Peugeot 405. Manual - part 23

10 Piston/connecting rod

assembly - removal

4

1 Remove the cylinder head, sump and oil
pump as described in Part A or B of this
Chapter (as applicable).
2 If there is a pronounced wear ridge at the
top of any bore, it may be necessary to
remove it with a scraper or ridge reamer, to
avoid piston damage during removal. Such a
ridge indicates excessive wear of the cylinder
bore.
3 Using a hammer and centre-punch, paint or
similar, mark each connecting rod big-end
bearing cap with its respective cylinder
number on the flat machined surface
provided; if the engine has been dismantled
before, note carefully any identifying marks
made previously (see illustration). Note that
No 1 cylinder is at the transmission (flywheel)
end of the engine.
4 Turn the crankshaft to bring pistons 1 and 4
to BDC (bottom dead centre).
5 Unscrew the nuts from No 1 piston big-end
bearing cap. Take off the cap, and recover the
bottom half bearing shell (see illustration). If
the bearing shells are to be re-used, tape the
cap and the shell together.
6 To prevent the possibility of damage to the
crankshaft bearing journals, tape over the
connecting rod stud threads (see
illustration).
7 Using a hammer handle, push the piston up
through the bore, and remove it from the top
of the cylinder block. Recover the bearing
shell, and tape it to the connecting rod for
safe-keeping.
8 Loosely refit the big-end cap to the
connecting rod, and secure with the nuts -
this will help to keep the components in their
correct order.
9 Remove No 4 piston assembly in the same
way.
10 Turn the crankshaft through 180° to bring
pistons 2 and 3 to BDC (bottom dead centre),
and remove them in the same way.

11 Crankshaft - removal

4

1 Remove the crankshaft sprocket and the oil
pump as described in Part A or B of this
Chapter (as applicable). Also unbolt and
remove the timing belt rear cover noting the
position of the special retaining studs (see
illustration).
2 Remove the pistons and connecting rods,
as described in Section 10. If no work is to be
done on the pistons and connecting rods,
there is no need to remove the cylinder head,
or to push the pistons out of the cylinder
bores. The pistons should just be pushed far
enough up the bores that they are positioned
clear of the crankshaft journals.
3 Check the crankshaft endfloat as described
in Section 14, then proceed as follows.

TU series 
aluminium block engines 

4 Work around the outside of the cylinder
block, and unscrew all the small (6 mm) bolts
securing the main bearing ladder to the base
of the cylinder block. Note the correct fitted
depth of both the front and rear crankshaft oil
seals in the cylinder block/main bearing
ladder.
5 Working in a diagonal sequence, evenly
and progressively slacken the ten large 
(11 mm) main bearing ladder retaining bolts

by a turn at a time. Once all the bolts are
loose, remove them from the ladder.
6 With all the retaining bolts removed,
carefully lift the main bearing ladder casting
away from the base of the cylinder block.
Recover the lower main bearing shells, and
tape them to their respective locations in the
casting. If the two locating dowels are a loose
fit, remove them and store them with the
casting for safe-keeping.
7 Lift out the crankshaft, and discard both the
oil seals. Remove the oil pump drive chain
from the end of the crankshaft. Where
necessary, slide off the drive sprocket, and
recover the Woodruff key.
8 Recover the upper main bearing shells, and
store them along with the relevant lower
bearing shell. Also recover the two
thrustwashers (one fitted either side of No 2
main bearing) from the cylinder block.

TU series 
cast-iron block engines

9 Unbolt and remove the crankshaft front and
rear oil seal housings from each end of the
cylinder block, noting the correct fitted
locations of the locating dowels. If the
locating dowels are a loose fit, remove them
and store them with the housings for safe-
keeping.
10 Remove the oil pump drive chain, and
slide the drive sprocket off the end of the
crankshaft. Remove the Woodruff key, and
store it with the sprocket for safe-keeping.
11 The main bearing caps should be
numbered 1 to 5 from the transmission
(flywheel) end of the engine. If not, mark them
accordingly using a centre-punch or paint.
12 Unscrew and remove the main bearing
cap bolts, and withdraw the caps. Recover
the lower main bearing shells, and tape them
to their respective caps for safe-keeping.
13 Carefully lift out the crankshaft, taking
care not to displace the upper main bearing
shell.
14 Recover the upper bearing shells from the
cylinder block, and tape them to their
respective caps for safe-keeping. Remove the
thrustwasher halves from the side of No 2
main bearing, and store them with the bearing
cap.

