Pin Clearance for Front Mounted Hydraulic Cylinders

Published: January 19, 2022 Last Updated: June 20, 2023 Industries, Waste

Telescopic cylinders are preferred for dump trucks because they offer a long stroke from a compact unit and can handle imbalanced loads. When front-mounted, these cylinders provide the additional benefits of increased front-of-body leverage and reduced stress on the dump body frame. It’s an ideal and reliable solution for extra-large trucks carrying heavy loads.
Even with these benefits, problems can arise when operating front-mounted hydraulic cylinders. The good news is you can prevent these issues with proper mounting and pin piston clearance.

Prevent Side Load On Front Mounted Dump Truck Cylinders

Side loading is one of the primary issues caused by insufficient hydraulic cylinder pin clearance. For those not familiar with the term, side load occurs when external forces, such as a heavy load, push the rod up, down, or to the side.
The longer the cylinder stroke and the further the rod extends, the higher the chance of dump truck cylinder side load. If not addressed and corrected, side load can permanently damage the cylinder rod and cause premature hydraulic cylinder failure.
Proper pin clearance can help prevent side load when front mounting telescopic hydraulic cylinders on dump trucks. Pin clearance is the space between the pin and the pinhole on a cylinder. This clearance gives the cylinder body extra room to sway slightly while dumping and helps prevent side load on the cylinder.

How to Calculate Pin Clearance

When calculating pin mounting clearance, the cylinder plunger or one of the sleeves should be extended to a minimum of 1/4” with the dump body in a down position. Make sure your mounts are secure on both ends, and the cylinder can float in the pin mountings. Adjust the dump truck cylinder pins as needed until you achieve proper clearance.
We created these guidelines to help you determine sufficient pin clearance on your hydraulic cylinder.
Follow the guidelines in the table below to allow for sufficient pin mounting clearance.

Mounting Eye Measurement Suggested Clearance between pin & pin hole
Single Less than 5″ wide 1/16″ to 1/8″
Single Greater than 5″ wide 1/8″ to 3/16″
Double Less than 5″ wide 1/8″ to 1/4″ per side
Double Greater than 5″ wide 1/4″ to 1/2″ per side

Need Help Calculating Pin Clearance for Dump Truck Cylinders?

The engineers at Hydraulic Cylinders, Inc. understand the dump truck industry and can answer your questions about pin mounting clearance and selecting the right hydraulic cylinder for your dump truck.
Give us a call at 1-866-818-0195 to speak with one of our cylinder experts. You can also visit our blog to find valuable information and maintenance tips for hydraulic cylinders.

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