Lowering rear end

[JTL]

Dropping the front was easy. The Bentley outlines the procedure the drop the rear; however, I have one question. The rear is about 26" and needs to go down to 25". The spring plate angle needs to be 36-37 degrees according to the Rennlist calculator.

Can the 1" drop be achieved by simply adjusting the t-bar cap on the outer splines until the angle gauge reads 36 degrees? How many outer splines does the 1" drop correspond to?

I'm a newbie to adjusting the rear. If anything I said doesn't make sense please let me know.

Thanks, jt
-84 targa

[bell]

before you take anything apart read....read....and read again as to what's involved.
plan on an alignment, and for the car to be on jackstands for a few days.
there are a different number of splines in the inner and outer part of the torsion bar, i forget which side has what at the moment.
if your 911 has stock spring plates there is a good chance that the entire tb will come out when you remove it, making a baseline impossible without marking the angles of the springplate......
it is a very involved job, but with patience it can be done.

next time i need it done i'll be paying an experienced wrench to do it......i hate doing things 3 times, which you will most likely encounter also

[911s55]

Doing the rear is totally different than the front.
You won't be able to get that much drop just fom the adjustment bolts on the spring plates, so you will have do some minor but time consuming work.
I'm not sure but the spring plate angle they are referring to is for unsprung measurements, so wheels, shocks etc need to be removed.
Do a search for ride height or spring plate adjustments, and check the tech articles, it's ALL in there.
If you read it to the point that you understand it, then you can do it?

[gtihop]

I just did this today! Alot of time! For an inch drop, you will have to move the inner splines on the bar 4 splines towards up and the outer splines on the springplates 4 splines down. MArk everything before you take it apart! The difference in number of splines makes each rotation/counter rotation about 6mm difference. Then if it doesn't sit quite right, you get to take it all apart again and try again! They always say things are easier the second time !

[Eagledriver]

Mark a line on the chassis along the top of the spring plate blade before you start. That way you'll know where the droop was when you started and will have an idea of where to end up.

-Andy

[JTL]

Thanks for the tips guys! I have read many posts on this subject, tech articles and my trusty Bentley manual.
Marking the current position will come in handy, for sure. I just a little foggy on the details since I haven't taken anything apart yet. To adjust the inner splines one has to actually take the tbar out and rotate it, in my case 4 'clicks' clockwise, like gtihop suggests? The outer spline adjustment is made by rotating the tbar cover, in my case 4 'clicks' counter clockwise?

Just like my clutch job, this project could very easily turn into a 'while you are int there' deals. The front dinged me a little with elephant pbbs and adj. sway bar. I figured the front tbars would be easy to swap later, which is not really the case at the rear.

jt

Here is the front at 24.5". It may have to come up just a little.

[gtihop]

Before you rotate the torsion bar or remove the springplate, use red paint and mark where you start at and also the end of the springplate/torsion bar. It'll give you a reference point in case you miscount the number of slines you moved. One thing I did notice is that after it is all done, when you connect the rear shocks back up, the rear end of the car is raised about 1/2 to 3/4 of an inch. I tried to get 24.5" on the rear and came pretty close at 24 9/16" .

[JTL]

Gtihop,
Thanks for pointing that out. That makes sense. I noticed the rear end was higher after installing new shocks.