diff --git a/pkg/apis/certmanager/v1alpha1/BUILD.bazel b/pkg/apis/certmanager/v1alpha1/BUILD.bazel
index f8e4c27a8..3fca26c21 100644
--- a/pkg/apis/certmanager/v1alpha1/BUILD.bazel
+++ b/pkg/apis/certmanager/v1alpha1/BUILD.bazel
@@ -4,8 +4,6 @@ go_library(
     name = "go_default_library",
     srcs = [
         "const.go",
-        "conversion.go",
-        "defaults.go",
         "doc.go",
         "generic_issuer.go",
         "register.go",
@@ -16,7 +14,6 @@ go_library(
         "types_issuer.go",
         "types_order.go",
         "zz_generated.deepcopy.go",
-        "zz_generated.defaults.go",
     ],
     importpath = "github.com/jetstack/cert-manager/pkg/apis/certmanager/v1alpha1",
     visibility = ["//visibility:public"],
diff --git a/pkg/apis/certmanager/v1alpha1/conversion.go b/pkg/apis/certmanager/v1alpha1/conversion.go
deleted file mode 100644
index ec8b98112..000000000
--- a/pkg/apis/certmanager/v1alpha1/conversion.go
+++ /dev/null
@@ -1,26 +0,0 @@
-/*
-Copyright 2019 The Jetstack cert-manager contributors.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-package v1alpha1
-
-import (
-	"k8s.io/apimachinery/pkg/runtime"
-)
-
-func addConversionFuncs(scheme *runtime.Scheme) error {
-	// Add non-generated conversion functions
-	return scheme.AddConversionFuncs()
-}
diff --git a/pkg/apis/certmanager/v1alpha1/defaults.go b/pkg/apis/certmanager/v1alpha1/defaults.go
deleted file mode 100644
index 233326a8b..000000000
--- a/pkg/apis/certmanager/v1alpha1/defaults.go
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
-Copyright 2019 The Jetstack cert-manager contributors.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-package v1alpha1
-
-import (
-	"k8s.io/apimachinery/pkg/runtime"
-)
-
-func addDefaultingFuncs(scheme *runtime.Scheme) error {
-	return RegisterDefaults(scheme)
-}
diff --git a/pkg/apis/certmanager/v1alpha1/register.go b/pkg/apis/certmanager/v1alpha1/register.go
index 27fbedc21..7033464eb 100644
--- a/pkg/apis/certmanager/v1alpha1/register.go
+++ b/pkg/apis/certmanager/v1alpha1/register.go
@@ -43,7 +43,7 @@ func init() {
 	// We only register manually written functions here. The registration of the
 	// generated functions takes place in the generated files. The separation
 	// makes the code compile even when the generated files are missing.
-	localSchemeBuilder.Register(addKnownTypes, addDefaultingFuncs, addConversionFuncs)
+	localSchemeBuilder.Register(addKnownTypes)
 }
 
 // Adds the list of known types to api.Scheme.
diff --git a/pkg/apis/certmanager/v1alpha1/zz_generated.defaults.go b/pkg/apis/certmanager/v1alpha1/zz_generated.defaults.go
deleted file mode 100644
index be6e1a6c6..000000000
--- a/pkg/apis/certmanager/v1alpha1/zz_generated.defaults.go
+++ /dev/null
@@ -1,32 +0,0 @@
-// +build !ignore_autogenerated
-
-/*
-Copyright 2019 The Jetstack cert-manager contributors.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-// This file was autogenerated by defaulter-gen. Do not edit it manually!
-
-package v1alpha1
-
-import (
-	runtime "k8s.io/apimachinery/pkg/runtime"
-)
-
-// RegisterDefaults adds defaulters functions to the given scheme.
-// Public to allow building arbitrary schemes.
-// All generated defaulters are covering - they call all nested defaulters.
-func RegisterDefaults(scheme *runtime.Scheme) error {
-	return nil
-}