Remove/Install Piston - AR03.10-P-7021MFC

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Engine 260 in model 118, 177, 247

Courtesy of MERCEDES-BENZ USA

Courtesy of MERCEDES-BENZ USA

	Risk of burn injuries, suffocation and poisoning when working on the exhaust system and the components connected to it. Risk of suffocation and risk of poisoning caused by inhalation of gaseous and solid components of the exhaust. Risk of poisoning caused by skin contact with solid components of the exhaust.	Wear protective clothing and safety glasses. Use the extraction system. Move people out of the danger zone.	AS49.00-Z-0001-01A
	Risk of injury. Skin or eye injuries may result when handling hot or glowing objects.	Wear protective gloves, protective clothing and safety glasses, if necessary.	AS00.00-Z-0002-01A
	Risk of injury to skin and eyes due to handling of engine oil. Risk of poisoning caused by swallowing engine oil	Wear protective gloves, protective clothing and safety glasses. Do not fill engine oil into beverage containers.	AS18.00-Z-0001-01A
	Risk of injury caused by scraping or cutting body parts on sharp vehicle parts	Always wear protective gloves when working on or near sharp and non-deburred vehicle parts. Deburr repair panels.	AS00.00-Z-0017-01A
Notice	Notes on avoiding damage through contamination and foreign objects		AH00.00-P-5000-01A
Notice	Notes on threaded connections fastened using a tightening angle-based tightening process		AH00.00-P-0020-01A
	Remove
1	Remove oil pan.		AR01.45-P-7500MFC
2	Remove balance shaft housing with oil deflector.		AR03.20-P-1105MFC
3	Remove oil pump with oil deflector.		AR18.10-P-6020MFC
4	Remove cylinder head.		AR01.30-P-5800MFC
5	Clean sealing surfaces of crankcase.		AR01.00-P-0050-01A
	Notes on application of flange sealants to seal major assemblies		AH00.00-P-0500-01MNE
		Loctite 7200	*BR00.45-Z-1038-04A
		Loctite 7063 (400 ml) cleaning spray	*BR00.45-Z-1046-04A
6	Carefully remove combustion residues at top-land zone of cylinder bores and blow out cylinder bores with compressed air.	There must not be any combustion residues remaining in the cylinder bores. Otherwise, the piston rings (6a, 6b, 6c) will be damaged.
7	Mark connecting rods (2) relative to respective cylinder.	If new pistons (5) are installed. Do not interchange connecting rods (2). Engine damage can occur otherwise.
8	Apply markings (arrow A) to connecting rod bearing caps (1) and connecting rods (2).	Connecting rods (2) and connecting rod bearing caps (1) are cracked (broken). Do not mix them up. Engine damage can occur otherwise.
9	Remove connecting rod bolts (3).
10	Remove connecting rod bearing caps (1).
11	Mark installation position of connecting rod bearing shells (4) in connecting rod bearing caps (1) and in connecting rods (2).	Do not mix up connecting rod bearing shells (4), connecting rod bearing caps (1), and connecting rods (2). Engine damage can occur otherwise.
12	Check piston crowns (5a) for existing travel direction arrows (D).	If the travel direction arrows (D) on the piston crowns (5a) are no longer recognizable due to soiling or carbonization, ↓ Clean the piston crowns (5a). Assembly cleaner If no travel direction arrows (D) are recognizable after cleaning, ↓ Mark piston crowns (5a) with travel direction arrows (D).	*BR00.45-Z-1028-04A
13	Mark installation position of pistons (5) relative to respective cylinder.	Do not interchange pistons (5). Engine damage can occur otherwise.
14	Remove pistons (5) with connecting rods (2) upwards out of crankcase.
15	Remove connecting rod bearing shells (4) from connecting rod bearing caps (1) and connecting rods (2).
16	Clamp connecting rods (2) with pistons (5) in vise.	Commercially available devices/tools Protective jaws
17	Mark piston pins (8) and connecting rods (2) relative to pistons (5).	If the pistons (5) are reused. Do not interchange piston pins (8), connecting rods (2) and pistons (5). Engine damage can occur otherwise.
18	Remove retaining rings (7) with a suitable tool.	Perform the work on a clean soft base. Otherwise, pistons (5) will be damaged.
19	Press piston pins (8) out of pistons (5).
20	Remove pistons (5) from connecting rods (2).
21	Remove connecting rods (2) from vise.
22	Clean all power unit components.	The power unit components must be absolutely free of soiling. Engine damage can occur otherwise. Assembly cleaner	*BR00.45-Z-1028-04A
	Check
23	Check pistons (5) and piston rings (6a, 6b, 6c) for wear and damage.
Notes on the assessment of pistons and piston rings	If the pistons (5) and piston rings (6a, 6b, 6c) are reused.		AH03.10-P-0001-04 MM
		If there is a problem, ↓ Replace pistons (5) and/or piston rings (6a, 6b, 6c).	AR03.10-P-7311MFC
24	Check piston rings (6a, 6b, 6c) for dimensional accuracy.	If the piston rings (6a, 6b, 6c) continue to be used. Commercially available devices/tools Outside micrometer Dimension	*BE03.10-P-1003-05L