2C•10 Engine removal and overhaul

10.3  Connecting rod and big-end bearing

cap marked for identification 

(No 3 cylinder shown)

10.6  To protect the crankshaft journals,

tape over the connecting rod stud threads

prior to removal

11.1  Timing belt rear cover special studs

10.5  Removing a big-end bearing cap 

and shell

XU series engines

15 Slacken and remove the retaining bolts,
and remove the oil seal carrier from the front
(timing belt) end of the cylinder block, along
with its gasket (where fitted) (see illustration).
16 Remove the oil pump drive chain, and
slide the drive sprocket and spacer (where
fitted) off the end of the crankshaft. Remove
the Woodruff key, and store it with the
sprocket for safe-keeping (see illustrations).
17 The main bearing caps should be
numbered 1 to 5, starting from the
transmission (flywheel/driveplate) end of the
engine (see illustration). If not, mark them
accordingly using a centre-punch. Also note
the correct fitted depth of the rear crankshaft
oil seal in the bearing cap.
18 On 1761 cc engines, undo the two bolts
(one at the front of the block, and one at the
rear) securing the centre main bearing cap to

the block. Remove the bolts, along with their
sealing washers.
19 On all engines, slacken and remove the
main bearing cap retaining bolts/nuts, and lift
off each bearing cap. Recover the lower
bearing shells, and tape them to their
respective caps for safe-keeping. Also
recover the lower thrustwasher halves from
the side of No 2 main bearing cap (see
illustration). Remove the rubber sealing strips
from the sides of No 1 main bearing cap, and
discard them.
20 Lift out the crankshaft, and discard the
rear oil seal (see illustration).
21 Recover the upper bearing shells from the
cylinder block, and tape them to their
respective caps for safe-keeping (see
illustration). Remove the upper thrustwasher
halves from the side of No 2 main bearing,
and store them with the lower halves.

Engine removal and overhaul  2C•11

11.16b  . . . then slide off the 

drive sprocket . . .

11.19  Removing No 2 main bearing cap.

Note the thrustwasher (arrowed)

11.17  Main bearing cap identification

markings (arrowed)

11.16c  . . . and remove the Woodruff key

from the crankshaft

11.16a  Remove the oil pump 

drive chain . . .

11.15  Removing the oil seal carrier from

the front of the cylinder block - XU engine

2C

11.20  Lifting out the crankshaft - 

XU series engine

11.21  Remove the upper main bearing

shells from the cylinder block/crankcase,

and store them with their lower shells

12.1  Cylinder block core plugs (arrowed)

12 Cylinder block/crankcase -

cleaning and inspection

2

Cleaning

1 Remove all external components and
electrical switches/sensors from the block.
For complete cleaning, the core plugs should
ideally be removed (see illustration). Drill a
small hole in the plugs, then insert a self-
tapping screw into the hole. Pull out the plugs
by pulling on the screw with a pair of grips, or
by using a slide hammer.
2 On aluminium block engines with wet liners,
remove the liners, referring to paragraph 18.
3 Where applicable, undo the retaining bolt
and remove the piston oil jet spray tube from
inside the cylinder block.
4 Scrape all traces of gasket from the cylinder
block/crankcase, and from the main bearing

ladder (where fitted), taking care not to
damage the gasket/sealing surfaces.
5 Remove all oil gallery plugs (where fitted).
The plugs are usually very tight - they may
have to be drilled out, and the holes re-
tapped. Use new plugs when the engine is
reassembled.
6 If any of the castings are extremely dirty, all
should be steam-cleaned.
7 After the castings are returned, clean all oil
holes and oil galleries one more time. Flush all
internal passages with warm water until the
water runs clear. Dry thoroughly, and apply a
light film of oil to all mating surfaces, to
prevent rusting. On cast-iron block engines,
also oil the cylinder bores. If you have access
to compressed air, use it to speed up the
drying process, and to blow out all the oil
holes and galleries. 

8 If the castings are not very dirty, you can do
an adequate cleaning job with hot (as hot as
you can stand!), soapy water and a stiff brush.
Take plenty of time, and do a thorough job.
Regardless of the cleaning method used, be
sure to clean all oil holes and galleries very
thoroughly, and to dry all components well.
On cast-iron block engines, protect the
cylinder bores as described above, to prevent
rusting.
9 All threaded holes must be clean, to ensure
accurate torque readings during reassembly.
To clean the threads, run the correct-size tap
into each of the holes to remove rust,
corrosion, thread sealant or sludge, and to
restore damaged threads (see illustration). If
possible, use compressed air to clear the
holes of debris produced by this operation.

10 Apply suitable sealant to the new oil
gallery plugs, and insert them into the holes in
the block. Tighten them securely.
11 Where applicable, clean the threads of the
piston oil jet retaining bolt, and apply a drop
of thread-locking compound to the bolt
threads. Refit the piston oil jet spray tube to
the cylinder block, and tighten its retaining
bolt to the specified torque setting.
12 If the engine is not going to be
reassembled right away, cover it with a large
plastic bag to keep it clean; protect all mating
surfaces and the cylinder bores as described
above, to prevent rusting.

