LuK’s latest repair kits contain all the components needed to complete a professional gearbox and differential overhaul. Schaeffler’s REPXPERT, Alistair Mason, provides a step-by-step guide to the repair process.
With routine service schedule mileages increasing, timing
belts being changed later and hybrid & electric vehicles becoming more
popular, independent workshops are having to work harder to ensure they stay
busy.
Schaeffler is seeing a trend in the automotive industry
where investment in ‘up-skilling’ to plan for the future and to keep all
repairs ‘in-house’ is at the forefront of workshop’s minds. Schaeffler is fully
aware of this, and by offering innovative new repair solutions, it can help
support the future of the independent aftermarket.
Some of Schaeffler’s latest products are gearbox and
differential repair kits, containing all the components required to complete a
professional gearbox or differential overhaul, and with 21 kits available, all
of the most popular applications are covered.
One of the most popular of these new repair opportunities is
for a BMW differential; most independent workshops would currently just source
and fit a reconditioned differential, losing out on the healthy profit to be
gained from overhauling the unit themselves.
The average price for the BMW repair kit is around £150,
while a reconditioned diff can cost between £500 and £600. This leaves a
minimum of scope of £350 for labour, and with the job taking around three
hours, this is a £100+ an hour job that independent workshops could be taking
advantage of.
Schaeffler’s leading REPXPERT, Alistair Mason, recently put
together a quick installation guide, outlining some of the key areas of the
repair process.
Step-by-step process
- Detach the differential from the vehicle and drain the oil. Remove the locking ring from the pinion nut then unscrew the nut using a counter hold tool. Next, remove the differential back plate and both output shaft oil seals.
- The next step is to detach the crown wheel
bearing retaining circlips, which will require circlip pliers – note how thick
they are on removal, as they’ll be used again – then, if necessary, remove
corrosion from the bearing casing. Slide the crown from side-to-side to ease
the bearings out, then, with the bearings removed, swivel the crown wheel
assembly out of the casing – crown wheel first.
- Disconnect the pinion assembly, which may need
to be pressed out as the front bearing is a tight fit, then take away the
pinion oil seal and front pinion bearing. Next, remove the inner bearing race
from the pinion and press out the front pinion bearing race, before drawing out
the rear pinion outer bearing race with a puller or slide hammer.
- Once the spacer shim has been removed, the
differential casing is fully stripped. Remove any corrosion from the seal
location points and clean the differential casing thoroughly. Next, detach both
bearing inner races from the crown wheel and clean the assembly, then press the
new crown wheel inner race bearings into place.
- Press the new outer bearings into the differential
casing and the new rear pinion bearing onto the pinion, then lubricate the new
bearings. Install the pinion into position, fit the new collapsible spacer and
then the front bearing.
- Fit the new pinion oil seal and mount the pinion
drive flange. Attach the counter hold tool to the pinion flange and torque the
pinion nut to 170Nm; however, greater force may be necessary in a bid to
collapse the spacer. Once torqued, check for smooth rotation and, using a
spring balance, tighten the pinion nut until 2kg of force is required to
rotate.
- Next, install the crown wheel assembly, which is
achieved by sliding the new bearing into position, then refit the circlips
noted earlier in the removal process, other bearing and remaining circlip.
- Using Engineers Blue, paint one of the pinion
teeth and rotate the pinion to transfer the Engineers Blue onto the crown wheel
tooth. The marking should be in the centre area of the tooth. If the crown
wheel tooth is marked in the outer area, the shimming is too loose; just the
inner area would indicate too tight. At this point, a slight ‘backlash’ should
be felt, which can be confirmed with a DTI gauge (0.15mm). Once confirmed, run
a thin bead of sealer to the back plate mounting face, refit the back plate and
fit the driveshaft seals.
- Finally, refit the differential onto the vehicle
and fill the correct grade and quantity of oil.
Full installation instructions and videos are available on Schaeffler’s REPXPERT portal www.repxpert.co.uk.
