Hi there
Both me and Alfan from this forum had positive experience refurbishing our Q4 steering racks with this company:
http://www.nagengast.pl/regeneration-en.html
It's a company from Poland, proven worldwide service. And by the way, they can redo Boge shocks also.
They do speak English but if needed you can let me know, I can offer some translation if needed being from Poland also.
Please have a look at the forum and search for rack refurbishing in Alfan's or my threads. Here's one:
viewtopic.php?f=22&t=1135&start=75#p13094
There is also a refurbished rack for sale in the ads section, I was in contact with the seller back when I did mine until I was sure it can be rebuilt, then I did not need to buy a new one anymore:
viewtopic.php?f=7&t=1858
But the way mine also leaked from side seals so all was replaced and works perfectly fine now.