Hydraulic cylinders

Two essentially similar types of hydraulic cylinders are used on the excavator. The cylinder that is used to operate the excavator boom or bucket is equipped with a rod stopper, which acts as a cushion only when the cylinder rod is fully retracted (and the bucket is pulled close to the arm). This type of cylinder is shown in the lower drawing.Arm cylinders have a cushion or stopper for operation in both directions. This type of cylinder is shown in the upper drawing

Theory of Operation

Cylinder piston rods are extended or retracted by oil flow to the back side of the cylinder (shown as (“oil path A”) or to the front of the cylinder (“oil path B”).The cylinder rod is extended as oil flow is pumped through the circuit to the back side of the piston. The force (F1) of the piston stroke can be expressed by the formula below, where P = circuit oil pressure and the inside diameter of the cylinder is expressed by D (Figure 1). F1 = P x πD2 /4
(P: Pressure, π = 3.14, D: Cylinder Inside Diameter)
When the cylinder rod is retracted, oil flow through the circuit from the pump to the front side of the cylinder generates a force (F2) that can be expressed by the formula in which the diameter of the piston rod is expressed by R, and the other two terms are the same as in the preceding expression.
F2 = P x (π(D2-R2))/4

Because the volume of oil needed to lengthen the cylinder rod (Q1) is greater than the volume of oil required to retract the cylinder rod, it takes more time to extend a cylinder than it does to retract it.
Q1 = S x π(D2)/4 Q2 = S x (π(D2-R2))/4 Q1 > Q2


The spare parts

We offer the seal kit for various models of Doosan excavators S280LC-3, S290LC-V, S300LC-V, S400LC-V, S420LC-V, DX300LC and Dx300LCA

Cylinders seal kits for S300LC-V and S290LC-V

SEAL KIT;BOOM CYL. (Cylinder diameter 140 mm & Rod diameter 95 mm ) with part Number 2440-9238KT (401107-00270) the details of seal kit components show in below table

Seq.Old part NumberNew part number Item descriptionFit QT’Y
1E5130320180-00271SEAL;SLIPPER (SPGW 140) (DOOSAN & WYS)1
200Z109-0115-00079RING;WEAR (AWR 140 * 135 * 9.5 ) (K9001149)2
300R730-0115-00080RING;SLYD (DZW 140 * 132 * 9.5)2
4E6311421S8010751O-RING (1BG 75)1
553B315-0180-00300RING;BACK UP (T3G 75)1
6E6311741S8011351O-RING (1BG 135)1
753B316-0180-00270RING;BACK UP (T3G 135)1
8E64900592180-1217D96O-RING (AN 160)1
9E5500310180-00302SEAL;BUFFER (HBHW 95 * 110.5 * 6)1
10E5303260115-00097U-PACKING (NOK IDI 95 * 115 * 12) (IDKW)1
11E6020310115-00099WIPER;DUST (DOOSAN DKBW 95 109 8/11)1
2440-9238KT (401107-00270)

SEAL KIT;ARM CYL. ( Cylinder diameter 150mm & Rod diameter 105mm ) with part Number 2440-9240KT (401107-00198) the details of seal kit components show in below table

Seq.Old part NumberNew part number Item descriptionFit QT’Y
1E5130340180-00360SEAL;SLIPPER (SPGWD 150*127*15.5)1
200Z111-0115-00121RING;WEAR (AWR 150*145*9.5/2.5)2
300R103-0115-00122RING;SLYD (DZW 150*142*9.5)2
4E6311461S8010855O-RING (1BG 85)1
553A358-01.180-00279RING;BACK UP (T3G 85)2
653A359-0180-00359RING;BACK UP (T3G 145)1
7E6311781S8011451O-RING (1BG 145)1
8E55003301.180-00471SEAL;BUFFER (HBHW 105*120.5*6)1
9E53033801.180-00213U-PACKING (IDKW 105*125*15),31
10E60203301.180-00489WIPER;DUST (DKBW 105*121*9/12)1
11E6490060180-00363O-RING (AS568-162) (O-RING (AN-162)1
12S80003412180-1026D19O-RING (1BP 34)1
2440-9240KT (401107-00198)

