Date: Fri, 07 Oct 2005 11:31:02 +0100 From: "Charles C." <c.k.christacopoulos_removeme_nospamee.ac.uk> Subject: Re: bottom shock mount on C900 a-arms
Craig's Saab C900 Site wrote: > "Charles C." <c.k.christacopoulos_removeme_nospamee.ac.uk> writes: > > >>Craig's Saab C900 Site wrote: >> >>>Dave Hinz <DaveHinznospamcop.net> writes: >>> >>> >>>>On Wed, 05 Oct 2005 20:50:42 -0600, Charles <cstoyernospamrpex.com> wrote: >>> >>>>>If you can get it off, maybe with some WD-40 or whatever penetrating >>>>>stuff they might sell in the UK, get a tap and die the right size and >>>>>clean up the threads before putting it back together. >>> >>>>WD-40 isn't a penetrating oil. It pretends to be, but for anything >>>>other than _W_ater _D_isplacement, it's a lousy compromise. >> >>>>Craig, someone must have a lower a-arm. If the threads are stripped, >>>>for a shock, I'd rather replace the a-arm than to improvise. >>> >>>Yeah I know they're easy to get since there are a few European wreckers here >>>in Sydney so there will be some C900's around waiting to be stripped. >>>Getting new bushes is trivial. I'm surprised that the thread for the shock >>>mount has appeared to have stripped so easily - I set my torque wrench to >>>the right setting (around 60 ft/lb > > >>WHAAAAAAAAT? Screams in astonishment. > > >>That thread is about a 10mm thread (less?). There is no way you tighten >>a nut on 10mm thread to anything more than 20 ft/lb (add that I have no >>theoretical engineering background). > > > Page 731-4 in 8V Bentley C900 manual... > > Tightening Torque for front shock absorber to lower control arm - 90 to 100 > Nm (66 to 74 ft-lb). Seems quite high but it's quite a critical fastener. Seen the photo in the haynes manual. Yup, bigger than a 10mm thread and a 17 or 19 mm nut. Still it makes no reference to torque settings. I have also checked a newer manual (thus thiner) that makes no mention of torque settings for the same bit. > > <snip my waffle> > >>I wonder, for internal threads there is an insert that can be used to >>rethread them. Would there be a similar sleeve to in effect rethread >>the bit in question. Rethreading (in effect) a bold will weaken it as >>it will be made thiner. Bold = bolt :-( > > > Well if I can get the nut back off againt without damaging anything else > (mainly the shock bushing itself), I'll see what's happened and then work > out what to do. Either get a replacement a-arm from a wrecker, or see if I > can repair the thread. I'm surprised that nylock nuts aren't used in that > location but for some reason they aren't nylocks on this car (same on the > lower shock mounting on the other side (which is a different situation - it > needs the outer CV replaced and steering boot on that side replaced too). > Perhaps the lower shock mount nuts should be nylocks? > > Craig. > The Nylock nuts are OK. (perhaps best as one use nuts). SAAB used in those times many different threads (finer threads than the normal metric bolts) and sometimes their nuts used a different (softer) metal instead of plastic to do the locking. I wonder if new SAABs have a lot more nylock nuts ... cheaper etc. Sang the photo in the book and anticipating a cross threaded nut ... I would try to put a cut, diagonally, on one of the flats of the nut (the most accessible flat side) with a hacksaw. Anything to weaken it... Keep at it ... better you than me. Charles -- Please remove _removeme_ to reply.