Every day, our experienced heavy equipment mechanics replace wear parts on concrete pumps. This is a crucial step in our refurbishment process. Inspecting, replacing, and testing wear parts make these used machines run and last like new for a very affordable price.
If you have some experience working on concrete pumps and other heavy equipment, you can follow the steps below to replace the wear parts to keep your concrete pump working reliably. These instructions are applicable to the Schwing models BPA500 and BPA450. The wear part replacement process should take you about 8 full hours, but it is worth it in terms of significantly reducing downtime on a job.
Remove the Concrete Hopper
- First thing to know is that the agitator comes off with the top portion of the hopper when it is removed. This is different from a Schwing WP750 or bigger capacity concrete pump where the agitator stays in the bottom bowl.
- Take the 8 bolts off the hopper. Note 2 of these bolts removes the switch-over arm shields from behind the hopper.
- Disconnect the 2 hydraulic lines going into the agitator. To ensure no oil leaks, tie the lines together or use plugs in each.
- Take the top hopper off the machine. You can use a forklift and some chains wrapped around the agitator shaft. Just make sure when you take the hopper off that you don’t bend or tear out the flange that goes under the grease line for the back bearing. The flange is a critical piece of the puzzle, since it greases the back bearing by the switch-over arm. Without the proper greasing action, you will be replacing your rock valve pretty quickly. So a little careful attention goes a long way.
Under the Front Face Plate
- Remove the front face plate.
- Use a 65mm wrench to unbolt the jam nut for the rock valve.
- Take the flange and washer off.
- Remove the 4 bolts from the reducing cone or 5″ outlet.
- Once you remove and the reducing cone, you will see 4 bolts that hold the mirror plate; make sure to remove these, too.
- Remove the 10 bolts from the bottom hopper face plate or transition.
- Use a chisel or a hammer to remove the 2 wedges on each side of the face plate.
- Slide this whole transition piece off the front of the rock valve shaft, make sure you don’t hit the bearing when sliding it out.
- Along with this transition, the mirror plate will come off, too.
Remove the Rock Valve
- Now you see the bottom bolt and the rock valve, take the switch-over arm retaining bolt that holds the switch-over arm to the back of the rock valve shaft; remove it with the cap of the switch-over arm.
- Slide the switch-over arm towards the hydraulic tank and pull the rock valve out of it. Be careful not to hit the back bearing (brass piece) as you slide the shaft out.
- When you slide the arm out, there is going to be a retaining cap with an o-ring in there. Remove the 3 bolts so you can take the rock valve shaft retaining cap with o-ring off. It is very important to remove the o-ring, since it is the buffer between the rock valve shaft and the bearing where the shaft is housed.
- Take the back bearing off to inspect it. Make sure the grease control ports are in perfect shape and that the bearing is not scored.
- Inspect the rock valve. Look at the cutting ring, compression seal, and rock valve shaft for signs of wear.
- Locate the wear plate and unscrew the 2 special bolts (M30x70) to remove the plate. We recommend replacing all bolts with new ones to prevent needing to cut them in the future if they seize up with rust.
- Once the wear plate is out, you will see 2 o-rings that go around the material cylinders. Clean the surface where the plate fits and replace the 2 o-rings. Use a wire wheel to ensure this surface is smooth.
Completing the Wear Part Replacement Job
- Now go in reverse ensuring that any worn parts are replaced and grease is applied where appropriate.
- As you replace each bolt or part, be sure to avoid banging or scraping brass parts or bearings.
- Inspect your work carefully as you rebuild the concrete pump.
For any questions about fixing your concrete pump, don’t hesitate to contact us.