Inspection

Cast-iron cylinder block

13 Visually check the castings for cracks and
corrosion. Look for stripped threads in the
threaded holes. If there has been any history
of internal water leakage, it may be worthwhile
having an engine overhaul specialist check
the cylinder block/crankcase with special
equipment. If defects are found, have them
repaired if possible, or renew the assembly.
14 Check each cylinder bore for scuffing and
scoring. Check for a wear ridge at the top of the
cylinder, indicating that the bore is badly worn.
15 If the necessary measuring equipment is
available, measure the bore diameter of each
cylinder liner at the top (just under the wear
ridge), centre, and bottom of the cylinder
bore, parallel to the crankshaft axis.
16 Next, measure the bore diameter at the
same three locations, at right-angles to the
crankshaft axis. Compare the results with the
figures given in the Specifications. Where no
figures are stated by Peugeot, if there is any
doubt about the condition of the cylinder
bores seek the advice of a Peugeot dealer or
suitable engine reconditioning specialist.
17 At the time of writing, it was not clear
whether oversize pistons were available for all
models. Consult your Peugeot dealer for the
latest information on piston availability. If
oversize pistons are available then it may be
possible to have the cylinder bores rebored
and fit the oversize pistons. If it proves
oversize pistons are not available, and the
bores are worn, renewal of the block seems to
be the only option.

Aluminium cylinder block 
with wet liners

18 Remove the liner clamps (where used),
then use a hard wood drift to tap out each
liner from the inside of the cylinder block.
When all the liners are released, tip the
cylinder block/crankcase on its side and
remove each liner from the top of the block.
As each liner is removed, stick masking tape
on its left-hand (transmission side) face, and
write the cylinder number on the tape. No 1
cylinder is at the transmission (flywheel/
driveplate) end of the engine. Remove the O-
ring from the base of each liner, and discard
(see illustrations).
19 Check each cylinder liner for scuffing and
scoring. Check for signs of a wear ridge at the
top of the liner, indicating that the bore is
excessively worn.
20 If the necessary measuring equipment is
available, measure the bore diameter of each
cylinder liner at the top (just under the wear
ridge), centre, and bottom of the cylinder
bore, parallel to the crankshaft axis.
21 Next, measure the bore diameter at the
same three locations, at right-angles to the
crankshaft axis. Compare the results with the
figures given in the Specifications.
22 Repeat the procedure for the remaining
cylinder liners.
23 If the liner wear exceeds the permitted
tolerances at any point, or if the cylinder liner
walls are badly scored or scuffed, then
renewal of the relevant liner assembly will be
necessary. If there is any doubt about the
condition of the cylinder bores, seek the
advice of a Peugeot dealer or engine recondi-
tioning specialist.
24 If renewal is necessary, new liners,
complete with pistons and piston rings, can
be purchased from a Peugeot dealer. Note
that it is not possible to buy liners individually
- they are supplied only as a matched
assembly complete with piston and rings.
25 To allow for manufacturing tolerances,
pistons and liners are separated into three
size groups. The size group of each piston is
indicated by a letter (A, B or C) stamped onto
its crown, and the size group of each liner is
indicated by a series of 1 to 3 notches on the
upper lip of the liner; a single notch for 
group A, two notches for group B, and three

2C•12 Engine removal and overhaul

12.9  Cleaning a cylinder block threaded

hole using a suitable tap

12.18b  . . . and recover the bottom 

O-ring seal (arrowed)

12.18a  On aluminium block engines,

remove each liner . . .

Warning: Wear eye protection
when using compressed air!

Warning: Wear eye protection
when cleaning out these holes
in this way!

A good alternative is to
inject aerosol-applied water-
dispersant lubricant into
each hole, using the long

spout usually supplied.

notches for group C. Ensure that each piston
and its respective liner are both of the same
size group. It is permissible to have different
size group piston and liner assemblies fitted
to the same engine, but never fit a piston of
one size group to a liner in a different group.
26 Prior to installing the liners, thoroughly
clean the liner mating surfaces in the cylinder
block, and use fine abrasive paper to polish
away any burrs or sharp edges which might
damage the liner O-rings. Clean the liners and
wipe dry, then fit a new O-ring to the base of
each liner. To aid installation, apply a smear of
oil to each O-ring and to the base of the liner.
27 If the original liners are being refitted, use
the marks made on removal to ensure that
each is refitted the correct way round, and is
inserted into its original position. Insert each
liner into the cylinder block, taking care not to
damage the O-ring, and press it home as far
as possible by hand. Using a hammer and a
block of wood, tap each liner lightly but fully
onto its locating shoulder. Wipe clean, then
lightly oil, all exposed liner surfaces, to
prevent rusting.
28 With all four liners correctly installed, use
a dial gauge (or a straight-edge and feeler
blade) to check that the protrusion of each
liner above the upper surface of the cylinder
block is within the limits given in the Specifi-
cations. The maximum difference between
any two liners must not be exceeded.
29 If new liners are being fitted, it is
permissible to interchange them to bring the
difference in protrusion within limits. Keep
each piston with its respective liner.
30 If liner protrusion cannot be brought
within limits, seek the advice of a Peugeot
dealer or engine reconditioning specialist
before proceeding with the engine rebuild.

