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kidporsche · Posted: Sun May 04, 2003 12:38 pm Post subject: Rear suspension

Still without luck on my rear alignment.

Does changing the ride height on the rear alter the camber/toe?
The location of the height eccentrics appears different from left to right.

After having a good look under my car today, I feel there is room for some adjustment of the toe. However, given the left rear wheel has 11mm of toe out, I don't think there is sufficient adjustment to correct for this, does anybody know how much adjustment I should be able expect on rear toe? (I have the adjustment tool on order, but until it comes in I can't be sure of how much movement I can get.)

The next problem is, I cannot see any part of the rear suspension that looks bent. The trailing arm looks fine, bushings seem ok, and the torsion bar carrier does not look like it has been bent. Does anyone have any suggestions on what to look at/for? I had planned to remove the trailing arm and have it checked, but forgot I will need to remove the rear brake, so until I can borrow an impact wrench that won't be happening.
_________________
Chris
1981 924 - RoW (Australian) spec

78porsche924 · Posted: Sun May 04, 2003 3:06 pm Post subject:

Did you check the mounts for the torsion bar carrier? Doubt anything is wrong with them but i know 2 of them do have rubber in them, they might be crap now. Actually now that i think of it, they all have rubber in them. Also, has the car ever been in an accident?

kidporsche · Posted: Mon May 05, 2003 7:34 am Post subject:

The car has never been in an accident while I have had it. As best I can tell, it has never been in an accident before that either. Everything underbody looks from the factory.
_________________
Chris
1981 924 - RoW (Australian) spec

wdb · Joined: 02 Nov 2002 Posts: 2024

its possible the PO had the rear end come around on him and bumped a curb, just hard enough to put a little twist is the trailing arm to make the tire tuck under a little..

924RACR · Posted: Mon May 05, 2003 10:26 pm Post subject:

Yes, adjusting the rear height will affect the camber and toe. Get the car level, that wouldn't hurt...

Otherwise, don't worry about proceeding further until you get the the adjusting tool.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

kidporsche · Posted: Tue May 06, 2003 8:51 am Post subject:

Vaughan,
you seem to have a fair bit of experience with the rear end alignment. Have you seen a car with this much toe? Do you think there is enough adjustment to eliminate 11mm of toe out?
_________________
Chris
1981 924 - RoW (Australian) spec

924RACR · Posted: Tue May 06, 2003 10:15 pm Post subject:

Yep, I do my own all the time, as I race my '79. I'm in fact coming in tonight to reset the alignment (we have an alignment rack and scales at work), as I've just put in a whole new suspension. I'm 99% sure that a half-inch/11mm is within the range of adjustment with the proper tools. Maybe I'll check tonight for ya.

Of course, as mentioned previously, it'll also be a function of the ride height and camber settings.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

924RACR · Posted: Wed May 07, 2003 10:46 pm Post subject:

Spent many hours last night being abused by my rear suspension (in fact, by the whole suspension). Sure, it's conceivable that you have a bent arm, but there's one helluva lot of movement there. Should be able to remove 11mm, unless it truly is already at the limit of it's travel. Without the right tool, they are tools, IMO. You must use the correct tool to have full range of motion.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

kidporsche · Posted: Thu May 08, 2003 7:35 am Post subject:

Cheers Vaughan,
Hopefully I'll have the part before long and we'll see how I go.
I saw in another post you suggested setting the ride height with a carpenter's level. I'm assuming that you raise/lower the rear until the door sills are level, is this correct? I would have thought you would use the height adjustment to set your corner weights, fixing the height when achieved your desired balance, or is there a better way of doing that?
_________________
Chris
1981 924 - RoW (Australian) spec

924RACR · Posted: Thu May 08, 2003 10:42 am Post subject:

Exactly correct, as you've surmised. Ideal case is to use scales to get equal cross weights. Failing that, the cars tend to be balanced well enough that setting them level tends to produce very good results.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype