Date: Fri, 7 Oct 2005 06:00:32 +0000 (UTC) From: Craig's Saab C900 Site <c900nospam.apana.org.au> Subject: Re: bottom shock mount on C900 a-arms
"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. >What is the size of the nut, circa 13mm? Not sure off-hand. >60(ish)feet pounds are for roadwheel nuts. Actually, the torque for those is specified as about the same range - 90 to 110 Nm (66 to 81 ft-lb). >You first have to get it off and then clean the threads and see the >damage. From memory the nut only held the shocker in its natural >resting place. It is not used to hold the A arm in place. A self >locking nut (+ washer or whatever similar) should only need hand tight >pressure. Torque setting is not given for that nut in the Haynes manual!!! That's correct re what the nut does. It pushes a big washer against one side of the shock lower mount bushing which holds the bottom of the shock in place on the a-arm. >Could you be looking at some different torque settings? I double-checked by looking in other places (such as the section on replacing balljoints) and the same numbers are quoted. >Take it off first and come back. >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. 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. -- Craig's Saab C900 Page --> http://nospam/~c900 Sydney, NSW Australia Craig's Classic Saab Workshop -- For Saab 99/C900/9000 Enthusiasts world-wide! http://www.nospam.net http://www.nospam c900nospam.apana.org.au Come and explore our site, and check out our web-forums, mailing list, etc.