diff --git a/linkerd/app/outbound/src/http/logical/policy/route/metrics/tests.rs b/linkerd/app/outbound/src/http/logical/policy/route/metrics/tests.rs
index 1bd231f8fb..ae132e94af 100644
--- a/linkerd/app/outbound/src/http/logical/policy/route/metrics/tests.rs
+++ b/linkerd/app/outbound/src/http/logical/policy/route/metrics/tests.rs
@@ -339,8 +339,39 @@ async fn http_route_request_body_frames() {
     assert_eq!(frames_total.get(), 0);
     assert_eq!(frames_bytes.get(), 0);
 
-    // Now, send some request body bytes.
-    todo!("send request body bytes")
+    /// Returns the next chunk from a boxed body.
+    async fn read_chunk(body: &mut std::pin::Pin<Box<BoxBody>>) -> Vec<u8> {
+        use bytes::Buf;
+        use http_body::Body;
+        use std::task::{Context, Poll};
+        let mut ctx = Context::from_waker(futures_util::task::noop_waker_ref());
+        let data = match body.as_mut().poll_data(&mut ctx) {
+            Poll::Ready(Some(Ok(d))) => d,
+            _ => panic!("next chunk should be ready"),
+        };
+        data.chunk().to_vec()
+    }
+
+    // And now, send request body bytes.
+    tracing::info!("sending request body bytes");
+    {
+        // Get the client's sending half, and the server's receiving half of the request body.
+        let (mut tx, mut rx) = (tx, Box::pin(rx));
+
+        tx.send_data(b"milk".as_slice().into()).await.unwrap();
+        let chunk = read_chunk(&mut rx).await;
+        debug_assert_eq!(chunk, b"milk");
+        assert_eq!(frames_total.get(), 1); // bytes are counted once polled.
+        assert_eq!(frames_bytes.get(), 4);
+
+        tx.send_data(b"syrup".as_slice().into()).await.unwrap();
+        let chunk = read_chunk(&mut rx).await;
+        debug_assert_eq!(chunk, b"syrup");
+        assert_eq!(frames_total.get(), 2);
+        assert_eq!(frames_bytes.get(), 4 + 5);
+    }
+
+    tracing::info!("passed");
 }
 
 #[tokio::test(flavor = "current_thread", start_paused = true)]
diff --git a/linkerd/http/prom/src/body_data/request.rs b/linkerd/http/prom/src/body_data/request.rs
index c3e228f60b..e2d0811f9d 100644
--- a/linkerd/http/prom/src/body_data/request.rs
+++ b/linkerd/http/prom/src/body_data/request.rs
@@ -3,7 +3,6 @@
 pub use super::metrics::{BodyDataMetrics, RequestBodyFamilies};
 
 use http::{Request, Response};
-use http_body::Body;
 use linkerd_error::Error;
 use linkerd_http_box::BoxBody;
 use linkerd_stack::{self as svc, layer::Layer, ExtractParam, NewService, Service};
@@ -81,11 +80,11 @@ where
 
 impl<ReqB, RespB, S, ReqX, L> Service<Request<ReqB>> for RecordBodyData<S, ReqX, L>
 where
-    S: Service<Request<ReqB>, Response = Response<RespB>>,
+    S: Service<Request<BoxBody>, Response = Response<RespB>>,
     S::Future: Send + 'static,
-    RespB: Body + Send + 'static,
-    RespB::Data: Send + 'static,
-    RespB::Error: Into<Error>,
+    ReqB: http_body::Body + Send + 'static,
+    ReqB::Data: Send + 'static,
+    ReqB::Error: Into<Error>,
     ReqX: ExtractParam<L, Request<ReqB>>,
     L: linkerd_metrics::prom::encoding::EncodeLabelSet
         + std::fmt::Debug
@@ -96,9 +95,9 @@ where
         + Sync
         + 'static,
 {
-    type Response = Response<BoxBody>;
+    type Response = S::Response;
     type Error = S::Error;
-    type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send>>;
+    type Future = S::Future;
 
     #[inline]
     fn poll_ready(
@@ -109,30 +108,19 @@ where
     }
 
     fn call(&mut self, req: Request<ReqB>) -> Self::Future {
-        use futures::{FutureExt, TryFutureExt};
-
         let Self {
             inner,
             extract,
             metrics,
         } = self;
 
-        let labels = extract.extract_param(&req);
-        let metrics = metrics.get(&labels);
-        let instrument = Box::new(|resp| Self::instrument_response(resp, metrics));
-
-        inner.call(req).map_ok(instrument).boxed()
-    }
-}
+        let req = {
+            let labels = extract.extract_param(&req);
+            let metrics = metrics.get(&labels);
+            let instrument = |b| super::body::Body::new(b, metrics);
+            req.map(instrument).map(BoxBody::new)
+        };
 
-impl<S, ReqX, L> RecordBodyData<S, ReqX, L> {
-    fn instrument_response<B>(resp: Response<B>, metrics: BodyDataMetrics) -> Response<BoxBody>
-    where
-        B: Body + Send + 'static,
-        B::Data: Send + 'static,
-        B::Error: Into<Error>,
-    {
-        resp.map(|b| super::body::Body::new(b, metrics))
-            .map(BoxBody::new)
+        inner.call(req)
     }
 }