Gearbox: disassembly and assembly

Make

SEAT

Model

Leon Mk1

Section

02R, 5-speed › Gearbox mechanics,operation, construction,diff. › Gearbox: disassembly and assembly

Power transmissionGearbox: disassembly and assembly

Installation –  Place the differential on the clutch housing.

–  Sealing washers -arrows- must always be renewed.   Note The figure only shows 3 or 4 bolts with their O-ring gaskets. –  Place the input shaft, layshaft and reverse gear shaft together. –  Partially diagonally screw the 4 nuts on the secondary shaft bearing cover and tighten to a torque of 25 Nm + 90°.   Note Clean remains of safety agent from the support thread for the reverse gear shaft. Use a tap. –  Install the reverse gear shaft support –  Fit the reverse gear fork.

Installation position of reverse gear prong and shaft. –  Fit the prongs with the connection guides.

–  Screw stud bolt -A- M8×100 mm into support for reverse gearshaft so that it is aligned after attaching transmission housing. –  Align the connection guides. –  Check that the change-over bolts of the gearbox prongs are housed in their respective mobile sleeves. –  Check that the magnet is not broken or cracked and place it in its housing in the clutch housing. –  Thoroughly clean contact surfaces of clutch casing and gearbox casing. Apply a uniform layer (not too thick) of sealant paste → Parts catalogue. –  Assemble the gearbox casing on the clutch housing. –  Tighten screws securing the clutch housing to the gearbox casing to a torque of 25 Nm + 90°.

–  Fit bolts for reverse gear shaft support -arrows- as shown: –  Position bolt -a-, unscrew the M8 x 100 mm stud and tighten bolt -b- by hand Tightening sequence: 1 -  Bolt -a- 30 Nm (M8 x 32) 2 -  Bolt -b- 25 Nm (M8 x 26)

–  Install the bearing bolts -arrow- for the gearbox prongs. Use a screwdriver to align the connection guides, so that each support bolt can be installed in its housing. –  Thoroughly clean contact surfaces of sealing cap for gear selector and casing. Apply a uniform layer (not too thick) of sealant paste → Parts catalogue. –  Install the cover on the gear selector. Install the gear selector shaft as follows: –  Place the connection guides in neutral position.

–  Place the projection -arrow 1- in the notch on the gearbox casing. Install the gear selector shaft so that connection finger -arrow 2- goes into to the engagement guides. –  Screw in gear selector securing bolts to gearbox casing and tighten to a torque of 25 Nm. Installation position of 5th gear wheel

–  The lobe present -arrow- on the internal diameter of the gear must be orientated towards the gearbox casing. –  Heat the gear of the 6thª gear to approx. 100 °C with the electric blower -SAT 1416-.

–  Press in sprocket with adapter -U 40200/20-.

Check 5th gear synchromesh ring for wear. –  Before checking for wear, thoroughly clean the synchroniser ring and 5th gear mesh. –  Fit the 5th gear synchromesh ring on ratchet. Press the synchro ring on the sprocket and measure the elevation “a” with a thickness jig.

Synchroniser ring	Measurement “a” on new synchroniser	Wear limit
5. Road speed	1,1 ... 1.7 mm	0.5 mm

–  Fit ratchet for 5th gear with the needle bearing. –  Install 5th gear synchromesh ring on ratchet

Install springs in synchromesh assembly of 5th gear –  Install spring rings 120° offset below extensions -C-. The bent end of the spring rings must be located in front of the locking elements -arrows-. –  Check that the teeth terminating in end -A- of the sliding sleeve are located in the same direction with the most pronounced lug -B- of the axle box. –  Check that locking pins are correctly installed → Anchor.

Assembly position of the 5th gear synchromesh/mobile element assembly –  Install 5th gear wheel on input shaft so that the teeth on the conical selector sleeve -arrow 1- and the high collar on the synchromesh element -arrow 2- pointing toward the transmission housing. –  Align recesses -arrow 3- with synchromesh hub to locking elements on synchromesh ring (-arrows- lower figure).

5thª gear synchromesh ring with locking elements incorporated -arrows- –  Cover all holes with rag to prevent foreign body from penetrating into the transmission.

–  Fit synchromesh assembly onto 5th gear ratchet. Use the adaptor -U 40200/20-.   Note When fitting synchromesh assembly to 5th gear, check the 5th gear synchromesh ring turns freely. –  Clean bolt holes for mounting synchromesh element and 5th gear with tap to remove bolt securing agents residues. Otherwise bolts can break. –  Partially screw in mounting bolts → Item on synchromesh and 5th gear wheel Installation position of the plate spring

–  The concave side of the plate springs -arrows- should point toward the synchronous hub and 5th gear wheel.

Before tightening mounting bolts on synchromesh hub and 5th gear wheel, press 5th gear selector sleeve downward -arrow 1- and engage gear. Also shift to 1st gear with shift lever -arrow 2- and -arrow 3- The input and output shafts remain locked when two gears are engaged; the synchromesh hub and 5th gear mesh do not turn. Tighten the bolts -A- to a torque of 80 Nm. –  Install 5th gear connection prong with a torque of 25Nm.

Adjust the mobile sleeve and the prong for the 5th gear –  Shift to 5th gear Loosen the bolt -B-. Press the mobile sleeve and the gear mouth in the direction of the -arrow-; then tighten the bolt -1- to 25 Nm. l  Control measurement: Between the mobile sleeve and the mobile pinion, a thickness gauge of 0.2 mm cannot be inserted. If necessary, repeat the adjustment process. –  Shift out of 5th gear. The sleeve must be situated in neutral position and the synchromesh ring must turn freely in this position. –  Successively select all gears several times.

–  Install the gasket and gearbox casing cover -arrow-. –  Tighten the bolts to secure the gearbox casing cover to a torque of 10 Nm. –  Fit guide socket for clutch release bearing and secure to casing using the three cylindrical bolts → Chapter –  Install thrust washer, spring, conical ring and left articulation flange → Chapter.

01 Transmission

The same page in: Leon Mk2.