diff --git a/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/config/BUILD b/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/config/BUILD
index 0873444dd62..24b372cf746 100644
--- a/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/config/BUILD
+++ b/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/config/BUILD
@@ -12,6 +12,7 @@ go_library(
     visibility = ["//visibility:public"],
     deps = [
         "//vendor/github.com/hashicorp/golang-lru:go_default_library",
+        "//vendor/k8s.io/api/admission/v1beta1:go_default_library",
         "//vendor/k8s.io/api/admissionregistration/v1beta1:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/runtime:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/runtime/serializer:go_default_library",
diff --git a/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/config/client.go b/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/config/client.go
index 808ef944ffe..bfa957c795f 100644
--- a/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/config/client.go
+++ b/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/config/client.go
@@ -24,8 +24,10 @@ import (
 	"net/url"
 
 	lru "github.com/hashicorp/golang-lru"
+	admissionv1beta1 "k8s.io/api/admission/v1beta1"
 	"k8s.io/api/admissionregistration/v1beta1"
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/serializer"
 	utilerrors "k8s.io/apimachinery/pkg/util/errors"
 	webhookerrors "k8s.io/apiserver/pkg/admission/plugin/webhook/errors"
 	"k8s.io/client-go/rest"
@@ -54,8 +56,13 @@ func NewClientManager() (ClientManager, error) {
 	if err != nil {
 		return ClientManager{}, err
 	}
+	admissionScheme := runtime.NewScheme()
+	admissionv1beta1.AddToScheme(admissionScheme)
 	return ClientManager{
 		cache: cache,
+		negotiatedSerializer: serializer.NegotiatedSerializerWrapper(runtime.SerializerInfo{
+			Serializer: serializer.NewCodecFactory(admissionScheme).LegacyCodec(admissionv1beta1.SchemeGroupVersion),
+		}),
 	}, nil
 }
 
@@ -79,11 +86,6 @@ func (cm *ClientManager) SetServiceResolver(sr ServiceResolver) {
 	}
 }
 
-// SetNegotiatedSerializer sets the NegotiatedSerializer.
-func (cm *ClientManager) SetNegotiatedSerializer(n runtime.NegotiatedSerializer) {
-	cm.negotiatedSerializer = n
-}
-
 // Validate checks if ClientManager is properly set up.
 func (cm *ClientManager) Validate() error {
 	var errs []error
diff --git a/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/mutating/BUILD b/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/mutating/BUILD
index cf175b51d10..36f81528cbe 100644
--- a/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/mutating/BUILD
+++ b/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/mutating/BUILD
@@ -15,7 +15,6 @@ go_library(
         "//vendor/k8s.io/api/admissionregistration/v1beta1:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/api/errors:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/runtime:go_default_library",
-        "//vendor/k8s.io/apimachinery/pkg/runtime/serializer:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/runtime/serializer/json:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/util/runtime:go_default_library",
         "//vendor/k8s.io/apiserver/pkg/admission:go_default_library",
diff --git a/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/mutating/admission.go b/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/mutating/admission.go
index 9982c82a3bb..57f82d4d5ae 100644
--- a/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/mutating/admission.go
+++ b/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/mutating/admission.go
@@ -31,7 +31,6 @@ import (
 	"k8s.io/api/admissionregistration/v1beta1"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/runtime"
-	"k8s.io/apimachinery/pkg/runtime/serializer"
 	"k8s.io/apimachinery/pkg/runtime/serializer/json"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apiserver/pkg/admission"
@@ -131,9 +130,6 @@ func (a *MutatingWebhook) SetServiceResolver(sr config.ServiceResolver) {
 // SetScheme sets a serializer(NegotiatedSerializer) which is derived from the scheme
 func (a *MutatingWebhook) SetScheme(scheme *runtime.Scheme) {
 	if scheme != nil {
-		a.clientManager.SetNegotiatedSerializer(serializer.NegotiatedSerializerWrapper(runtime.SerializerInfo{
-			Serializer: serializer.NewCodecFactory(scheme).LegacyCodec(admissionv1beta1.SchemeGroupVersion),
-		}))
 		a.convertor.Scheme = scheme
 		a.defaulter = scheme
 		a.jsonSerializer = json.NewSerializer(json.DefaultMetaFactory, scheme, scheme, false)
diff --git a/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/validating/BUILD b/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/validating/BUILD
index b5c62d09864..01f2f57c7d6 100644
--- a/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/validating/BUILD
+++ b/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/validating/BUILD
@@ -14,7 +14,6 @@ go_library(
         "//vendor/k8s.io/api/admissionregistration/v1beta1:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/api/errors:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/runtime:go_default_library",
-        "//vendor/k8s.io/apimachinery/pkg/runtime/serializer:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/util/runtime:go_default_library",
         "//vendor/k8s.io/apiserver/pkg/admission:go_default_library",
         "//vendor/k8s.io/apiserver/pkg/admission/configuration:go_default_library",
diff --git a/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/validating/admission.go b/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/validating/admission.go
index fc77e5b9555..d3bcb338963 100644
--- a/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/validating/admission.go
+++ b/staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/validating/admission.go
@@ -31,7 +31,6 @@ import (
 	"k8s.io/api/admissionregistration/v1beta1"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/runtime"
-	"k8s.io/apimachinery/pkg/runtime/serializer"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apiserver/pkg/admission"
 	"k8s.io/apiserver/pkg/admission/configuration"
@@ -128,9 +127,6 @@ func (a *ValidatingAdmissionWebhook) SetServiceResolver(sr config.ServiceResolve
 // SetScheme sets a serializer(NegotiatedSerializer) which is derived from the scheme
 func (a *ValidatingAdmissionWebhook) SetScheme(scheme *runtime.Scheme) {
 	if scheme != nil {
-		a.clientManager.SetNegotiatedSerializer(serializer.NegotiatedSerializerWrapper(runtime.SerializerInfo{
-			Serializer: serializer.NewCodecFactory(scheme).LegacyCodec(admissionv1beta1.SchemeGroupVersion),
-		}))
 		a.convertor.Scheme = scheme
 	}
 }