Diesel sump bolts

[talkingwhippet]

Hi - congrats on upgrading forum!
Just wanted to check whether the 2 bolts that hold gearbox to sump on diesel are essential.
I've just replaced sump gasket & renewed some sump bolts to cure a leak & discovered the above bolts are missing.
If I need to replace these, what part no am I looking for or can I use a standard bolt size - if so, what size am I looking for?
Tried vagcat & VW workshop manual, but not covered anywhere as far as I can see.
Many thanks,
Talking Whippet

[HarryMann]

Yes, you need them...

Sorry cannot find them in ETKA, somebody else might though..

They are I think(!) M10 and about 65mm long, but the length is CRITICAL, as they run into the blind holes in the ally sump casting.

So use a piece of welding rod or similar and mark the full length and make sure bolts are a bit shorter... taking into account the sump will be pulled up to the bellhousing closer when you tighten them*

*Tightening - Sumps have been broken tightening these bolts.. there is a correct order of assembly !

1) Socket head (hex or polydrive) set screws go in first LOOSE to position the sump, but not tightened/torqued.
2) Then those two long bolts nipped-up a bit, to pull the sump backwards into position
3) Nip up all the sump screws
4) Tighten the rear bolts bolts
5) Tighten or torque (< 15 ft-lbs) all the set-screws

Do not overtighten the large bolts and clean the blind threads in the sump first so they run up nicely... using a tap or Thread chaser or at the least blast out with powrful spray of WD40.

I'll keep looking for the correct length and size.. you should be able to establish the thread size easily by trial and error

[HarryMann]

PS. Just noticed you are near CJ.. He should have a couple of those bolts... but still check their length against what you measure... those sumps are expensive!

Also, if you have aready tightened up the sump set-screws you definitely need to loosen them first to allow sump to slide rearwards.
Also, if screws not in sump yet, clean the block threads, esp. the awkward ones at the rear and in corners, with say ear buds...

A 1/4" socket set with long extension is very handy to get on those rear ones. In fact ideal for all of them.

[talkingwhippet]

Excellent!
Thanks for reply - have already chased ALL sump bolt holes with a thread-restoring tap, so nice & clean. Lot of gunk in some of them. Need to get some new ones anyway as some missing, so not fully tightened yet. Will contact CJ & see what he's got - has been very helpful in the past.


Merry Christmas!!