The lifters will lock up. You can pull them, and exercise them in a vise with plastic jaw inserts or wood or whatever and they will compress again.

Don't know if this is your problem but it's a guess...

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250