Cat D8 Series Dozer Hydraulic Cylinders
This category covers blade tilt cylinders, tilt cylinder groups, ripper cylinder groups, ripper tip and ripper tilt cylinders, and hydraulic cylinder tubes for Caterpillar D8 series crawler dozers — the D8L, D8N, D8R, D8R II, and D8T. These are heavy production machines, and the blade and ripper cylinders take enormous load, so matching the right group to your model and serial number matters. Broken Tractor stocks complete cylinder groups, ripper cylinders, and replacement tubes ready to ship.
Fits Models At A Glance
D8L, D8N, D8R, D8R II, D8T — with shared cylinder tubes fitting 12H, 12H ES, 12H NA, 12K, 140H motor graders and D9N, D9R, D9T dozers
Fitment note: Verify your serial number and blade configuration (SU, U, or S) before ordering. Several D8 cylinder groups changed between the D8N, the D8R/D8R II, and the D8T — the same blade function can take a different group depending on your machine.
What's In This Category
Blade Tilt Cylinders & Tilt Cylinder Groups
Complete tilt cylinder groups for the D8N, D8R, and D8R II (6E1175), the D8R and D8T (2407347), and the D8L and D9N (3G5707), plus the individual blade tilt cylinder for the D8N, D8R, and D8R II (6E1103). These control blade pitch for cutting and carrying, and they're among the hardest-worked cylinders on the machine.
Ripper Cylinder Groups
Ripper cylinder group (1553653), ripper tip cylinder groups (1553652, 1650102), and ripper tilt cylinder group (9T0143) for the D8R, D8R II, D8T, and D8N. These raise, lower, and pitch the rear ripper shanks for breaking hardpan and rock.
Hydraulic Cylinder Tubes
Cylinder tubes for the D8N/D8R/D8R II (6E1176, also fits 12H and 140H graders), the D8N (9T0332), the D8R/D8T (2388637), and the D8L/D9N/D9R/D9T (1661855). Replace the tube when the bore is scored but the rod, gland, and piston are still serviceable — a major cost saver on these large cylinders.
Fitment Tip
The D8 line splits into three cylinder eras. The D8L (and D9N) use the 3G5707 tilt group and share the 1661855 tube with the D9 series. The D8N and D8R/D8R II use the 6E-series cylinders (6E1175 tilt group, 6E1103 tilt cylinder, 6E1176 tube). The D8R and D8T moved to the 2407347 tilt group and 2388637 tube. On the ripper end, watch the serial coverage — the 1553652 and 1650102 ripper tip groups both fit the D8R/D8R II/D8T but cover different serial ranges. The D8 serial number is on the rear of the machine, left side, high on the frame rail, and may be hidden by the ripper. Pre-2001 machines use an 8-digit serial; 2001 and newer use a 17-digit VIN. Call us with your serial and blade/ripper configuration and we'll confirm the right group before you buy.
Frequently Asked Questions
Which tilt cylinder group fits my Cat D8R or D8T dozer?
It depends on the exact machine. The D8N, D8R, and D8R II use tilt cylinder group 6E1175 (or the individual blade tilt cylinder 6E1103). The later D8R and D8T use tilt cylinder group 2407347. Because the D8R spans both groups depending on serial number, confirm your serial before ordering — this is the most common wrong-part call on the D8 tilt cylinder.
What's the difference between the D8 ripper cylinder groups 1553652 and 1650102?
Both are ripper tip cylinder groups that fit the D8R, D8R II, and D8T, but they cover different serial ranges and build configurations. The 1553653 is the full ripper cylinder group, while 1553652 and 1650102 are ripper tip groups. Match the group to your serial number and ripper type (single-shank vs multi-shank) before ordering, since the ripper setup determines which cylinder you need.
Can I replace just the cylinder tube on my Cat D8 instead of the whole cylinder group?
Yes. Broken Tractor stocks D8 hydraulic cylinder tubes separately — 6E1176 for the D8N/D8R/D8R II, 9T0332 for the D8N, 2388637 for the D8R/D8T, and 1661855 for the D8L/D9N/D9R/D9T. If the cylinder bore is scored but the rod, gland, and piston are still good, replacing just the tube saves thousands over a complete cylinder group. Inspect the rod and gland first to confirm they're reusable.
Does the D8N tilt cylinder interchange with the D8T tilt cylinder?
No. The D8N uses the 6E1175 tilt cylinder group and 6E1103 blade tilt cylinder, while the D8T uses the 2407347 tilt cylinder group. They are not interchangeable. The D8R sits in the middle and can take either group depending on its serial number, so always verify the serial before ordering a D8-series tilt cylinder.
Why is my Cat D8 blade slow or drifting under load?
Slow or drifting blade movement on a D8 usually points to worn internal cylinder seals or a leaking control valve. Because these are large high-pressure cylinders, even a small amount of internal bypass shows up as noticeable drift. Pressure-test the cylinders individually — if they hold when plugged but drift when reconnected, the control valve is the issue. If a cylinder bypasses internally and the bore is scored, replace the tube or the complete group rather than just reselling.
Where is the serial number on a Cat D8 dozer?
On the D8 and other large Cat dozers, the serial number is on the rear of the machine, left side, high up on the end of the left frame rail — it may be partly hidden by the ripper attachment. Pre-2001 machines use an 8-digit serial; 2001 and newer machines use a 17-digit VIN. You need this number, plus your blade and ripper configuration, to order the correct cylinder group.
Not sure which cylinder group or tube fits your machine? Call or text us at (800) 909-7060 or submit a parts request and we'll match it to your serial number and configuration.
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