13 Piston/connecting rod

assembly - inspection

3

1 Before the inspection process can begin,
the piston/connecting rod assemblies must
be cleaned, and the original piston rings
removed from the pistons.
2 Carefully expand the old rings over the top
of the pistons. The use of two or three old
feeler blades will be helpful in preventing the
rings dropping into empty grooves (see
illustration). Be careful not to scratch the
piston with the ends of the ring. The rings are
brittle, and will snap if they are spread too far.
They’re also very sharp - protect your hands
and fingers. Note that the third ring
incorporates an expander. Always remove the
rings from the top of the piston. Keep each set
of rings with its piston if the old rings are to be
re-used.
3 Scrape away all traces of carbon from the
top of the piston. A hand-held wire brush (or a
piece of fine emery cloth) can be used, once
the majority of the deposits have been
scraped away.

4 Remove the carbon from the ring grooves
in the piston, using an old ring. Break the ring
in half to do this (be careful not to cut your
fingers - piston rings are sharp). Be careful to
remove only the carbon deposits - do not
remove any metal, and do not nick or scratch
the sides of the ring grooves.
5 Once the deposits have been removed,
clean the piston/connecting rod assembly
with paraffin or a suitable solvent, and dry
thoroughly. Make sure that the oil return holes
in the ring grooves are clear.
6 If the pistons and cylinder bores are not
damaged or worn excessively, and if the
cylinder block does not need to be rebored,
the original pistons can be refitted. Normal
piston wear shows up as even vertical wear
on the piston thrust surfaces, and slight
looseness of the top ring in its groove. New
piston rings should always be used when the
engine is reassembled.
7 Carefully inspect each piston for cracks
around the skirt, around the gudgeon pin
holes, and at the piston ring “lands” (between
the ring grooves).
8 Look for scoring and scuffing on the piston
skirt, holes in the piston crown, and burned
areas at the edge of the crown. If the skirt is
scored or scuffed, the engine may have been
suffering from overheating, and/or abnormal
combustion which caused excessively high
operating temperatures. The cooling and
lubrication systems should be checked
thoroughly. Scorch marks on the sides of the
pistons show that blow-by has occurred. A
hole in the piston crown, or burned areas at
the edge of the piston crown, indicates that
abnormal combustion (pre-ignition, knocking,
or detonation) has been occurring. If any of
the above problems exist, the causes must be
investigated and corrected, or the damage will
occur again. The causes may include
incorrect ignition/injection pump timing, or a
faulty injector (as applicable).
9 Corrosion of the piston, in the form of
pitting, indicates that coolant has been
leaking into the combustion chamber and/or
the crankcase. Again, the cause must be
corrected, or the problem may persist in the
rebuilt engine.
10 On aluminium-block engines with wet
liners, it is not possible to renew the pistons
separately; pistons are only supplied with

piston rings and a liner, as a part of a matched
assembly (see Section 12). On iron-block
engines, pistons can be purchased from a
Peugeot dealer.
11 Examine each connecting rod carefully for
signs of damage, such as cracks around the
big-end and small-end bearings. Check that
the rod is not bent or distorted. Damage is
highly unlikely, unless the engine has been
seized or badly overheated. Detailed checking
of the connecting rod assembly can only be
carried out by a Peugeot dealer or engine
repair specialist with the necessary
equipment.
12 On XU series engines, due to the
tightening procedure for the connecting rod
big-end cap retaining nuts, it is highly
recommended that the big-end cap nuts and
bolts are renewed as a complete set prior to
refitting.
13 On all 8-valve engines the gudgeon pins
are an interference fit in the connecting rod
small-end bearing. Therefore, piston and/or
connecting rod renewal should be entrusted
to a Peugeot dealer or engine repair
specialist, who will have the necessary tooling
to remove and install the gudgeon pins.
14 On 16-valve engines, the gudgeon pins
are of the floating type, secured in position by
two circlips. On these engines, the pistons
and connecting rods can be separated as
follows.
15 Using a small flat-bladed screwdriver,
prise out the circlips, and push out the
gudgeon pin (see illustrations). Hand
pressure should be sufficient to remove the
pin. Identify the piston and rod to ensure

Engine removal and overhaul  2C•13

13.2  Removing a piston ring with the 

aid of a feeler gauge

2C

13.15a  On 16-valve engines, 

prise out the circlip . . .

13.15b  . . . and withdraw the gudgeon pin