Printable Version of Topic

Click here to view this topic in its original format

914World.com _ 914World Garage _ Bit OT: Rear ride height on a 911

Posted by: Mark Henry Jul 12 2005, 05:48 PM

One of my customers has a 911 (’71 with a update body kit) and the rear tires are just starting to rub on the outside. Not on the lip but just above it.

I tried the move the torsion bars 1 spline, but that got me about a 3 inch raise, I only need about an inch. I’ve tried both the inner and outer splines.

If I can’t raise it I’ll cut the spacers 3/8 each side.

The car has sagged this year, as it the first year the customer has gotten some good seat time. The most time this car has seen in probably over 10 years. I spent a lot of time sorting this car out and this is the only major issue now.

Posted by: TimT Jul 12 2005, 06:24 PM

Youll have to play with re-indexing the torsion bars..

OR recommend adjustable spring plates, which make ride height adjustment/corner balancing much easier on these cars

There is information available that tells you the angle the swing arm should be, compared to the rockers...

I dont have that handy

Posted by: Cap'n Krusty Jul 12 2005, 06:39 PM

It's a simple but detailed procedure. You need to look in the manual. The amount of change you need is attained by a change in BOTH ends of the torsion bar, and can be calculated almost exactly using simple math and a little geometry. You need a level for the chassis (use the door sills on both sides), and a protractor with a built in level for the spring plates. You also need to know where you started out. This should have been done by marking the angular position of the UNLOADED spring plates before you removed them. With a bit of effort, you should be able to fix it right. Plan on spending a full day. It takes me 2-4 hours to lower a car, and I've probably done close to a hundred of them. The Cap'n

Posted by: Mark Henry Jul 12 2005, 07:29 PM

Thanks Cap'n

You don't know if the bushings start with a VW part#?
I have lots (every year) of very similar VW rubber bushings

QUOTE
You also need to know where you started out. This should have been done by marking the angular position of the UNLOADED spring plates before you removed them.

Done, done and done.

Posted by: ArtechnikA Jul 12 2005, 07:43 PM

QUOTE (Mark Henry @ Jul 12 2005, 09:29 PM)
You don't know if the bushings start with a VW part#?
I have lots (every year) of very similar VW rubber bushings

like 911 (and 914) front A-Arm bushings, 911 rear bushings are not officially individually replaceable. officially, you replace the spring plate.

unofficially, there are aftermarket bushings available. the NeaTrix are the closest to OEM. there are a few kinds of polyurethane/Delrin bushings available. makes a difference if you have the OEM or the adjustable spring plate.

Posted by: Mark Henry Jul 12 2005, 07:55 PM

OEM plates.

The bushings are real close to -67 bus bushings...I'll measure them in the AM.

Just tring to save a 1-1/2 week wait for bushings.

Posted by: Cap'n Krusty Jul 13 2005, 08:35 AM

QUOTE (ArtechnikA @ Jul 12 2005, 05:43 PM)
[
[/QUOTE]
like 911 (and 914) front A-Arm bushings, 911 rear bushings are not officially individually replaceable. officially, you replace the spring plate.

Oh really? How come they're in the book and, BTW, on my shelf? I've changed a bunch of 'em, and plan to do the ones in my own car as soon as I have time. Yeah, right, time ................ They're NOT the same as VW, and I wouldn't even think about subbing in something thet's "almost" right. The Cap'n

Posted by: ArtechnikA Jul 13 2005, 08:43 AM

QUOTE (Cap'n Krusty @ Jul 13 2005, 10:35 AM)
Oh really? How come they're in the book and, BTW, on my shelf? I've changed a bunch of 'em, and plan to do the ones in my own car as soon as I have time.

because you have a very early car...

ETKA shows them as individually replaceable through 1967.

i suppose the pre-'68 parts might fit the later spring plates - i don't have a lot of spring plates to tinker with. but the car in question is a '71 (like mine) and when i went looking for bushings there were no factory parts listed for that application.

do the pre-'68 parts fit LWB spring plates ?

Posted by: ! Jul 13 2005, 09:29 AM

You might want to have your customer consider upgrading torsion bars at the same time....

Posted by: Brando Jul 13 2005, 10:28 AM

Sagging...

Are the rear tortion bar bushings okay? Are the tortion bars fairly new? Rear shocks not blown/leaking? Remember that if the front end is not flat and even it will throw off the rear end's gemoetry. It's all relative. I find it easier usually to break out the leveling protractor and set the rear at the same degree down. With new bushings this should be 'balanced' in the rear. Then set the front by reindexing the splines evenly and making fine adjustments there.

Again, with old bushings it's probably never going to be perfect, but close is good. If you're getting more than ¼" difference between left and right after letting the rear end settle and balancing out the front, it's time to start looking at other wear items (shocks, bushings, torsion bars, etc).

Posted by: Mark Henry Jul 13 2005, 10:55 AM

Rubbing about even on both fenders, front end's not too bad.
Just want the basics, we'll be sorting the car this winter, just need to keep it going for now.

Going to give 'er another try now.