SEAL KIT;BUCKET CYL. ( Cylinder diameter 140 mm & Rod diameter 90mm ) with part Number 2440-9241KT (401107-00335) the details of seal kit components show in below table

SeqOld part NumberNew part number Item descriptionFit QT’Y
1E5130320180-00271SEAL;SLIPPER (SPGW 140) (DOOSAN & WYS)1
200W267-0115-00279RING;WEAR (AWR 140*135*9.5 ) (K9001149)2
300R730-0115-00080RING;SLYD (DZW 140*132*9.5)2
4E6311341S8010701O-RING (1BG 70)1
553U252-0180-00268RING;BACK UP (T3G 70)1
6E6311741S8011351O-RING (1BG 135)1
753B316-0180-00270RING;BACK UP (T3G 135)1
8E64900592180-1217D96O-RING (AN 160)1
9E5500300180-00265SEAL;BUFFER (HBHW 90*105.5*6)1
10E5303200115-00071U-PACKING (NOK  JIDI 90*110*12)1
11E6020300115-00072WIPER;DUST (DKBW 90*104*8)1
2440-9241KT (401107-00335)

Cylinders seal kits for S400LC-V and S420LC-V

SEAL KIT;BOOM CYL. (Cylinder diameter 165 mm & Rod diameter 115 mm ) with part Number 2440-9295KT (401107-00272) the details of seal kit components show in below table

SeqOld part NumberNew part number Item descriptionFit QT’Y
1E5130370180-00303SEAL;SLIPPER (SPGW 165)1
200Z112-0115-00095RING;WEAR  ( AWR 165*160*15 )2
300R729-0115-00093RING;SLYD ( DZW 165*157*9.5 )2
4E6311481S8010901O-RING (1BG 90 )1
553A429-0180-00299RING;BACK UP ( T3G 90 )2
653A433-1180-00298RING;BACK UP ( T3G 155 )1
7E6311821S8011551O-RING ( 1BG 155 )1
8E64900621.180-00168O-RING (AN 165 )1
9E5500350180-00301SEAL;STEP ( HBHW 115 * 130.5 * 6 )(k9001950)1
10E5303590115-00096U-PACKING (JIDI 115*135*16 )1
11E6020350115-00098WIPER;DUST (DKBW 115*131*9 ) 121
2440-9295KT (401107-00272)

SEAL KIT;ARM CYL. ( Cylinder diameter 180mm & Rod diameter 120mm ) with part Number 2440-9293KT (401107-00205 ) the details of seal kit components show in below table

SeqOld part NumberNew part number Item descriptionFit QT’Y
1E51304001.180-00571SEAL;SLIPPER   (SPGW 180)1
200Z114-01.180-00419RING;WEAR  ( GWR 180 * 172 * 22.5 )2
300R106-01.180-00367RING;SLYD   ( DZW 180 * 172 * 9.5 )2
4E6311501S8010855O-RING   (1BG 95 )1
553A473-01.180-00271RING;BACK UP   ( T3G 95 )2
653A472-01.180-00270RING;BACK UP  ( T3G 170 )1
7E6311881S8011701O-RING   ( 1BG 170 )1
8E64900912180-1216D150O-RING   (AN 260 )1
9E55003601.180-00473SEAL;BUFFER ( HBHW 120 * 135.5 * 6 )1
10E53037001.180-00214U-PACKING (JIDI  120 * 140 * 15 ) (3)1
11E60203601.180-00501WIPER;DUST  (DKBW 120 * 136 * 9 ) 121
2440-9293KT (401107-00205 )

SEAL KIT;BUCKET CYL. ( Cylinder diameter 160 mm & Rod diameter 110mm ) with part Number 2440-9294KT ( 401107-00337 ) the details of seal kit components show in below table

