Optional:
- The original macerator discharge hose is a 1-inch ID Kanaflex hose. You can get on EBay by the foot, just click on the link.
- Macerator pump replacement: Shurflo Macerator
Before starting, make sure that the house battery is off or disconnected. Clean and empty both holding tanks. Some waste fluid is expected to drip when you start disconnecting the macerator inlet and outlet ports, so be prepared. I used a small bucket to catch all the remaining waste fluids in the line.
1. Raise the passenger wheels on ramps for easy access to underside of the RV. I made wooden ramps for this purpose. For safety, chock the driver side wheels to prevent the RV from rolling off the ramps.
2. Loosen the 4 bolts/nuts holding the macerator intake port to the drainpipe, be ready for any liquids. Let the liquid drain into the bucket or container of choice, and then stuff some paper towels/rugs to the pump and drainpipe opening. Loosening and removing the 2 upper bolts/nuts is difficult as there is not enough space to maneuver a tool in that area.
3. Now unscrew the (x2) discharge hose holding clamps from the macerator metal shield. Using a utility knife, cut the green discharge hose about a quarter inch past the pump discharge outlet port. Roadtrek used some kind of sealant around the pump discharge port connection making the hose impossible to remove.
4. Unscrew the small white plastic clamp that holds the gray waste gate valve cable.
6. Disconnect the impeller extension turning rod. Just unscrew it from the rear end of the macerator pump by undoing 2 set screws.
7. Trace the positive power wire from the pump unveiling it from the plastic split wire loom, then cut the wire just next to the butt connector. The negative ground wire is connected to the pump shield and no need to remove it as the pump and shield needs to be removed in one piece.
8. Unscrew 2 small self-tapping screws that holds the pump metal shield front (facing the passenger side) to the exhaust heat shield (not pictured).
9. Unscrew the pump metal shield arm from the frame. The pump and its enclosure should be free at this point.
10. To get to the pump, you need to disassemble the pump surround shield first. Remove the 6 rivets (3 on each side) that hold the shield top cover. Then undo the 4 bolts/nuts that hold the pump to the bottom of the shield.
11. Undo 3 bolts that hold the plastic intake port. Removing the bolts is somewhat tricky as the bolts are blocked by the square plastic piece of the intake port. I used a #2 Philips head bit and a ratcheting wrench to inch the bolts out.
12. Remove the steel cutting blade nut. There is a slot in rear end of the motor for a flathead screwdriver to manually hold the shaft while loosening the nut the secures the steel cutting blade.
After removing the steel cutting blades (remember the blade orientations), the impeller housing should easily slide out the motor shaft. The impeller "paddles" are almost gone, and now feels spongy compared to the rubbery new set. I'm not sure if using tank chemicals has played a role to the degradation of the impeller. The old impeller is green while the new impeller is blue, maybe it is made of different material so it has different feel to it.
13. All you have to do now is to reverse the process to reinstall the pump.
1. Raise the passenger wheels on ramps for easy access to underside of the RV. I made wooden ramps for this purpose. For safety, chock the driver side wheels to prevent the RV from rolling off the ramps.
2. Loosen the 4 bolts/nuts holding the macerator intake port to the drainpipe, be ready for any liquids. Let the liquid drain into the bucket or container of choice, and then stuff some paper towels/rugs to the pump and drainpipe opening. Loosening and removing the 2 upper bolts/nuts is difficult as there is not enough space to maneuver a tool in that area.
3. Now unscrew the (x2) discharge hose holding clamps from the macerator metal shield. Using a utility knife, cut the green discharge hose about a quarter inch past the pump discharge outlet port. Roadtrek used some kind of sealant around the pump discharge port connection making the hose impossible to remove.
4. Unscrew the small white plastic clamp that holds the gray waste gate valve cable.
5. Unscrew the metal strap that supports the waste gate valve into the pump shield.
7. Trace the positive power wire from the pump unveiling it from the plastic split wire loom, then cut the wire just next to the butt connector. The negative ground wire is connected to the pump shield and no need to remove it as the pump and shield needs to be removed in one piece.
8. Unscrew 2 small self-tapping screws that holds the pump metal shield front (facing the passenger side) to the exhaust heat shield (not pictured).
9. Unscrew the pump metal shield arm from the frame. The pump and its enclosure should be free at this point.
10. To get to the pump, you need to disassemble the pump surround shield first. Remove the 6 rivets (3 on each side) that hold the shield top cover. Then undo the 4 bolts/nuts that hold the pump to the bottom of the shield.
RT has welded a square flange adapter to the pump intake port; this connects with 4 bolts/nuts to the holding tank drain.
11. Undo 3 bolts that hold the plastic intake port. Removing the bolts is somewhat tricky as the bolts are blocked by the square plastic piece of the intake port. I used a #2 Philips head bit and a ratcheting wrench to inch the bolts out.
