diff --git a/go/porcelain/deploy_test.go b/go/porcelain/deploy_test.go
index c85bcb69..eeae1e97 100644
--- a/go/porcelain/deploy_test.go
+++ b/go/porcelain/deploy_test.go
@@ -101,4 +101,32 @@ func TestOpenAPIClientWithWeirdResponse(t *testing.T) {
 	_, operationError := client.Operations.UploadDeployFile(params, authInfo)
 	require.Error(t, operationError)
 	require.Equal(t, "[PUT /deploys/{deploy_id}/files/{path}][408] uploadDeployFile default  &{Code:408 Message:a message}", operationError.Error())
+
+}
+
+func TestConcurrentFileUpload(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		rw.Header().Set("Content-Type", "application/json; charset=utf-8")
+		rw.WriteHeader(408)
+		rw.Write([]byte(`{ "foo": "bar", "message": "a message", "code": 408 }`))
+	}))
+	defer server.Close()
+
+	httpClient := http.DefaultClient
+	authInfo := runtime.ClientAuthInfoWriterFunc(func(r runtime.ClientRequest, _ strfmt.Registry) error {
+		r.SetHeaderParam("User-Agent", "buildbot")
+		r.SetHeaderParam("Authorization", "Bearer 1234")
+		return nil
+	})
+
+	hu, _ := url.Parse(server.URL)
+	tr := apiClient.NewWithClient(hu.Host, "/api/v1", []string{"http"}, httpClient)
+	client := NewRetryable(tr, strfmt.Default, 1)
+	for i := 0; i < 30; i++ {
+		go func() {
+			body := ioutil.NopCloser(bytes.NewReader([]byte("hello world")))
+			params := operations.NewUploadDeployFileParams().WithDeployID("1234").WithPath("foo/bar/biz").WithFileBody(body)
+			_, _ = client.Operations.UploadDeployFile(params, authInfo)
+		}()
+	}
 }
diff --git a/go/porcelain/http/http.go b/go/porcelain/http/http.go
index 6c5393d8..ca852f8f 100644
--- a/go/porcelain/http/http.go
+++ b/go/porcelain/http/http.go
@@ -31,10 +31,11 @@ func NewRetryableTransport(tr runtime.ClientTransport, attempts int) *RetryableT
 }
 
 func (t *RetryableTransport) Submit(op *runtime.ClientOperation) (interface{}, error) {
-	client := op.Client
-
-	if client == nil {
-		client = http.DefaultClient
+	var client http.Client
+	if op.Client == nil {
+		client = *http.DefaultClient
+	} else {
+		client = *op.Client
 	}
 
 	transport := client.Transport
@@ -46,13 +47,9 @@ func (t *RetryableTransport) Submit(op *runtime.ClientOperation) (interface{}, e
 		attempts: t.attempts,
 	}
 
-	op.Client = client
-
+	op.Client = &client
 	res, err := t.tr.Submit(op)
 
-	// restore original transport
-	op.Client.Transport = transport
-
 	return res, err
 }