diff --git a/src/c/file.d b/src/c/file.d
index 877b43f64..eb9a05d2b 100755
--- a/src/c/file.d
+++ b/src/c/file.d
@@ -4667,11 +4667,7 @@ static void
 seq_out_enlarge_vector(cl_object strm)
 {
   cl_object vector = SEQ_OUTPUT_VECTOR(strm);
-  if (!ECL_ADJUSTABLE_ARRAY_P(vector)) {
-    FEerror("Can't adjust the dimensions of the sequence of sequence stream ~A", 1, strm);
-  }
-  vector = _ecl_funcall3(@'adjust-array', vector,
-                         ecl_ash(ecl_make_fixnum(vector->vector.dim), 1));
+  si_adjust_vector(vector, ecl_ash(ecl_make_fixnum(vector->vector.dim), 1));
   SEQ_OUTPUT_VECTOR(strm) = vector;
 }
 
diff --git a/src/c/serialize.d b/src/c/serialize.d
index cb289da70..ec20f7a12 100644
--- a/src/c/serialize.d
+++ b/src/c/serialize.d
@@ -97,8 +97,7 @@ alloc(pool_t pool, cl_index size)
   cl_index next_fillp = fillp + bytes;
   if (next_fillp >= pool->data->vector.dim) {
     cl_index new_dim = next_fillp + next_fillp / 2;
-    pool->data = _ecl_funcall3(@'adjust-array', pool->data,
-                               ecl_make_fixnum(new_dim));
+    pool->data = si_adjust_vector(pool->data, ecl_make_fixnum(new_dim));
   }
   pool->data->vector.fillp = next_fillp;
   return fillp;
diff --git a/src/c/string.d b/src/c/string.d
index 2a4dc010c..df1d82d4f 100644
--- a/src/c/string.d
+++ b/src/c/string.d
@@ -922,10 +922,9 @@ nstring_case(cl_narg narg, cl_object fun, ecl_casefun casefun, ecl_va_list ARGS)
     if (output_size < output->base_string.dim) {
       break;
     }
-    output = _ecl_funcall3(@'adjust-array', output,
-                           ecl_make_fixnum(input_size > output_size
-                                           ? input_size
-                                           : output_size + 128));
+    output = si_adjust_vector(output, ecl_make_fixnum(input_size > output_size
+                                                      ? input_size
+                                                      : output_size + 128));
   } while (1);
   output->base_string.fillp = output_size;
   if (ecl_fits_in_base_string(output)) {