diff --git a/src/pcl/boot.lisp b/src/pcl/boot.lisp
index e5c372e7b..edc436d63 100644
--- a/src/pcl/boot.lisp
+++ b/src/pcl/boot.lisp
@@ -2812,8 +2812,9 @@ bootstrapping.
                                   (apply #'real-make-a-method args)))
                               (early-gf-methods gf))))
         (setf (generic-function-method-class gf) *the-class-standard-method*)
-        (setf (generic-function-method-combination gf)
-              *standard-method-combination*)
+        (let ((mc *standard-method-combination*))
+          (setf (generic-function-method-combination gf) mc)
+          (add-to-weak-hashset gf (method-combination-%generic-functions mc)))
         (set-methods gf methods)))
 
     (dolist (fn *!early-functions*)
@@ -2852,12 +2853,12 @@ bootstrapping.
                           'standard-method
                           qualifiers lambda-list specializers initargs nil
                           'source (translate-source-location fun))))))
-            (setf (generic-function-method-class gf)
-                  *the-class-standard-method*
-                  (generic-function-method-combination gf)
-                  (ecase method-combination
-                    (standard *standard-method-combination*)
-                    (or *or-method-combination*)))
+            (let ((mc (ecase method-combination
+                        (standard *standard-method-combination*)
+                        (or *or-method-combination*))))
+              (setf (generic-function-method-class gf) *the-class-standard-method*
+                    (generic-function-method-combination gf) mc)
+              (add-to-weak-hashset gf (method-combination-%generic-functions mc)))
             (set-methods gf (mapcar #'make-method methods)))))
 
   (/show "leaving !FIX-EARLY-GENERIC-FUNCTIONS"))
diff --git a/tests/clos-method-combination-caches.pure.lisp b/tests/clos-method-combination-caches.pure.lisp
new file mode 100644
index 000000000..cb0373842
--- /dev/null
+++ b/tests/clos-method-combination-caches.pure.lisp
@@ -0,0 +1,21 @@
+;;;; testing the consistency of method combination sets
+
+;;;; This software is part of the SBCL system. See the README file for
+;;;; more information.
+;;;;
+;;;; While most of SBCL is derived from the CMU CL system, the test
+;;;; files (like this one) were written from scratch after the fork
+;;;; from CMU CL.
+;;;;
+;;;; This software is in the public domain and is provided with
+;;;; absolutely no warranty. See the COPYING and CREDITS files for
+;;;; more information.
+
+(let (problems)
+  (flet ((check (gf)
+           (let* ((mc (sb-mop:generic-function-method-combination gf))
+                  (gfs (sb-pcl::method-combination-%generic-functions mc)))
+             (unless (sb-pcl::weak-hashset-memberp gf gfs)
+               (push gf problems)))))
+    (sb-pcl::map-all-generic-functions #'check))
+  (assert (null problems)))