		If there is a problem, ↓ Replace piston rings (6a, 6b, 6c) and pistons (5).	AR03.10-P-7311MFC
25	Check side clearance of piston rings (6a, 6b, 6c).	If the piston rings (6a, 6b, 6c) continue to be used. Commercially available devices/tools Feeler gauge	AR03.10-P-7311-01MFC
		Piston ring vertical clearance	*BE03.10-P-1001-05L
		If there is a problem, ↓ Replace piston rings (6a, 6b, 6c) and pistons (5).	AR03.10-P-7311MFC
26	Check end gap of piston rings (6a, 6b, 6c).	If the piston rings (6a, 6b, 6c) continue to be used. Commercially available devices/tools Feeler gauge	AR03.10-P-7311-02MFC
		Piston ring end gap	*BE03.10-P-1002-05L
		If there is a problem, ↓ Replace piston rings (6a, 6b, 6c) and pistons (5).	AR03.10-P-7311MFC
27	Check connecting rod bearing shells (4) and connecting rod journals for wear and damage. Notes on assessing wear on connecting rod bearings and connecting rod journals		AH03.10-P-0001-03 MM
		If there is a problem, ↓ Replace connecting rod bearing shells (4) and/or crankshaft. Install new connecting rod bearings	AR03.10-P-6111-06MR
		Install new crankshaft	AR03.20-P-4351MFC
		Specified engine oils for Cars, Vans (service) - Overview	BB00.40-P-0223-02A
28	Check cylinder barrels. General information on inspecting cylinder walls	If justified complaints are present during the exchange, ↓ Replace crankcase.	AH01.00-P-0300-01A
29	Check remaining power unit components for wear and damage; replace if necessary.
	Install
30	Clamp connecting rods (2) in vise.	Commercially available devices/tools Protective jaws
31	Wet piston pins (8) and connecting rod small ends with engine oil.
	Specified engine oils for Cars, Vans (service) - Overview		BB00.40-P-0223-02A
32	Assign pistons (5), connecting rods (2), and piston pins (8) to each other.	Watch out for markings for restoration of the same installation position such as for removal. Engine damage can occur otherwise.
33	Manually press piston pins (8) into pistons (5).	Note the applied markings during removal. Engine damage can occur otherwise.
34	Install new retaining rings (7) with a suitable tool.	The opening (arrow B) of the retaining rings (7) must point vertically in the direction of the piston crown (5a) after assembly. Engine damage can occur otherwise. Replace retaining rings (7).
35	Remove connecting rods (2) with pistons (5) from vise.
36	Wet cylinder bores, pistons (5) and connecting rod journals with engine oil.
	Specified engine oils for Cars, Vans (service) - Overview		BB00.40-P-0223-02A
37	Install pistons (5) in direction of travel.	Install pistons (5) with piston ring end gaps offset by 120°. Engine damage can occur otherwise. Observe the travel direction arrows (D) on the piston crowns (5a). Engine damage can occur otherwise. Crank crankshaft until connecting rods (2) do not touch connecting rod journal when inserting a piston (5) in cylinder bores. Otherwise damage will occur on the connecting rod (2) and crankshaft. Tensioning strap	Fig 1
38	Check connecting rod bolts (3); replace if necessary.		AR03.10-P-6111-01MFC
		Connecting rod bolts	*BE03.10-P-1001-03A
39	Install connecting rod bearing shells (4).		AR03.10-P-6111-06MR
	Specified engine oils for Cars, Vans (service) - Overview		BB00.40-P-0223-02A
40	Position connecting rod bolt (3) and tighten it.
	Specified engine oils for Cars, Vans (service) - Overview		BB00.40-P-0223-02A
			AR03.10-P-6111-02MR
		Screw/bolt, connecting rod bearing cap to connecting rod	*BA03.10-P-1001-01J
		Tightening angle with magnet	Fig 2
41	Crank crankshaft by hand and check for unobstructed movement of crank assembly.	If the crankshaft turns sluggishly or jams, ↓ Check the assignment and correct seating of the connecting rod bearing shells (4) and the connecting rod bearing cap (1).	AR03.10-P-6111-02MR
		Specified engine oils for Cars, Vans (service) - Overview	BB00.40-P-0223-02A
		Screw/bolt, connecting rod bearing cap to connecting rod	*BA03.10-P-1001-01J
		Tightening angle with magnet	Fig 2
42	Install cylinder head.		AR01.30-P-5800MFC
43	Install oil pump with oil deflector.		AR18.10-P-6020MFC
44	Install balance shaft housing with oil deflector.		AR03.20-P-1105MFC
45	Install oil pan.		AR01.45-P-7500MFC
	Check
46	Check engine oil level and correct if necessary.
		Vehicle must be horizontal and standing on its wheels. Measurement errors occur otherwise. Never pour in engine oil to above the maximum value. Engine damage will occur otherwise.	AP18.00-P-1812MFA
	Risk of accident from vehicle starting off by itself when engine running. Risk of injury (bruises and burns) resulting from working on the engine while it is being started or when it is running.	Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.	AS00.00-Z-0005-01A
47	Perform engine test run. While doing so, check engine for proper operation and leak tightness.