After removing the steel cutting blades (remember the blade orientations), the impeller housing should easily slide out the motor shaft. The impeller "paddles" are almost gone, and now feels spongy compared to the rubbery new set. I'm not sure if using tank chemicals has played a role to the degradation of the impeller. The old impeller is green while the new impeller is blue, maybe it is made of different material so it has different feel to it.
13. All you have to do now is to reverse the process to reinstall the pump.
SHURflo Macerator parts diagram
Additional notes/tips:
- Use a watertight butt connector when reconnecting the pump positive wire.
- A regular hose clamp can be used to secure the discharge hose to the pump outlet port. RT used an ear hose clamp of some sort and I did not have the right tool to remove it, a wire cutter did the trick.
- Once the discharge hose is freed/ cut from the macerator, the small piece of green hose that was left on the macerator barbed outlet fitting needs to be removed before reattaching the original hose. Reconnecting the hose back into the macerator barbed fitting is hard as it is a very tight fit; the stiff hose does not help either. Immersing the end of the hose in hot water soften it a bit and expands a little during reinstallation.
- Applying a small amount of silicone sealant around the macerator barbed outlet fitting before reconnecting the hose is a good idea to provide a watertight fit.
Good luck.
Thanks for the great macerator repair blog. Just pulled mine. Mushy green inside. Do you remember where you bought the impeller repair kit? I see there are a few companies out there, but thought I'd ask. Thanks in advance, Doug (Ho-hum on Sprinter Source)
ReplyDeleteHi Doug, first I apologize for the really late reply. I was out on a roadtrip for weeks, no internet connection were we stayed. Anyways, I got the impeller kit on Ebay, it is part number 94-571-00 by Shurflo. Hope that helps.
DeleteThanks. Roadtrips with no internet are the best. True vacation. Got the part at a local marine supply. Thanks again for the great write-up. Your remote macerator mod is of great interest. Next project.
DeleteThis is a great write-up, any other updates on this? I saw it was written and 2013 and wondering how it is holding up. I just got a 2008 RS and the macerator was making a noise, but nothing was happening, so I'm assuming I need to do this repair and just ordered the part through your link.
ReplyDeleteThat is the last time I’ve replaced it. The replacement blue color impeller appears to be made of different rubber and it has more rubbery feel to it than the original. I also made a habit not to run the macerator dry; once the discharge starts to sputter I immediately stop it.
DeleteIf your macerator is not running, check coach battery voltage, check the fuse, check the switch for continuity, manually turn the macerator using the black knob next to holding tank waste gate valve handles- push it in to engage then turn it back and forth to unstuck the macerating blades. Sign of a worn out impeller is you hear the motor running but it’s not discharging- but this could also a sign of a blocked drain line.
DeleteI tried manually using the wastegate valve handle and it did not work, unfortunately, and the motor is running, so it looks like I'm doing this.
DeleteI am having trouble understanding fixing the green discharge hose, let me see if this is correct...
1) Put the end of the green discharge hose in nearly boiling water for several minutes to soften it.
2) Thread it back in to the other side of the hose that was cut (I dont understand that, I guess it will fit if soft enough?)
3) Put Silicone where they touch (I actually got a marine grade sealant that appeared to be more robust than silicone)
4) Put the Screw Hose Clamp around both ends after the silicone is applied.
Is that correct? Can you offer any other insights?
Also, are you on patreon, or do you have a paypal/venmo I can donate to? I really appreciate the help, and I have to have this fix done by tomorrow night and amazon just delivered the impeller (I used your link), you are really a lifesaver!
The green hose that is fixed into the macerator discharge outlet is really hard to remove so I ended up cutting the hose just past the outlet port.
DeleteThe small piece of green hose that was left on the macerator (barb type) discharge outlet needs to be removed before attaching the hose back. Threading/ pushing the hose back into the macerator port is hard as it is rubbery stiff, making is softer (immersing it in hot water) does help.
You can apply a thin amount of silicone or similar to the macerator barb fitting before threading the hose back in then use a hose clamp (x1) to secure the hose in place.
Thanks for offering a donation, but helping out a fellow RV’ers is more rewarding for me and that is one of the reasons this blog exists. Thank you.
Thanks for info. Have a question as to the inside diameter of the hose, as mine cracked 4 feet from the outer end.
ReplyDeleteIt's 1-inch ID. The original hose is made by Kanaflex: https://ebay.us/I1q5Fo
DeleteFor future use. The flange that roadtrek uses to fasten the pump to the gate valve unscrews. Make it easy to access the impeller by removing that first to access the small screws
ReplyDeleteMine was glued into the square flange fitting. I've tried to remove/ unscrew it to no avail. Others might be lucky. Thanks for the info.
Delete