diff --git a/powerline/bindings/vim/__init__.py b/powerline/bindings/vim/__init__.py
index 4210cc26..51e76263 100644
--- a/powerline/bindings/vim/__init__.py
+++ b/powerline/bindings/vim/__init__.py
@@ -9,8 +9,7 @@ try:
 except ImportError:
 	vim = {}
 
-if not hasattr(vim, 'bindeval'):
-	import json
+from powerline.lib.unicode import unicode
 
 
 try:
@@ -19,6 +18,22 @@ except AttributeError:
 	vim_encoding = 'utf-8'
 
 
+python_to_vim_types = {
+	unicode: (
+		lambda o: b'\'' + (o.translate({
+			ord('\''): '\'\'',
+		}).encode(vim_encoding)) + b'\''
+	),
+	bytes: (lambda o: b'\'' + o.replace(b'\'', b'\'\'') + b'\''),
+	int: (str if str is bytes else (lambda o: unicode(o).encode('ascii'))),
+}
+python_to_vim_types[float] = python_to_vim_types[int]
+
+
+def python_to_vim(o):
+	return python_to_vim_types[type(o)](o)
+
+
 if hasattr(vim, 'bindeval'):
 	def vim_get_func(f, rettype=None):
 		'''Return a vim function binding.'''
@@ -39,11 +54,25 @@ else:
 		__slots__ = ('f', 'rettype')
 
 		def __init__(self, f, rettype=None):
-			self.f = f
+			self.f = f.encode('utf-8')
 			self.rettype = rettype
 
 		def __call__(self, *args):
-			r = vim.eval(self.f + '(' + json.dumps(args)[1:-1] + ')')
+			expr = self.f + b'(' + (b','.join((
+				python_to_vim(o) for o in args
+			))) + b')'
+			try:
+				r = vim.eval(expr)
+			except UnicodeDecodeError:
+				r = bytes(bytearray((
+					int(chunk) for chunk in (
+						vim.eval(
+							b'substitute(' + expr + b', ' +
+							b'\'^.*$\', \'\\=join(map(range(len(submatch(0))), ' +
+							b'"char2nr(submatch(0)[v:val])"))\', "")'
+						).split()
+					)
+				)))
 			if self.rettype:
 				return self.rettype(r)
 			return r
@@ -140,7 +169,7 @@ else:
 
 	def vim_setoption(option, value):
 		vim.command('let &g:{option} = {value}'.format(
-			option=option, value=json.encode(value)))
+			option=option, value=python_to_vim(value)))
 
 
 if hasattr(vim, 'tabpages'):
diff --git a/tests/test_segments.py b/tests/test_segments.py
index 2cc6545b..629b3759 100644
--- a/tests/test_segments.py
+++ b/tests/test_segments.py
@@ -8,6 +8,7 @@ from functools import partial
 
 from powerline.segments import shell, tmux, common
 from powerline.lib.vcs import get_fallback_create_watcher
+from powerline.lib.unicode import out_u
 
 import tests.vim as vim_module
 
@@ -18,10 +19,10 @@ from tests import TestCase, SkipTest
 def get_dummy_guess(**kwargs):
 	if 'directory' in kwargs:
 		def guess(path, create_watcher):
-			return Args(branch=lambda: os.path.basename(path), **kwargs)
+			return Args(branch=lambda: out_u(os.path.basename(path)), **kwargs)
 	else:
 		def guess(path, create_watcher):
-			return Args(branch=lambda: os.path.basename(path), directory=path, **kwargs)
+			return Args(branch=lambda: out_u(os.path.basename(path)), directory=path, **kwargs)
 	return guess