AC bracket mount hack

[clunker]

In looking to solve oil leaks, I removed the large AC bracket (alternator up top). Found a couple of bolts missing and likely a source of leaks. (Chain tensioner pump etc was not a source).

The upper most mount bolt for the AC bracket on the front of the engine, that goes into the tensioner pivot access, was 'converted' to a really curious set up - frankly a kludge. See pics. Instead of a single, say M12x1.75x36mm bolt it is this hybrid stud:
- one end is M12x1.72 protruding say 6mm beyond the spacer
- the other end is an SAE 1/2-20 thread
- the pair are tack welded with a couple of washer sandwiching a lock washer(!) and slotted nut
Obviously the 6mm of M12 barely sat in the threaded head opening (it just pulled out) and oil leaked accordingly. This arrangement was providing almost no support to the AC bracket.

I intend to grind off the weld, remove this hybrid bolt and put a regular M12x1.72x36mm bolt in there (there does seem to be thread in the head opening further inside - 36mm bolt with the 20mm spacer on the bracket, leaves 16mm thread into the head and should prevent it impacting the tensioner pivot inside there (as per older posts.)

I assume this is just a horrible hack, but thought I would check if anyone happen to have seen or know of a reason this was like this.

[Shvegel]

All they had was a 1/2" coarse / fine stud and they either jammed it in the head or ran a metric die across it and screwed it in.  The knew it wasn't in very far so they welded the nut to the bracket to keep it from backing out.  The 1.75 pitch is an oddball so that particular bolt is a little tougher to find.

[clunker]

I removed the hybrid stud and cleaned up the bracket.

Issue now is the bolt access hole that this mount goes into, that holds fuel line bracket and keeps tensioner sprocket pivot shaft in place (the shaft with the M6 thread in end.):

Other previous posts ( eg www.sl113.org/forums/index.php?topic=7987 ) have suggested this pivot shaft sits about 14mm inside the head - but mine sits just 9mm inside (see pic). The tensioner sprocket seems fine (see pic), but should I put an M6 in the end and try to drive it in a bit further? If not, then I will just use an M12 x 1.5 x 30mm bolt for the AC bracket upper bolt (will seal thread and put seal either side of fuel line bracket.)

Thoughts?

[ja17]

Yes if you can just drive the pivot in a bit you may find some good threads still in the head. Don't install a bolt too long, you will extract the threads or possibly crack the head!

[clunker]

Thanks Joe.

I threaded an longer M6 bolt in the pivot, but could not drive it in any further (use reasonable but not head cracking force). I think the pivot far enough in to the head at other end, so I will go with an M12x1.5x30 plus a washer or two to make sure I stay under the 29mm it adds up to. Will put thread seal of course, and also sealant either side of the fuel line bracket. I think that should do it.

As per another post, I probably also had a leak from a non-level chain tensioner mount (manifold gasket in the way), and with this upper front bolt leak solved, hopefully that will be most of the big leaks stopped.

I do have one more question - there is an open threaded M10 hole on the lower left (looking at front of engine) at front of the engine next to crank. It is below the M10 bolt hole for the AC bracket. It is listed on a previous post (by jeffc280sl I think) as possible leak site - marked on attached pic. What is this for? it is open/unused on my engine - does it need to be capped with a bolt? probably not, it looks too close to the crank, but wanted to check thoughts.

[There is another open threaded bolt hole on the side on my engine (also marked on the pic), which is a missing stud that should have been an additional AC bracket support. The bracket is well supported anyway, but it also may have leaked oil - that one will be easy to address.]

[ja17]

Seal all threaded holes into the block just to make sure. The in-used threaded hole in your picture is for  mounting an engine anti-torque shock on sedan versions.

[Shvegel]

If you are retaining the AC I would suggest putting a Sanden compressor in.  It is lighter and produces far less vibration than the original York unit.

[clunker]

Thanks Joe - knew it had a use somewhere even if not on the W113!

@Shvegel - yes indeed would use the Sanden and a new condensor. For now all the AC equipment (including evaporator and condensors) is out, but I am leaving the monster AC bracket in place in case I do decide to revisit AC one day.

[clunker]

Just to close this thread off:

I cleaned up the AC bracket upper bolt hole and reinstalled the bracket. I determined I had max 10mm available for the M12x1.5 upper bolt to go into head without hitting the tensioner pivot. In the end I used an M12x1.5x40mm with a spacer bushing on the outside to get this exact - see pics (brown goop is sealant applied to both sides of fuel line bracket.) This is certainly more support than before, feels solid and should seal / solve that leak.

The two openings in crank case I closed with M10x1.5x10mm bolts with sealant. I decided not to replace the side stud, rather just cap it off, as AC bracket well supported.

When reinstalling the AC bracket, the lower front bolt was very fiddly to get in (it is right next to the balancer) and I had to loosely put in other bolts and hold the bracket up / align this bolt hole, in order to get the bolt to purchase with my fingertips.

I had also planned to align the under-thermostat hose clamps to be more accessible, but in the end it was whatever cleared the AC bracket that determined that the clamps must both be at front and inaccessible with removing the bracket.

Thanks for your help.