Dometic 310 Toilet Leaking at Foot Pedal: Complete Fix Guide

Quick Take

Since you've already replaced the toilet valve on your Dometic 310 and you're still seeing water pooling under the foot pedal pivot area, the leak is most likely coming from the pedal mechanism seal or the shaft seal where the foot pedal pivot rod enters the toilet base. This is a common failure point on the 310 series after the rubber seals deteriorate from age and use. The water you're seeing dripping between the fixed exterior part and the moving pivot part indicates the shaft seal needs replacement, which requires removing the foot pedal assembly.

Common Causes

The Dometic 310's foot pedal mechanism has several seals that commonly fail over time. The primary culprit in your case is likely the shaft seal that seals where the pivot rod passes through the toilet base. This seal deteriorates from constant movement and exposure to water and chemicals.

Another possibility is the pedal spring housing seal, which can allow water to seep around the entire pedal mechanism. Sometimes the plastic housing itself can develop hairline cracks that aren't immediately visible but allow water to weep through slowly.

Since you mentioned the leak appears to be coming from between the fixed and moving parts of the pedal, it's almost certainly not related to the inlet or outlet connections you already checked. The toilet valve you replaced controls water flow but wouldn't cause leaking in the pedal area.

Preparation

Before starting this repair, turn off your water pump and drain the toilet's water supply by opening the blade valve and flushing until no more water comes out. You'll need a few basic tools: a Phillips head screwdriver, needle-nose pliers, and possibly a small pry tool or flathead screwdriver.

Order the pedal mechanism seal kit or the complete pedal assembly if the housing is cracked. The seal kit typically costs around $15-20, while the complete assembly runs about $45-60. Having both on hand isn't a bad idea since the plastic housing can be brittle on older units.

Take photos of the pedal assembly before disassembly - the spring mechanism can be tricky to reassemble properly. Work in good lighting and have a towel handy to catch any remaining water that may drain out during the process.

Repair Steps

Start by removing the foot pedal assembly. There are typically two screws holding the pedal housing to the toilet base. WARNING: The spring mechanism is under tension and can cause injury if released suddenly. Keep your hands clear of the spring mechanism, control the pedal assembly firmly, and remove the screws slowly to prevent sudden spring release. Once the screws are out, the entire pedal assembly should lift away from the toilet base.

Examine the shaft seal where the pivot rod enters the toilet base. This rubber seal often appears cracked, hardened, or compressed when it's failing. Remove the old seal carefully - it may be stuck to both the rod and the housing. Clean all surfaces thoroughly with a damp cloth to remove any mineral deposits or debris.

Install the new shaft seal, ensuring it's properly seated in its groove. Apply a thin layer of sanitary/potable water safe silicone grease to help with installation and future removal. If the plastic housing shows any cracks, now is the time to replace the entire pedal assembly rather than just the seals.

Reassemble the pedal mechanism, making sure the spring is properly positioned and the pivot rod moves smoothly. Reinstall the assembly to the toilet base with the two screws, being careful not to overtighten as this can crack the plastic housing. Test the pedal operation before turning the water back on, then check for leaks after filling the toilet bowl.

When to Get Help

If you find that the toilet base itself has cracks around the pedal mounting area, this typically requires professional repair or toilet replacement. The base is under stress from the pedal mechanism, and cracks here often indicate the toilet is nearing the end of its useful life.

Call a professional if you discover the leak is actually coming from inside the toilet base rather than the external seals. This could indicate internal damage that's not economically repairable on a Dometic 310. Similarly, if multiple seal replacements don't solve the problem, there may be warpage or damage to the mounting surfaces that requires professional assessment.

Consider professional help if you're uncomfortable working with the spring-loaded pedal mechanism, as improper reassembly can affect the toilet's flush operation. A mobile RV technician can typically complete this repair in 30-45 minutes for around $100-150 in labor plus parts.