SeqOld part NumberNew part number Item descriptionFit QT’Y
1E51303601.180-00572SEAL;SLIPPER  (SPGW 160)1
200Z118-01.180-00433RING;WEAR  ( AWR 160 * 155 *15 )2
300R104-01.180-00369RING;SLYD ( DZW 160 * 150 * 9.5 )2
4E6311461S8010855O-RING (1BG 85)1
553U434-01.180-00282RING;BACK UP2
653U433-0RING;BACK UP1
7E6311801S8011501O-RING 1BG-1501
8E64900902180-1216D149O-RING1
9E55003401.180-00474SEAL;BUFFER  ( HBHW 110 * 125.5 * 6 )1
10E53035001.180-00216U-PACKING (  (IDI 110 * 130 *15 ) NOK N851
11E60203401.180-00502WIPER;DUST (DKBW 110 * 126 * 9 ) 121
2440-9294KT ( 401107-00337 )

Cylinders seal kits for DX300LC and DX300LCA

SEAL KIT;BOOM CYL. (Cylinder diameter 140 mm & Rod diameter 95 mm ) with part Number K9001007 (401107-00274) the details of seal kit components show in below table

SeqPart NumberItem descriptionFit QT’Y
1K9001148SEAL;SLIPPER (OK 140*119*8)1
2115-00079RING;WEAR (AWR 140*135*9.5)2
3K9001149RING;DUST (DZW 140*132*6)2
4S8010751O-RING (1BG 75)2
51.180-00663RING;BACK UP (T3G 75)1
61.180-00659SEAL;BUFFER (HBHW 95)1
71.180-00660U-PACKING (IUW2 95*115*12)1
8K9001146RING;BACK UP (BRBW 95*115*3)1
9115-00099WIPER;DUST (DKBW 95*109*8)1
10S8011351O-RING (1BG135)1
111.180-00662RING;BACK UP (T3G 135 )1
122180-1217D96O-RING ( AN 160 )1
K9001007 (401107-00274)

SEAL KIT;ARM CYL. ( Cylinder diameter 150mm & Rod diameter 105mm ) with part Number K9001008 (401107-00203A) the details of seal kit components show in below table

SeqPart NumberItem descriptionFit QT’Y
1K9001166SEAL;SLIPPER (OK 150*129*8 )1
2115-00121RING;WEAR  (AWR 150*145*9.5)2
3K9001167RING;SLYD (DZW 150*142*6)2
4S8010851O-RING (1BG 85)1
5K9001168RING;BACK UP (T3G 85)2
6K9001164RING;BACK UP (T3G 145)1
7S8011451O-RING (1BG 145)1
8180-00363O-RING (AN 162 )1
91.180-00655SEAL;BUFFER (HBHW 105)1
101.180-00656PACKING;U (IUW2 105*125*15)1
11K9001163RING;BACK UP (BRBW 105*125*3)1
121.180-00489WIPER;DUST (DKBW 105*121*9)1
K9001008 (401107-00203A)

SEAL KIT;BUCKET CYL. ( Cylinder diameter 140 mm & Rod diameter 90mm ) with part Number K9001009 (401107-00339A)the details of seal kit components show in below table

SeqPart NumberItem descriptionFit QT’Y
1K9001148SEAL;SLIPPER (OK 140*119*8)1
2115-00079RING;WEAR (AWR 140*135*9.5 )2
3K9001149RING;SLYD  (DZW 140*132*6 )2
4S8010701O-RING (1BG 70)1
5K9001156RING;BACK UP  (T3G 70)2
61.180-00662RING;BACK UP (T3G 135)1
7S8011351O-RING (1BG 135)1
82180-1217D96O-RING (AN 160 )1
91.180-00657SEAL;BUFFER  (HBHW 90)1
10K9001153U-PACKING (IUW2 90*110*12)1
11K9001154RING;BACK UP (BRBW 90*110*3)1
12115-00072WIPER;DUST (DKBW 90*104*8 )1
K9001009 (401107-00339A)