CHECK VALUES FOR CONNECTING ROD BOLT

Number	Designation				Engine 137, 260, 270, 271, 274, 275, 285
BE03.10-P-1001-03A	Connecting rod bolts	Thread diameter		M	7x1
		Shank length	When new	mm	38
		Shank length	max.	mm	38, 4

CHECK VALUES FOR PISTON RINGS

Number	Designation			Engine 260
BE03.10-P-1001-05L	Piston ring vertical clearance	Groove 1	mm	0, 03...0, 07
		Groove 2	mm	0, 02...0, 06
		Groove 3	mm	0, 01...0, 18

CHECK VALUES FOR PISTON RINGS

Number	Designation			Engine 260
BE03.10-P-1002-05L	Piston ring end gap	Groove 1	mm	0, 2...0, 3
		Groove 2	mm	0, 3...0, 5
		Groove 3	mm	0, 2...0, 7

CHECK VALUES FOR PISTON RINGS

Number	Designation			Engine 260
BE03.10-P-1003-05L	Dimension	Plain compression ring	mm	83, 0x1, 2x3, 1
		Taper-faced hook scraper ring	mm	83, 0x1, 2x2, 9
		Oil scraper ring	mm	83, 0x2, 0x2, 4

CONNECTING ROD

Number	Designation				Engine 260
BA03.10-P-1001-01J	Screw/bolt, connecting rod bearing cap to connecting rod	For initial tightening of new bolts	Stage 1	Nm	5
			Stage 2	Nm	15
			Stage 3	∠°	180
			Stage 4		Loosen bolts
			Stage 5	Nm	5
			Stage 6	Nm	15
			Stage 7	∠°	90
		In case of reusability	Stage 1	Nm	5
			Stage 2	Nm	15
			Stage 3	∠°	90

Fig 1: Identifying Tensioning Strap (000 589 04 14 00)

Courtesy of MERCEDES-BENZ USA

Fig 2: Identifying Tightening Angle With Magnet (450 589 00 13 00)

Courtesy of MERCEDES-BENZ USA

REPAIR MATERIALS

Number	Designation	Order number
BR00.45-Z-1028-04A	Assembly cleaner	A 000 986 56 01
BR00.45-Z-1038-04A	Loctite 7200	A 010 989 90 71
BR00.45-Z-1046-04A	Loctite 7063 (400 ml) cleaning spray	A 001 986 71 71 09