short
period at 570 p.s.i. (40 kg/cm
2
) (on synchronised gears).
To check the sealing of the cylinders controlling the gears (test bench 2290-T).
Insert the pipe assembly (P) or (P1) between the feed pipe assembly (5 pipes) and the front pipe assembly of the gearbox. Fit the pipe (B) successively
on each of the openings of the pipe assembly (P) or (P1), the other openings being closed, the end of the pipe (B) connected to the test bench pump.
Build up the pressure to 2,490 p.s.i. (170 kg/cm
2
). There should be no drop in pressure.
To check the operation of the gears (test bench 2290-T, assembled as in the above paragraph).
Engine stopped, one wheel raised, declutch (hand control). Pass successively through each gear.
Operate the pump and turn the wheel by hand. Read the pressure at the precise moment that the wheel stops turning, this pressure should be less than
1,920 p.s.i. (135 kg/cm
2
).
If not, check the pipe assembly, the synchro and the gearbox cover.
To adjust the pipe assemblies controlling the gears (Replacement of a pipe assembly).
20 Check the position of the piston in relation to the bearing face of the cylinder, using a depth gauge placed on one washer (distance “d”, see Pl. 55, fig.
7).
21 Check the same measurement on the corresponding cylinder of the new pipe assembly.
22 Modify the thickness of the shims in order to keep the same setting.
23 Carry out the same operations on each cylinder of the old and new pipe assemblies.
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